{ "title": "MCP and A2A Protocol Boundary Register", "schemaVersion": "1.0", "researchFreeze": "2026-08-26", "protocolRevision": "MCP 2026-07-28 / A2A 1.0", "mcpRevision": "2026-07-28", "a2aCompatibilityLine": "1.0", "a2aWebsiteSpecificationLabel": "1.0.0", "a2aRepositoryPatchTag": "v1.0.1", "a2aVersionSemantics": "A2A negotiates major.minor 1.0; patch tags identify specification releases and are not negotiated.", "count": 25, "records": [ { "ID": "B01", "Use case": "Read a file from an allowed directory", "Recommended boundary": "MCP", "Reason": "Bounded resource or tool operation; caller retains orchestration.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B01", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B02", "Use case": "Search a source repository for a symbol", "Recommended boundary": "MCP", "Reason": "Structured search capability with exact arguments.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B02", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B03", "Use case": "Create an issue in a known repository", "Recommended boundary": "MCP", "Reason": "Defined side-effecting operation with object-level authorization.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B03", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B04", "Use case": "Ask a security specialist to assess an unfamiliar codebase", "Recommended boundary": "A2A", "Reason": "Delegated outcome requiring an agent-owned plan and report Artifact.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B04", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B05", "Use case": "Retrieve a customer record", "Recommended boundary": "MCP", "Reason": "Addressable data or bounded query.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B05", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B06", "Use case": "Resolve a difficult customer billing dispute", "Recommended boundary": "A2A + MCP", "Reason": "Delegate the case to a billing agent; use MCP for account and refund systems.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B06", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B07", "Use case": "Convert time zones", "Recommended boundary": "MCP or direct API", "Reason": "Deterministic operation; agent lifecycle adds little value.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B07", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B08", "Use case": "Plan an international business trip", "Recommended boundary": "A2A + MCP", "Reason": "Specialist agents may own research; MCP exposes booking, calendar and policy capabilities.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B08", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B09", "Use case": "Run one CI build", "Recommended boundary": "MCP", "Reason": "Known operation; optional MCP Task if long-running.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B09", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B10", "Use case": "Coordinate release readiness across security, QA and compliance", "Recommended boundary": "A2A + MCP", "Reason": "Outcome delegation across specialists with capability access inside each.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B10", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B11", "Use case": "Answer a question from a documentation corpus", "Recommended boundary": "MCP", "Reason": "Search/resource retrieval is usually sufficient.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B11", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B12", "Use case": "Produce an independent market-research report", "Recommended boundary": "A2A + MCP", "Reason": "Agent owns research strategy; tools/data accessed through MCP.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B12", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B13", "Use case": "Monitor an A2A Task until completion", "Recommended boundary": "A2A", "Reason": "Native Task lifecycle.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B13", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B14", "Use case": "Monitor one long-running database export", "Recommended boundary": "MCP Tasks", "Reason": "Long-running execution of a bounded capability request.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B14", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B15", "Use case": "Negotiate a supplier quote", "Recommended boundary": "A2A", "Reason": "Multi-turn outcome-oriented interaction with independent party.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B15", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B16", "Use case": "Download an invoice PDF", "Recommended boundary": "MCP", "Reason": "Addressable resource or tool result.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B16", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B17", "Use case": "Investigate an outage", "Recommended boundary": "A2A + MCP", "Reason": "Specialists plan analysis; MCP reaches observability and remediation systems.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B17", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B18", "Use case": "Restart a service", "Recommended boundary": "MCP", "Reason": "Defined operation, separately authorized.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B18", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B19", "Use case": "Generate a patch from a delegated code review", "Recommended boundary": "A2A + MCP", "Reason": "Agent produces Artifact; MCP reads/writes repository.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B19", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B20", "Use case": "Expose an internal research agent to an MCP-only desktop host", "Recommended boundary": "MCP façade", "Reason": "Acceptable adapter if bounded result semantics are sufficient.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B20", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B21", "Use case": "Expose a deterministic calculator as a remote agent", "Recommended boundary": "Avoid A2A", "Reason": "Use MCP or ordinary API; agent abstraction obscures a simple capability.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B21", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B22", "Use case": "Allow agents from separate companies to collaborate", "Recommended boundary": "A2A", "Reason": "Independent identity, Agent Cards and delegated Tasks are central.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B22", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B23", "Use case": "Allow one IDE agent to use local developer tools", "Recommended boundary": "MCP", "Reason": "Local stdio and bounded tools fit.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B23", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B24", "Use case": "Publish a vendor-supported capability to many AI hosts", "Recommended boundary": "MCP", "Reason": "Reusable server implementation and capability discovery.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B24", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] }, { "ID": "B25", "Use case": "Publish a vendor-operated specialist agent to many coordinators", "Recommended boundary": "A2A", "Reason": "Independent agent identity, skills and Task lifecycle.", "Important caveat": "Authorization, identity and data policy remain implementation responsibilities.", "id": "R8-B25", "packageSourceIds": [ "S003", "S004", "S038" ], "sourceIds": [ "S339", "S340", "S054" ] } ] }