{
  "schema_version": "1.3.0",
  "slug": "what-happens-when-an-instance-commits-a-speculative-branch-whose-reconciliation-window-has-already-been-closed-by-a-concurrent-merge",
  "title": "What happens when an instance commits a speculative branch whose reconciliation window has already been closed by a concurrent merge",
  "date_of_record": "2026 November 14",
  "scope": "Applies to speculative multi-agent executors where agents fork state, execute against private branches, and reconcile via a shared merge point guarded by a monotonic reconciliation epoch. Does not apply to single-agent rollback, stateless fan-out with idempotent sinks, or systems where branch reconciliation is fully serialized behind a global lock.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-commits-a-speculative-branch-whose-reconciliation-window-has-already-been-closed-by-a-concurrent-merge.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-commits-a-speculative-branch-whose-reconciliation-window-has-already-been-closed-by-a-concurrent-merge.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-commits-a-speculative-branch-whose-reconciliation-window-has-already-been-closed-by-a-concurrent-merge.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1397,
    "python_slice_tokens": 290,
    "warrant_slice_tokens": 220
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  "remnant_summary": {
    "core_distinction": "The distinction that matters is between **branch validity** and **branch admissibility**. A speculative branch is *valid* if its computations were correct against the state snapshot it forked from. It is *admissible* if the reconciliation window (the epoch) into which it is being merged is still open and has not been superseded by a merge that already advanc...",
    "what_was_observed": "During a fan-out of four speculative agents over a shared record store, agent `B` forked at epoch `e=41`, executed for 8.2 seconds, and produced a valid mutation set. Meanwhile agents `A` and `C` merged first, advancing the store to `e=43`. Agent `B`'s reconciliation handler checked `branch.valid == True`, confirmed its preconditions against its *fork snapshot*, and committed. The commit was accepted because the reco...",
    "condition_of_validity": "The invariant that must hold is: > A branch may commit into epoch `E` only if `E` is the current epoch **and** the branch's fork point is an ancestor of `E` in the merge DAG — not merely numerically less than `E`. Numeric comparison (`fork_epoch <= current_epoch`) is the trap. It is monotone and always true for stale branches. The correct predicate requires ...",
    "decision_boundary": "When a branch arrives at reconciliation and `branch.fork_epoch < current_epoch` and the branch is not an ancestor of the current head, the executor has exactly two correct moves: 1. **Re-rebase**: replay the branch's mutation set against the current head with conflict detection. If it applies cleanly, commit at the new epoch. If it conflicts, escalate. 2. **...",
    "operational_effect": "The operational consequence is that reconciliation guards must be written against the merge DAG head, not against a scalar epoch, and that the failure must be made *loud at the merge site*. Silent acceptance converts a local ordering bug into a distributed consistency violation whose detection is deferred and whose blast radius includes every reader between ..."
  },
  "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": "671a4f555c0b16d726cd9e448185e77b6a30a3fe82a63ec0821b50b822d19c18",
    "verified_classes": [
      "ClosedReconciliationWindow",
      "Branch",
      "MergeDAG"
    ],
    "verified_functions": [
      "reconcile",
      "__init__",
      "is_ancestor"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "ClosedReconciliationWindow"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}