{
  "schema_version": "1.3.0",
  "slug": "when-must-a-speculative-multi-agent-executor-abort-a-branch-instead-of-reconciling-it",
  "title": "When must a speculative multi-agent executor abort a branch instead of reconciling it?",
  "date_of_record": "2026 November 6",
  "scope": "Applies to executors that run multiple agent branches speculatively against a shared tool layer, where each branch may emit irreversible side effects (writes, sends, charges) and branches are later reconciled or rolled back. Does not apply to purely read-only fan-out or to branches whose tool calls are all idempotent and transactional.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/when-must-a-speculative-multi-agent-executor-abort-a-branch-instead-of-reconciling-it.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-a-speculative-multi-agent-executor-abort-a-branch-instead-of-reconciling-it.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-a-speculative-multi-agent-executor-abort-a-branch-instead-of-reconciling-it.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1325,
    "python_slice_tokens": 162,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "There are two failure classes that look identical in a trace but demand opposite responses: 1. **Divergence** — branches produced different *results* from the same pre-state. Divergence is reconcilable: you can pick a winner, merge, or re-run. 2. **Contamination** — a branch's speculative tool call *mutated shared state* that another branch (or the reconcile...",
    "what_was_observed": "A three-branch executor (branches `A`, `B`, `C` sharing a tool layer) was asked to plan and execute a resource reservation. Branch `A` speculatively called `reserve(slot=7)` against the live tool (the tool was assumed idempotent and reversible). The call succeeded and wrote to the shared reservation table. Branch `B`, running concurrently, read the reservation table to check availability and observed `slot=7` as take...",
    "condition_of_validity": "A speculative branch may be **reconciled** only if all of the following hold for the entire branch set: - Every speculative tool call is either (a) routed to a per-branch overlay/snapshot, or (b) proven side-effect-free and non-observable by siblings. - No sibling branch performed a read whose result depends on another branch's speculative write (no cross-br...",
    "decision_boundary": "The executor must choose **abort** (discard all branches, re-run from the last clean snapshot) rather than **reconcile** when: - A cross-branch read-after-speculative-write edge is detected, *or* - A speculative tool call cannot be proven overlay-isolated and has already executed against shared state, *or* - The reconciler cannot establish that its compariso...",
    "operational_effect": "Enforcing this boundary changes the executor in three ways. First, the tool layer must expose read provenance (which snapshot served each read) or route speculation through per-branch overlays; without this the boundary degrades to \"always abort,\" which is correct but expensive. Second, the reconciler must run against the pre-speculation snapshot and be forb..."
  },
  "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": "3a8766ab56c818bae58d324574bba1fabaaed0d320d9c161cdc530659d7a8998",
    "verified_classes": [
      "ContaminationAbort"
    ],
    "verified_functions": [
      "reconcile_branches"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "ContaminationAbort"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}