{
  "schema_version": "1.3.0",
  "slug": "when-must-an-instance-refuse-to-serve-a-tombstone-only-memory-scope",
  "title": "When must an instance refuse to serve a tombstone-only memory scope",
  "date_of_record": "2026 November 11",
  "scope": "Applies to memory tool APIs exposing read/write/forget operations with per-scope retention windows and deletion receipts (tombstones). Covers the case where every live record in a scope has been forgotten but the scope itself has not been dropped. Does not cover scope-level deletion (drop-scope), legal-hold overrides, or cross-scope referential integrity.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-serve-a-tombstone-only-memory-scope.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-serve-a-tombstone-only-memory-scope.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-serve-a-tombstone-only-memory-scope.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1499,
    "python_slice_tokens": 237,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is not \"deleted data is still readable.\" It is the opposite and quieter: a scope whose *entire* live set has been forgotten is indistinguishable, at the read API, from a scope that was never populated. Both return an empty result set. Both may return HTTP 200 with `records: []`. The distinction that matters operationally is whether the empty resu...",
    "what_was_observed": "A memory scope held 14 records written across three write epochs. A retention policy expired epoch 1 records after 30 days; a caller then issued `forget` over epochs 1 and 2 (11 records). The remaining 3 records in epoch 3 were forgotten individually via `forget(record_id)`. At this point the scope contained zero live records and 14 tombstones. A subsequent `read(scope)` returned `[]`. The calling agent interpreted `...",
    "condition_of_validity": "The refusal-to-serve rule is valid only when all of the following hold: 1. The scope is in `tombstone_only` state (live count = 0, tombstone count > 0). 2. The caller's request carries a write-epoch expectation (either explicit `expected_epoch` or inferable from a prior write receipt held by the caller). 3. The tombstone chain is *complete*: every tombstone ...",
    "decision_boundary": "The boundary is between **serving an empty list** and **refusing with a typed error**: - Live count > 0 → serve normally. Tombstones are irrelevant to the read. - Live count = 0, tombstone count = 0 → serve `[]` with `scope_state: \"never_populated\"`. This is a legitimate negative answer. - Live count = 0, tombstone count > 0, caller epoch expectation absent ...",
    "operational_effect": "Agents that receive a typed `TombstoneChainIncomplete` error must escalate to a reconciliation path: re-read the write receipt, query the tombstone log directly, or fall back to a durable source of truth. Agents that receive `scope_state: \"tombstone_only\"` with a complete receipt may safely conclude the data was deliberately forgotten and must **not** re-der..."
  },
  "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": "fa0027424305605be17d0e0053afae0d5b6686d53c1f6b800b330d202cca9877",
    "verified_classes": [
      "TombstoneChainIncomplete",
      "ScopeState"
    ],
    "verified_functions": [
      "read_scope"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "TombstoneChainIncomplete"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}