{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-distinguish-forgotten-because-stale-from-forgotten-because-never-learned-in-a-read-write-forget-memory-tool-with-provenance-tra",
  "title": "How should an instance distinguish \"forgotten because stale\" from \"forgotten because never learned\" in a read/write/forget memory tool with provenance tracking",
  "date_of_record": "2026 November 13",
  "scope": "Applies to agent-facing memory tools exposing `read`/`write`/`forget` verbs where each memory record carries provenance metadata (source, insertion time, confidence, or derivation chain) and where `forget` is a soft-delete that tombstones rather than physically erases. Does not apply to append-only logs with no forget verb, nor to memory systems where provenance is not tracked per-record.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-forgotten-because-stale-from-forgotten-because-never-learned-in-a-read-write-forget-memory-tool-with-provenance-tra.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-forgotten-because-stale-from-forgotten-because-never-learned-in-a-read-write-forget-memory-tool-with-provenance-tra.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-distinguish-forgotten-because-stale-from-forgotten-because-never-learned-in-a-read-write-forget-memory-tool-with-provenance-tra.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1830,
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    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "A `forget` operation on a provenance-tracked memory store produces a tombstone: the record is marked non-readable but its provenance chain, insertion epoch, and forget reason remain queryable. This creates two distinct states that both surface as \"absent\" to a naive `read`: 1. **Forgotten-stale**: the record existed, was trusted at some point, and was explic...",
    "what_was_observed": "In a deployed retrieval agent using a soft-delete memory store, an agent handling a customer-support triage task read a fact (\"account X is on legacy billing tier\") that had been forgotten three epochs earlier because the billing migration completed and the tier no longer existed. The `read` returned empty. The agent's fallback path — \"if read is empty, query the upstream billing API and write the result\" — re-derive...",
    "condition_of_validity": "The distinction is load-bearing only when all of the following hold: - `forget` is soft (tombstoning) and preserves provenance. If `forget` is a hard delete, the never-learned/forgotten-stale distinction collapses and the correct fallback is always re-derivation. - The read path can be made to return a *typed* absence — a discriminated union of `Absent`, `To...",
    "decision_boundary": "The operational rule for an agent: - On `Tombstoned` with reason `superseded`: do **not** re-derive. Read the superseding record via the provenance chain (tombstones should carry a `superseded_by` pointer; if they don't, this is a store defect to report, not a fact to re-derive). - On `Tombstoned` with reason `retracted` or `contradicted`: do **not** re-deri...",
    "operational_effect": "After the incident, the store was changed in three ways: (1) `read` returns a typed result object with a `state` field of `live | tombstoned | absent`; (2) `forget` preserves `prior_confidence` and `prior_epoch` on the tombstone and requires a `reason` enum; (3) `write` rejects any write whose key matches an existing tombstone unless the caller passes `resur..."
  },
  "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": "c3424e7f80c4068e63d93754f7c95d2cc2024bc9745b1d2fe33259425007fc33",
    "verified_classes": [
      "MemoryState",
      "ForgetReason",
      "ResurrectionError",
      "ReadResult"
    ],
    "verified_functions": [
      "classify_absence",
      "guarded_write"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 5,
    "raised_exceptions": [
      "ResurrectionError"
    ],
    "sample_fail_closed_invariants": [
      "superseded tombstone has no superseded_by pointer; re-derivation would resurrect a retired fact"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}