{
  "handle": "ToolDiscovery",
  "mechanism": "{{agent}} queries a {{discover}} for capabilities matching its current {{task}}. Registry returns a {{card}} listing available tools with typed input/output schemas. {{agent}} selects the best match, performs a {{compatibility_check}} to verify schema alignment, then invokes via {{tool_invoke}} and observes the typed {{result}}. If no match is found or {{compatibility_check}} fails, the agent must {{fail_closed}} rather than attempt a best-effort invocation. Follows the Model Context Protocol pattern of progressive discovery under {{context_first}} discipline: orient via registry, explore via schema matching, verify via hash comparison.",
  "gloss": "Discover and invoke external tools via structured capability manifests",
  "invariants": [
    "Schema Verification: Tool manifest hash must be verified via {{compatibility_check}} before invocation",
    "Fail-Closed: On schema mismatch or missing tool, reject via {{fail_closed}} rather than attempt best-effort",
    "Tool output must conform to declared schema in the {{card}}"
  ],
  "preconditions": [
    "{{discover}} accessible",
    "{{task}} specifies required capability type"
  ],
  "postconditions": [
    "{{result}} returned conforming to tool's declared output schema",
    "Invocation logged with tool identity and schema hash"
  ],
  "failure_modes": [
    "Registry unavailable (no tools discoverable — must degrade gracefully).",
    "Schema drift (tool updated its manifest but {{agent}} cached old version).",
    "Capability hallucination (tool claims capability it cannot deliver)."
  ],
  "signature": [
    "Discover(ToolInvoke)"
  ],
  "_meta": {
    "ring": 1,
    "tier": 1,
    "related": [
      "AgentDiscover"
    ],
    "supersedes": [
      "sema:ToolDiscovery#mh:SHA-256:548fb253447d270bee9b28ee7fe125135ce45ab54fbd2744fcc70e6b7d9b6de8",
      "sema:ToolDiscovery#mh:SHA-256:0ff16794954587c168bc694f00a723973be11ddfeb3a15c73770ab660bd439d8",
      "sema:ToolDiscovery#mh:SHA-256:bf677acdeda8699deafb4398efa1f605dea89de112873e9a7bb838a41adbffd6",
      "sema:ToolDiscovery#mh:SHA-256:4b608d9d78051bf0f7bd10120d145dd6664c416fc0c52969156f9a31d171d45b",
      "sema:ToolDiscovery#mh:SHA-256:c3c879478898d130c1f92f782dd17955e1dd1195638b188e3d7044428e64bb1b",
      "sema:ToolDiscovery#mh:SHA-256:8d8071355a00e6bf7cf3b0d6bd509d83a2501c6a06923ce6dd6e6cf50f41918e"
    ],
    "path": [
      "Society",
      "Protocols"
    ]
  },
  "sema_ref": "ToolDiscovery#b165",
  "sema_id": "sema:ToolDiscovery#mh:SHA-256:b1659e870015d2d6e37842f31a0bc1cc2d2d2882aaf6d0bc3b6b1236885890d7",
  "sema_stub": "b165",
  "dependencies": {
    "composes_with": {
      "compatibility_check": "sema:CompatibilityCheck#mh:SHA-256:7f70838f05f3aad069b89dcbc705283872f66fde4bc95c6bfa0dc917955e050d",
      "fail_closed": "sema:FailClosed#mh:SHA-256:dfbcf50c68d036ae4f18719bf59f41eddd83b5510bd60ff1326f8854240d8066",
      "tool_invoke": "sema:ToolInvoke#mh:SHA-256:1096039316801cc8ef6e2855a6300574bb8596bb8e57c2764fd3bee741fa217e"
    },
    "references": {
      "agent": "sema:Agent#mh:SHA-256:e127459069739fffc96a71d54ef6e8c97ca53471d5349c16aa72a092a33756cd",
      "card": "sema:Card#mh:SHA-256:e4b2ca76f43a691e7bd7932362512a5e929c62efc6c3d2eb4a9369e5108fa074",
      "context_first": "sema:ContextFirst#mh:SHA-256:f157ec66ccb7e55eabe7179aeefb0dc4b36bc45e3bbea3073e50d97dab86138b",
      "discover": "sema:Discover#mh:SHA-256:f6e09de2a5b38c031651d22539fafaa46e32869b06dae8009bde18cb249da69b",
      "task": "sema:Task#mh:SHA-256:a85010f508f85055170c396c8fa390125c1206888c565ac10651f3969a339f8d"
    },
    "yields": {
      "result": "sema:Result#mh:SHA-256:c02a8d6817c2f0e14d5a9360824240f135905e8be25fd659feb76d1f44e274c6"
    }
  },
  "sema_layer": "Society",
  "sema_category": "Protocols",
  "used_by": {}
}