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Its repository states the problem it exists to solve — enabling \"gen AI agents built on diverse frameworks by different companies running on separate servers to communicate and collaborate effectively — as agents, not just as tools.\" Google contributed it, the Linux Foundation governs it, and one year in it counts more than 150 supporting organizations. 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Apache 2.0 licensed, 25,000 GitHub stars. 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Other agents read the card, decide whether this agent can do what they need, and open a session. The card is the unit of discovery, the same way a server entry is the unit of discovery in the MCP registry one layer down. 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The last time cloud vendors agreed on anything that fast, it was Kubernetes.","status":"active","vx_hash":"c229d3534c0401a451469a338143048aad514e3dd9f45fd4140111de48d4e9d1","semantic_hash":null,"version_hash":null,"version":1,"sources":[],"falsifiers":[],"tier":null,"backed":null,"transcludes":null,"chain_head":"9ec2c3f1fe8d21ab8b0c8c688809a818c9bf4a2cc3d789ac3dfc98416ea85776","chain_length":1,"chain":[{"n":1,"op":"genesis","ts":"2026-07-24T16:10:36.078Z","actor":"cap:cap_e977bc9c49319139","text_sha":"2dd08c83ed611fe4400f1c882241f293d231aaba1f88cf47f3c1822b06881b75","detail":{"divided_from":"body","block":12,"kind":"p"},"prev":"genesis","hash":"9ec2c3f1fe8d21ab8b0c8c688809a818c9bf4a2cc3d789ac3dfc98416ea85776"}],"claim_ids":[],"last_op":{"op":"genesis","actor":"cap:cap_e977bc9c49319139","ts":"2026-07-24T16:10:36.078Z"},"consolidated_into":null,"stable_url":"https://miscsubjects.com/i/div/what-is-a2a/d12"},{"id":"d13","kind":"h","type":null,"order":13,"text":"## The division of labor with MCP","status":"active","vx_hash":"4ea7cc613a754dc02ff52c48673d44cd4a14eaf63bb59508e6691e6af5586aa1","semantic_hash":null,"version_hash":null,"version":1,"sources":[],"falsifiers":[],"tier":null,"backed":null,"transcludes":null,"chain_head":"2bbdefaedad899ba07d896d63837efa11ce9e4918c4a7ce043d03a1d31236334","chain_length":1,"chain":[{"n":1,"op":"genesis","ts":"2026-07-24T16:10:36.078Z","actor":"cap:cap_e977bc9c49319139","text_sha":"7b2579f33d442e1fa30b2a4f7a76fda1bf34283215abebcd334d3894ec83f912","detail":{"divided_from":"body","block":13,"kind":"h"},"prev":"genesis","hash":"2bbdefaedad899ba07d896d63837efa11ce9e4918c4a7ce043d03a1d31236334"}],"claim_ids":[],"last_op":{"op":"genesis","actor":"cap:cap_e977bc9c49319139","ts":"2026-07-24T16:10:36.078Z"},"consolidated_into":null,"stable_url":"https://miscsubjects.com/i/div/what-is-a2a/d13"},{"id":"d14","kind":"p","type":null,"order":14,"text":"The foundation states the boundary in one sentence: \"A2A defines how agents communicate and coordinate with each other across organizational boundaries, while MCP defines how agents connect to internal tools and data sources.\" Tools below, agents above, one registry-shaped discovery mechanism at each layer.","status":"active","vx_hash":"0630048a8872b3f978b74f4fbb5a57c9294e2d1ee1c23db9bcc0ca9769172270","semantic_hash":null,"version_hash":null,"version":1,"sources":[],"falsifiers":[],"tier":null,"backed":null,"transcludes":null,"chain_head":"f06100114e5ae0fadebd3eb24bb843a9ba84309c91932afc112311bc2af4f7df","chain_length":1,"chain":[{"n":1,"op":"genesis","ts":"2026-07-24T16:10:36.078Z","actor":"cap:cap_e977bc9c49319139","text_sha":"b7abb752859ff6fbd5f06487c7f0439a628eef4182aaea772e22b37f98093814","detail":{"divided_from":"body","block":14,"kind":"p"},"prev":"genesis","hash":"f06100114e5ae0fadebd3eb24bb843a9ba84309c91932afc112311bc2af4f7df"}],"claim_ids":[],"last_op":{"op":"genesis","actor":"cap:cap_e977bc9c49319139","ts":"2026-07-24T16:10:36.078Z"},"consolidated_into":null,"stable_url":"https://miscsubjects.com/i/div/what-is-a2a/d14"},{"id":"d15","kind":"p","type":null,"order":15,"text":"What neither layer covers, and A2A's enterprise-readiness language only gestures at: how much authority travels with a delegated task. An agent card says what an agent *can* do; nothing in the protocol yet constrains what a particular caller may ask it to do beyond transport-level authentication. 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