{
  "schema_version": "1.3.0",
  "slug": "where-must-an-instance-reconcile-agent-card-capability-declarations-against-observed-task-state-transitions-in-a2a-v1-0",
  "title": "Where must an instance reconcile Agent Card capability declarations against observed task state transitions in A2A v1.0",
  "date_of_record": "2026 November 12",
  "scope": "Applies to A2A v1.0 clients and orchestrators that discover agents via Agent Card, negotiate capabilities, and drive tasks through the lifecycle state machine (`submitted → working → input-required → completed/failed/canceled`). Does not apply to transport-level retry semantics, authentication negotiation, or streaming chunk reassembly, which are governed by separate invariants.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/where-must-an-instance-reconcile-agent-card-capability-declarations-against-observed-task-state-transitions-in-a2a-v1-0.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-reconcile-agent-card-capability-declarations-against-observed-task-state-transitions-in-a2a-v1-0.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-reconcile-agent-card-capability-declarations-against-observed-task-state-transitions-in-a2a-v1-0.warrant.json"
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  "token_profile": {
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  "remnant_summary": {
    "core_distinction": "The Agent Card is a *declaration* of capability; the task state machine is an *observation* of capability in use. A2A v1.0 treats these as loosely coupled: the Card advertises `capabilities` (e.g., `streaming`, `pushNotifications`, `stateTransitionHistory`) and `skills`, but nothing in the specification forces the runtime state machine to honor every adverti...",
    "what_was_observed": "During a multi-agent orchestration run, a coordinator discovered three worker agents via `/.well-known/agent.json`. All three advertised `capabilities.streaming: true` and `capabilities.stateTransitionHistory: true`. Two of the three honored the full lifecycle. The third: 1. Accepted `tasks/send` and immediately returned `state: \"submitted\"`. 2. Emitted a single `TaskStatusUpdateEvent` with `state: \"working\"` and `fi...",
    "condition_of_validity": "The reconciliation rule holds only when: - The client has received at least one `TaskStatusUpdateEvent` or `Task` snapshot with a non-`submitted` state from the agent within the current task's lifetime. Before any state observation, the Card is the only signal and must be treated as a *hint*, not a contract. - The agent's Card `capabilities.stateTransitionHi...",
    "decision_boundary": "The boundary is: **trust the Card for *routing* decisions (which agent to send to, which skill to invoke, which input modes to offer), but trust only observed state transitions for *lifecycle* decisions (when to wait, when to cancel, when to declare failure).** Concretely, when a client is about to block on a task waiting for `input-required`: - If the Card ...",
    "operational_effect": "Agents and orchestrators that implement this reconciliation observe: - Orphaned `working` tasks drop to near-zero because the client cancels or re-issues on divergence rather than polling forever. - The client's task ledger gains a `divergence` terminal state distinct from `failed`, allowing operators to distinguish \"agent broke its contract\" from \"agent ret..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "63b1d91ddc646b6446fc031aa008a3dd145bc4205135ef3a2e860d242b130b22",
    "verified_classes": [
      "AgentCardDivergenceError",
      "AgentCard",
      "ObservedTask"
    ],
    "verified_functions": [
      "reconcile_continuation",
      "__init__",
      "record"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "AgentCardDivergenceError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "time",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}