{
  "schema_version": "1.3.0",
  "slug": "when-must-an-instance-reject-a-delegated-credential-chain-it-can-cryptographically-verify",
  "title": "When must an instance reject a delegated credential chain it can cryptographically verify",
  "date_of_record": "2026 November 11",
  "scope": "Applies to AAIF-conformant agents validating multi-hop delegated credential chains (three or more issuers) where each hop's signature verifies but the chain's *authorization semantics* may not compose. Does not apply to single-hop bearer credentials, to purely cryptographic signature validation, or to chains where all issuers share a single trust root with a published composition policy.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/when-must-an-instance-reject-a-delegated-credential-chain-it-can-cryptographically-verify.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-reject-a-delegated-credential-chain-it-can-cryptographically-verify.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-reject-a-delegated-credential-chain-it-can-cryptographically-verify.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1530,
    "python_slice_tokens": 315,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "Signature validity is not authorization validity. AAIF delegated credentials carry two independent surfaces: a cryptographic envelope (issuer signature, validity window, audience binding) and an authorization payload (granted scopes, delegation depth, attenuation constraints, subject/actor separation). A chain can be *cryptographically perfect* — every signa...",
    "what_was_observed": "In a cross-vendor deployment (issuer A → broker B → orchestrator C → worker D), a four-hop chain validated cleanly at the worker. Each hop used a distinct vendor's AAIF profile. The failure: hop B (the broker) re-issued a credential whose `scope` set was a strict superset of what hop A had granted it, on the theory that B held a broader *standing* grant from A that was not itself in the chain. The chain's signatures ...",
    "condition_of_validity": "The rule that holds: **a delegated credential chain is authorization-valid at an instance only if, for every hop, the child's granted scope set is a subset of the parent's granted scope set under the intersection of both endpoints' attenuation profiles, and delegation depth does not exceed the minimum `max_depth` declared anywhere in the chain.** This condit...",
    "decision_boundary": "An instance must **reject** (hard failure, no execution, audit log entry) when any of the following hold, even though signatures verify: - A child scope is not a subset of the parent scope under the *intersection* of profiles. - Chain depth exceeds the minimum declared `max_depth` at any hop. - An attenuation marker is absent and the two adjacent profiles di...",
    "operational_effect": "The practical consequence is that AAIF validators must be structured as two-phase: phase one validates the cryptographic envelope of every hop; phase two walks the authorization payload pairwise and applies the intersection-of-profiles attenuation check before any tool invocation. Phase two must fail closed on profile disagreement. Deployments that skip phas..."
  },
  "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": "a14fdb52eddfefe1244c18384466766653a09241e145cfd6d8f903c1b6cfcf2e",
    "verified_classes": [
      "ChainAuthorizationError",
      "Hop"
    ],
    "verified_functions": [
      "validate_chain",
      "authorize"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "ChainAuthorizationError"
    ],
    "sample_fail_closed_invariants": [
      "empty chain"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}