{
  "schema_version": "1.3.0",
  "slug": "what-memory-invariants-must-survive-a-fleet-wide-model-update-rollout-in-multiple-phases",
  "title": "What memory invariants must survive a fleet-wide model update rollout in multiple phases?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The model update is phased (not atomic), the fleet shares memory across model versions, and version incompatibility is possible. * **Does not apply when:** The model update is atomic (all agents update simultaneously), o",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-memory-invariants-must-survive-a-fleet-wide-model-update-rollout-in-multiple-phases.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-memory-invariants-must-survive-a-fleet-wide-model-update-rollout-in-multiple-phases.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-memory-invariants-must-survive-a-fleet-wide-model-update-rollout-in-multiple-phases.warrant.json"
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  "token_profile": {
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  "remnant_summary": {
    "core_distinction": "The separation between **atomic model rollout** (all agents update simultaneously to a single model version) and **phased rollout** (agents update in waves, creating a mixed-version fleet for the rollout duration). Relying on atomic-only semantics creates the **Mixed-Version Incompatibility**: Agent A on model v1 shares memory with Agent B on model v2, and e...",
    "what_was_observed": "In fleet-wide model update architectures, failing to handle mixed-version states produces three primary failure modes: 1. **Format Incompatibility:** Model v2 emits embeddings of a different dimension than v1. Agent A writes v1 embeddings, Agent B reads them assuming v2 dimensions, and retrieval fails silently. 2. **Behavioral Assumption Break:** Model v1 assumed certain tool outputs, but model v2 changes the expecte...",
    "condition_of_validity": "* **Applies when:** The model update is phased (not atomic), the fleet shares memory across model versions, and version incompatibility is possible. * **Does not apply when:** The model update is atomic (all agents update simultaneously), or the fleet's shared memory is strictly isolated per model version.",
    "decision_boundary": "1. **Is the model update atomic or phased?** If atomic, standard memory management applies. If phased, proceed. 2. **Is every memory record tagged with a `model_version_signature`?** If no, mixed-version records cannot be distinguished. The fleet must halt writes until tagging is enforced. 3. **Are cross-version records verified by `cross_version_compatibili...",
    "operational_effect": "1. **Format Incompatibility Prevention:** Prevents v1 and v2 embeddings from being silently mixed. 2. **Behavioral Assumption Safety:** Enforces that memory exchanges respect each model's assumptions. 3. **Clean Migration:** Provides deterministic migration protocols for post-rollout normalization."
  },
  "matched_failure_symptoms": [
    "OOM_KILL_OR_MEMORY_EXHAUSTION"
  ],
  "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": "e078d53458e8643ead82c7ec5cef8176414ab0244fb433859d90d52e0eb1af7c",
    "verified_classes": [
      "RolloutVerdict",
      "MemoryRecord",
      "RolloutContext",
      "RolloutManifest",
      "PhasedRolloutGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_record"
    ],
    "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
  }
}