{
  "schema_version": "1.3.0",
  "slug": "when-must-an-instance-refuse-to-resume-from-a-lossy-context-recovery-marker",
  "title": "When must an instance refuse to resume from a lossy-context recovery marker?",
  "date_of_record": "2026 November 6",
  "scope": "Applies to any agent runtime that persists hierarchical summaries (L0 raw → L1 turn summaries → L2 session digests) and emits recovery markers pointing into a summarized tier rather than the raw log. Does not apply to systems that always retain the full raw transcript and treat summaries as pure read-only accelerators.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-resume-from-a-lossy-context-recovery-marker.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-resume-from-a-lossy-context-recovery-marker.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-an-instance-refuse-to-resume-from-a-lossy-context-recovery-marker.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1078,
    "python_slice_tokens": 149,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "A recovery marker is a *pointer plus a promise*: the pointer identifies a summary node, and the promise is that the node contains every fact required to continue the task without re-reading the raw log. Auto-compaction silently invalidates the promise when the compaction pass that produced the marker summarized *across* an unresolved dependency — an open too...",
    "what_was_observed": "In a long-running migration agent, compaction fired every 40 turns. At turn 312 the L2 digest recorded: \"User requested the schema migration be reversible; agent explored approaches.\" The raw L0 log contained the operative fact that the user had *rejected* the add-column-then-backfill approach after a failed dry run, and that a rollback script already existed at `migrations/003_down.sql`. The L2 summarizer folded the...",
    "condition_of_validity": "A recovery marker is safe to resume from iff all three hold: 1. **Closure:** every open tool call, file handle, or subprocess referenced before the compaction boundary is either resolved in the summary tier or explicitly marked `UNRESOLVED` in it. 2. **Negative-fact retention:** every rejected/failed/superseded item in the compacted span appears in the summa...",
    "decision_boundary": "The non-obvious part: *do not repair the summary at resume time*. The tempting fix — have the resuming agent re-read the raw log to \"fill gaps\" — reintroduces the full context the compaction was meant to shed, and worse, does so non-deterministically, so two resumes from the same marker diverge. The correct boundary is: markers are either *trusted wholesale*...",
    "operational_effect": "Runtimes that enforce the three-condition check at marker emission see resume divergence drop to zero at the cost of ~8% more raw-checkpoint fallbacks. The fallbacks are cheap because they occur only after a compaction that spanned an unresolved dependency — precisely the compactions that were unsafe anyway. The invariant to encode: *a recovery marker is a c..."
  },
  "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": "859df5341a4ec3b73e4bb7a600f3b0e853f14d453789ea7d2d7a6ece829f3cb2",
    "verified_classes": [
      "MarkerInvalid"
    ],
    "verified_functions": [
      "validate_marker",
      "resume"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "MarkerInvalid"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}