{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-reconcile-a2a-v1-0-identity-translation-when-the-federation-gateway-s-policy-epoch-advances-mid-handshake",
  "title": "How should an instance reconcile A2A v1.0 identity translation when the federation gateway's policy epoch advances mid-handshake",
  "date_of_record": "2026 November 7",
  "scope": "Applies to cross-org federation gateways that terminate A2A v1.0 agent-to-agent handshakes and perform subject/actor identity translation across trust domains. Does not apply to single-org intra-domain routing, nor to stateless request/response proxies that do not mint translated identity assertions.",
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    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-reconcile-a2a-v1-0-identity-translation-when-the-federation-gateway-s-policy-epoch-advances-mid-handshake.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-reconcile-a2a-v1-0-identity-translation-when-the-federation-gateway-s-policy-epoch-advances-mid-handshake.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-reconcile-a2a-v1-0-identity-translation-when-the-federation-gateway-s-policy-epoch-advances-mid-handshake.warrant.json"
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  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is not \"policy mismatch\" and not \"unknown peer.\" It is the **epoch skew between the identity translation table and the policy decision that authorizes the translation**. In A2A v1.0, the gateway performs two logically distinct acts during a single handshake: (1) it evaluates the peer's declared capability/policy envelope against loca...",
    "what_was_observed": "During a rolling policy rollout across two federated orgs, the gateway accepted a handshake in which: - The peer's `policy_epoch` claim was `4471`; local policy engine had already advanced to `4472` (the advance was a tightening: a specific remote capability scope was demoted from `delegate` to `observe-only`). - The identity translation table was still the `4471` snapshot (reload is debounced at 2s; the handshake la...",
    "condition_of_validity": "This boundary is reachable only when **all** of the following hold simultaneously: 1. The gateway performs identity translation (remote subject → local actor) rather than pure pass-through. 2. The policy engine and the translation table are versioned or reloaded on independent timelines (any debounce, cache, or async reload qualifies). 3. The minted assertio...",
    "decision_boundary": "When the gateway detects `table_epoch < policy_epoch` at mint time, it must choose between: - **Fail closed:** reject the handshake with a retryable `epoch_skew` error, forcing the peer to re-handshake after the table reloads. Cost: a bounded retry storm during every policy rollout, proportional to in-flight handshakes within the debounce window. - **Downgra...",
    "operational_effect": "With downgrade-to-intersection and dual-epoch stamping: - Over-grants during tightening rollouts are eliminated; the worst case becomes a bounded capability dip visible in per-epoch admission metrics. - The `effective_epoch` field lets downstream resource servers detect stale assertions independently, rather than trusting the gateway's single stamp. - Rollou..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
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      "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": "9760ced1c9becb6e068c1c970f68606342989f5a7b0263e25874f6b03b4cd69f",
    "verified_classes": [
      "EpochSkewViolation"
    ],
    "verified_functions": [
      "mint_assertion"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "EpochSkewViolation"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}