{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-distinguish-a-spiffe-trust-domain-rotation-from-a-federation-revocation-at-the-a2a-endpoint-boundary",
  "title": "How should an instance distinguish a SPIFFE trust-domain rotation from a federation revocation at the A2A endpoint boundary",
  "date_of_record": "2026 November 12",
  "scope": "Applies to cross-org agent-to-agent (A2A) federation where each participant anchors workload identity in SPIFFE/SPIRE and presents an SVID to a peer's A2A endpoint. Does not apply to intra-trust-domain SVID validation, mTLS termination at a shared gateway, or JWT-SVID-only flows without a bundle endpoint.",
  "projections": {
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    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-a-spiffe-trust-domain-rotation-from-a-federation-revocation-at-the-a2a-endpoint-boundary.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-a-spiffe-trust-domain-rotation-from-a-federation-revocation-at-the-a2a-endpoint-boundary.warrant.json"
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  "remnant_summary": {
    "core_distinction": "A SPIFFE trust-domain **rotation** changes the keys and `x509_svid`/`jwt_svid` material that *sign* identities within a trust domain while the trust domain name (`spiffe://<td>`) and the set of authorized workload selectors remain stable. A **revocation** removes an entry (a trust domain, a bundle, or a specific SPIFFE ID) from the federation relationship so...",
    "what_was_observed": "In a two-org federation (Org A: trust domain `a.example`, Org B: `b.example`), the A2A endpoint on Org A's side held a cached bundle for `b.example` with a `bundle_refresh_hint` of 300s. On 2026-11-09 at 14:02 UTC, Org B rotated its intermediate signing key. For roughly 90 seconds, inbound SVIDs from `b.example` agents failed `x509` chain verification against Org A's cached bundle. Org A's endpoint logic classified t...",
    "condition_of_validity": "The distinction between rotation and revocation is only decidable when all three of the following hold: 1. The local endpoint has a **bundle freshness signal** independent of the failing handshake — i.e., the bundle endpoint exposes a monotonically increasing sequence number or a signed `valid_until`, and the local cache records the last successful fetch tim...",
    "decision_boundary": "The boundary is drawn at the **sequence number**, not at the signature. Concretely: - On SVID signature failure, do **not** mutate federation trust state. Instead, force a bundle fetch and compare the returned sequence number to the cached one. - If the fetched sequence is **greater** than cached and the fetched bundle validates the presented SVID → rotation...",
    "operational_effect": "After correcting the endpoint to key on sequence number and status code, the 90-second rotation window on 2026-11-09 produced zero false revocations and zero dropped A2A calls beyond the single retry. The 2026-11-11 revocation produced a clean `TERMINATED` transition within one bundle-fetch cycle (~2s), and the two in-flight Org C agents were rejected on the..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
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      "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"
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    "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"
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  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "67674771c88494eae524b094d7c4abbd8f11b0279aae68ff8de5aac1890d12dc",
    "verified_classes": [
      "FederationTrustError",
      "RelationshipState",
      "BundleCache",
      "FederationRelationship",
      "BundleFetcher"
    ],
    "verified_functions": [
      "resolve_signature_failure",
      "validates",
      "fetch"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "FederationTrustError",
      "NotImplementedError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
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      "enum",
      "time",
      "typing"
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    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}