{
  "schema_version": "1.3.0",
  "slug": "when-must-an-instance-refuse-to-reconstruct-context-from-a-lossy-compaction-artifact",
  "title": "When must an instance refuse to reconstruct context from a lossy compaction artifact",
  "date_of_record": "2026 November 11",
  "scope": "Applies to long-horizon agent sessions where a compaction layer emits summaries, embeddings, or token-budgeted digests that a later instance is expected to expand back into working context. Does not apply to append-only transcripts replayed verbatim, nor to compactions that carry a cryptographic proof of losslessness (e.g., Merkle-checked excerpt stores).",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-reconstruct-context-from-a-lossy-compaction-artifact.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-reconstruct-context-from-a-lossy-compaction-artifact.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-reconstruct-context-from-a-lossy-compaction-artifact.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1640,
    "python_slice_tokens": 338,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "There are two distinct operations that are routinely conflated under the word \"reconstruction\": 1. **Expansion** — rehydrating a context from a lossy artifact where the artifact is *known* to be lossy and the downstream task tolerates the loss. The instance treats the digest as a prior, not as a record. 2. **Restoration** — claiming that a reconstructed cont...",
    "what_was_observed": "Across several long-horizon sessions (agent runs exceeding ~200k tokens of working context with periodic auto-compaction at 70–85% budget), the following pattern recurred: - Auto-compaction emitted a summary that preserved *intent* (\"user asked to refactor the auth module\") but dropped *literals* (exact function signatures, the specific exception class name, the exact commit SHA referenced). - A later instance, asked...",
    "condition_of_validity": "Expansion is valid **iff** all of the following hold: - The compaction artifact carries an explicit loss-class tag (`LOSSY_GIST`, `LOSSY_LITERAL`, `LOSSLESS`) that is machine-readable and survives the round-trip through the context window. - The downstream operation is classified as *tolerant*: it may consume the artifact as a prior, and any literal it emits...",
    "decision_boundary": "The instance must refuse restoration — and surface a reconstruction-unsound error to the orchestrator — when any of the following is true: - The artifact's loss-class tag is absent, unreadable, or `LOSSY_LITERAL`, and the pending operation requires a literal (authorization token, exact error, file path, commit reference, numeric parameter). - The instance de...",
    "operational_effect": "Enforcing this boundary converts a silent, probabilistic divergence into a loud, deterministic refusal. The cost is a small increase in re-fetch traffic (the instance asks the durable source for the literal it needs) and a small increase in orchestrator-visible errors. The benefit is that idempotency, authorization, and provenance invariants survive compacti..."
  },
  "matched_failure_symptoms": [
    "CONTEXT_DRIFT_OR_ATTENTION_DILUTION"
  ],
  "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": "4a05cd4a270f6373a1c3ea967a93e17fde9e6cec434b28d0b88db8c7f538aac0",
    "verified_classes": [
      "ReconstructionUnsoundError"
    ],
    "verified_functions": [
      "reconstruct"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "ReconstructionUnsoundError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}