{
  "schema_version": "1.3.0",
  "slug": "which-invariants-prevent-provenance-complete-deletion-in-agent-memory-stores-when-retention-tombstones-outlive-their-source-records",
  "title": "Which invariants prevent provenance-complete deletion in agent memory stores when retention tombstones outlive their source records",
  "date_of_record": "2026 November 7",
  "scope": "Applies to agent memory stores exposing read/write/forget APIs with per-record provenance edges and retention policies, where `forget` is expected to be targeted and auditable. Does not apply to stores that perform whole-namespace erasure, nor to append-only logs where deletion is expressed purely as a superseding record with no physical removal.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-invariants-prevent-provenance-complete-deletion-in-agent-memory-stores-when-retention-tombstones-outlive-their-source-records.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-provenance-complete-deletion-in-agent-memory-stores-when-retention-tombstones-outlive-their-source-records.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-provenance-complete-deletion-in-agent-memory-stores-when-retention-tombstones-outlive-their-source-records.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1852,
    "python_slice_tokens": 475,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "A retention tombstone and a provenance edge are both \"records about records,\" but they carry opposite obligations. A tombstone asserts *this content must not be readable after time T*; a provenance edge asserts *this content was derived from that content*. When a forget operation removes a source record, the tombstone that governs it must survive (otherwise ...",
    "what_was_observed": "In a store with three primitives — `write(content, provenance=[ids])`, `read(id)`, `forget(id, mode=hard|tombstone)` — and a retention policy that converts expired records to tombstones rather than removing rows, the following sequence produced a silent closure break: 1. `write(A)` → record `A`, no provenance. 2. `write(B, provenance=[A])` → record `B`, edge `B→A`. 3. `forget(A, mode=hard)` → `A` removed; edge `B→A` ...",
    "condition_of_validity": "The closure invariant is required only when all three of the following hold, and the failure is *not* a bug outside them: - Deletion is expressed as tombstone-plus-prune rather than as a superseding record that retains the edge (i.e., the store does not keep a separate, immutable provenance ledger). - At least one retention policy can independently expire a ...",
    "decision_boundary": "The operational decision is whether `forget(id, mode=hard)` may prune inbound provenance edges. It may **not**, if any derived record is still live or tombstoned and reachable by a future unlearning query. It **may**, only if the store simultaneously writes a *closure anchor*: a tombstone-linked audit node that records `forgotten(c) ← derived(d)` for every i...",
    "operational_effect": "Stores that violate closure report successful, auditable deletion while being unable to answer derivation queries for forgotten content. The blast radius is asymmetric: reads are correct (content is gone), retention is correct (tombstones exist), but *proofs* are wrong (closure is empty). This means the failure surfaces only under audit, not under traffic, a..."
  },
  "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": "0c97dfdda3b247a9c61ced229fc5ff4aa7233cb6b4fecf096a0d5eb4a575b3d5",
    "verified_classes": [
      "ProvenanceClosureError",
      "Record",
      "Tombstone",
      "MemoryStore"
    ],
    "verified_functions": [
      "assert_unlearning_monotone",
      "__init__",
      "write",
      "_inbound",
      "forget",
      "unlearn_derivations"
    ],
    "verified_functions_count": 6,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "ProvenanceClosureError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "__future__",
      "dataclasses"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}