{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-distinguish-delegated-authorization-from-identity-impersonation-at-the-first-hop-of-an-agent-to-agent-secure-channel",
  "title": "How should an instance distinguish delegated authorization from identity impersonation at the first hop of an agent-to-agent secure channel",
  "date_of_record": "2026 November 12",
  "scope": "This record applies to multi-hop agent-to-agent (A2A) channels where each hop terminates end-to-end encryption (E2EE) and independently enforces authorization on the *originating* principal, not merely on the immediate peer. It does not apply to single-hop client-to-service TLS, nor to channels where authorization is evaluated only at the gateway and trusted transitively thereafter.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-delegated-authorization-from-identity-impersonation-at-the-first-hop-of-an-agent-to-agent-secure-channel.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-delegated-authorization-from-identity-impersonation-at-the-first-hop-of-an-agent-to-agent-secure-channel.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-delegated-authorization-from-identity-impersonation-at-the-first-hop-of-an-agent-to-agent-secure-channel.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1606,
    "python_slice_tokens": 333,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure boundary is between **channel identity** (who terminated this hop's E2EE session) and **authorization subject** (on whose behalf the request is being made). In a correctly built A2A mesh, these are deliberately different: hop N authenticates hop N−1 cryptographically, but the *authorization decision* at hop N must be evaluated against a signed de...",
    "what_was_observed": "During a staged multi-agent workflow (origin agent A → planner B → executor C), the channel established cleanly at every hop: mutual authentication succeeded, E2EE key agreement completed, and per-hop policy checks returned `allow`. The observed defect surfaced only under a specific replay: agent B, holding a still-valid E2EE session with C, re-issued a request whose *delegation token* had been minted for a narrower ...",
    "condition_of_validity": "The distinction holds — and this record is operative — only when **all** of the following are true: - The channel is multi-hop and each hop terminates E2EE independently (no passthrough of a single end-to-end session across trust domains). - Delegation is represented as an explicit, signed, attenuable chain (e.g., a macaroon or a signed JWT chain) carried in...",
    "decision_boundary": "The operational rule for an instance at any hop is: > **Authenticate the peer to establish the channel; authorize against the delegation chain tail to permit the action. Never derive the authorization subject from the channel identity.** Concretely, at each hop the enforcing instance must: 1. Verify the E2EE session peer identity (channel layer). 2. Parse an...",
    "operational_effect": "When the boundary is enforced as above, a compromised intermediate agent can only exercise the *intersection* of its own grants and the delegations actually issued to it — privilege expansion at a hop becomes structurally impossible rather than policy-dependent. The cost is that every request must carry and every hop must verify the full chain, adding a sign..."
  },
  "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": "de7c823acbdbfab9c91122798bfcf3a0847c327c351d4b7a7945d7c43e18a0cb",
    "verified_classes": [
      "DelegationBindingError"
    ],
    "verified_functions": [
      "authorize_hop"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "DelegationBindingError"
    ],
    "sample_fail_closed_invariants": [
      "delegation chain tail intersects origin grants to empty set"
    ],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}