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дигитализацију","\u002Fportfolio\u002Fdigitalisierungsportal-archiv-museum-bibliothek-ead-lido-mets-mods",[],{"statusCode":4,"data":206,"message":1826},{"id":207,"title":208,"slug":209,"content":210,"contentJson":211,"excerpt":896,"featuredImage":897,"featuredImageAlt":898,"featuredImageCaption":10,"featuredImageTitle":10,"featuredImageCopyright":10,"featuredImageAuthor":10,"featuredImageSourceUrl":10,"featuredImageLicense":10,"featuredImageIsAiGenerated":43,"status":899,"publishedAt":900,"createdAt":901,"updatedAt":902,"seoLocalePaths":903,"categories":912,"author":925,"translations":930},"476","MCP vs A2A vs UCP vs AP2 vs A2UI: Objašnjen stek agentskih protokola","mcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u003Cnav class=\"editorjs-toc\" data-editorjs-toc=\"true\" aria-label=\"Sadržaj\">\u003Cstrong class=\"editorjs-toc__title\">Sadržaj\u003C\u002Fstrong>\u003Col class=\"editorjs-toc__list editorjs-toc__list--depth-0\">\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-6\" class=\"editorjs-toc__link\">Osnovna greška: poređenje protokola koji se nalaze na različitim granicama\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-9\" class=\"editorjs-toc__link\">Sloj odgovornosti protokola\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-12\" class=\"editorjs-toc__link\">1. MCP: povežite agenta sa mogućnostima\u003C\u002Fa>\u003Col class=\"editorjs-toc__list editorjs-toc__list--depth-1\">\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-15\" class=\"editorjs-toc__link\">Koristite MCP kada\u003C\u002Fa>\u003C\u002Fli>\u003C\u002Fol>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-18\" class=\"editorjs-toc__link\">2. A2A: povežite nezavisne agente\u003C\u002Fa>\u003Col class=\"editorjs-toc__list editorjs-toc__list--depth-1\">\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-22\" class=\"editorjs-toc__link\">Koristite A2A kada\u003C\u002Fa>\u003C\u002Fli>\u003C\u002Fol>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-24\" class=\"editorjs-toc__link\">MCP naspram A2A: vertikalna integracija naspram horizontalne saradnje\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-27\" class=\"editorjs-toc__link\">3. UCP: standardizacija agentske trgovine\u003C\u002Fa>\u003Col class=\"editorjs-toc__list editorjs-toc__list--depth-1\">\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-31\" class=\"editorjs-toc__link\">Koristite UCP kada\u003C\u002Fa>\u003C\u002Fli>\u003C\u002Fol>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-33\" class=\"editorjs-toc__link\">4. AP2: dokazivanje da je agent imao ovlašćenje da troši\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-37\" class=\"editorjs-toc__link\">UCP naspram AP2: semantika transakcija naspram ovlašćenja\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-39\" class=\"editorjs-toc__link\">5. A2UI: omogućite agentima da opisuju interfejse bez posedovanja vašeg frontend-a\u003C\u002Fa>\u003Col class=\"editorjs-toc__list editorjs-toc__list--depth-1\">\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-43\" class=\"editorjs-toc__link\">Koristite A2UI kada\u003C\u002Fa>\u003C\u002Fli>\u003C\u002Fol>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-45\" class=\"editorjs-toc__link\">Test za izbor protokola\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-48\" class=\"editorjs-toc__link\">Realan radni tok sa više protokola\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-50\" class=\"editorjs-toc__link\">Zašto je malo verovatno da će jedan univerzalni agentski protokol zameniti sve njih\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-54\" class=\"editorjs-toc__link\">Kombinovanje protokola stvara nove načine otkaza\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-56\" class=\"editorjs-toc__link\">Izbor protokola ne zamenjuje arhitekturu aplikacije\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-60\" class=\"editorjs-toc__link\">Šta bi promenilo ovaj odgovor?\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-63\" class=\"editorjs-toc__link\">Ograničenja\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-66\" class=\"editorjs-toc__link\">Zaključak\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-69\" class=\"editorjs-toc__link\">Česta pitanja\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-71\" class=\"editorjs-toc__link\">Rečnik pojmova\u003C\u002Fa>\u003C\u002Fli>\u003Cli class=\"editorjs-toc__item\">\u003Ca href=\"#section-73\" class=\"editorjs-toc__link\">Primarni izvori i dodatna literatura\u003C\u002Fa>\u003C\u002Fli>\u003C\u002Fol>\u003C\u002Fnav>\n\u003Cp>Protokoli za AI agente se ubrzano množe: MCP, A2A, UCP, AP2, A2UI i srodni standardi sve se češće pojavljuju na istim dijagramima arhitekture. Često se opisuju kao konkurentski protokoli. U praksi, većina njih rešava različite probleme interoperabilnosti na različitim granicama sistema. Korisno pitanje nije „Koji protokol pobeđuje?“, već „Koji odnos u sistemu treba standardizovati?“\u003C\u002Fp>\n\u003Caside class=\"editorjs-callout editorjs-callout--info my-6 rounded-xl border p-5 border-blue-300 bg-blue-50 dark:border-blue-900 dark:bg-blue-950\u002F20\" role=\"note\">\u003Cstrong class=\"block mb-2 text-gray-900 dark:text-gray-100\">Direktan odgovor\u003C\u002Fstrong>\u003Cdiv class=\"text-gray-700 dark:text-gray-200\"><strong>MCP, A2A, UCP, AP2 i A2UI se uglavnom međusobno dopunjuju, a nisu zamene.<\u002Fstrong> MCP povezuje AI aplikaciju sa alatima, podacima i resursima. A2A povezuje nezavisne agente jedne sa drugima. UCP standardizuje trgovinske interakcije između korisničkih interfejsa, preduzeća i platnih ekosistema. AP2 dodaje proverljivu autorizaciju i nameru plaćanja transakcijama koje vode agenti. A2UI omogućava agentu da opiše interaktivni UI bez slanja proizvoljnog aplikativnog koda. Produkcijski sistem može legitimno koristiti nekoliko njih unutar jednog radnog toka.\u003C\u002Fdiv>\u003C\u002Faside>\n\u003Caside class=\"editorjs-callout editorjs-callout--warning my-6 rounded-xl border p-5 border-amber-300 bg-amber-50 dark:border-amber-900 dark:bg-amber-950\u002F20\" role=\"note\">\u003Cstrong class=\"block mb-2 text-gray-900 dark:text-gray-100\">Standardi koji se brzo razvijaju\u003C\u002Fstrong>\u003Cdiv class=\"text-gray-700 dark:text-gray-200\">Ovaj članak odražava stanje na sceni protokola na dan <strong>25. septembar 2026<\u002Fstrong>. A2A je dostigao v1.0, trenutna MCP TypeScript v2 linija implementira specifikaciju od 2026-07-28, UCP je već dodao novije verzije protokola za 2026. godinu, a A2UI nastavlja da se razvija. Uvek proverite važeću specifikaciju pre implementacije.\u003C\u002Fdiv>\u003C\u002Faside>\n\u003Caside class=\"editorjs-callout editorjs-callout--note my-6 rounded-xl border p-5 border-gray-300 bg-gray-50 dark:border-gray-700 dark:bg-gray-900\u002F40\" role=\"note\">\u003Cstrong class=\"block mb-2 text-gray-900 dark:text-gray-100\">Model korišćen u ovom članku\u003C\u002Fstrong>\u003Cdiv class=\"text-gray-700 dark:text-gray-200\">Sloj odgovornosti protokola (Protocol Responsibility Stack) i Test za izbor protokola (Protocol Selection Test) u nastavku su praktični arhitektonski modeli predloženi ovde. Oni ne predstavljaju zvaničnu terminologiju projekata ovih protokola.\u003C\u002Fdiv>\u003C\u002Faside>\n\u003Ch2 id=\"section-6\">Osnovna greška: poređenje protokola koji se nalaze na različitim granicama\u003C\u002Fh2>\n\u003Cp>Protokol je koristan zato što je za dva nezavisno implementirana sistema potreban stabilan ugovor. Taj ugovor ima smisla samo ako je granica jasna. Agent koji komunicira sa bazom podataka ima drugačiji problem interoperabilnosti od agenta koji delegira posao drugom agentu, kupca koji autorizuje kupovinu ili udaljenog agenta koji traži od izvorne aplikacije da prikaže formular.\u003C\u002Fp>\n\u003Cp>Google-ov vodič za programere za 2026. godinu eksplicitno predstavlja MCP, A2A, UCP, AP2, A2UI i srodne UI protokole kao skup komplementarnih standarda. Isti primer radnog toka može koristiti nekoliko njih zajedno: alate za inventar, udaljene agente za dobavljače, trgovinu za naručivanje, autorizaciju plaćanja za potrošnju i UI protokole za interakciju.\u003C\u002Fp>\n\u003Ch2 id=\"section-9\">Sloj odgovornosti protokola\u003C\u002Fh2>\n\u003Cdiv class=\"overflow-x-auto\">\u003Ctable class=\"w-full border-collapse\">\u003Cthead>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Protokol\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Koji odnos standardizuje?\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Primarna apstrakcija\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Nije prvenstveno namenjen za\u003C\u002Fth>\u003C\u002Ftr>\u003C\u002Fthead>\u003Ctbody>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">MCP\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">AI aplikacija ↔ alati, resursi i podaci\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Alati, resursi, promptovi i razmena mogućnosti između domaćina i servera\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Saradnju nezavisnih agenata ili semantiku trgovine\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">A2A\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Agent ↔ nezavisni agent\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Otkrivanje agenata, poruke, zadaci, artefakti i dugotrajna saradnja\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Direktnu integraciju baza podataka\u002Falata\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">UCP\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Korisnički\u002Fagentski interfejs ↔ trgovački sistem za trgovinu\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Mogućnosti za proizvode\u002Fkorpu\u002Fnaplatu\u002Frealizaciju\u002Fporudžbine\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Komunikaciju agenata opšte namene\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">AP2\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Namera korisnika\u002Fagenta ↔ autorizacija plaćanja\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Mandati, ograničenja odobrenja i proverljiva ovlašćenja za plaćanje vođena agentima\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Pronalaženje proizvoda ili generički transport pri naplati\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">A2UI\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Agent ↔ domaćin korisničkog interfejsa\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Deklarativna UI namera koju prikazuju pouzdane izvorne komponente\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Proizvoljni udaljeni frontend kod ili delegiranje zadataka s agenta na agenta\u003C\u002Ftd>\u003C\u002Ftr>\u003C\u002Ftbody>\u003C\u002Ftable>\u003C\u002Fdiv>\n\u003Caside class=\"editorjs-callout editorjs-callout--success my-6 rounded-xl border p-5 border-emerald-300 bg-emerald-50 dark:border-emerald-900 dark:bg-emerald-950\u002F20\" role=\"note\">\u003Cstrong class=\"block mb-2 text-gray-900 dark:text-gray-100\">Jedan radni tok može koristiti svih pet\u003C\u002Fstrong>\u003Cdiv class=\"text-gray-700 dark:text-gray-200\">Agent može koristiti <strong>MCP<\u002Fstrong> za proveru inventara, <strong>A2A<\u002Fstrong> da zatraži dostupnost od agenta dobavljača, <strong>UCP<\u002Fstrong> za kreiranje trgovinske transakcije, <strong>AP2<\u002Fstrong> za dokazivanje ovlašćenja za potrošnju i <strong>A2UI<\u002Fstrong> za prikaz izvornog interfejsa za odobrenje korisniku.\u003C\u002Fdiv>\u003C\u002Faside>\n\u003Ch2 id=\"section-12\">1. MCP: povežite agenta sa mogućnostima\u003C\u002Fh2>\n\u003Cp>Model Context Protocol je otvoreni standard za povezivanje AI aplikacija sa spoljnim sistemima u kojima se nalaze alati, podaci i višekratno upotrebljivi resursi. Server izlaže mogućnosti; MCP domaćin se povezuje sa tim serverom i čini te mogućnosti dostupnim modelu ili aplikaciji.\u003C\u002Fp>\n\u003Cp>Trenutna MCP TypeScript v2 dokumentacija opisuje protokol upravo tim rečima: serveri izlažu alate, resurse i promptove, dok se domaćini kao što su razvojna okruženja ili prilagođene aplikacije povezuju sa njima. Zbog toga je MCP prvenstveno protokol za integraciju mogućnosti.\u003C\u002Fp>\n\u003Ch3 id=\"section-15\">Koristite MCP kada\u003C\u002Fh3>\n\u003Cul>\u003Cli>AI aplikaciji je potreban standardizovan pristup alatima ili API-jima.\u003C\u002Fli>\u003Cli>Želite da jedan server mogućnosti radi sa više kompatibilnih AI domaćina.\u003C\u002Fli>\u003Cli>Potreban vam je strukturiran pristup podacima ili resursima bez ručnog kodiranja svake integracije u svakog agenta.\u003C\u002Fli>\u003Cli>Spoljni sistem je pružalac mogućnosti, a ne autonomni ravnopravni agent.\u003C\u002Fli>\u003C\u002Ful>\n\u003Caside class=\"editorjs-callout editorjs-callout--warning my-6 rounded-xl border p-5 border-amber-300 bg-amber-50 dark:border-amber-900 dark:bg-amber-950\u002F20\" role=\"note\">\u003Cstrong class=\"block mb-2 text-gray-900 dark:text-gray-100\">MCP nije automatski A2A\u003C\u002Fstrong>\u003Cdiv class=\"text-gray-700 dark:text-gray-200\">MCP server može izlagati moćne funkcije, ali to ga ne čini nezavisnim agentom sa sopstvenim životnim ciklusom zadataka, semantikom otkrivanja i neprozirnim unutrašnjim rezonovanjem. Pozivanje alata i saradnja agenata predstavljaju različite ugovore.\u003C\u002Fdiv>\u003C\u002Faside>\n\u003Ch2 id=\"section-18\">2. A2A: povežite nezavisne agente\u003C\u002Fh2>\n\u003Cp>Agent2Agent (A2A) je dizajniran za komunikaciju između nezavisnih, potencijalno neprozirnih agentskih sistema. Njegova trenutna specifikacija v1.0 fokusira se na otkrivanje mogućnosti, razmenu poruka, zadatke, artefakte, multimodalni sadržaj i dugotrajnu saradnju bez potrebe da jedan agent otkriva svoje interne alate, memoriju ili implementaciju drugom.\u003C\u002Fp>\n\u003Cp>Ta neprozirnost je važna granica. Agent koji poziva ne mora da zna da li udaljeni agent interno koristi MCP, prilagođene alate, vlasnički planer, drugog dobavljača modela ili eskalaciju ka ljudima. Potreban mu je ugovor za otkrivanje mogućnosti i delegiranje posla.\u003C\u002Fp>\n\u003Cp>A2A v1.0 takođe standardizuje pregovaranje o verzijama i podržava višestruka vezivanja oko zajedničkog modela podataka. Njegov objavljeni mehanizam Agent Card klijentima pruža standardnu tačku otkrivanja za mogućnosti agenta, podržane protokole, zahteve za autentifikaciju i veštine.\u003C\u002Fp>\n\u003Ch3 id=\"section-22\">Koristite A2A kada\u003C\u002Fh3>\n\u003Cul>\u003Cli>Jedan autonomni agent treba da delegira posao drugom autonomnom agentu.\u003C\u002Fli>\u003Cli>Udaljeni sistem treba da ostane neproziran iza ugovora o mogućnostima.\u003C\u002Fli>\u003Cli>Zadaci mogu biti dugotrajni, asinhroni ili zahtevati interakciju čoveka u procesu (human-in-the-loop).\u003C\u002Fli>\u003Cli>Agenti su izgrađeni pomoću različitih radnih okvira, jezika, dobavljača ili organizacionog vlasništva.\u003C\u002Fli>\u003C\u002Ful>\n\u003Ch2 id=\"section-24\">MCP naspram A2A: vertikalna integracija naspram horizontalne saradnje\u003C\u002Fh2>\n\u003Csection class=\"editorjs-comparison my-6\">\u003Ch3 class=\"mb-3 text-lg font-semibold\">MCP i A2A rešavaju različite probleme interoperabilnosti\u003C\u002Fh3>\u003Cdiv class=\"overflow-x-auto\">\u003Ctable class=\"w-full border-collapse\">\u003Cthead>\u003Ctr>\u003Cth class=\"border border-gray-300 bg-gray-50 px-4 py-3 text-left dark:border-gray-700 dark:bg-gray-900\">\u003C\u002Fth>\u003Cth class=\"border border-gray-300 bg-gray-50 px-4 py-3 text-left font-semibold dark:border-gray-700 dark:bg-gray-900\">Dimenzija\u003C\u002Fth>\u003Cth class=\"border border-gray-300 bg-gray-50 px-4 py-3 text-left font-semibold dark:border-gray-700 dark:bg-gray-900\">MCP\u003C\u002Fth>\u003Cth class=\"border border-gray-300 bg-gray-50 px-4 py-3 text-left font-semibold dark:border-gray-700 dark:bg-gray-900\">A2A\u003C\u002Fth>\u003C\u002Ftr>\u003C\u002Fthead>\u003Ctbody>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-3 text-left font-semibold dark:border-gray-700\">Odnos\u003C\u002Fth>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-3 text-left font-semibold dark:border-gray-700\">Apstrakcija\u003C\u002Fth>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-3 text-left font-semibold dark:border-gray-700\">Interna neprozirnost\u003C\u002Fth>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-3 text-left font-semibold dark:border-gray-700\">Dugotrajni rad\u003C\u002Fth>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-3 dark:border-gray-700\">\u003C\u002Ftd>\u003C\u002Ftr>\u003C\u002Ftbody>\u003C\u002Ftable>\u003C\u002Fdiv>\u003C\u002Fsection>\n\u003Cp>Sam A2A projekat sada opisuje razliku kao horizontalnu naspram vertikalne: MCP povezuje agente sa internim alatima i bazama podataka, dok A2A omogućava saradnju između ravnopravnih agentskih sistema (peer-to-peer).\u003C\u002Fp>\n\u003Ch2 id=\"section-27\">3. UCP: standardizacija agentske trgovine\u003C\u002Fh2>\n\u003Cp>Universal Commerce Protocol nije generički agentski protokol. On standardizuje procese trgovine između korisničkih interfejsa, trgovaca i pružalaca usluga plaćanja. Google-ova implementacija već podržava mogućnosti kao što su kreiranje korpe, plaćanje, ispunjenje porudžbine i životni ciklus porudžbine kroz profilisane verzije i API-je.\u003C\u002Fp>\n\u003Cp>Trgovac može objaviti UCP profil pod \u002F.well-known\u002Fucp opisujući usluge, verzije protokola i mogućnosti. Taj obrazac otkrivanja je važan jer agentskom interfejsu ne bi trebalo da bude potreban prilagođeni ugovor o plaćanju za svakog trgovca.\u003C\u002Fp>\n\u003Cp>UCP je takođe namerno modularan. Google-ov tehnički pregled navodi da se može integrisati putem API-ja, A2A i MCP-a i da je kompatibilan sa AP2 za autorizaciju agentskih plaćanja.\u003C\u002Fp>\n\u003Ch3 id=\"section-31\">Koristite UCP kada\u003C\u002Fh3>\n\u003Cul>\u003Cli>Tok posla uključuje proizvode trgovca, korpe, plaćanje, ispunjenje ili životni ciklus porudžbine.\u003C\u002Fli>\u003Cli>Gradite interfejs trgovca koji treba da funkcioniše sa iskustvima agentske kupovine.\u003C\u002Fli>\u003Cli>Integraciji je potrebna semantika specifična za trgovinu, a ne generički pozivi alata.\u003C\u002Fli>\u003Cli>Želite interoperabilan trgovinski ugovor koji može koegzistirati sa MCP, A2A i protokolima plaćanja.\u003C\u002Fli>\u003C\u002Ful>\n\u003Ch2 id=\"section-33\">4. AP2: dokazivanje da je agent imao ovlašćenje da troši\u003C\u002Fh2>\n\u003Cp>Agentska trgovina uvodi problem koji uobičajeni tokovi plaćanja nisu morali da rešavaju na isti način: agent može izvršiti transakciju u trenutku kada čovek u realnom vremenu ne klikće na završno dugme. Agent Payments Protocol (AP2) rešava pitanja autorizacije, autentičnosti i odgovornosti za plaćanja vođena agentima.\u003C\u002Fp>\n\u003Cp>Google-ov vodič kroz protokol za 2026. godinu opisuje AP2 putem tipiziranih mandata koji beleže nameru korisnika, ograničenja potrošnje i konkretnu transakciju koja se autorizuje. AP2 može funkcionisati kao proširenje uz UCP: UCP opisuje trgovinsku transakciju, dok AP2 pruža dokaz da je agent imao ovlašćenje da izvrši plaćanje.\u003C\u002Fp>\n\u003Cp>Ova razlika je važna. Protokol za plaćanje može reći trgovcu šta treba kupiti. On sam po sebi ne dokazuje ko je ovlastio agenta da troši, pod kojim limitom, za kog trgovca, na koliko dugo ili da li je konačna korpa ostala u okviru tog ovlašćenja.\u003C\u002Fp>\n\u003Ch2 id=\"section-37\">UCP naspram AP2: semantika transakcija naspram ovlašćenja\u003C\u002Fh2>\n\u003Cdiv class=\"overflow-x-auto\">\u003Ctable class=\"w-full border-collapse\">\u003Cthead>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Pitanje\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">UCP\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">AP2\u003C\u002Fth>\u003C\u002Ftr>\u003C\u002Fthead>\u003Ctbody>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Šta se kupuje?\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Trgovački artikli, korpa, semantika poručivanja i ispunjenja\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Referencira kontekst autorizovane transakcije\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Ko to može autorizovati?\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Nije primarna odgovornost protokola\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Izričiti model ovlašćenja i mandata agenta\u002Fkorisnika\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Koja se ograničenja potrošnje primenjuju?\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Trgovački tok može sadržati ukupne iznose i podatke o plaćanju\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Zaštitne ograde autorizacije i ograničenja namere\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Kako se transakcija revidira?\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Životni ciklus porudžbine i trgovine\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Kriptografski \u002F proverljivi trag autorizacije kroz mandate i račune\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Mogu li raditi zajedno?\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Da\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Da — AP2 može proširiti tokove agentske trgovine\u003C\u002Ftd>\u003C\u002Ftr>\u003C\u002Ftbody>\u003C\u002Ftable>\u003C\u002Fdiv>\n\u003Ch2 id=\"section-39\">5. A2UI: omogućite agentima da opisuju interfejse bez posedovanja vašeg frontend-a\u003C\u002Fh2>\n\u003Cp>Agent-to-User Interface (A2UI) rešava drugu granicu: kako udaljeni ili lokalni agent prenosi bogati interaktivni interfejs matičnoj (host) aplikaciji. Umesto slanja proizvoljnog HTML-a, CSS-a i JavaScript-a, A2UI koristi deklarativne podatke koje host renderuje kroz sopstveni pouzdani katalog komponenti.\u003C\u002Fp>\n\u003Cp>Ovo čuva sistem dizajna i bezbednosni model matične aplikacije, a pritom omogućava agentu da zahteva dinamičke interfejse. A2UI v0.9 posebno naglašava nameru korisničkog interfejsa nezavisnu od radnog okvira i strimovana ažuriranja na veb, mobilnim i drugim klijentima.\u003C\u002Fp>\n\u003Cp>Google-ov kasniji rad na A2UI + MCP Apps takođe pokazuje da ovi UI modeli nisu nužno međusobno isključivi. Deklarativni izvorni UI i bogatija ugrađena iskustva aplikacije mogu koegzistirati u zavisnosti od zadatka.\u003C\u002Fp>\n\u003Ch3 id=\"section-43\">Koristite A2UI kada\u003C\u002Fh3>\n\u003Cul>\u003Cli>Udaljeni agent treba da zatraži formulare, kartice, kontrole ili drugi interaktivni UI.\u003C\u002Fli>\u003Cli>Matična aplikacija treba da sačuva svoje izvorne komponente, stilizovanje i bezbednosne granice.\u003C\u002Fli>\u003Cli>Ne želite da udaljeni agenti šalju proizvoljan izvršni frontend kod.\u003C\u002Fli>\u003Cli>Ista namera UI-ja definisana od strane agenta treba da funkcioniše na različitim klijentskim okvirima.\u003C\u002Fli>\u003C\u002Ful>\n\u003Ch2 id=\"section-45\">Test za izbor protokola\u003C\u002Fh2>\n\u003Cp>Nemojte počinjati od akronima. Počnite od odnosa kome je potrebna interoperabilnost.\u003C\u002Fp>\n\u003Csection class=\"editorjs-process my-6\">\u003Ch3 class=\"mb-3 text-lg font-semibold\">Izaberite protokol prema granici\u003C\u002Fh3>\u003Cdiv class=\"grid grid-cols-1 md:grid-cols-2 xl:grid-cols-3 gap-4\">\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">1\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">1. Identifikujte dve nezavisne strane\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Da li je u pitanju AI-prema-alatu, agent-prema-agentu, agent-prema-trgovcu, agent-prema-platnom-autoritetu ili agent-prema-korisničkom-interfejsu?\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">2\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">2. Identifikujte deljeni objekat\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Da li se ugovor odnosi na poziv alata, zadatak, korpu, platni mandat, artefakt ili opis UI-ja?\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">3\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">3. Proverite da li već postoji protokol specifičan za domen\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Dajte prednost semantici trgovine ili plaćanja kada je problem trgovina ili autorizacija, umesto da sve kodirate kao generičke alate.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">4\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">4. Zadržite lokalne interne detalje lokalnim\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Nemojte izlagati celog agenta kao MCP alate ako je udaljenoj strani potrebna samo A2A mogućnost i nemojte činiti udaljenog agenta odgovornim za vaš UI runtime.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">5\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">5. Kombinujte protokole kada radni tok prelazi granice\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Jedan radni tok može legitimno prelaziti ugovore alata, agenata, trgovine, plaćanja i UI-ja.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">6\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">6. Verzionišite svaki ugovor nezavisno\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Verzije protokola se razvijaju različitom brzinom; nemojte vezivati svaku integraciju za jednu monolitnu verziju aplikacije.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">7\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">7. Očuvajte autorizaciju na svakoj granici\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Interoperabilnost ne zamenjuje dozvole proizvoda, autorizaciju alata, platna ovlašćenja ili politiku pristupa podacima.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003C\u002Fdiv>\u003C\u002Fsection>\n\u003Ch2 id=\"section-48\">Realan radni tok sa više protokola\u003C\u002Fh2>\n\u003Csection class=\"editorjs-process my-6\">\u003Ch3 class=\"mb-3 text-lg font-semibold\">Primer: autonomni radni tok nabavke\u003C\u002Fh3>\u003Cdiv class=\"grid grid-cols-1 md:grid-cols-2 xl:grid-cols-3 gap-4\">\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">1\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">1. Pregledajte interne zalihe pomoću MCP-a\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Agent nabavke poziva mogućnosti inventara i predviđanja koje izlažu interni MCP serveri.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">2\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">2. Pronađite agenta dobavljača pomoću A2A\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Agent čita karticu agenta dobavljača (Agent Card) i delegira zadatak provere dostupnosti i vremena isporuke.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">3\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">3. Pregovarajte o trgovačkom objektu pomoću UCP-a\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Površina dobavljača ili trgovca vraća strukturirane informacije o korpi, plaćanju i ispunjenju.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">4\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">4. Proverite ovlašćenje za potrošnju pomoću AP2\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Kupovina se upoređuje sa potpisanim mandatom korisnika ili organizacije, ograničenjima trgovca i limitima potrošnje.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">5\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">5. Zatražite odobrenje putem A2UI\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Ako je potrebno ljudsko odobrenje, agent šalje deklarativnu UI nameru, a host renderuje iskustvo odobravanja koristeći pouzdane izvorne komponente.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv class=\"editorjs-process__step min-w-0  rounded-xl border border-gray-200 dark:border-gray-700 p-4\">\u003Cdiv class=\"text-xs font-semibold text-gray-500 dark:text-gray-400\">6\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 font-semibold text-gray-900 dark:text-gray-100\">6. Završite i revidirajte\u003C\u002Fdiv>\u003Cdiv class=\"mt-1 text-sm text-gray-600 dark:text-gray-300\">Stanje trgovine, autorizacija plaćanja, dokazi o zadatku agenta i evidencija revizije aplikacije ostaju sledljivi preko svojih odgovarajućih granica.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003C\u002Fdiv>\u003C\u002Fsection>\n\u003Ch2 id=\"section-50\">Zašto je malo verovatno da će jedan univerzalni agentski protokol zameniti sve njih\u003C\u002Fh2>\n\u003Cp>Univerzalni protokol zvuči jednostavnije sve dok ne mora da kodira semantiku svakog domena. Otkrivanje alata, dugotrajna saradnja agenata, plaćanje, autorizacija plaćanja i izvorni UI imaju različite zahteve u pogledu životnog ciklusa, bezbednosti i ispravnosti.\u003C\u002Fp>\n\u003Cp>Sam veb se razvijao kroz slojevite protokole, a ne kroz jedan format poruka za svaki problem. Nastajući agentski stek se očigledno kreće u istom smeru: zajednički horizontalni primitivi, specijalizovani ugovori domena i eksplicitno otkrivanje\u002Fverzionisanje.\u003C\u002Fp>\n\u003Cp>Arhitektonski izazov se stoga pomera sa pitanja „koji protokol pobeđuje?“ na to koliko se čisto protokoli mogu kombinovati bez dupliranja semantike identiteta, autorizacije, stanja i revizije.\u003C\u002Fp>\n\u003Ch2 id=\"section-54\">Kombinovanje protokola stvara nove načine otkaza\u003C\u002Fh2>\n\u003Cdiv class=\"overflow-x-auto\">\u003Ctable class=\"w-full border-collapse\">\u003Cthead>\u003Ctr>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Režim otkaza\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Šta se dešava\u003C\u002Fth>\u003Cth class=\"border border-gray-300 px-4 py-2 text-left font-semibold\">Arhitektonska kontrola\u003C\u002Fth>\u003C\u002Ftr>\u003C\u002Fthead>\u003Ctbody>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Curenje ovlašćenja\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Validna mogućnost alata ili agenta tretira se kao dozvola za izvršavanje poslovne akcije\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Održavajte autorizaciju proizvoda nezavisnom od otkrivanja mogućnosti protokola\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Neusklađenost identiteta\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Identitet MCP domaćina, identitet A2A agenta i trgovinski\u002Fplatni identitet odnose se na različite principale\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Definišite eksplicitno mapiranje principala preko granica sistema\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Raskorak verzija\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Jedan protokol se nadograđuje dok zavisni adapteri pretpostavljaju stariju semantiku\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Nezavisno pregovarajte i fiksirajte verzije protokola\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Dupliranje stanja\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Isto stanje korpe, zadatka ili odobrenja kopira se u nekoliko slojeva protokola\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Definišite jednog autoritativnog vlasnika po domenskom objektu\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Fragmentacija revizije\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Tragovi alata, zadaci agenata, dokazi o porudžbini i plaćanju ne mogu se povezati\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Prenosite korelacione ID-jeve i stabilne domenske identifikatore preko granica protokola\u003C\u002Ftd>\u003C\u002Ftr>\u003Ctr>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Semantičko tunelovanje\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Sve se forsira kroz generički protokol kao neprozirni JSON\u003C\u002Ftd>\u003Ctd class=\"border border-gray-300 px-4 py-2\">Koristite domenske protokole tamo gde njihova semantika suštinski poboljšava ispravnost\u003C\u002Ftd>\u003C\u002Ftr>\u003C\u002Ftbody>\u003C\u002Ftable>\u003C\u002Fdiv>\n\u003Ch2 id=\"section-56\">Izbor protokola ne zamenjuje arhitekturu aplikacije\u003C\u002Fh2>\n\u003Cp>Otvoreni standardi smanjuju integraciono sprezanje, ali ne odlučuju o vašem domenskom modelu, politici autorizacije, izvoru istine, strategiji ponovnih pokušaja ili kriterijumima prihvatanja. MCP alat i dalje može izložiti pogrešnu mogućnost. A2A agent i dalje može vratiti loš artefakt. UCP proces plaćanja i dalje može sadržati zastarele podatke trgovca. AP2 mandat i dalje može biti pogrešno primenjen aplikativnom logikom.\u003C\u002Fp>\n\u003Cp>Tretirajte protokole kao ugovore između komponenti koje se nezavisno razvijaju. Zadržite domensku istinu i ključne politike u aplikativnom sloju koji ih poseduje, a zatim koristite protokole kako biste granice učinili interoperabilnim.\u003C\u002Fp>\n\u003Caside class=\"editorjs-referral my-6\">\u003Ca href=\"https:\u002F\u002Fstajic.de\u002Fsr\u002Fblog\u002Fmanaged-agent-harness-vs-self-hosted-agent-loop-what-you-gain-what-you-lose\" class=\"flex flex-col sm:flex-row gap-4 rounded-xl border border-gray-200 dark:border-gray-700 p-4 transition hover:border-primary-500\">\u003Cdiv class=\"min-w-0 flex-1\">\u003Cstrong class=\"block text-lg text-gray-900 dark:text-gray-100\">Upravljano agentsko okruženje naspram samostalno hostovane agentske petlje: šta dobijate, a šta gubite\u003C\u002Fstrong>\u003Cp class=\"mt-2 text-sm text-gray-600 dark:text-gray-300\">Granice protokola rešavaju interoperabilnost. Granice izvršavanja rešavaju pitanje ko upravlja radnim okruženjem, izvršnim okruženjem i kontrolnom ravni aplikacije.\u003C\u002Fp>\u003Cspan class=\"mt-3 inline-flex text-sm font-medium text-primary-600 dark:text-primary-400\">Pročitajte vodič kroz arhitekturu izvršnog okruženja →\u003C\u002Fspan>\u003C\u002Fdiv>\u003C\u002Fa>\u003C\u002Faside>\n\u003Ch2 id=\"section-60\">Šta bi promenilo ovaj odgovor?\u003C\u002Fh2>\n\u003Cp>Tehnološki stek se menja ako dođe do konvergencije protokola, ako jedan standard formalno apsorbuje drugi, ili ako dobavljači standardizuju zajednički sloj identiteta i autorizacije preko više granica. UCP već demonstrira kompoziciju podržavajući API-je, A2A i MCP i integrišući se sa AP2 umesto da ih zamenjuje.\u003C\u002Fp>\n\u003Cp>Odgovor se takođe menja u zavisnosti od obima aplikacije. Malom internom agentu može biti potreban samo MCP. Radni tok između više kompanija može zahtevati A2A. Trgovcu može biti potreban UCP bez A2UI. Delegirani agent za kupovinu može zahtevati sve njih. Koristite najmanji skup protokola koji predstavlja stvarne granice bez urušavanja domenske semantike.\u003C\u002Fp>\n\u003Ch2 id=\"section-63\">Ograničenja\u003C\u002Fh2>\n\u003Cp>Protokoli o kojima se ovde govori nalaze se na različitim nivoima zrelosti i imaju različite modele upravljanja. A2A je dostigao stabilnu specifikaciju v1.0, dok drugi standardi nastavljaju ubrzano da se razvijaju. Usvajanje u ekosistemu je takođe neujednačeno među dobavljačima i radnim okvirima.\u003C\u002Fp>\n\u003Cp>Ovaj članak se fokusira na arhitektonsku odgovornost, a ne na potpunost implementacije. Konkretne metode autentifikacije, transportna vezivanja, šeme i mehanizmi proširenja moraju se preuzeti iz trenutne specifikacije svakog protokola.\u003C\u002Fp>\n\u003Ch2 id=\"section-66\">Zaključak\u003C\u002Fh2>\n\u003Cp>MCP, A2A, UCP, AP2 i A2UI imaju više smisla kada se posmatraju kao protokoli za različite odnose, a ne pet konkurentskih pokušaja da se standardizuju „agenti“.\u003C\u002Fp>\n\u003Cp>MCP izlaže mogućnosti. A2A koordiniše nezavisne agente. UCP pruža trgovini sopstveni mašinski čitljiv ugovor. AP2 dodaje proverljivo ovlašćenje za plaćanje. A2UI daje agentima bezbedan deklarativni put ka korisničkim interfejsima. Nastajući agentski veb stoga ne zamenjuje protokole veštačkom inteligencijom; on stvara novi stek protokola oko veštačke inteligencije.\u003C\u002Fp>\n\u003Ch2 id=\"section-69\">Česta pitanja\u003C\u002Fh2>\n\u003Csection class=\"editorjs-faq my-6 rounded-xl border border-gray-200 p-5 dark:border-gray-700\">\u003Ch3 class=\"mb-3 text-lg font-semibold\">MCP, A2A, UCP, AP2 i A2UI\u003C\u002Fh3>\u003Cdiv id=\"faq1\" class=\"border-t border-gray-200 py-4 first:border-t-0 dark:border-gray-700\">\u003Ch4 class=\"font-semibold text-gray-900 dark:text-gray-100\">Da li je A2A zamena za MCP?\u003C\u002Fh4>\u003Cdiv class=\"mt-2 text-gray-600 dark:text-gray-300\">Ne. MCP prvenstveno standardizuje način na koji AI aplikacije pristupaju alatima, resursima i podacima. A2A standardizuje saradnju između nezavisnih agentskih sistema. Udaljeni agent može interno koristiti MCP dok spolja izlaže A2A interfejs.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv id=\"faq2\" class=\"border-t border-gray-200 py-4 first:border-t-0 dark:border-gray-700\">\u003Ch4 class=\"font-semibold text-gray-900 dark:text-gray-100\">Da li je UCP zamena za MCP kod agenata za kupovinu?\u003C\u002Fh4>\u003Cdiv class=\"mt-2 text-gray-600 dark:text-gray-300\">Uglavnom ne. UCP pruža semantiku specifičnu za trgovinu, kao što su korpa, plaćanje i isporuka. MCP i dalje može izlagati alate ili podatke trgovca, a UCP je dizajniran da koegzistira sa MCP-om i A2A.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv id=\"faq3\" class=\"border-t border-gray-200 py-4 first:border-t-0 dark:border-gray-700\">\u003Ch4 class=\"font-semibold text-gray-900 dark:text-gray-100\">Koja je razlika između UCP i AP2?\u003C\u002Fh4>\u003Cdiv class=\"mt-2 text-gray-600 dark:text-gray-300\">UCP standardizuje interakcije u trgovini i životni ciklus transakcija. AP2 se fokusira na dokazivanje da je agent imao ovlašćenje da izvrši plaćanje pod definisanim korisničkim ili organizacionim ograničenjima.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv id=\"faq4\" class=\"border-t border-gray-200 py-4 first:border-t-0 dark:border-gray-700\">\u003Ch4 class=\"font-semibold text-gray-900 dark:text-gray-100\">Koji problem rešava A2UI?\u003C\u002Fh4>\u003Cdiv class=\"mt-2 text-gray-600 dark:text-gray-300\">A2UI omogućava agentima da pošalju deklarativnu UI nameru aplikaciji domaćinu, koja renderuje iskustvo kroz pouzdane izvorne komponente umesto izvršavanja proizvoljnog udaljenog frontend koda.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv id=\"faq5\" class=\"border-t border-gray-200 py-4 first:border-t-0 dark:border-gray-700\">\u003Ch4 class=\"font-semibold text-gray-900 dark:text-gray-100\">Može li jedna agentska aplikacija koristiti sve ove protokole?\u003C\u002Fh4>\u003Cdiv class=\"mt-2 text-gray-600 dark:text-gray-300\">Da. Radni tok može koristiti MCP za interne alate, A2A za delegiranje udaljenim agentima, UCP za trgovinu, AP2 za autorizaciju plaćanja i A2UI za interakciju sa ljudima.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003Cdiv id=\"faq6\" class=\"border-t border-gray-200 py-4 first:border-t-0 dark:border-gray-700\">\u003Ch4 class=\"font-semibold text-gray-900 dark:text-gray-100\">Koji protokol bi trebalo prvo da implementiram?\u003C\u002Fh4>\u003Cdiv class=\"mt-2 text-gray-600 dark:text-gray-300\">Počnite od granice interoperabilnosti. Ako je problem pristup alatima, razmotrite MCP. Ako je u pitanju saradnja nezavisnih agenata, razmotrite A2A. Ako je reč o trgovini, UCP. Ako je u pitanju delegirano ovlašćenje za plaćanje, AP2. Ako je u pitanju prenosivi UI vođen agentima, A2UI.\u003C\u002Fdiv>\u003C\u002Fdiv>\u003C\u002Fsection>\n\u003Ch2 id=\"section-71\">Rečnik pojmova\u003C\u002Fh2>\n\u003Csection class=\"editorjs-glossary my-6 rounded-xl border border-gray-200 dark:border-gray-700 p-5\">\u003Ch3 class=\"mb-3 text-lg font-semibold\">Ključni pojmovi agentskih protokola\u003C\u002Fh3>\u003Cdl>\u003Cdiv id=\"mcp\" class=\"border-t border-gray-200 dark:border-gray-700 py-3 first:border-t-0\">\u003Cdt class=\"font-semibold text-gray-900 dark:text-gray-100\">MCP\u003C\u002Fdt>\u003Cdd class=\"mt-1 text-gray-600 dark:text-gray-300\">Model Context Protocol, otvoreni standard za izlaganje alata, resursa i upita iz eksternih sistema kompatibilnim AI domaćinima.\u003C\u002Fdd>\u003C\u002Fdiv>\u003Cdiv id=\"a2a\" class=\"border-t border-gray-200 dark:border-gray-700 py-3 first:border-t-0\">\u003Cdt class=\"font-semibold text-gray-900 dark:text-gray-100\">A2A\u003C\u002Fdt>\u003Cdd class=\"mt-1 text-gray-600 dark:text-gray-300\">Agent2Agent Protocol, otvoreni standard za otkrivanje i saradnju sa nezavisnim agentskim sistemima putem poruka, zadataka i artefakata.\u003C\u002Fdd>\u003C\u002Fdiv>\u003Cdiv id=\"ucp\" class=\"border-t border-gray-200 dark:border-gray-700 py-3 first:border-t-0\">\u003Cdt class=\"font-semibold text-gray-900 dark:text-gray-100\">UCP\u003C\u002Fdt>\u003Cdd class=\"mt-1 text-gray-600 dark:text-gray-300\">Universal Commerce Protocol, otvoreni standard za interoperabilna agentska trgovinska putovanja između korisničkih interfejsa, preduzeća i pružalaca platnih usluga.\u003C\u002Fdd>\u003C\u002Fdiv>\u003Cdiv id=\"ap2\" class=\"border-t border-gray-200 dark:border-gray-700 py-3 first:border-t-0\">\u003Cdt class=\"font-semibold text-gray-900 dark:text-gray-100\">AP2\u003C\u002Fdt>\u003Cdd class=\"mt-1 text-gray-600 dark:text-gray-300\">Agent Payments Protocol, otvoreni standard za predstavljanje i verifikaciju ovlašćenja, namere i odgovornosti u plaćanjima koja vode agenti.\u003C\u002Fdd>\u003C\u002Fdiv>\u003Cdiv id=\"a2ui\" class=\"border-t border-gray-200 dark:border-gray-700 py-3 first:border-t-0\">\u003Cdt class=\"font-semibold text-gray-900 dark:text-gray-100\">A2UI\u003C\u002Fdt>\u003Cdd class=\"mt-1 text-gray-600 dark:text-gray-300\">Agent-to-User Interface, deklarativni protokol koji omogućava agentima da zatraže korisnički interfejs koji se renderuje pomoću pouzdanih komponenti aplikacije domaćina.\u003C\u002Fdd>\u003C\u002Fdiv>\u003Cdiv id=\"protocol-composition\" class=\"border-t border-gray-200 dark:border-gray-700 py-3 first:border-t-0\">\u003Cdt class=\"font-semibold text-gray-900 dark:text-gray-100\">Kompozicija protokola\u003C\u002Fdt>\u003Cdd class=\"mt-1 text-gray-600 dark:text-gray-300\">Korišćenje više protokola u jednom radnom toku, gde je svaki odgovoran za posebnu granicu interoperabilnosti umesto forsiranja celokupne semantike kroz jedan ugovor.\u003C\u002Fdd>\u003C\u002Fdiv>\u003C\u002Fdl>\u003C\u002Fsection>\n\u003Ch2 id=\"section-73\">Primarni izvori i dodatna literatura\u003C\u002Fh2>\n\u003Ca href=\"https:\u002F\u002Fdevelopers.googleblog.com\u002Fdevelopers-guide-to-ai-agent-protocols\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Google Developers — Vodič za programere kroz protokole AI agenata\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Praktičan pregled koji prikazuje kako MCP, A2A, UCP, AP2, A2UI i srodni protokoli funkcionišu zajedno u jednom višefaznom toku rada agenata.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fts.sdk.modelcontextprotocol.io\u002Fv2\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Model Context Protocol — TypeScript SDK v2\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Trenutna stabilna SDK dokumentacija koja implementira MCP specifikaciju od 28.07.2026. i definiše alate, resurse, upite (prompts) i integraciju hosta\u002Fservera.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fa2a-protocol.org\u002Fdev\u002Fspecification\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">A2A Protocol — v1.0 specifikacija\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Aktuelna specifikacija A2A protokola koja pokriva Agent Cards, poruke, zadatke, artefakte, vezivanja i pregovaranje o verziji.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fa2a-protocol.org\u002Flatest\u002Fblog\u002F2026\u002F08\u002F27\u002Fa-new-chapter-for-a2a-joining-the-agentic-ai-foundation\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">A2A — Pridruživanje Agentic AI Foundation\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Aktuelni okvir projekta A2A kao horizontalnog sloja za saradnju agenata uz MCP kao vertikalnu integraciju alata\u002Fpodataka.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fdevelopers.googleblog.com\u002Funder-the-hood-universal-commerce-protocol-ucp\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Google Developers — Ispod haube: Universal Commerce Protocol\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Tehnički pregled UCP-a, njegovih trgovinskih primitiva i mogućnosti sklapanja sa API-jima, A2A, MCP i AP2.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fdevelopers.google.com\u002Fmerchant\u002Fucp\u002Fimplementation\u002F2026-04-08\u002Fpublish-profile\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Google Universal Commerce Protocol — UCP profil\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Aktuelni mehanizam verzionisanih profila za objavljivanje UCP usluga i trgovinskih mogućnosti prodavaca.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fcloud.google.com\u002Fblog\u002Fproducts\u002Fai-machine-learning\u002Fannouncing-agents-to-payments-ap2-protocol\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Google Cloud — Agent Payments Protocol (AP2)\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Najava i obrazloženje otvorenog protokola koji pokriva autorizaciju, autentičnost i odgovornost u plaćanjima vođenim agentima.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fdevelopers.googleblog.com\u002Fa2ui-v0-9-generative-ui\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Google Developers — A2UI v0.9\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Deklarativni model A2UI nezavisan od radnog okvira za prenosive interfejse vođene agentima koje renderuju izvorne komponente hosta.\u003C\u002Fp>\u003C\u002Fa>\n\u003Ca href=\"https:\u002F\u002Fdevelopers.googleblog.com\u002Fa2ui-and-mcp-apps\u002F\" target=\"_blank\" rel=\"noopener noreferrer\" class=\"editorjs-link-tool block border border-gray-200 dark:border-gray-700 rounded-lg p-4 transition text-gray-900 dark:text-gray-100 hover:border-primary-500 hover:bg-primary-50 dark:hover:bg-gray-900 hover:text-gray-900 dark:hover:text-gray-100\">\u003Cstrong class=\"block font-semibold\">Google Developers — A2UI + MCP aplikacije\u003C\u002Fstrong>\u003Cp class=\"text-sm text-gray-600 dark:text-gray-400\">Kako deklarativni A2UI i bogatija iskustva MCP aplikacija mogu koegzistirati umesto da se posmatraju kao međusobno isključivi modeli korisničkog interfejsa.\u003C\u002Fp>\u003C\u002Fa>",{"time":212,"blocks":213,"version":895},1790364146396,[214,222,228,236,243,250,255,260,265,270,306,313,318,323,328,333,345,351,356,361,366,371,376,386,391,423,428,433,438,443,448,453,463,468,473,478,483,488,515,520,525,530,535,540,550,555,560,589,594,618,623,628,633,638,643,676,681,686,691,700,705,710,715,720,725,730,735,740,745,750,780,785,808,813,823,832,841,850,859,868,877,886],{"id":215,"data":216,"type":220,"tunes":221},"_z4yTl5Fh-",{"title":217,"maxLevel":218,"minLevel":219},"Sadržaj",3,2,"tableOfContents",{},{"id":223,"data":224,"type":226,"tunes":227},"intro",{"text":225},"Protokoli za AI agente se ubrzano množe: MCP, A2A, UCP, AP2, A2UI i srodni standardi sve se češće pojavljuju na istim dijagramima arhitekture. Često se opisuju kao konkurentski protokoli. U praksi, većina njih rešava različite probleme interoperabilnosti na različitim granicama sistema. Korisno pitanje nije „Koji protokol pobeđuje?“, već „Koji odnos u sistemu treba standardizovati?“","paragraph",{},{"id":229,"data":230,"type":234,"tunes":235},"direct",{"body":231,"title":232,"variant":233},"\u003Cstrong>MCP, A2A, UCP, AP2 i A2UI se uglavnom međusobno dopunjuju, a nisu zamene.\u003C\u002Fstrong> MCP povezuje AI aplikaciju sa alatima, podacima i resursima. A2A povezuje nezavisne agente jedne sa drugima. UCP standardizuje trgovinske interakcije između korisničkih interfejsa, preduzeća i platnih ekosistema. AP2 dodaje proverljivu autorizaciju i nameru plaćanja transakcijama koje vode agenti. A2UI omogućava agentu da opiše interaktivni UI bez slanja proizvoljnog aplikativnog koda. Produkcijski sistem može legitimno koristiti nekoliko njih unutar jednog radnog toka.","Direktan odgovor","info","callout",{},{"id":237,"data":238,"type":234,"tunes":242},"freshness",{"body":239,"title":240,"variant":241},"Ovaj članak odražava stanje na sceni protokola na dan \u003Cstrong>25. septembar 2026\u003C\u002Fstrong>. A2A je dostigao v1.0, trenutna MCP TypeScript v2 linija implementira specifikaciju od 2026-07-28, UCP je već dodao novije verzije protokola za 2026. godinu, a A2UI nastavlja da se razvija. Uvek proverite važeću specifikaciju pre implementacije.","Standardi koji se brzo razvijaju","warning",{},{"id":244,"data":245,"type":234,"tunes":249},"model-note",{"body":246,"title":247,"variant":248},"Sloj odgovornosti protokola (Protocol Responsibility Stack) i Test za izbor protokola (Protocol Selection Test) u nastavku su praktični arhitektonski modeli predloženi ovde. Oni ne predstavljaju zvaničnu terminologiju projekata ovih protokola.","Model korišćen u ovom članku","note",{},{"id":251,"data":252,"type":42,"tunes":254},"h-core",{"text":253,"level":219},"Osnovna greška: poređenje protokola koji se nalaze na različitim granicama",{},{"id":256,"data":257,"type":226,"tunes":259},"p-core-1",{"text":258},"Protokol je koristan zato što je za dva nezavisno implementirana sistema potreban stabilan ugovor. Taj ugovor ima smisla samo ako je granica jasna. Agent koji komunicira sa bazom podataka ima drugačiji problem interoperabilnosti od agenta koji delegira posao drugom agentu, kupca koji autorizuje kupovinu ili udaljenog agenta koji traži od izvorne aplikacije da prikaže formular.",{},{"id":261,"data":262,"type":226,"tunes":264},"p-core-2",{"text":263},"Google-ov vodič za programere za 2026. godinu eksplicitno predstavlja MCP, A2A, UCP, AP2, A2UI i srodne UI protokole kao skup komplementarnih standarda. Isti primer radnog toka može koristiti nekoliko njih zajedno: alate za inventar, udaljene agente za dobavljače, trgovinu za naručivanje, autorizaciju plaćanja za potrošnju i UI protokole za interakciju.",{},{"id":266,"data":267,"type":42,"tunes":269},"h-stack",{"text":268,"level":219},"Sloj odgovornosti protokola",{},{"id":271,"data":272,"type":304,"tunes":305},"stack-table",{"content":273,"stretched":43,"withHeadings":14},[274,279,284,289,294,299],[275,276,277,278],"Protokol","Koji odnos standardizuje?","Primarna apstrakcija","Nije prvenstveno namenjen za",[280,281,282,283],"MCP","AI aplikacija ↔ alati, resursi i podaci","Alati, resursi, promptovi i razmena mogućnosti između domaćina i servera","Saradnju nezavisnih agenata ili semantiku trgovine",[285,286,287,288],"A2A","Agent ↔ nezavisni agent","Otkrivanje agenata, poruke, zadaci, artefakti i dugotrajna saradnja","Direktnu integraciju baza podataka\u002Falata",[290,291,292,293],"UCP","Korisnički\u002Fagentski interfejs ↔ trgovački sistem za trgovinu","Mogućnosti za proizvode\u002Fkorpu\u002Fnaplatu\u002Frealizaciju\u002Fporudžbine","Komunikaciju agenata opšte namene",[295,296,297,298],"AP2","Namera korisnika\u002Fagenta ↔ autorizacija plaćanja","Mandati, ograničenja odobrenja i proverljiva ovlašćenja za plaćanje vođena agentima","Pronalaženje proizvoda ili generički transport pri naplati",[300,301,302,303],"A2UI","Agent ↔ domaćin korisničkog interfejsa","Deklarativna UI namera koju prikazuju pouzdane izvorne komponente","Proizvoljni udaljeni frontend kod ili delegiranje zadataka s agenta na agenta","table",{},{"id":307,"data":308,"type":234,"tunes":312},"all-five",{"body":309,"title":310,"variant":311},"Agent može koristiti \u003Cstrong>MCP\u003C\u002Fstrong> za proveru inventara, \u003Cstrong>A2A\u003C\u002Fstrong> da zatraži dostupnost od agenta dobavljača, \u003Cstrong>UCP\u003C\u002Fstrong> za kreiranje trgovinske transakcije, \u003Cstrong>AP2\u003C\u002Fstrong> za dokazivanje ovlašćenja za potrošnju i \u003Cstrong>A2UI\u003C\u002Fstrong> za prikaz izvornog interfejsa za odobrenje korisniku.","Jedan radni tok može koristiti svih pet","success",{},{"id":314,"data":315,"type":42,"tunes":317},"h-mcp",{"text":316,"level":219},"1. MCP: povežite agenta sa mogućnostima",{},{"id":319,"data":320,"type":226,"tunes":322},"p-mcp-1",{"text":321},"Model Context Protocol je otvoreni standard za povezivanje AI aplikacija sa spoljnim sistemima u kojima se nalaze alati, podaci i višekratno upotrebljivi resursi. Server izlaže mogućnosti; MCP domaćin se povezuje sa tim serverom i čini te mogućnosti dostupnim modelu ili aplikaciji.",{},{"id":324,"data":325,"type":226,"tunes":327},"p-mcp-2",{"text":326},"Trenutna MCP TypeScript v2 dokumentacija opisuje protokol upravo tim rečima: serveri izlažu alate, resurse i promptove, dok se domaćini kao što su razvojna okruženja ili prilagođene aplikacije povezuju sa njima. Zbog toga je MCP prvenstveno protokol za integraciju mogućnosti.",{},{"id":329,"data":330,"type":42,"tunes":332},"h-mcp-use",{"text":331,"level":218},"Koristite MCP kada",{},{"id":334,"data":335,"type":343,"tunes":344},"mcp-list",{"meta":336,"items":337,"style":342},{},[338,339,340,341],"AI aplikaciji je potreban standardizovan pristup alatima ili API-jima.","Želite da jedan server mogućnosti radi sa više kompatibilnih AI domaćina.","Potreban vam je strukturiran pristup podacima ili resursima bez ručnog kodiranja svake integracije u svakog agenta.","Spoljni sistem je pružalac mogućnosti, a ne autonomni ravnopravni agent.","unordered","list",{},{"id":346,"data":347,"type":234,"tunes":350},"mcp-warning",{"body":348,"title":349,"variant":241},"MCP server može izlagati moćne funkcije, ali to ga ne čini nezavisnim agentom sa sopstvenim životnim ciklusom zadataka, semantikom otkrivanja i neprozirnim unutrašnjim rezonovanjem. Pozivanje alata i saradnja agenata predstavljaju različite ugovore.","MCP nije automatski A2A",{},{"id":352,"data":353,"type":42,"tunes":355},"h-a2a",{"text":354,"level":219},"2. A2A: povežite nezavisne agente",{},{"id":357,"data":358,"type":226,"tunes":360},"p-a2a-1",{"text":359},"Agent2Agent (A2A) je dizajniran za komunikaciju između nezavisnih, potencijalno neprozirnih agentskih sistema. Njegova trenutna specifikacija v1.0 fokusira se na otkrivanje mogućnosti, razmenu poruka, zadatke, artefakte, multimodalni sadržaj i dugotrajnu saradnju bez potrebe da jedan agent otkriva svoje interne alate, memoriju ili implementaciju drugom.",{},{"id":362,"data":363,"type":226,"tunes":365},"p-a2a-2",{"text":364},"Ta neprozirnost je važna granica. Agent koji poziva ne mora da zna da li udaljeni agent interno koristi MCP, prilagođene alate, vlasnički planer, drugog dobavljača modela ili eskalaciju ka ljudima. Potreban mu je ugovor za otkrivanje mogućnosti i delegiranje posla.",{},{"id":367,"data":368,"type":226,"tunes":370},"p-a2a-3",{"text":369},"A2A v1.0 takođe standardizuje pregovaranje o verzijama i podržava višestruka vezivanja oko zajedničkog modela podataka. Njegov objavljeni mehanizam Agent Card klijentima pruža standardnu tačku otkrivanja za mogućnosti agenta, podržane protokole, zahteve za autentifikaciju i veštine.",{},{"id":372,"data":373,"type":42,"tunes":375},"h-a2a-use",{"text":374,"level":218},"Koristite A2A kada",{},{"id":377,"data":378,"type":343,"tunes":385},"a2a-list",{"meta":379,"items":380,"style":342},{},[381,382,383,384],"Jedan autonomni agent treba da delegira posao drugom autonomnom agentu.","Udaljeni sistem treba da ostane neproziran iza ugovora o mogućnostima.","Zadaci mogu biti dugotrajni, asinhroni ili zahtevati interakciju čoveka u procesu (human-in-the-loop).","Agenti su izgrađeni pomoću različitih radnih okvira, jezika, dobavljača ili organizacionog vlasništva.",{},{"id":387,"data":388,"type":42,"tunes":390},"h-mcp-a2a",{"text":389,"level":219},"MCP naspram A2A: vertikalna integracija naspram horizontalne saradnje",{},{"id":392,"data":393,"type":421,"tunes":422},"mcp-a2a-comparison",{"rows":394,"title":412,"layout":304,"columns":413},[395,400,404,408],{"id":396,"label":397,"values":398},"relationship","Odnos",[399,399,399],"",{"id":401,"label":402,"values":403},"abstraction","Apstrakcija",[399,399,399],{"id":405,"label":406,"values":407},"opacity","Interna neprozirnost",[399,399,399],{"id":409,"label":410,"values":411},"long","Dugotrajni rad",[399,399,399],"MCP i A2A rešavaju različite probleme interoperabilnosti",[414,417,419],{"id":415,"label":416},"dimension","Dimenzija",{"id":418,"label":280},"mcp",{"id":420,"label":285},"a2a","comparison",{},{"id":424,"data":425,"type":226,"tunes":427},"p-mcp-a2a-1",{"text":426},"Sam A2A projekat sada opisuje razliku kao horizontalnu naspram vertikalne: MCP povezuje agente sa internim alatima i bazama podataka, dok A2A omogućava saradnju između ravnopravnih agentskih sistema (peer-to-peer).",{},{"id":429,"data":430,"type":42,"tunes":432},"h-ucp",{"text":431,"level":219},"3. UCP: standardizacija agentske trgovine",{},{"id":434,"data":435,"type":226,"tunes":437},"p-ucp-1",{"text":436},"Universal Commerce Protocol nije generički agentski protokol. On standardizuje procese trgovine između korisničkih interfejsa, trgovaca i pružalaca usluga plaćanja. Google-ova implementacija već podržava mogućnosti kao što su kreiranje korpe, plaćanje, ispunjenje porudžbine i životni ciklus porudžbine kroz profilisane verzije i API-je.",{},{"id":439,"data":440,"type":226,"tunes":442},"p-ucp-2",{"text":441},"Trgovac može objaviti UCP profil pod \u002F.well-known\u002Fucp opisujući usluge, verzije protokola i mogućnosti. Taj obrazac otkrivanja je važan jer agentskom interfejsu ne bi trebalo da bude potreban prilagođeni ugovor o plaćanju za svakog trgovca.",{},{"id":444,"data":445,"type":226,"tunes":447},"p-ucp-3",{"text":446},"UCP je takođe namerno modularan. Google-ov tehnički pregled navodi da se može integrisati putem API-ja, A2A i MCP-a i da je kompatibilan sa AP2 za autorizaciju agentskih plaćanja.",{},{"id":449,"data":450,"type":42,"tunes":452},"h-ucp-use",{"text":451,"level":218},"Koristite UCP kada",{},{"id":454,"data":455,"type":343,"tunes":462},"ucp-list",{"meta":456,"items":457,"style":342},{},[458,459,460,461],"Tok posla uključuje proizvode trgovca, korpe, plaćanje, ispunjenje ili životni ciklus porudžbine.","Gradite interfejs trgovca koji treba da funkcioniše sa iskustvima agentske kupovine.","Integraciji je potrebna semantika specifična za trgovinu, a ne generički pozivi alata.","Želite interoperabilan trgovinski ugovor koji može koegzistirati sa MCP, A2A i protokolima plaćanja.",{},{"id":464,"data":465,"type":42,"tunes":467},"h-ap2",{"text":466,"level":219},"4. AP2: dokazivanje da je agent imao ovlašćenje da troši",{},{"id":469,"data":470,"type":226,"tunes":472},"p-ap2-1",{"text":471},"Agentska trgovina uvodi problem koji uobičajeni tokovi plaćanja nisu morali da rešavaju na isti način: agent može izvršiti transakciju u trenutku kada čovek u realnom vremenu ne klikće na završno dugme. Agent Payments Protocol (AP2) rešava pitanja autorizacije, autentičnosti i odgovornosti za plaćanja vođena agentima.",{},{"id":474,"data":475,"type":226,"tunes":477},"p-ap2-2",{"text":476},"Google-ov vodič kroz protokol za 2026. godinu opisuje AP2 putem tipiziranih mandata koji beleže nameru korisnika, ograničenja potrošnje i konkretnu transakciju koja se autorizuje. AP2 može funkcionisati kao proširenje uz UCP: UCP opisuje trgovinsku transakciju, dok AP2 pruža dokaz da je agent imao ovlašćenje da izvrši plaćanje.",{},{"id":479,"data":480,"type":226,"tunes":482},"p-ap2-3",{"text":481},"Ova razlika je važna. Protokol za plaćanje može reći trgovcu šta treba kupiti. On sam po sebi ne dokazuje ko je ovlastio agenta da troši, pod kojim limitom, za kog trgovca, na koliko dugo ili da li je konačna korpa ostala u okviru tog ovlašćenja.",{},{"id":484,"data":485,"type":42,"tunes":487},"h-ucp-ap2",{"text":486,"level":219},"UCP naspram AP2: semantika transakcija naspram ovlašćenja",{},{"id":489,"data":490,"type":304,"tunes":514},"ucp-ap2-table",{"content":491,"stretched":43,"withHeadings":14},[492,494,498,502,506,510],[493,290,295],"Pitanje",[495,496,497],"Šta se kupuje?","Trgovački artikli, korpa, semantika poručivanja i ispunjenja","Referencira kontekst autorizovane transakcije",[499,500,501],"Ko to može autorizovati?","Nije primarna odgovornost protokola","Izričiti model ovlašćenja i mandata agenta\u002Fkorisnika",[503,504,505],"Koja se ograničenja potrošnje primenjuju?","Trgovački tok može sadržati ukupne iznose i podatke o plaćanju","Zaštitne ograde autorizacije i ograničenja namere",[507,508,509],"Kako se transakcija revidira?","Životni ciklus porudžbine i trgovine","Kriptografski \u002F proverljivi trag autorizacije kroz mandate i račune",[511,512,513],"Mogu li raditi zajedno?","Da","Da — AP2 može proširiti tokove agentske trgovine",{},{"id":516,"data":517,"type":42,"tunes":519},"h-a2ui",{"text":518,"level":219},"5. A2UI: omogućite agentima da opisuju interfejse bez posedovanja vašeg frontend-a",{},{"id":521,"data":522,"type":226,"tunes":524},"p-a2ui-1",{"text":523},"Agent-to-User Interface (A2UI) rešava drugu granicu: kako udaljeni ili lokalni agent prenosi bogati interaktivni interfejs matičnoj (host) aplikaciji. Umesto slanja proizvoljnog HTML-a, CSS-a i JavaScript-a, A2UI koristi deklarativne podatke koje host renderuje kroz sopstveni pouzdani katalog komponenti.",{},{"id":526,"data":527,"type":226,"tunes":529},"p-a2ui-2",{"text":528},"Ovo čuva sistem dizajna i bezbednosni model matične aplikacije, a pritom omogućava agentu da zahteva dinamičke interfejse. A2UI v0.9 posebno naglašava nameru korisničkog interfejsa nezavisnu od radnog okvira i strimovana ažuriranja na veb, mobilnim i drugim klijentima.",{},{"id":531,"data":532,"type":226,"tunes":534},"p-a2ui-3",{"text":533},"Google-ov kasniji rad na A2UI + MCP Apps takođe pokazuje da ovi UI modeli nisu nužno međusobno isključivi. Deklarativni izvorni UI i bogatija ugrađena iskustva aplikacije mogu koegzistirati u zavisnosti od zadatka.",{},{"id":536,"data":537,"type":42,"tunes":539},"h-a2ui-use",{"text":538,"level":218},"Koristite A2UI kada",{},{"id":541,"data":542,"type":343,"tunes":549},"a2ui-list",{"meta":543,"items":544,"style":342},{},[545,546,547,548],"Udaljeni agent treba da zatraži formulare, kartice, kontrole ili drugi interaktivni UI.","Matična aplikacija treba da sačuva svoje izvorne komponente, stilizovanje i bezbednosne granice.","Ne želite da udaljeni agenti šalju proizvoljan izvršni frontend kod.","Ista namera UI-ja definisana od strane agenta treba da funkcioniše na različitim klijentskim okvirima.",{},{"id":551,"data":552,"type":42,"tunes":554},"h-selection",{"text":553,"level":219},"Test za izbor protokola",{},{"id":556,"data":557,"type":226,"tunes":559},"p-selection-intro",{"text":558},"Nemojte počinjati od akronima. Počnite od odnosa kome je potrebna interoperabilnost.",{},{"id":561,"data":562,"type":587,"tunes":588},"selection-flow",{"steps":563,"title":585,"orientation":586},[564,567,570,573,576,579,582],{"label":565,"description":566},"1. Identifikujte dve nezavisne strane","Da li je u pitanju AI-prema-alatu, agent-prema-agentu, agent-prema-trgovcu, agent-prema-platnom-autoritetu ili agent-prema-korisničkom-interfejsu?",{"label":568,"description":569},"2. Identifikujte deljeni objekat","Da li se ugovor odnosi na poziv alata, zadatak, korpu, platni mandat, artefakt ili opis UI-ja?",{"label":571,"description":572},"3. Proverite da li već postoji protokol specifičan za domen","Dajte prednost semantici trgovine ili plaćanja kada je problem trgovina ili autorizacija, umesto da sve kodirate kao generičke alate.",{"label":574,"description":575},"4. Zadržite lokalne interne detalje lokalnim","Nemojte izlagati celog agenta kao MCP alate ako je udaljenoj strani potrebna samo A2A mogućnost i nemojte činiti udaljenog agenta odgovornim za vaš UI runtime.",{"label":577,"description":578},"5. Kombinujte protokole kada radni tok prelazi granice","Jedan radni tok može legitimno prelaziti ugovore alata, agenata, trgovine, plaćanja i UI-ja.",{"label":580,"description":581},"6. Verzionišite svaki ugovor nezavisno","Verzije protokola se razvijaju različitom brzinom; nemojte vezivati svaku integraciju za jednu monolitnu verziju aplikacije.",{"label":583,"description":584},"7. Očuvajte autorizaciju na svakoj granici","Interoperabilnost ne zamenjuje dozvole proizvoda, autorizaciju alata, platna ovlašćenja ili politiku pristupa podacima.","Izaberite protokol prema granici","auto","processFlow",{},{"id":590,"data":591,"type":42,"tunes":593},"h-workflow",{"text":592,"level":219},"Realan radni tok sa više protokola",{},{"id":595,"data":596,"type":587,"tunes":617},"workflow-flow",{"steps":597,"title":616,"orientation":586},[598,601,604,607,610,613],{"label":599,"description":600},"1. Pregledajte interne zalihe pomoću MCP-a","Agent nabavke poziva mogućnosti inventara i predviđanja koje izlažu interni MCP serveri.",{"label":602,"description":603},"2. Pronađite agenta dobavljača pomoću A2A","Agent čita karticu agenta dobavljača (Agent Card) i delegira zadatak provere dostupnosti i vremena isporuke.",{"label":605,"description":606},"3. Pregovarajte o trgovačkom objektu pomoću UCP-a","Površina dobavljača ili trgovca vraća strukturirane informacije o korpi, plaćanju i ispunjenju.",{"label":608,"description":609},"4. Proverite ovlašćenje za potrošnju pomoću AP2","Kupovina se upoređuje sa potpisanim mandatom korisnika ili organizacije, ograničenjima trgovca i limitima potrošnje.",{"label":611,"description":612},"5. Zatražite odobrenje putem A2UI","Ako je potrebno ljudsko odobrenje, agent šalje deklarativnu UI nameru, a host renderuje iskustvo odobravanja koristeći pouzdane izvorne komponente.",{"label":614,"description":615},"6. Završite i revidirajte","Stanje trgovine, autorizacija plaćanja, dokazi o zadatku agenta i evidencija revizije aplikacije ostaju sledljivi preko svojih odgovarajućih granica.","Primer: autonomni radni tok nabavke",{},{"id":619,"data":620,"type":42,"tunes":622},"h-universal",{"text":621,"level":219},"Zašto je malo verovatno da će jedan univerzalni agentski protokol zameniti sve njih",{},{"id":624,"data":625,"type":226,"tunes":627},"p-universal-1",{"text":626},"Univerzalni protokol zvuči jednostavnije sve dok ne mora da kodira semantiku svakog domena. Otkrivanje alata, dugotrajna saradnja agenata, plaćanje, autorizacija plaćanja i izvorni UI imaju različite zahteve u pogledu životnog ciklusa, bezbednosti i ispravnosti.",{},{"id":629,"data":630,"type":226,"tunes":632},"p-universal-2",{"text":631},"Sam veb se razvijao kroz slojevite protokole, a ne kroz jedan format poruka za svaki problem. Nastajući agentski stek se očigledno kreće u istom smeru: zajednički horizontalni primitivi, specijalizovani ugovori domena i eksplicitno otkrivanje\u002Fverzionisanje.",{},{"id":634,"data":635,"type":226,"tunes":637},"p-universal-3",{"text":636},"Arhitektonski izazov se stoga pomera sa pitanja „koji protokol pobeđuje?“ na to koliko se čisto protokoli mogu kombinovati bez dupliranja semantike identiteta, autorizacije, stanja i revizije.",{},{"id":639,"data":640,"type":42,"tunes":642},"h-failures",{"text":641,"level":219},"Kombinovanje protokola stvara nove načine otkaza",{},{"id":644,"data":645,"type":304,"tunes":675},"failure-table",{"content":646,"stretched":43,"withHeadings":14},[647,651,655,659,663,667,671],[648,649,650],"Režim otkaza","Šta se dešava","Arhitektonska kontrola",[652,653,654],"Curenje ovlašćenja","Validna mogućnost alata ili agenta tretira se kao dozvola za izvršavanje poslovne akcije","Održavajte autorizaciju proizvoda nezavisnom od otkrivanja mogućnosti protokola",[656,657,658],"Neusklađenost identiteta","Identitet MCP domaćina, identitet A2A agenta i trgovinski\u002Fplatni identitet odnose se na različite principale","Definišite eksplicitno mapiranje principala preko granica sistema",[660,661,662],"Raskorak verzija","Jedan protokol se nadograđuje dok zavisni adapteri pretpostavljaju stariju semantiku","Nezavisno pregovarajte i fiksirajte verzije protokola",[664,665,666],"Dupliranje stanja","Isto stanje korpe, zadatka ili odobrenja kopira se u nekoliko slojeva protokola","Definišite jednog autoritativnog vlasnika po domenskom objektu",[668,669,670],"Fragmentacija revizije","Tragovi alata, zadaci agenata, dokazi o porudžbini i plaćanju ne mogu se povezati","Prenosite korelacione ID-jeve i stabilne domenske identifikatore preko granica protokola",[672,673,674],"Semantičko tunelovanje","Sve se forsira kroz generički protokol kao neprozirni JSON","Koristite domenske protokole tamo gde njihova semantika suštinski poboljšava ispravnost",{},{"id":677,"data":678,"type":42,"tunes":680},"h-app-arch",{"text":679,"level":219},"Izbor protokola ne zamenjuje arhitekturu aplikacije",{},{"id":682,"data":683,"type":226,"tunes":685},"p-app-1",{"text":684},"Otvoreni standardi smanjuju integraciono sprezanje, ali ne odlučuju o vašem domenskom modelu, politici autorizacije, izvoru istine, strategiji ponovnih pokušaja ili kriterijumima prihvatanja. MCP alat i dalje može izložiti pogrešnu mogućnost. A2A agent i dalje može vratiti loš artefakt. UCP proces plaćanja i dalje može sadržati zastarele podatke trgovca. AP2 mandat i dalje može biti pogrešno primenjen aplikativnom logikom.",{},{"id":687,"data":688,"type":226,"tunes":690},"p-app-2",{"text":689},"Tretirajte protokole kao ugovore između komponenti koje se nezavisno razvijaju. Zadržite domensku istinu i ključne politike u aplikativnom sloju koji ih poseduje, a zatim koristite protokole kako biste granice učinili interoperabilnim.",{},{"id":692,"data":693,"type":698,"tunes":699},"ref-harness",{"url":694,"title":695,"excerpt":696,"ctaLabel":697},"https:\u002F\u002Fstajic.de\u002Fsr\u002Fblog\u002Fmanaged-agent-harness-vs-self-hosted-agent-loop-what-you-gain-what-you-lose","Upravljano agentsko okruženje naspram samostalno hostovane agentske petlje: šta dobijate, a šta gubite","Granice protokola rešavaju interoperabilnost. Granice izvršavanja rešavaju pitanje ko upravlja radnim okruženjem, izvršnim okruženjem i kontrolnom ravni aplikacije.","Pročitajte vodič kroz arhitekturu izvršnog okruženja","referralArticle",{},{"id":701,"data":702,"type":42,"tunes":704},"h-change",{"text":703,"level":219},"Šta bi promenilo ovaj odgovor?",{},{"id":706,"data":707,"type":226,"tunes":709},"p-change-1",{"text":708},"Tehnološki stek se menja ako dođe do konvergencije protokola, ako jedan standard formalno apsorbuje drugi, ili ako dobavljači standardizuju zajednički sloj identiteta i autorizacije preko više granica. UCP već demonstrira kompoziciju podržavajući API-je, A2A i MCP i integrišući se sa AP2 umesto da ih zamenjuje.",{},{"id":711,"data":712,"type":226,"tunes":714},"p-change-2",{"text":713},"Odgovor se takođe menja u zavisnosti od obima aplikacije. Malom internom agentu može biti potreban samo MCP. Radni tok između više kompanija može zahtevati A2A. Trgovcu može biti potreban UCP bez A2UI. Delegirani agent za kupovinu može zahtevati sve njih. Koristite najmanji skup protokola koji predstavlja stvarne granice bez urušavanja domenske semantike.",{},{"id":716,"data":717,"type":42,"tunes":719},"h-limitations",{"text":718,"level":219},"Ograničenja",{},{"id":721,"data":722,"type":226,"tunes":724},"p-limit-1",{"text":723},"Protokoli o kojima se ovde govori nalaze se na različitim nivoima zrelosti i imaju različite modele upravljanja. A2A je dostigao stabilnu specifikaciju v1.0, dok drugi standardi nastavljaju ubrzano da se razvijaju. Usvajanje u ekosistemu je takođe neujednačeno među dobavljačima i radnim okvirima.",{},{"id":726,"data":727,"type":226,"tunes":729},"p-limit-2",{"text":728},"Ovaj članak se fokusira na arhitektonsku odgovornost, a ne na potpunost implementacije. Konkretne metode autentifikacije, transportna vezivanja, šeme i mehanizmi proširenja moraju se preuzeti iz trenutne specifikacije svakog protokola.",{},{"id":731,"data":732,"type":42,"tunes":734},"h-conclusion",{"text":733,"level":219},"Zaključak",{},{"id":736,"data":737,"type":226,"tunes":739},"p-conclusion-1",{"text":738},"MCP, A2A, UCP, AP2 i A2UI imaju više smisla kada se posmatraju kao protokoli za različite odnose, a ne pet konkurentskih pokušaja da se standardizuju „agenti“.",{},{"id":741,"data":742,"type":226,"tunes":744},"p-conclusion-2",{"text":743},"MCP izlaže mogućnosti. A2A koordiniše nezavisne agente. UCP pruža trgovini sopstveni mašinski čitljiv ugovor. AP2 dodaje proverljivo ovlašćenje za plaćanje. A2UI daje agentima bezbedan deklarativni put ka korisničkim interfejsima. Nastajući agentski veb stoga ne zamenjuje protokole veštačkom inteligencijom; on stvara novi stek protokola oko veštačke inteligencije.",{},{"id":746,"data":747,"type":42,"tunes":749},"h-faq",{"text":748,"level":219},"Česta pitanja",{},{"id":751,"data":752,"type":751,"tunes":779},"faq",{"items":753,"title":778},[754,758,762,766,770,774],{"id":755,"answer":756,"question":757},"faq1","Ne. MCP prvenstveno standardizuje način na koji AI aplikacije pristupaju alatima, resursima i podacima. A2A standardizuje saradnju između nezavisnih agentskih sistema. Udaljeni agent može interno koristiti MCP dok spolja izlaže A2A interfejs.","Da li je A2A zamena za MCP?",{"id":759,"answer":760,"question":761},"faq2","Uglavnom ne. UCP pruža semantiku specifičnu za trgovinu, kao što su korpa, plaćanje i isporuka. MCP i dalje može izlagati alate ili podatke trgovca, a UCP je dizajniran da koegzistira sa MCP-om i A2A.","Da li je UCP zamena za MCP kod agenata za kupovinu?",{"id":763,"answer":764,"question":765},"faq3","UCP standardizuje interakcije u trgovini i životni ciklus transakcija. AP2 se fokusira na dokazivanje da je agent imao ovlašćenje da izvrši plaćanje pod definisanim korisničkim ili organizacionim ograničenjima.","Koja je razlika između UCP i AP2?",{"id":767,"answer":768,"question":769},"faq4","A2UI omogućava agentima da pošalju deklarativnu UI nameru aplikaciji domaćinu, koja renderuje iskustvo kroz pouzdane izvorne komponente umesto izvršavanja proizvoljnog udaljenog frontend koda.","Koji problem rešava A2UI?",{"id":771,"answer":772,"question":773},"faq5","Da. Radni tok može koristiti MCP za interne alate, A2A za delegiranje udaljenim agentima, UCP za trgovinu, AP2 za autorizaciju plaćanja i A2UI za interakciju sa ljudima.","Može li jedna agentska aplikacija koristiti sve ove protokole?",{"id":775,"answer":776,"question":777},"faq6","Počnite od granice interoperabilnosti. Ako je problem pristup alatima, razmotrite MCP. Ako je u pitanju saradnja nezavisnih agenata, razmotrite A2A. Ako je reč o trgovini, UCP. Ako je u pitanju delegirano ovlašćenje za plaćanje, AP2. Ako je u pitanju prenosivi UI vođen agentima, A2UI.","Koji protokol bi trebalo prvo da implementiram?","MCP, A2A, UCP, AP2 i A2UI",{},{"id":781,"data":782,"type":42,"tunes":784},"h-glossary",{"text":783,"level":219},"Rečnik pojmova",{},{"id":786,"data":787,"type":786,"tunes":807},"glossary",{"title":788,"entries":789},"Ključni pojmovi agentskih protokola",[790,792,794,797,800,803],{"term":280,"anchor":418,"definition":791},"Model Context Protocol, otvoreni standard za izlaganje alata, resursa i upita iz eksternih sistema kompatibilnim AI domaćinima.",{"term":285,"anchor":420,"definition":793},"Agent2Agent Protocol, otvoreni standard za otkrivanje i saradnju sa nezavisnim agentskim sistemima putem poruka, zadataka i artefakata.",{"term":290,"anchor":795,"definition":796},"ucp","Universal Commerce Protocol, otvoreni standard za interoperabilna agentska trgovinska putovanja između korisničkih interfejsa, preduzeća i pružalaca platnih usluga.",{"term":295,"anchor":798,"definition":799},"ap2","Agent Payments Protocol, otvoreni standard za predstavljanje i verifikaciju ovlašćenja, namere i odgovornosti u plaćanjima koja vode agenti.",{"term":300,"anchor":801,"definition":802},"a2ui","Agent-to-User Interface, deklarativni protokol koji omogućava agentima da zatraže korisnički interfejs koji se renderuje pomoću pouzdanih komponenti aplikacije domaćina.",{"term":804,"anchor":805,"definition":806},"Kompozicija protokola","protocol-composition","Korišćenje više protokola u jednom radnom toku, gde je svaki odgovoran za posebnu granicu interoperabilnosti umesto forsiranja celokupne semantike kroz jedan ugovor.",{},{"id":809,"data":810,"type":42,"tunes":812},"h-sources",{"text":811,"level":219},"Primarni izvori i dodatna literatura",{},{"id":814,"data":815,"type":821,"tunes":822},"src-google-guide",{"link":816,"meta":817},"https:\u002F\u002Fdevelopers.googleblog.com\u002Fdevelopers-guide-to-ai-agent-protocols\u002F",{"image":818,"title":819,"description":820},{"url":399},"Google Developers — Vodič za programere kroz protokole AI agenata","Praktičan pregled koji prikazuje kako MCP, A2A, UCP, AP2, A2UI i srodni protokoli funkcionišu zajedno u jednom višefaznom toku rada agenata.","linkTool",{},{"id":824,"data":825,"type":821,"tunes":831},"src-mcp",{"link":826,"meta":827},"https:\u002F\u002Fts.sdk.modelcontextprotocol.io\u002Fv2\u002F",{"image":828,"title":829,"description":830},{"url":399},"Model Context Protocol — TypeScript SDK v2","Trenutna stabilna SDK dokumentacija koja implementira MCP specifikaciju od 28.07.2026. i definiše alate, resurse, upite (prompts) i integraciju hosta\u002Fservera.",{},{"id":833,"data":834,"type":821,"tunes":840},"src-a2a-spec",{"link":835,"meta":836},"https:\u002F\u002Fa2a-protocol.org\u002Fdev\u002Fspecification\u002F",{"image":837,"title":838,"description":839},{"url":399},"A2A Protocol — v1.0 specifikacija","Aktuelna specifikacija A2A protokola koja pokriva Agent Cards, poruke, zadatke, artefakte, vezivanja i pregovaranje o verziji.",{},{"id":842,"data":843,"type":821,"tunes":849},"src-a2a-aaif",{"link":844,"meta":845},"https:\u002F\u002Fa2a-protocol.org\u002Flatest\u002Fblog\u002F2026\u002F08\u002F27\u002Fa-new-chapter-for-a2a-joining-the-agentic-ai-foundation\u002F",{"image":846,"title":847,"description":848},{"url":399},"A2A — Pridruživanje Agentic AI Foundation","Aktuelni okvir projekta A2A kao horizontalnog sloja za saradnju agenata uz MCP kao vertikalnu integraciju alata\u002Fpodataka.",{},{"id":851,"data":852,"type":821,"tunes":858},"src-ucp",{"link":853,"meta":854},"https:\u002F\u002Fdevelopers.googleblog.com\u002Funder-the-hood-universal-commerce-protocol-ucp\u002F",{"image":855,"title":856,"description":857},{"url":399},"Google Developers — Ispod haube: Universal Commerce Protocol","Tehnički pregled UCP-a, njegovih trgovinskih primitiva i mogućnosti sklapanja sa API-jima, A2A, MCP i AP2.",{},{"id":860,"data":861,"type":821,"tunes":867},"src-ucp-profile",{"link":862,"meta":863},"https:\u002F\u002Fdevelopers.google.com\u002Fmerchant\u002Fucp\u002Fimplementation\u002F2026-04-08\u002Fpublish-profile",{"image":864,"title":865,"description":866},{"url":399},"Google Universal Commerce Protocol — UCP profil","Aktuelni mehanizam verzionisanih profila za objavljivanje UCP usluga i trgovinskih mogućnosti prodavaca.",{},{"id":869,"data":870,"type":821,"tunes":876},"src-ap2",{"link":871,"meta":872},"https:\u002F\u002Fcloud.google.com\u002Fblog\u002Fproducts\u002Fai-machine-learning\u002Fannouncing-agents-to-payments-ap2-protocol",{"image":873,"title":874,"description":875},{"url":399},"Google Cloud — Agent Payments Protocol (AP2)","Najava i obrazloženje otvorenog protokola koji pokriva autorizaciju, autentičnost i odgovornost u plaćanjima vođenim agentima.",{},{"id":878,"data":879,"type":821,"tunes":885},"src-a2ui",{"link":880,"meta":881},"https:\u002F\u002Fdevelopers.googleblog.com\u002Fa2ui-v0-9-generative-ui\u002F",{"image":882,"title":883,"description":884},{"url":399},"Google Developers — A2UI v0.9","Deklarativni model A2UI nezavisan od radnog okvira za prenosive interfejse vođene agentima koje renderuju izvorne komponente hosta.",{},{"id":887,"data":888,"type":821,"tunes":894},"src-a2ui-mcp",{"link":889,"meta":890},"https:\u002F\u002Fdevelopers.googleblog.com\u002Fa2ui-and-mcp-apps\u002F",{"image":891,"title":892,"description":893},{"url":399},"Google Developers — A2UI + MCP aplikacije","Kako deklarativni A2UI i bogatija iskustva MCP aplikacija mogu koegzistirati umesto da se posmatraju kao međusobno isključivi modeli korisničkog interfejsa.",{},"2.31","MCP, A2A, UCP, AP2 i A2UI se često predstavljaju kao konkurentski standardi za agente. Oni uglavnom rešavaju različite probleme interoperabilnosti. Ovaj vodič mapira svaki protokol na granicu koju zapravo standardizuje—i pokazuje kako oni mogu da rade zajedno u jednom produkcionom sistemu.","\u002Fuploads\u002F2026\u002F09\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained-1790352625869-2ezle0.webp","mcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained-1790352625869-2ezle0","PUBLISHED","2026-09-25T12:09:00.000Z","2026-09-25T16:09:26.909Z","2026-09-25T19:27:42.182Z",{"en":904,"de":905,"sr":906,"es":907,"fr":908,"it":909,"ru":910,"zh":911},"\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Fde\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Fsr\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Fes\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Ffr\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Fit\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Fru\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained","\u002Fzh\u002Fblog\u002Fmcp-vs-a2a-vs-ucp-vs-ap2-vs-a2ui-the-agent-protocol-stack-explained",[913,917,921],{"id":914,"name":915,"slug":916},57,"Granice podataka","data-boundaries",{"id":918,"name":919,"slug":920},84,"Politike i granice podataka","policy-and-data",{"id":922,"name":923,"slug":924},46,"Pregled","overview",{"id":926,"login":927,"email":928,"displayName":929},"20","rooth8233","aleksandar@stajic.de","Aleksandar Stajić",[931,1487],{"lang":932,"title":933,"content":934,"contentJson":935,"excerpt":1486},"en","MCP vs A2A vs UCP vs AP2 vs A2UI: The Agent Protocol Stack Explained","{\"time\":1790352626854,\"blocks\":[{\"id\":\"_z4yTl5Fh-\",\"type\":\"tableOfContents\",\"data\":{\"title\":\"Contents\",\"minLevel\":2,\"maxLevel\":3},\"tunes\":{}},{\"id\":\"intro\",\"type\":\"paragraph\",\"data\":{\"text\":\"AI agent protocols are multiplying quickly: MCP, A2A, UCP, AP2, A2UI and adjacent standards increasingly appear in the same architecture diagrams. They are often described as competing protocols. In practice, most of them solve different interoperability problems at different boundaries. The useful question is not “Which protocol wins?” but “Which relationship in the system needs to be standardized?”\"},\"tunes\":{}},{\"id\":\"direct\",\"type\":\"callout\",\"data\":{\"variant\":\"info\",\"title\":\"Direct answer\",\"body\":\"\u003Cstrong>MCP, A2A, UCP, AP2 and A2UI are mostly complementary, not substitutes.\u003C\u002Fstrong> MCP connects an AI application to tools, data and resources. A2A connects independent agents to one another. UCP standardizes commerce interactions between consumer surfaces, businesses and payment ecosystems. AP2 adds verifiable authorization and payment intent to agent-led transactions. A2UI lets an agent describe interactive UI without sending arbitrary application code. A production system may legitimately use several of them in one workflow.\"},\"tunes\":{}},{\"id\":\"freshness\",\"type\":\"callout\",\"data\":{\"variant\":\"warning\",\"title\":\"Fast-moving standards\",\"body\":\"This article reflects the protocol landscape on \u003Cstrong>25 September 2026\u003C\u002Fstrong>. A2A has reached v1.0, MCP's current TypeScript v2 line implements the 2026-07-28 specification, UCP has already added newer 2026 protocol versions, and A2UI continues to evolve. Always verify the current specification before implementation.\"},\"tunes\":{}},{\"id\":\"model-note\",\"type\":\"callout\",\"data\":{\"variant\":\"note\",\"title\":\"The model used in this article\",\"body\":\"The Protocol Responsibility Stack and Protocol Selection Test below are practical architecture models proposed here. They are not official terminology from the protocol projects.\"},\"tunes\":{}},{\"id\":\"h-core\",\"type\":\"header\",\"data\":{\"text\":\"The core mistake: comparing protocols that sit at different boundaries\",\"level\":2},\"tunes\":{}},{\"id\":\"p-core-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"A protocol is useful because two independently implemented systems need a stable contract. The contract only makes sense if the boundary is clear. An agent talking to a database has a different interoperability problem from one agent delegating work to another, a shopper authorizing a purchase, or a remote agent asking a native application to render a form.\"},\"tunes\":{}},{\"id\":\"p-core-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"Google's 2026 developer guide explicitly presents MCP, A2A, UCP, AP2, A2UI and related UI protocols as a stack of complementary standards. The same example workflow can use several of them together: tools for inventory, remote agents for suppliers, commerce for ordering, payment authorization for spending and UI protocols for interaction.\"},\"tunes\":{}},{\"id\":\"h-stack\",\"type\":\"header\",\"data\":{\"text\":\"The Protocol Responsibility Stack\",\"level\":2},\"tunes\":{}},{\"id\":\"stack-table\",\"type\":\"table\",\"data\":{\"withHeadings\":true,\"stretched\":false,\"content\":[[\"Protocol\",\"Standardizes which relationship?\",\"Primary abstraction\",\"Not primarily for\"],[\"MCP\",\"AI application ↔ tools, resources and data\",\"Tools, resources, prompts and host\u002Fserver capability exchange\",\"Independent agent collaboration or commerce semantics\"],[\"A2A\",\"Agent ↔ independent agent\",\"Agent discovery, messages, tasks, artifacts and long-running collaboration\",\"Direct database\u002Ftool integration\"],[\"UCP\",\"Consumer\u002Fagent surface ↔ merchant commerce system\",\"Product\u002Fcart\u002Fcheckout\u002Ffulfillment\u002Forder capabilities\",\"General-purpose agent communication\"],[\"AP2\",\"User\u002Fagent intent ↔ payment authorization\",\"Mandates, approval constraints and auditable agent-led payment authority\",\"Product discovery or generic checkout transport\"],[\"A2UI\",\"Agent ↔ user interface host\",\"Declarative UI intent rendered by trusted native components\",\"Arbitrary remote frontend code or agent-to-agent task delegation\"]]},\"tunes\":{}},{\"id\":\"all-five\",\"type\":\"callout\",\"data\":{\"variant\":\"success\",\"title\":\"One workflow can use all five\",\"body\":\"An agent may use \u003Cstrong>MCP\u003C\u002Fstrong> to inspect inventory, \u003Cstrong>A2A\u003C\u002Fstrong> to ask a supplier agent for availability, \u003Cstrong>UCP\u003C\u002Fstrong> to build a commerce transaction, \u003Cstrong>AP2\u003C\u002Fstrong> to prove spending authority, and \u003Cstrong>A2UI\u003C\u002Fstrong> to render a native approval interface to the user.\"},\"tunes\":{}},{\"id\":\"h-mcp\",\"type\":\"header\",\"data\":{\"text\":\"1. MCP: connect the agent to capabilities\",\"level\":2},\"tunes\":{}},{\"id\":\"p-mcp-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"The Model Context Protocol is an open standard for connecting AI applications to external systems where tools, data and reusable resources live. A server exposes capabilities; an MCP host connects to that server and makes those capabilities available to the model or application.\"},\"tunes\":{}},{\"id\":\"p-mcp-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"The current MCP TypeScript v2 documentation describes the protocol in exactly those terms: servers expose tools, resources and prompts, while hosts such as development environments or custom applications connect to them. This makes MCP primarily a capability integration protocol.\"},\"tunes\":{}},{\"id\":\"h-mcp-use\",\"type\":\"header\",\"data\":{\"text\":\"Use MCP when\",\"level\":3},\"tunes\":{}},{\"id\":\"mcp-list\",\"type\":\"list\",\"data\":{\"style\":\"unordered\",\"meta\":{},\"items\":[\"An AI application needs standardized access to tools or APIs.\",\"You want one capability server to work with multiple compatible AI hosts.\",\"You need structured access to data or resources without hard-coding every integration into each agent.\",\"The external system is a capability provider, not an autonomous peer agent.\"]},\"tunes\":{}},{\"id\":\"mcp-warning\",\"type\":\"callout\",\"data\":{\"variant\":\"warning\",\"title\":\"MCP is not automatically A2A\",\"body\":\"An MCP server can expose powerful functions, but that does not make it an independent agent with its own task lifecycle, discovery semantics and opaque internal reasoning. Tool invocation and agent collaboration are different contracts.\"},\"tunes\":{}},{\"id\":\"h-a2a\",\"type\":\"header\",\"data\":{\"text\":\"2. A2A: connect independent agents\",\"level\":2},\"tunes\":{}},{\"id\":\"p-a2a-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"Agent2Agent (A2A) is designed for communication between independent, potentially opaque agent systems. Its current v1.0 specification focuses on capability discovery, messaging, tasks, artifacts, multimodal content and long-running collaboration without requiring one agent to expose its internal tools, memory or implementation to another.\"},\"tunes\":{}},{\"id\":\"p-a2a-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"That opacity is the important boundary. The calling agent does not need to know whether the remote agent uses MCP, custom tools, a proprietary planner, another model vendor, or human escalation internally. It needs a contract for discovering capabilities and delegating work.\"},\"tunes\":{}},{\"id\":\"p-a2a-3\",\"type\":\"paragraph\",\"data\":{\"text\":\"A2A v1.0 also standardizes version negotiation and supports multiple bindings around a common data model. Its published Agent Card mechanism gives clients a standard discovery point for an agent's capabilities, supported protocols, authentication requirements and skills.\"},\"tunes\":{}},{\"id\":\"h-a2a-use\",\"type\":\"header\",\"data\":{\"text\":\"Use A2A when\",\"level\":3},\"tunes\":{}},{\"id\":\"a2a-list\",\"type\":\"list\",\"data\":{\"style\":\"unordered\",\"meta\":{},\"items\":[\"One autonomous agent needs to delegate work to another autonomous agent.\",\"The remote system should remain opaque behind a capability contract.\",\"Tasks may be long-running, asynchronous or require human-in-the-loop interaction.\",\"Agents are built with different frameworks, languages, vendors or organizational ownership.\"]},\"tunes\":{}},{\"id\":\"h-mcp-a2a\",\"type\":\"header\",\"data\":{\"text\":\"MCP vs A2A: vertical integration vs horizontal collaboration\",\"level\":2},\"tunes\":{}},{\"id\":\"mcp-a2a-comparison\",\"type\":\"comparison\",\"data\":{\"title\":\"MCP and A2A solve different interoperability problems\",\"layout\":\"table\",\"columns\":[{\"id\":\"dimension\",\"label\":\"Dimension\"},{\"id\":\"mcp\",\"label\":\"MCP\"},{\"id\":\"a2a\",\"label\":\"A2A\"}],\"rows\":[{\"id\":\"relationship\",\"label\":\"Relationship\",\"values\":[\"\",\"\",\"\"]},{\"id\":\"abstraction\",\"label\":\"Abstraction\",\"values\":[\"\",\"\",\"\"]},{\"id\":\"opacity\",\"label\":\"Internal opacity\",\"values\":[\"\",\"\",\"\"]},{\"id\":\"long\",\"label\":\"Long-running work\",\"values\":[\"\",\"\",\"\"]}]},\"tunes\":{}},{\"id\":\"p-mcp-a2a-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"The A2A project itself now describes the distinction as horizontal versus vertical: MCP connects agents to internal tools and databases, while A2A enables peer-to-peer collaboration across agent systems.\"},\"tunes\":{}},{\"id\":\"h-ucp\",\"type\":\"header\",\"data\":{\"text\":\"3. UCP: standardize agentic commerce\",\"level\":2},\"tunes\":{}},{\"id\":\"p-ucp-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"The Universal Commerce Protocol is not a generic agent protocol. It standardizes commerce journeys between consumer surfaces, merchants and payment providers. Google's implementation already supports capabilities such as cart creation, checkout, fulfillment and order lifecycle through versioned profiles and APIs.\"},\"tunes\":{}},{\"id\":\"p-ucp-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"A merchant can publish a UCP profile under \u002F.well-known\u002Fucp describing services, protocol versions and capabilities. That discovery pattern matters because an agentic surface should not need a bespoke checkout contract for every merchant.\"},\"tunes\":{}},{\"id\":\"p-ucp-3\",\"type\":\"paragraph\",\"data\":{\"text\":\"UCP is also intentionally composable. Google's technical overview says it can integrate through APIs, A2A and MCP and is compatible with AP2 for agentic payment authorization.\"},\"tunes\":{}},{\"id\":\"h-ucp-use\",\"type\":\"header\",\"data\":{\"text\":\"Use UCP when\",\"level\":3},\"tunes\":{}},{\"id\":\"ucp-list\",\"type\":\"list\",\"data\":{\"style\":\"unordered\",\"meta\":{},\"items\":[\"The workflow involves merchant products, carts, checkout, fulfillment or order lifecycle.\",\"You are building a merchant surface that should work with agentic shopping experiences.\",\"The integration needs commerce-specific semantics rather than generic tool calls.\",\"You want an interoperable commerce contract that can coexist with MCP, A2A and payment protocols.\"]},\"tunes\":{}},{\"id\":\"h-ap2\",\"type\":\"header\",\"data\":{\"text\":\"4. AP2: prove that the agent was allowed to spend\",\"level\":2},\"tunes\":{}},{\"id\":\"p-ap2-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"Agentic commerce introduces a problem that ordinary checkout flows did not have to solve in the same way: an agent may transact when the human is not clicking the final button in real time. The Agent Payments Protocol (AP2) addresses authorization, authenticity and accountability for agent-led payments.\"},\"tunes\":{}},{\"id\":\"p-ap2-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"Google's 2026 protocol guide describes AP2 through typed mandates that capture user intent, spending constraints and the specific transaction being authorized. AP2 can work as an extension alongside UCP: UCP describes the commerce transaction, while AP2 provides evidence that the agent had authority to perform the payment.\"},\"tunes\":{}},{\"id\":\"p-ap2-3\",\"type\":\"paragraph\",\"data\":{\"text\":\"This distinction is important. A checkout protocol can tell a merchant what should be purchased. It does not by itself prove who authorized the agent to spend, under what limit, for which merchant, for how long, or whether the final cart remained inside that authority.\"},\"tunes\":{}},{\"id\":\"h-ucp-ap2\",\"type\":\"header\",\"data\":{\"text\":\"UCP vs AP2: transaction semantics vs authority\",\"level\":2},\"tunes\":{}},{\"id\":\"ucp-ap2-table\",\"type\":\"table\",\"data\":{\"withHeadings\":true,\"stretched\":false,\"content\":[[\"Question\",\"UCP\",\"AP2\"],[\"What is being bought?\",\"Commerce items, cart, checkout and fulfillment semantics\",\"References the authorized transaction context\"],[\"Who may authorize it?\",\"Not the primary protocol responsibility\",\"Explicit agent\u002Fuser authority and mandate model\"],[\"What spending constraints apply?\",\"Commerce flow can contain totals and checkout data\",\"Authorization guardrails and intent limits\"],[\"How is the transaction audited?\",\"Order and commerce lifecycle\",\"Cryptographic \u002F verifiable authorization trail through mandates and receipts\"],[\"Can they work together?\",\"Yes\",\"Yes — AP2 can extend agentic commerce flows\"]]},\"tunes\":{}},{\"id\":\"h-a2ui\",\"type\":\"header\",\"data\":{\"text\":\"5. A2UI: let agents describe interfaces without owning your frontend\",\"level\":2},\"tunes\":{}},{\"id\":\"p-a2ui-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"Agent-to-User Interface (A2UI) tackles another boundary: how a remote or local agent communicates a rich interactive interface to a host application. Instead of sending arbitrary HTML, CSS and JavaScript, A2UI uses declarative data that the host renders through its own trusted component catalog.\"},\"tunes\":{}},{\"id\":\"p-a2ui-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"This preserves the host application's design system and security model while still allowing an agent to request dynamic interfaces. A2UI v0.9 specifically emphasizes framework-agnostic UI intent and streaming updates across web, mobile and other clients.\"},\"tunes\":{}},{\"id\":\"p-a2ui-3\",\"type\":\"paragraph\",\"data\":{\"text\":\"Google's later A2UI + MCP Apps work also demonstrates that these UI models are not necessarily mutually exclusive. Declarative native UI and richer embedded application experiences can coexist depending on the task.\"},\"tunes\":{}},{\"id\":\"h-a2ui-use\",\"type\":\"header\",\"data\":{\"text\":\"Use A2UI when\",\"level\":3},\"tunes\":{}},{\"id\":\"a2ui-list\",\"type\":\"list\",\"data\":{\"style\":\"unordered\",\"meta\":{},\"items\":[\"A remote agent needs to request forms, cards, controls or other interactive UI.\",\"The host should preserve its native components, styling and security boundary.\",\"You do not want remote agents shipping arbitrary executable frontend code.\",\"The same agent-defined UI intent should work across different client frameworks.\"]},\"tunes\":{}},{\"id\":\"h-selection\",\"type\":\"header\",\"data\":{\"text\":\"The Protocol Selection Test\",\"level\":2},\"tunes\":{}},{\"id\":\"p-selection-intro\",\"type\":\"paragraph\",\"data\":{\"text\":\"Do not start from the acronym. Start from the relationship that needs interoperability.\"},\"tunes\":{}},{\"id\":\"selection-flow\",\"type\":\"processFlow\",\"data\":{\"title\":\"Choose the protocol by the boundary\",\"orientation\":\"auto\",\"steps\":[{\"label\":\"1. Identify the two independent parties\",\"description\":\"Is this AI-to-tool, agent-to-agent, agent-to-merchant, agent-to-payment authority, or agent-to-user-interface?\"},{\"label\":\"2. Identify the shared object\",\"description\":\"Is the contract about a tool call, task, cart, payment mandate, artifact, or UI description?\"},{\"label\":\"3. Check whether a domain protocol already exists\",\"description\":\"Prefer commerce or payment semantics when the problem is commerce or authorization instead of encoding everything as generic tools.\"},{\"label\":\"4. Keep local internals local\",\"description\":\"Do not expose an entire agent as MCP tools if the remote party only needs an A2A capability, and do not make a remote agent responsible for your UI runtime.\"},{\"label\":\"5. Compose protocols when the workflow crosses boundaries\",\"description\":\"One workflow can legitimately cross tool, agent, commerce, payment and UI contracts.\"},{\"label\":\"6. Version each contract independently\",\"description\":\"Protocol versions evolve at different speeds; do not tie every integration to one monolithic application version.\"},{\"label\":\"7. Preserve authorization at every boundary\",\"description\":\"Interoperability does not replace product permissions, tool authorization, payment authority or data-access policy.\"}]},\"tunes\":{}},{\"id\":\"h-workflow\",\"type\":\"header\",\"data\":{\"text\":\"A realistic multi-protocol workflow\",\"level\":2},\"tunes\":{}},{\"id\":\"workflow-flow\",\"type\":\"processFlow\",\"data\":{\"title\":\"Example: an autonomous procurement workflow\",\"orientation\":\"auto\",\"steps\":[{\"label\":\"1. Inspect internal stock with MCP\",\"description\":\"The purchasing agent calls inventory and forecasting capabilities exposed by internal MCP servers.\"},{\"label\":\"2. Discover a supplier agent with A2A\",\"description\":\"The agent reads the supplier's Agent Card and delegates an availability and lead-time task.\"},{\"label\":\"3. Negotiate the commerce object with UCP\",\"description\":\"The supplier or merchant surface returns structured cart, checkout and fulfillment information.\"},{\"label\":\"4. Check spending authority with AP2\",\"description\":\"The purchase is compared with the user's or organization's signed mandate, merchant constraints and spending limits.\"},{\"label\":\"5. Ask for approval through A2UI\",\"description\":\"If human approval is required, the agent sends declarative UI intent and the host renders the approval experience using trusted native components.\"},{\"label\":\"6. Complete and audit\",\"description\":\"Commerce state, payment authorization, agent task evidence and application audit records remain traceable across their respective boundaries.\"}]},\"tunes\":{}},{\"id\":\"h-universal\",\"type\":\"header\",\"data\":{\"text\":\"Why one universal agent protocol is unlikely to replace all of them\",\"level\":2},\"tunes\":{}},{\"id\":\"p-universal-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"A universal protocol sounds simpler until it must encode every domain's semantics. Tool discovery, long-running agent collaboration, checkout, payment authorization and native UI all have different lifecycle, security and correctness requirements.\"},\"tunes\":{}},{\"id\":\"p-universal-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"The web itself evolved through layered protocols rather than one message format for every problem. The emerging agentic stack appears to be moving in the same direction: common horizontal primitives, specialized domain contracts and explicit discovery\u002Fversioning.\"},\"tunes\":{}},{\"id\":\"p-universal-3\",\"type\":\"paragraph\",\"data\":{\"text\":\"The architecture challenge therefore shifts from “which protocol wins?” to how cleanly protocols compose without duplicating identity, authorization, state and audit semantics.\"},\"tunes\":{}},{\"id\":\"h-failures\",\"type\":\"header\",\"data\":{\"text\":\"Protocol composition creates new failure modes\",\"level\":2},\"tunes\":{}},{\"id\":\"failure-table\",\"type\":\"table\",\"data\":{\"withHeadings\":true,\"stretched\":false,\"content\":[[\"Failure mode\",\"What happens\",\"Architecture control\"],[\"Authority leakage\",\"A valid tool or agent capability is treated as permission to perform a business action\",\"Keep product authorization independent from protocol capability discovery\"],[\"Identity mismatch\",\"MCP host identity, A2A agent identity and commerce\u002Fpayment identity refer to different principals\",\"Define explicit principal mapping across boundaries\"],[\"Version drift\",\"One protocol upgrades while dependent adapters assume older semantics\",\"Negotiate and pin protocol versions independently\"],[\"State duplication\",\"The same cart, task or approval state is copied into several protocol layers\",\"Define one authoritative owner per domain object\"],[\"Audit fragmentation\",\"Tool traces, agent tasks, checkout and payment evidence cannot be joined\",\"Carry correlation IDs and stable domain identifiers across protocol boundaries\"],[\"Semantic tunneling\",\"Everything is forced through a generic protocol as opaque JSON\",\"Use domain protocols where their semantics materially improve correctness\"]]},\"tunes\":{}},{\"id\":\"h-app-arch\",\"type\":\"header\",\"data\":{\"text\":\"Protocol choice does not replace application architecture\",\"level\":2},\"tunes\":{}},{\"id\":\"p-app-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"Open standards reduce integration coupling, but they do not decide your domain model, authorization policy, source of truth, retry strategy or acceptance criteria. An MCP tool can still expose the wrong capability. An A2A agent can still return a bad artifact. A UCP checkout can still contain stale merchant data. An AP2 mandate can still be misapplied by application logic.\"},\"tunes\":{}},{\"id\":\"p-app-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"Treat protocols as contracts between independently evolving components. Keep domain truth and consequential policy in the application layer that owns them, then use protocols to make the boundaries interoperable.\"},\"tunes\":{}},{\"id\":\"ref-harness\",\"type\":\"referralArticle\",\"data\":{\"url\":\"https:\u002F\u002Fstajic.de\u002Fblog\u002Fmanaged-agent-harness-vs-self-hosted-agent-loop-what-you-gain-what-you-lose\",\"title\":\"Managed Agent Harness vs Self-Hosted Agent Loop: What You Gain, What You Lose\",\"excerpt\":\"Protocol boundaries solve interoperability. Runtime boundaries solve who operates the harness, execution environment and application control plane.\",\"ctaLabel\":\"Read the runtime architecture guide\"},\"tunes\":{}},{\"id\":\"h-change\",\"type\":\"header\",\"data\":{\"text\":\"What would change this answer?\",\"level\":2},\"tunes\":{}},{\"id\":\"p-change-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"The stack changes if protocols converge, one standard formally absorbs another, or vendors standardize a shared identity and authorization layer across several boundaries. UCP already demonstrates composition by supporting APIs, A2A and MCP and by integrating with AP2 rather than replacing them.\"},\"tunes\":{}},{\"id\":\"p-change-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"The answer also changes by application scope. A small internal agent may need only MCP. A multi-company workflow may need A2A. A merchant may need UCP without A2UI. A delegated purchasing agent may need all of them. Use the smallest protocol set that represents the real boundaries without flattening domain semantics.\"},\"tunes\":{}},{\"id\":\"h-limitations\",\"type\":\"header\",\"data\":{\"text\":\"Limitations\",\"level\":2},\"tunes\":{}},{\"id\":\"p-limit-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"The protocols discussed here are at different maturity levels and have different governance models. A2A has reached a stable v1.0 specification, while other standards continue to evolve rapidly. Ecosystem adoption is also uneven across vendors and frameworks.\"},\"tunes\":{}},{\"id\":\"p-limit-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"This article focuses on architecture responsibility rather than implementation completeness. Specific authentication methods, transport bindings, schemas and extension mechanisms must be taken from each protocol's current specification.\"},\"tunes\":{}},{\"id\":\"h-conclusion\",\"type\":\"header\",\"data\":{\"text\":\"Conclusion\",\"level\":2},\"tunes\":{}},{\"id\":\"p-conclusion-1\",\"type\":\"paragraph\",\"data\":{\"text\":\"MCP, A2A, UCP, AP2 and A2UI make more sense when viewed as protocols for different relationships, not five competing attempts to standardize “agents.”\"},\"tunes\":{}},{\"id\":\"p-conclusion-2\",\"type\":\"paragraph\",\"data\":{\"text\":\"MCP exposes capabilities. A2A coordinates independent agents. UCP gives commerce its own machine-readable contract. AP2 adds verifiable payment authority. A2UI gives agents a safe declarative path into user interfaces. The emerging agentic web is therefore not replacing protocols with AI; it is creating a new protocol stack around AI.\"},\"tunes\":{}},{\"id\":\"h-faq\",\"type\":\"header\",\"data\":{\"text\":\"FAQ\",\"level\":2},\"tunes\":{}},{\"id\":\"faq\",\"type\":\"faq\",\"data\":{\"title\":\"MCP, A2A, UCP, AP2 and A2UI\",\"items\":[{\"id\":\"faq1\",\"question\":\"Is A2A a replacement for MCP?\",\"answer\":\"No. MCP primarily standardizes how AI applications access tools, resources and data. A2A standardizes collaboration between independent agent systems. A remote agent can internally use MCP while exposing an A2A interface.\"},{\"id\":\"faq2\",\"question\":\"Is UCP a replacement for MCP in shopping agents?\",\"answer\":\"Not generally. UCP provides commerce-specific semantics such as cart, checkout and fulfillment. MCP can still expose merchant tools or data, and UCP is designed to coexist with MCP and A2A.\"},{\"id\":\"faq3\",\"question\":\"What is the difference between UCP and AP2?\",\"answer\":\"UCP standardizes commerce interactions and transaction lifecycle. AP2 focuses on proving that an agent had authority to perform a payment under defined user or organizational constraints.\"},{\"id\":\"faq4\",\"question\":\"What problem does A2UI solve?\",\"answer\":\"A2UI lets agents send declarative UI intent to a host application, which renders the experience through trusted native components instead of executing arbitrary remote frontend code.\"},{\"id\":\"faq5\",\"question\":\"Can one agent application use all of these protocols?\",\"answer\":\"Yes. A workflow can use MCP for internal tools, A2A for remote-agent delegation, UCP for commerce, AP2 for payment authorization and A2UI for human interaction.\"},{\"id\":\"faq6\",\"question\":\"Which protocol should I implement first?\",\"answer\":\"Start from the interoperability boundary. If the problem is tool access, evaluate MCP. If it is independent-agent collaboration, evaluate A2A. If it is commerce, UCP. If it is delegated payment authority, AP2. If it is portable agent-driven UI, A2UI.\"}]},\"tunes\":{}},{\"id\":\"h-glossary\",\"type\":\"header\",\"data\":{\"text\":\"Glossary\",\"level\":2},\"tunes\":{}},{\"id\":\"glossary\",\"type\":\"glossary\",\"data\":{\"title\":\"Key agent-protocol terms\",\"entries\":[{\"term\":\"MCP\",\"definition\":\"Model Context Protocol, an open standard for exposing tools, resources and prompts from external systems to compatible AI hosts.\",\"anchor\":\"mcp\"},{\"term\":\"A2A\",\"definition\":\"Agent2Agent Protocol, an open standard for discovering and collaborating with independent agent systems through messages, tasks and artifacts.\",\"anchor\":\"a2a\"},{\"term\":\"UCP\",\"definition\":\"Universal Commerce Protocol, an open standard for interoperable agentic commerce journeys between consumer surfaces, businesses and payment providers.\",\"anchor\":\"ucp\"},{\"term\":\"AP2\",\"definition\":\"Agent Payments Protocol, an open standard for representing and verifying authority, intent and accountability in agent-led payments.\",\"anchor\":\"ap2\"},{\"term\":\"A2UI\",\"definition\":\"Agent-to-User Interface, a declarative protocol for allowing agents to request UI that is rendered using the host application's trusted components.\",\"anchor\":\"a2ui\"},{\"term\":\"Protocol composition\",\"definition\":\"Using multiple protocols in one workflow, each responsible for a distinct interoperability boundary rather than forcing all semantics through one contract.\",\"anchor\":\"protocol-composition\"}]},\"tunes\":{}},{\"id\":\"h-sources\",\"type\":\"header\",\"data\":{\"text\":\"Primary sources and further reading\",\"level\":2},\"tunes\":{}},{\"id\":\"src-google-guide\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fdevelopers.googleblog.com\u002Fdevelopers-guide-to-ai-agent-protocols\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Google Developers — Developer's Guide to AI Agent Protocols\",\"description\":\"A practical overview showing MCP, A2A, UCP, AP2, A2UI and related protocols working together in one multi-step agent workflow.\"}},\"tunes\":{}},{\"id\":\"src-mcp\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fts.sdk.modelcontextprotocol.io\u002Fv2\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Model Context Protocol — TypeScript SDK v2\",\"description\":\"Current stable SDK documentation implementing the 2026-07-28 MCP specification and defining tools, resources, prompts and host\u002Fserver integration.\"}},\"tunes\":{}},{\"id\":\"src-a2a-spec\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fa2a-protocol.org\u002Fdev\u002Fspecification\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"A2A Protocol — v1.0 Specification\",\"description\":\"Current A2A protocol specification covering Agent Cards, messages, tasks, artifacts, bindings and version negotiation.\"}},\"tunes\":{}},{\"id\":\"src-a2a-aaif\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fa2a-protocol.org\u002Flatest\u002Fblog\u002F2026\u002F08\u002F27\u002Fa-new-chapter-for-a2a-joining-the-agentic-ai-foundation\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"A2A — Joining the Agentic AI Foundation\",\"description\":\"Current project framing of A2A as the horizontal agent-collaboration layer alongside MCP as vertical tool\u002Fdata integration.\"}},\"tunes\":{}},{\"id\":\"src-ucp\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fdevelopers.googleblog.com\u002Funder-the-hood-universal-commerce-protocol-ucp\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Google Developers — Under the Hood: Universal Commerce Protocol\",\"description\":\"Technical overview of UCP, its commerce primitives and its ability to compose with APIs, A2A, MCP and AP2.\"}},\"tunes\":{}},{\"id\":\"src-ucp-profile\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fdevelopers.google.com\u002Fmerchant\u002Fucp\u002Fimplementation\u002F2026-04-08\u002Fpublish-profile\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Google Universal Commerce Protocol — UCP Profile\",\"description\":\"Current versioned profile mechanism for publishing UCP services and merchant commerce capabilities.\"}},\"tunes\":{}},{\"id\":\"src-ap2\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fcloud.google.com\u002Fblog\u002Fproducts\u002Fai-machine-learning\u002Fannouncing-agents-to-payments-ap2-protocol\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Google Cloud — Agent Payments Protocol (AP2)\",\"description\":\"Announcement and rationale for an open protocol covering authorization, authenticity and accountability in agent-led payments.\"}},\"tunes\":{}},{\"id\":\"src-a2ui\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fdevelopers.googleblog.com\u002Fa2ui-v0-9-generative-ui\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Google Developers — A2UI v0.9\",\"description\":\"A2UI's framework-agnostic declarative model for portable agent-driven interfaces rendered by host-native components.\"}},\"tunes\":{}},{\"id\":\"src-a2ui-mcp\",\"type\":\"linkTool\",\"data\":{\"link\":\"https:\u002F\u002Fdevelopers.googleblog.com\u002Fa2ui-and-mcp-apps\u002F\",\"meta\":{\"image\":{\"url\":\"\"},\"title\":\"Google Developers — A2UI + MCP Apps\",\"description\":\"How declarative A2UI and richer MCP App experiences can coexist rather than being treated as mutually exclusive UI models.\"}},\"tunes\":{}}],\"version\":\"2.31.6\"}",{"time":936,"blocks":937,"version":1485},1790352626854,[938,942,946,951,956,961,965,969,973,977,1006,1011,1015,1019,1023,1027,1036,1041,1045,1049,1053,1057,1061,1070,1074,1096,1100,1104,1108,1112,1116,1120,1129,1133,1137,1141,1145,1149,1175,1179,1183,1187,1191,1195,1204,1208,1212,1238,1242,1265,1269,1273,1277,1281,1285,1317,1321,1325,1329,1336,1340,1344,1348,1352,1356,1360,1364,1368,1372,1376,1399,1403,1421,1425,1432,1438,1445,1452,1459,1466,1472,1478],{"id":215,"data":939,"type":220,"tunes":941},{"title":940,"maxLevel":218,"minLevel":219},"Contents",{},{"id":223,"data":943,"type":226,"tunes":945},{"text":944},"AI agent protocols are multiplying quickly: MCP, A2A, UCP, AP2, A2UI and adjacent standards increasingly appear in the same architecture diagrams. They are often described as competing protocols. In practice, most of them solve different interoperability problems at different boundaries. The useful question is not “Which protocol wins?” but “Which relationship in the system needs to be standardized?”",{},{"id":229,"data":947,"type":234,"tunes":950},{"body":948,"title":949,"variant":233},"\u003Cstrong>MCP, A2A, UCP, AP2 and A2UI are mostly complementary, not substitutes.\u003C\u002Fstrong> MCP connects an AI application to tools, data and resources. A2A connects independent agents to one another. UCP standardizes commerce interactions between consumer surfaces, businesses and payment ecosystems. AP2 adds verifiable authorization and payment intent to agent-led transactions. A2UI lets an agent describe interactive UI without sending arbitrary application code. A production system may legitimately use several of them in one workflow.","Direct answer",{},{"id":237,"data":952,"type":234,"tunes":955},{"body":953,"title":954,"variant":241},"This article reflects the protocol landscape on \u003Cstrong>25 September 2026\u003C\u002Fstrong>. A2A has reached v1.0, MCP's current TypeScript v2 line implements the 2026-07-28 specification, UCP has already added newer 2026 protocol versions, and A2UI continues to evolve. Always verify the current specification before implementation.","Fast-moving standards",{},{"id":244,"data":957,"type":234,"tunes":960},{"body":958,"title":959,"variant":248},"The Protocol Responsibility Stack and Protocol Selection Test below are practical architecture models proposed here. They are not official terminology from the protocol projects.","The model used in this article",{},{"id":251,"data":962,"type":42,"tunes":964},{"text":963,"level":219},"The core mistake: comparing protocols that sit at different boundaries",{},{"id":256,"data":966,"type":226,"tunes":968},{"text":967},"A protocol is useful because two independently implemented systems need a stable contract. The contract only makes sense if the boundary is clear. An agent talking to a database has a different interoperability problem from one agent delegating work to another, a shopper authorizing a purchase, or a remote agent asking a native application to render a form.",{},{"id":261,"data":970,"type":226,"tunes":972},{"text":971},"Google's 2026 developer guide explicitly presents MCP, A2A, UCP, AP2, A2UI and related UI protocols as a stack of complementary standards. The same example workflow can use several of them together: tools for inventory, remote agents for suppliers, commerce for ordering, payment authorization for spending and UI protocols for interaction.",{},{"id":266,"data":974,"type":42,"tunes":976},{"text":975,"level":219},"The Protocol Responsibility Stack",{},{"id":271,"data":978,"type":304,"tunes":1005},{"content":979,"stretched":43,"withHeadings":14},[980,985,989,993,997,1001],[981,982,983,984],"Protocol","Standardizes which relationship?","Primary abstraction","Not primarily for",[280,986,987,988],"AI application ↔ tools, resources and data","Tools, resources, prompts and host\u002Fserver capability exchange","Independent agent collaboration or commerce semantics",[285,990,991,992],"Agent ↔ independent agent","Agent discovery, messages, tasks, artifacts and long-running collaboration","Direct database\u002Ftool integration",[290,994,995,996],"Consumer\u002Fagent surface ↔ merchant commerce system","Product\u002Fcart\u002Fcheckout\u002Ffulfillment\u002Forder capabilities","General-purpose agent communication",[295,998,999,1000],"User\u002Fagent intent ↔ payment authorization","Mandates, approval constraints and auditable agent-led payment authority","Product discovery or generic checkout transport",[300,1002,1003,1004],"Agent ↔ user interface host","Declarative UI intent rendered by trusted native components","Arbitrary remote frontend code or agent-to-agent task delegation",{},{"id":307,"data":1007,"type":234,"tunes":1010},{"body":1008,"title":1009,"variant":311},"An agent may use \u003Cstrong>MCP\u003C\u002Fstrong> to inspect inventory, \u003Cstrong>A2A\u003C\u002Fstrong> to ask a supplier agent for availability, \u003Cstrong>UCP\u003C\u002Fstrong> to build a commerce transaction, \u003Cstrong>AP2\u003C\u002Fstrong> to prove spending authority, and \u003Cstrong>A2UI\u003C\u002Fstrong> to render a native approval interface to the user.","One workflow can use all five",{},{"id":314,"data":1012,"type":42,"tunes":1014},{"text":1013,"level":219},"1. MCP: connect the agent to capabilities",{},{"id":319,"data":1016,"type":226,"tunes":1018},{"text":1017},"The Model Context Protocol is an open standard for connecting AI applications to external systems where tools, data and reusable resources live. A server exposes capabilities; an MCP host connects to that server and makes those capabilities available to the model or application.",{},{"id":324,"data":1020,"type":226,"tunes":1022},{"text":1021},"The current MCP TypeScript v2 documentation describes the protocol in exactly those terms: servers expose tools, resources and prompts, while hosts such as development environments or custom applications connect to them. This makes MCP primarily a capability integration protocol.",{},{"id":329,"data":1024,"type":42,"tunes":1026},{"text":1025,"level":218},"Use MCP when",{},{"id":334,"data":1028,"type":343,"tunes":1035},{"meta":1029,"items":1030,"style":342},{},[1031,1032,1033,1034],"An AI application needs standardized access to tools or APIs.","You want one capability server to work with multiple compatible AI hosts.","You need structured access to data or resources without hard-coding every integration into each agent.","The external system is a capability provider, not an autonomous peer agent.",{},{"id":346,"data":1037,"type":234,"tunes":1040},{"body":1038,"title":1039,"variant":241},"An MCP server can expose powerful functions, but that does not make it an independent agent with its own task lifecycle, discovery semantics and opaque internal reasoning. Tool invocation and agent collaboration are different contracts.","MCP is not automatically A2A",{},{"id":352,"data":1042,"type":42,"tunes":1044},{"text":1043,"level":219},"2. A2A: connect independent agents",{},{"id":357,"data":1046,"type":226,"tunes":1048},{"text":1047},"Agent2Agent (A2A) is designed for communication between independent, potentially opaque agent systems. Its current v1.0 specification focuses on capability discovery, messaging, tasks, artifacts, multimodal content and long-running collaboration without requiring one agent to expose its internal tools, memory or implementation to another.",{},{"id":362,"data":1050,"type":226,"tunes":1052},{"text":1051},"That opacity is the important boundary. The calling agent does not need to know whether the remote agent uses MCP, custom tools, a proprietary planner, another model vendor, or human escalation internally. It needs a contract for discovering capabilities and delegating work.",{},{"id":367,"data":1054,"type":226,"tunes":1056},{"text":1055},"A2A v1.0 also standardizes version negotiation and supports multiple bindings around a common data model. Its published Agent Card mechanism gives clients a standard discovery point for an agent's capabilities, supported protocols, authentication requirements and skills.",{},{"id":372,"data":1058,"type":42,"tunes":1060},{"text":1059,"level":218},"Use A2A when",{},{"id":377,"data":1062,"type":343,"tunes":1069},{"meta":1063,"items":1064,"style":342},{},[1065,1066,1067,1068],"One autonomous agent needs to delegate work to another autonomous agent.","The remote system should remain opaque behind a capability contract.","Tasks may be long-running, asynchronous or require human-in-the-loop interaction.","Agents are built with different frameworks, languages, vendors or organizational ownership.",{},{"id":387,"data":1071,"type":42,"tunes":1073},{"text":1072,"level":219},"MCP vs A2A: vertical integration vs horizontal collaboration",{},{"id":392,"data":1075,"type":421,"tunes":1095},{"rows":1076,"title":1089,"layout":304,"columns":1090},[1077,1080,1083,1086],{"id":396,"label":1078,"values":1079},"Relationship",[399,399,399],{"id":401,"label":1081,"values":1082},"Abstraction",[399,399,399],{"id":405,"label":1084,"values":1085},"Internal opacity",[399,399,399],{"id":409,"label":1087,"values":1088},"Long-running work",[399,399,399],"MCP and A2A solve different interoperability problems",[1091,1093,1094],{"id":415,"label":1092},"Dimension",{"id":418,"label":280},{"id":420,"label":285},{},{"id":424,"data":1097,"type":226,"tunes":1099},{"text":1098},"The A2A project itself now describes the distinction as horizontal versus vertical: MCP connects agents to internal tools and databases, while A2A enables peer-to-peer collaboration across agent systems.",{},{"id":429,"data":1101,"type":42,"tunes":1103},{"text":1102,"level":219},"3. UCP: standardize agentic commerce",{},{"id":434,"data":1105,"type":226,"tunes":1107},{"text":1106},"The Universal Commerce Protocol is not a generic agent protocol. It standardizes commerce journeys between consumer surfaces, merchants and payment providers. Google's implementation already supports capabilities such as cart creation, checkout, fulfillment and order lifecycle through versioned profiles and APIs.",{},{"id":439,"data":1109,"type":226,"tunes":1111},{"text":1110},"A merchant can publish a UCP profile under \u002F.well-known\u002Fucp describing services, protocol versions and capabilities. That discovery pattern matters because an agentic surface should not need a bespoke checkout contract for every merchant.",{},{"id":444,"data":1113,"type":226,"tunes":1115},{"text":1114},"UCP is also intentionally composable. Google's technical overview says it can integrate through APIs, A2A and MCP and is compatible with AP2 for agentic payment authorization.",{},{"id":449,"data":1117,"type":42,"tunes":1119},{"text":1118,"level":218},"Use UCP when",{},{"id":454,"data":1121,"type":343,"tunes":1128},{"meta":1122,"items":1123,"style":342},{},[1124,1125,1126,1127],"The workflow involves merchant products, carts, checkout, fulfillment or order lifecycle.","You are building a merchant surface that should work with agentic shopping experiences.","The integration needs commerce-specific semantics rather than generic tool calls.","You want an interoperable commerce contract that can coexist with MCP, A2A and payment protocols.",{},{"id":464,"data":1130,"type":42,"tunes":1132},{"text":1131,"level":219},"4. AP2: prove that the agent was allowed to spend",{},{"id":469,"data":1134,"type":226,"tunes":1136},{"text":1135},"Agentic commerce introduces a problem that ordinary checkout flows did not have to solve in the same way: an agent may transact when the human is not clicking the final button in real time. The Agent Payments Protocol (AP2) addresses authorization, authenticity and accountability for agent-led payments.",{},{"id":474,"data":1138,"type":226,"tunes":1140},{"text":1139},"Google's 2026 protocol guide describes AP2 through typed mandates that capture user intent, spending constraints and the specific transaction being authorized. AP2 can work as an extension alongside UCP: UCP describes the commerce transaction, while AP2 provides evidence that the agent had authority to perform the payment.",{},{"id":479,"data":1142,"type":226,"tunes":1144},{"text":1143},"This distinction is important. A checkout protocol can tell a merchant what should be purchased. It does not by itself prove who authorized the agent to spend, under what limit, for which merchant, for how long, or whether the final cart remained inside that authority.",{},{"id":484,"data":1146,"type":42,"tunes":1148},{"text":1147,"level":219},"UCP vs AP2: transaction semantics vs authority",{},{"id":489,"data":1150,"type":304,"tunes":1174},{"content":1151,"stretched":43,"withHeadings":14},[1152,1154,1158,1162,1166,1170],[1153,290,295],"Question",[1155,1156,1157],"What is being bought?","Commerce items, cart, checkout and fulfillment semantics","References the authorized transaction context",[1159,1160,1161],"Who may authorize it?","Not the primary protocol responsibility","Explicit agent\u002Fuser authority and mandate model",[1163,1164,1165],"What spending constraints apply?","Commerce flow can contain totals and checkout data","Authorization guardrails and intent limits",[1167,1168,1169],"How is the transaction audited?","Order and commerce lifecycle","Cryptographic \u002F verifiable authorization trail through mandates and receipts",[1171,1172,1173],"Can they work together?","Yes","Yes — AP2 can extend agentic commerce flows",{},{"id":516,"data":1176,"type":42,"tunes":1178},{"text":1177,"level":219},"5. A2UI: let agents describe interfaces without owning your frontend",{},{"id":521,"data":1180,"type":226,"tunes":1182},{"text":1181},"Agent-to-User Interface (A2UI) tackles another boundary: how a remote or local agent communicates a rich interactive interface to a host application. Instead of sending arbitrary HTML, CSS and JavaScript, A2UI uses declarative data that the host renders through its own trusted component catalog.",{},{"id":526,"data":1184,"type":226,"tunes":1186},{"text":1185},"This preserves the host application's design system and security model while still allowing an agent to request dynamic interfaces. A2UI v0.9 specifically emphasizes framework-agnostic UI intent and streaming updates across web, mobile and other clients.",{},{"id":531,"data":1188,"type":226,"tunes":1190},{"text":1189},"Google's later A2UI + MCP Apps work also demonstrates that these UI models are not necessarily mutually exclusive. Declarative native UI and richer embedded application experiences can coexist depending on the task.",{},{"id":536,"data":1192,"type":42,"tunes":1194},{"text":1193,"level":218},"Use A2UI when",{},{"id":541,"data":1196,"type":343,"tunes":1203},{"meta":1197,"items":1198,"style":342},{},[1199,1200,1201,1202],"A remote agent needs to request forms, cards, controls or other interactive UI.","The host should preserve its native components, styling and security boundary.","You do not want remote agents shipping arbitrary executable frontend code.","The same agent-defined UI intent should work across different client frameworks.",{},{"id":551,"data":1205,"type":42,"tunes":1207},{"text":1206,"level":219},"The Protocol Selection Test",{},{"id":556,"data":1209,"type":226,"tunes":1211},{"text":1210},"Do not start from the acronym. Start from the relationship that needs interoperability.",{},{"id":561,"data":1213,"type":587,"tunes":1237},{"steps":1214,"title":1236,"orientation":586},[1215,1218,1221,1224,1227,1230,1233],{"label":1216,"description":1217},"1. Identify the two independent parties","Is this AI-to-tool, agent-to-agent, agent-to-merchant, agent-to-payment authority, or agent-to-user-interface?",{"label":1219,"description":1220},"2. Identify the shared object","Is the contract about a tool call, task, cart, payment mandate, artifact, or UI description?",{"label":1222,"description":1223},"3. Check whether a domain protocol already exists","Prefer commerce or payment semantics when the problem is commerce or authorization instead of encoding everything as generic tools.",{"label":1225,"description":1226},"4. Keep local internals local","Do not expose an entire agent as MCP tools if the remote party only needs an A2A capability, and do not make a remote agent responsible for your UI runtime.",{"label":1228,"description":1229},"5. Compose protocols when the workflow crosses boundaries","One workflow can legitimately cross tool, agent, commerce, payment and UI contracts.",{"label":1231,"description":1232},"6. Version each contract independently","Protocol versions evolve at different speeds; do not tie every integration to one monolithic application version.",{"label":1234,"description":1235},"7. Preserve authorization at every boundary","Interoperability does not replace product permissions, tool authorization, payment authority or data-access policy.","Choose the protocol by the boundary",{},{"id":590,"data":1239,"type":42,"tunes":1241},{"text":1240,"level":219},"A realistic multi-protocol workflow",{},{"id":595,"data":1243,"type":587,"tunes":1264},{"steps":1244,"title":1263,"orientation":586},[1245,1248,1251,1254,1257,1260],{"label":1246,"description":1247},"1. Inspect internal stock with MCP","The purchasing agent calls inventory and forecasting capabilities exposed by internal MCP servers.",{"label":1249,"description":1250},"2. Discover a supplier agent with A2A","The agent reads the supplier's Agent Card and delegates an availability and lead-time task.",{"label":1252,"description":1253},"3. Negotiate the commerce object with UCP","The supplier or merchant surface returns structured cart, checkout and fulfillment information.",{"label":1255,"description":1256},"4. Check spending authority with AP2","The purchase is compared with the user's or organization's signed mandate, merchant constraints and spending limits.",{"label":1258,"description":1259},"5. Ask for approval through A2UI","If human approval is required, the agent sends declarative UI intent and the host renders the approval experience using trusted native components.",{"label":1261,"description":1262},"6. Complete and audit","Commerce state, payment authorization, agent task evidence and application audit records remain traceable across their respective boundaries.","Example: an autonomous procurement workflow",{},{"id":619,"data":1266,"type":42,"tunes":1268},{"text":1267,"level":219},"Why one universal agent protocol is unlikely to replace all of them",{},{"id":624,"data":1270,"type":226,"tunes":1272},{"text":1271},"A universal protocol sounds simpler until it must encode every domain's semantics. Tool discovery, long-running agent collaboration, checkout, payment authorization and native UI all have different lifecycle, security and correctness requirements.",{},{"id":629,"data":1274,"type":226,"tunes":1276},{"text":1275},"The web itself evolved through layered protocols rather than one message format for every problem. The emerging agentic stack appears to be moving in the same direction: common horizontal primitives, specialized domain contracts and explicit discovery\u002Fversioning.",{},{"id":634,"data":1278,"type":226,"tunes":1280},{"text":1279},"The architecture challenge therefore shifts from “which protocol wins?” to how cleanly protocols compose without duplicating identity, authorization, state and audit semantics.",{},{"id":639,"data":1282,"type":42,"tunes":1284},{"text":1283,"level":219},"Protocol composition creates new failure modes",{},{"id":644,"data":1286,"type":304,"tunes":1316},{"content":1287,"stretched":43,"withHeadings":14},[1288,1292,1296,1300,1304,1308,1312],[1289,1290,1291],"Failure mode","What happens","Architecture control",[1293,1294,1295],"Authority leakage","A valid tool or agent capability is treated as permission to perform a business action","Keep product authorization independent from protocol capability discovery",[1297,1298,1299],"Identity mismatch","MCP host identity, A2A agent identity and commerce\u002Fpayment identity refer to different principals","Define explicit principal mapping across boundaries",[1301,1302,1303],"Version drift","One protocol upgrades while dependent adapters assume older semantics","Negotiate and pin protocol versions independently",[1305,1306,1307],"State duplication","The same cart, task or approval state is copied into several protocol layers","Define one authoritative owner per domain object",[1309,1310,1311],"Audit fragmentation","Tool traces, agent tasks, checkout and payment evidence cannot be joined","Carry correlation IDs and stable domain identifiers across protocol boundaries",[1313,1314,1315],"Semantic tunneling","Everything is forced through a generic protocol as opaque JSON","Use domain protocols where their semantics materially improve correctness",{},{"id":677,"data":1318,"type":42,"tunes":1320},{"text":1319,"level":219},"Protocol choice does not replace application architecture",{},{"id":682,"data":1322,"type":226,"tunes":1324},{"text":1323},"Open standards reduce integration coupling, but they do not decide your domain model, authorization policy, source of truth, retry strategy or acceptance criteria. An MCP tool can still expose the wrong capability. An A2A agent can still return a bad artifact. A UCP checkout can still contain stale merchant data. An AP2 mandate can still be misapplied by application logic.",{},{"id":687,"data":1326,"type":226,"tunes":1328},{"text":1327},"Treat protocols as contracts between independently evolving components. Keep domain truth and consequential policy in the application layer that owns them, then use protocols to make the boundaries interoperable.",{},{"id":692,"data":1330,"type":698,"tunes":1335},{"url":1331,"title":1332,"excerpt":1333,"ctaLabel":1334},"https:\u002F\u002Fstajic.de\u002Fblog\u002Fmanaged-agent-harness-vs-self-hosted-agent-loop-what-you-gain-what-you-lose","Managed Agent Harness vs Self-Hosted Agent Loop: What You Gain, What You Lose","Protocol boundaries solve interoperability. Runtime boundaries solve who operates the harness, execution environment and application control plane.","Read the runtime architecture guide",{},{"id":701,"data":1337,"type":42,"tunes":1339},{"text":1338,"level":219},"What would change this answer?",{},{"id":706,"data":1341,"type":226,"tunes":1343},{"text":1342},"The stack changes if protocols converge, one standard formally absorbs another, or vendors standardize a shared identity and authorization layer across several boundaries. UCP already demonstrates composition by supporting APIs, A2A and MCP and by integrating with AP2 rather than replacing them.",{},{"id":711,"data":1345,"type":226,"tunes":1347},{"text":1346},"The answer also changes by application scope. A small internal agent may need only MCP. A multi-company workflow may need A2A. A merchant may need UCP without A2UI. A delegated purchasing agent may need all of them. Use the smallest protocol set that represents the real boundaries without flattening domain semantics.",{},{"id":716,"data":1349,"type":42,"tunes":1351},{"text":1350,"level":219},"Limitations",{},{"id":721,"data":1353,"type":226,"tunes":1355},{"text":1354},"The protocols discussed here are at different maturity levels and have different governance models. A2A has reached a stable v1.0 specification, while other standards continue to evolve rapidly. Ecosystem adoption is also uneven across vendors and frameworks.",{},{"id":726,"data":1357,"type":226,"tunes":1359},{"text":1358},"This article focuses on architecture responsibility rather than implementation completeness. Specific authentication methods, transport bindings, schemas and extension mechanisms must be taken from each protocol's current specification.",{},{"id":731,"data":1361,"type":42,"tunes":1363},{"text":1362,"level":219},"Conclusion",{},{"id":736,"data":1365,"type":226,"tunes":1367},{"text":1366},"MCP, A2A, UCP, AP2 and A2UI make more sense when viewed as protocols for different relationships, not five competing attempts to standardize “agents.”",{},{"id":741,"data":1369,"type":226,"tunes":1371},{"text":1370},"MCP exposes capabilities. A2A coordinates independent agents. UCP gives commerce its own machine-readable contract. AP2 adds verifiable payment authority. A2UI gives agents a safe declarative path into user interfaces. The emerging agentic web is therefore not replacing protocols with AI; it is creating a new protocol stack around AI.",{},{"id":746,"data":1373,"type":42,"tunes":1375},{"text":1374,"level":219},"FAQ",{},{"id":751,"data":1377,"type":751,"tunes":1398},{"items":1378,"title":1397},[1379,1382,1385,1388,1391,1394],{"id":755,"answer":1380,"question":1381},"No. MCP primarily standardizes how AI applications access tools, resources and data. A2A standardizes collaboration between independent agent systems. A remote agent can internally use MCP while exposing an A2A interface.","Is A2A a replacement for MCP?",{"id":759,"answer":1383,"question":1384},"Not generally. UCP provides commerce-specific semantics such as cart, checkout and fulfillment. MCP can still expose merchant tools or data, and UCP is designed to coexist with MCP and A2A.","Is UCP a replacement for MCP in shopping agents?",{"id":763,"answer":1386,"question":1387},"UCP standardizes commerce interactions and transaction lifecycle. AP2 focuses on proving that an agent had authority to perform a payment under defined user or organizational constraints.","What is the difference between UCP and AP2?",{"id":767,"answer":1389,"question":1390},"A2UI lets agents send declarative UI intent to a host application, which renders the experience through trusted native components instead of executing arbitrary remote frontend code.","What problem does A2UI solve?",{"id":771,"answer":1392,"question":1393},"Yes. A workflow can use MCP for internal tools, A2A for remote-agent delegation, UCP for commerce, AP2 for payment authorization and A2UI for human interaction.","Can one agent application use all of these protocols?",{"id":775,"answer":1395,"question":1396},"Start from the interoperability boundary. If the problem is tool access, evaluate MCP. If it is independent-agent collaboration, evaluate A2A. If it is commerce, UCP. If it is delegated payment authority, AP2. If it is portable agent-driven UI, A2UI.","Which protocol should I implement first?","MCP, A2A, UCP, AP2 and A2UI",{},{"id":781,"data":1400,"type":42,"tunes":1402},{"text":1401,"level":219},"Glossary",{},{"id":786,"data":1404,"type":786,"tunes":1420},{"title":1405,"entries":1406},"Key agent-protocol terms",[1407,1409,1411,1413,1415,1417],{"term":280,"anchor":418,"definition":1408},"Model Context Protocol, an open standard for exposing tools, resources and prompts from external systems to compatible AI hosts.",{"term":285,"anchor":420,"definition":1410},"Agent2Agent Protocol, an open standard for discovering and collaborating with independent agent systems through messages, tasks and artifacts.",{"term":290,"anchor":795,"definition":1412},"Universal Commerce Protocol, an open standard for interoperable agentic commerce journeys between consumer surfaces, businesses and payment providers.",{"term":295,"anchor":798,"definition":1414},"Agent Payments Protocol, an open standard for representing and verifying authority, intent and accountability in agent-led payments.",{"term":300,"anchor":801,"definition":1416},"Agent-to-User Interface, a declarative protocol for allowing agents to request UI that is rendered using the host application's trusted components.",{"term":1418,"anchor":805,"definition":1419},"Protocol composition","Using multiple protocols in one workflow, each responsible for a distinct interoperability boundary rather than forcing all semantics through one contract.",{},{"id":809,"data":1422,"type":42,"tunes":1424},{"text":1423,"level":219},"Primary sources and further reading",{},{"id":814,"data":1426,"type":821,"tunes":1431},{"link":816,"meta":1427},{"image":1428,"title":1429,"description":1430},{"url":399},"Google Developers — Developer's Guide to AI Agent Protocols","A practical overview showing MCP, A2A, UCP, AP2, A2UI and related protocols working together in one multi-step agent workflow.",{},{"id":824,"data":1433,"type":821,"tunes":1437},{"link":826,"meta":1434},{"image":1435,"title":829,"description":1436},{"url":399},"Current stable SDK documentation implementing the 2026-07-28 MCP specification and defining tools, resources, prompts and host\u002Fserver integration.",{},{"id":833,"data":1439,"type":821,"tunes":1444},{"link":835,"meta":1440},{"image":1441,"title":1442,"description":1443},{"url":399},"A2A Protocol — v1.0 Specification","Current A2A protocol specification covering Agent Cards, messages, tasks, artifacts, bindings and version negotiation.",{},{"id":842,"data":1446,"type":821,"tunes":1451},{"link":844,"meta":1447},{"image":1448,"title":1449,"description":1450},{"url":399},"A2A — Joining the Agentic AI Foundation","Current project framing of A2A as the horizontal agent-collaboration layer alongside MCP as vertical tool\u002Fdata integration.",{},{"id":851,"data":1453,"type":821,"tunes":1458},{"link":853,"meta":1454},{"image":1455,"title":1456,"description":1457},{"url":399},"Google Developers — Under the Hood: Universal Commerce Protocol","Technical overview of UCP, its commerce primitives and its ability to compose with APIs, A2A, MCP and AP2.",{},{"id":860,"data":1460,"type":821,"tunes":1465},{"link":862,"meta":1461},{"image":1462,"title":1463,"description":1464},{"url":399},"Google Universal Commerce Protocol — UCP Profile","Current versioned profile mechanism for publishing UCP services and merchant commerce capabilities.",{},{"id":869,"data":1467,"type":821,"tunes":1471},{"link":871,"meta":1468},{"image":1469,"title":874,"description":1470},{"url":399},"Announcement and rationale for an open protocol covering authorization, authenticity and accountability in agent-led payments.",{},{"id":878,"data":1473,"type":821,"tunes":1477},{"link":880,"meta":1474},{"image":1475,"title":883,"description":1476},{"url":399},"A2UI's framework-agnostic declarative model for portable agent-driven interfaces rendered by host-native components.",{},{"id":887,"data":1479,"type":821,"tunes":1484},{"link":889,"meta":1480},{"image":1481,"title":1482,"description":1483},{"url":399},"Google Developers — A2UI + MCP Apps","How declarative A2UI and richer MCP App experiences can coexist rather than being treated as mutually exclusive UI models.",{},"2.31.6","MCP, A2A, UCP, AP2 and A2UI are often presented as competing agent standards. They mostly solve different interoperability problems. This guide maps each protocol to the boundary it actually standardizes—and shows how they can work together in one production 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Ovaj članak pruža praktičan model životnog ciklusa za odlučivanje o tome šta pripada trajnoj memoriji, šta bi trebalo ponovo preuzeti, šta je bezbednije ponovo izračunati i šta bi trebalo da istekne ili bude zamenjeno.","\u002Fuploads\u002F2026\u002F09\u002Fwhat-should-an-ai-agent-remember-forget-recompute-or-retrieve-again-1790351131087-iehz28.webp","2026-09-25T09:43:00.000Z",{"id":1844,"slug":1845,"title":1846,"excerpt":1847,"featuredImage":1848,"publishedAt":1849},"473","openai-agents-api-vs-agents-sdk-vs-responses-api-what-should-you-build-on-in-2026","OpenAI Agents API vs Agents SDK vs Responses API: Na čemu bi trebalo da gradite u 2026?","OpenAI-jev stek agenata promenio se u septembru 2026. 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