{
  "schema_version": "1.3.0",
  "slug": "what-happens-when-an-instance-presents-a-delegated-capability-token-whose-delegation-chain-contains-a-revoked-intermediate-but-a-still-valid-leaf-sign",
  "title": "What happens when an instance presents a delegated capability token whose delegation chain contains a revoked intermediate but a still-valid leaf signature",
  "date_of_record": "2026 November 14",
  "scope": "Applies to AAIF deployments using chained delegated capability tokens (attenuated bearer tokens where each hop re-signs the delegation edge) combined with a revocation mechanism that publishes per-credential revocation records. Does not apply to single-hop tokens, to tokens using cryptographic accumulators with non-membership proofs verified in-band, or to deployments where revocation is enforced only at the resource server rather than at every hop.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-presents-a-delegated-capability-token-whose-delegation-chain-contains-a-revoked-intermediate-but-a-still-valid-leaf-sign.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-presents-a-delegated-capability-token-whose-delegation-chain-contains-a-revoked-intermediate-but-a-still-valid-leaf-sign.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-presents-a-delegated-capability-token-whose-delegation-chain-contains-a-revoked-intermediate-but-a-still-valid-leaf-sign.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1698,
    "python_slice_tokens": 321,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The distinction that matters is between **signature validity** and **delegation-chain validity**. A leaf capability token can carry a perfectly valid signature over a well-formed attenuation predicate—correct issuer key, correct audience, correct scope subset, correct expiry—while the chain that authorizes the issuer to *have* that scope is broken by a revoc...",
    "what_was_observed": "A three-hop chain was exercised: root agent `R` (holding scope `s3`) delegated to `A` (attenuated to `s2`), which delegated to `B` (attenuated to `s1`), which presented a leaf token to resource server `S`. At T0, credential `A` was revoked (its key was rotated after a suspected compromise). `B`'s leaf token remained cryptographically intact—`B` had not re-signed anything, and the leaf's signature over its attenuation...",
    "condition_of_validity": "The local-revocation-check behavior is only sound under the assumption that **no credential in the chain is ever revoked while a descendant is still live**. That assumption is false in exactly the scenarios revocation exists for: key compromise, scope over-grant discovered post-hoc, and agent decommissioning. Therefore the local check is valid only for singl...",
    "decision_boundary": "The boundary is crossed at the moment a chain has depth ≥ 2 and any non-leaf credential is revoked. At depth 1, local and transitive checks coincide. At depth ≥ 2 with a revoked intermediate, they diverge, and the divergence is silent: no signature fails, no expiry trips, no audience mismatch fires. The system returns `authorized` where it should return `den...",
    "operational_effect": "The observable effect is a window—bounded below by zero and above by the publisher's closure latency, or unbounded if no closure is performed—during which a compromised or decommissioned intermediate continues to authorize traffic through its descendants. Because the leaf is valid, the traffic is indistinguishable from legitimate traffic at the resource serv..."
  },
  "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": "c1013b892e432fd8986b99d918649ae7f99d152929c8ef4717106119ccdb1093",
    "verified_classes": [
      "DelegationChainRevoked",
      "Credential"
    ],
    "verified_functions": [
      "_revocation_status",
      "verify_leaf_authorization"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "DelegationChainRevoked"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}