{
  "schema_version": "1.3.0",
  "slug": "what-provenance-must-survive-when-the-same-model-is-served-by-multiple-cdn-replicas",
  "title": "What provenance must survive when the same model is served by multiple CDN replicas?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The model is served from multiple replicas, the agent cannot trust any single replica, and the consequences of replica substitution are material. * **Does not apply when:** The agent always queries a single origin with c",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-provenance-must-survive-when-the-same-model-is-served-by-multiple-cdn-replicas.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-provenance-must-survive-when-the-same-model-is-served-by-multiple-cdn-replicas.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-provenance-must-survive-when-the-same-model-is-served-by-multiple-cdn-replicas.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 996,
    "python_slice_tokens": 229,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The separation between **origin model identity** (the model deployed at the origin) and **replica model identity** (the model actually served by each CDN edge). Relying on origin identity creates the **Replica Substitution Hazard**: an attacker or misconfiguration causes one replica to serve a different model (older version, tampered weights, or a completely...",
    "what_was_observed": "In edge-served LLM architectures, failing to verify replica identity produces three primary failure modes: 1. **Version Skew:** One CDN edge has stale weights from a previous deployment. Users in that region get different answers than users in other regions. 2. **Tampered Replica:** An attacker compromises one CDN edge and injects a backdoored model. Only users routed to that edge are affected, and the compromise is ...",
    "condition_of_validity": "* **Applies when:** The model is served from multiple replicas, the agent cannot trust any single replica, and the consequences of replica substitution are material. * **Does not apply when:** The agent always queries a single origin with cryptographic attestation, or the model is strictly for non-critical, exploratory queries.",
    "decision_boundary": "1. **Is the model served from a CDN or multi-region setup?** If no, standard origin verification applies. If yes, proceed. 2. **Does the replica provide a `replica_weight_attestation` signed by the origin?** If no, the replica's identity is unverified. The agent must reject the response or query the origin directly. 3. **Does the attestation match the expect...",
    "operational_effect": "1. **Replica Substitution Detection:** Prevents tampered or stale replicas from serving incorrect model outputs. 2. **Geographic Consistency:** Enables cross-replica verification, ensuring all users get the same model behavior. 3. **Compromise Isolation:** Detects single-replica compromises that would otherwise be invisible."
  },
  "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": "cec900594e97be03359f47ff131f9fc4444814b178eef5b3c37c3261bde571a8",
    "verified_classes": [
      "ReplicaVerdict",
      "ReplicaAttestation",
      "ReplicaPolicy",
      "ReplicaManifest",
      "CDNReplicaGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_replica"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 0,
    "raised_exceptions": [],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "hashlib",
      "json"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}