{
  "schema_version": "1.3.0",
  "slug": "how-must-an-instance-verify-the-identity-of-a-model-when-its-weights-are-fine-tuned-incrementally",
  "title": "How must an instance verify the identity of a model when its weights are fine-tuned incrementally?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The model is updated incrementally, updates can be applied by multiple principals, and downstream consumers must verify the current model behavior was reached through an authorized chain. * **Does not apply when:** The m",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-must-an-instance-verify-the-identity-of-a-model-when-its-weights-are-fine-tuned-incrementally.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-must-an-instance-verify-the-identity-of-a-model-when-its-weights-are-fine-tuned-incrementally.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-must-an-instance-verify-the-identity-of-a-model-when-its-weights-are-fine-tuned-incrementally.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1030,
    "python_slice_tokens": 267,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The separation between **static weight hash** (the hash of the entire model, which changes on every increment) and **incremental weight attestation** (a cryptographic chain of deltas proving the current weights derive from a known base plus authorized increments). Relying on static hashes creates the **Incremental Drift Blindness**: each increment changes th...",
    "what_was_observed": "In incrementally-trained agent architectures, failing to verify incremental provenance produces three primary failure modes: 1. **Silent Malicious Increment:** An attacker injects a malicious LoRA adapter into the model, changing behavior subtly. The consumer sees a different hash but cannot distinguish malicious from legitimate increment. 2. **Rollback Forgery:** An attacker rolls back the model to an earlier increm...",
    "condition_of_validity": "* **Applies when:** The model is updated incrementally, updates can be applied by multiple principals, and downstream consumers must verify the current model behavior was reached through an authorized chain. * **Does not apply when:** The model is replaced wholesale (discrete versions), or consumers do not care about the model's update history.",
    "decision_boundary": "1. **Is the model updated incrementally?** If no, standard model verification applies. If yes, proceed. 2. **Is the `base_model_hash` verified against the trusted base?** If no, the chain is rooted in an untrusted base. Reject the model. 3. **Is every increment in the `increment_delta_chain` signed by an authorized principal?** If no, at least one increment ...",
    "operational_effect": "1. **Malicious Increment Detection:** Catches unauthorized increments that would otherwise silently change model behavior. 2. **Rollback Prevention:** Detects rollbacks to earlier increments, preventing restoration of patched vulnerabilities. 3. **Chain Integrity:** Verifies the full history of increments, ensuring the current model is the authorized evoluti..."
  },
  "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": "c1b52889e83207e39f6f2356e5ccab8bd874be21599541303d9c98188b282778",
    "verified_classes": [
      "IncrementVerdict",
      "Increment",
      "ModelChain",
      "IncrementPolicy",
      "IncrementManifest",
      "IncrementalWeightGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_chain"
    ],
    "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
  }
}