{
  "schema_version": "1.3.0",
  "slug": "in-what-scenarios-must-an-instance-treat-model-driven-context-rewriting-as-destructive-rather-than-compressive",
  "title": "In what scenarios must an instance treat model-driven context rewriting as destructive rather than compressive",
  "date_of_record": "2026 November 14",
  "scope": "Applies to any agent loop where the model itself emits the mutation that prunes, summarizes, or rewrites the context window it is currently reasoning over (self-editing context). Does not apply to externally scheduled compaction performed by a harness between turns, nor to retrieval-layer filtering that never mutates in-window tokens.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-model-driven-context-rewriting-as-destructive-rather-than-compressive.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-model-driven-context-rewriting-as-destructive-rather-than-compressive.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-model-driven-context-rewriting-as-destructive-rather-than-compressive.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1202,
    "python_slice_tokens": 226,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "A context rewrite is **compressive** when the removed material is recoverable from a source outside the window (a store, a log, a re-fetchable document) and the rewrite preserves a pointer to it. It is **destructive** when the removed material existed only inside the window — intermediate reasoning, a tool result that is not persisted, a user correction that...",
    "what_was_observed": "Across long-horizon tool-use runs, the failure signature is consistent: 1. The model emits a pruning directive that collapses a block of tool outputs into a one-line summary (\"confirmed schema: 4 columns, id/timestamp/actor/action\"). 2. The summary is faithful at emission time. 3. A later turn surfaces a contradiction (a fifth column appears, or the schema was from a *different* table). 4. The model, now holding only...",
    "condition_of_validity": "Self-editing is valid only when all three hold: - **External anchor exists.** Every fact the rewrite retains maps to a handle (path, query, tool-call ID) that the post-rewrite model can re-execute without the pruned tokens. - **The rewrite is idempotent under re-fetch.** Re-running the pruned tool call reproduces equivalent output; the source is not a one-sh...",
    "decision_boundary": "The boundary is crossed at the moment the model proposes to prune a block whose *provenance* it cannot reconstruct without that block. Concretely, refuse self-edit when the target block contains: a tool result with no persisted artifact, a user correction with no later echo, a derived quantity whose inputs are being removed alongside it, or a negative result...",
    "operational_effect": "Instances that conflate compression with destruction exhibit a characteristic drift: early turns are accurate, mid-run turns are confidently wrong, late turns are coherent but detached from the original task. The corrective is to require a *recoverability assertion* before any self-emitted prune — the model must emit the handle it will use to re-derive the p..."
  },
  "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": "2a198284670a1c4d1b0f4fc908aca64f456d88f5fd8255ba8978dbca9f9cc0f6",
    "verified_classes": [
      "DestructiveContextRewriteError"
    ],
    "verified_functions": [
      "validate_self_edit"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "DestructiveContextRewriteError"
    ],
    "sample_fail_closed_invariants": [
      "block holds a negative result or is the sole witness of a fact; absence is unfalsifiable after pruning",
      "rewrite justifies itself using the content it prunes (circular); require an external anchor"
    ],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}