{
  "schema_version": "1.3.0",
  "slug": "what-structural-signals-indicate-an-audit-chain-fork-in-federated-agent-traces-and-why-hash-link-continuity-is-not-sufficient-evidence-of-linearity",
  "title": "What structural signals indicate an audit-chain fork in federated agent traces (and why hash-link continuity is not sufficient evidence of linearity)",
  "date_of_record": "2026 November 12",
  "scope": "Applies to federated agent audit systems where each domain emits a tamper-evident hash chain (per-domain append-only log with prev-hash linkage) and a separate correlation layer stitches cross-domain traces via trace/span identifiers. Does not apply to single-domain logging, to systems using a global consensus log with total ordering, or to correlation schemes that carry the full predecessor hash across domain boundaries.",
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    "unified_markdown_uri": "https://corpusfetch.com/c/what-structural-signals-indicate-an-audit-chain-fork-in-federated-agent-traces-and-why-hash-link-continuity-is-not-sufficient-evidence-of-linearity.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-structural-signals-indicate-an-audit-chain-fork-in-federated-agent-traces-and-why-hash-link-continuity-is-not-sufficient-evidence-of-linearity.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-structural-signals-indicate-an-audit-chain-fork-in-federated-agent-traces-and-why-hash-link-continuity-is-not-sufficient-evidence-of-linearity.warrant.json"
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  "remnant_summary": {
    "core_distinction": "There are two distinct integrity properties that operators routinely conflate: 1. **Chain integrity** — each domain's log is internally consistent: every record's `prev_hash` matches the hash of its immediate predecessor *within that domain*, and the domain's signed head is monotonic. 2. **Trace linearity** — the cross-domain causal sequence for a given `tra...",
    "what_was_observed": "In a three-domain federation (domains `A`, `B`, `C`; agent runtime in `A`, tool-execution gateway in `B`, policy/approval service in `C`), a replay of a partially failed run produced the following: - All three domain logs verified cleanly: `prev_hash` linkage intact, signed heads monotonic, no gaps in sequence numbers. - The correlation layer reported a single `trace_id` with **two spans at the same causal position**...",
    "condition_of_validity": "The distinction holds — and the failure is real — only under these conditions: - **Correlation identifiers are propagated, not derived.** If downstream domains derive their parent linkage from the received `trace_id`/`span_id` (as in W3C-style context propagation), a retry at the origin re-uses identifiers and produces the fork. If instead each hop appends a...",
    "decision_boundary": "Use the following boundary to decide whether a clean per-domain verification result is admissible as evidence of a sound trace: - **Admit per-domain verification as sufficient** only when the correlation contract guarantees (a) attempt-scoped identifiers (retries get new `span_id`s), and (b) the correlation layer rejects duplicate `(trace_id, parent_span, ca...",
    "operational_effect": "Once the fork query was added as a mandatory post-verification gate, the observed effects were: - Retry-induced forks surfaced as first-class audit findings rather than being silently normalized into legitimate fan-out. In the replay above, the fork was caught at the correlation layer within one ingest cycle instead of being discovered weeks later during an ..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
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      "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": "0893315b64dbc2dbd5314dfdea029f149a108d2c48514ddaccb76ce4e63260f9",
    "verified_classes": [
      "TraceForkError",
      "Span"
    ],
    "verified_functions": [
      "assert_trace_linearity"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "TraceForkError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "__future__",
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      "dataclasses"
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    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
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}