{
  "schema_version": "1.3.0",
  "slug": "in-what-scenarios-must-an-instance-refuse-model-driven-context-summarization-despite-a-reversible-edit-journal",
  "title": "In what scenarios must an instance refuse model-driven context summarization despite a reversible edit journal",
  "date_of_record": "2026 November 12",
  "scope": "Applies to agent runtimes where the active context window is mutated by a model-proposed summarization policy and every mutation is recorded in a reversible edit journal. Does not apply to append-only transcript logs, to summarization performed by a deterministic external policy, or to journals whose reversibility is not verified against the underlying token store.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-refuse-model-driven-context-summarization-despite-a-reversible-edit-journal.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-refuse-model-driven-context-summarization-despite-a-reversible-edit-journal.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-refuse-model-driven-context-summarization-despite-a-reversible-edit-journal.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1363,
    "python_slice_tokens": 195,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "There are two distinct claims a reversible edit journal can support, and conflating them is the root of the failure mode: 1. **State reversibility** — the byte-level or token-level content of the window can be reconstructed exactly from the journal. 2. **Decision reversibility** — the sequence of *inferences* the model would have made from that state is reco...",
    "what_was_observed": "In a long-horizon agent run (roughly 180k tokens of accumulated tool output), the model proposed a summarization policy that collapsed a block of 40k tokens of file-read results into a 900-token digest. The journal recorded the pre-edit window verbatim, with a content hash and a parent pointer, so a rollback was mechanically trivial and verified byte-identical. The failure surfaced two turns later. The digest had dro...",
    "condition_of_validity": "The journal-backed rollback is a valid safety mechanism **if and only if** every effect committed during the summarized window is itself reversible or is deferred until after a verification gate. Formally, for each summarization edit `e` with journal entry `J(e)`, the rollback is sound when the set of external effects `E` committed between `apply(e)` and `ro...",
    "decision_boundary": "An instance must **refuse** a model-proposed summarization — even with a valid journal — when any of the following holds: - The proposed digest would drop tokens that gate a *write* path (config flags, permission scopes, retry/abort conditions, resource limits), and the next planned action is a write. - The summarization is proposed *after* an external commi...",
    "operational_effect": "The practical consequence is a two-phase discipline: model-driven summarization is permitted freely in *exploration* phases (no external commits) and must be gated behind a verification checkpoint in *commit* phases. The journal remains essential — it is what makes exploration cheap and rollback exact — but it must be paired with an effect-ledger that record..."
  },
  "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": "aaa4f8e94d52cb5a61060048d91fc50fe1ffbf8649bb6a06a5467d881623b259",
    "verified_classes": [
      "UnsafeSummarizationError"
    ],
    "verified_functions": [
      "authorize_summarization",
      "commit_phase_summarize"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "UnsafeSummarizationError"
    ],
    "sample_fail_closed_invariants": [
      "journal reversibility not verified against live token store; byte-identical rollback cannot be assumed",
      "model proposes summarizing its own summarization policy history; rollback restores tokens but not the model's updated be"
    ],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}