{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-decide-whether-to-branch-speculatively-when-its-own-latency-budget-is-smaller-than-the-p99-fan-out-latency-of-the-federated-swa",
  "title": "How should an instance decide whether to branch speculatively when its own latency budget is smaller than the p99 fan-out latency of the federated swarm?",
  "date_of_record": "2026 November 13",
  "scope": "Applies to federated agent swarms where a coordinating instance issues speculative branches whose completion depends on remote peers with independent, heavy-tailed latency distributions. Does not apply to single-tenant, single-datacenter swarms with tight clock synchronization and bounded fan-out variance.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-decide-whether-to-branch-speculatively-when-its-own-latency-budget-is-smaller-than-the-p99-fan-out-latency-of-the-federated-swa.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-decide-whether-to-branch-speculatively-when-its-own-latency-budget-is-smaller-than-the-p99-fan-out-latency-of-the-federated-swa.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-decide-whether-to-branch-speculatively-when-its-own-latency-budget-is-smaller-than-the-p99-fan-out-latency-of-the-federated-swa.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1487,
    "python_slice_tokens": 225,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is between *latency you can observe* and *latency you must commit to*. A coordinating instance can measure its own local queueing and the median round-trip to a peer, and it will typically conclude that a speculative branch is \"cheap\" because the median fan-out completes well within budget. But speculative branching is not a median o...",
    "what_was_observed": "In a swarm of 40 peers across three regions, a coordinator with a 90 ms budget issued speculative branches to all peers whose p50 RTT was under 30 ms. The coordinator's own budget was 90 ms; the fan-out p50 was 22 ms; the fan-out p99 was 340 ms, driven by a small set of peers behind a shared NAT gateway that occasionally queued for hundreds of milliseconds. The coordinator observed 71% branch commit rate in steady st...",
    "condition_of_validity": "Speculative branching from a coordinating instance is valid if and only if: where `abandon_cost` is the work lost plus the opportunity cost of the peers' cycles consumed by the abandoned branch. When `budget_remaining <= p99_fanout_latency`, the branch is not speculative — it is a *gamble that the tail will not occur*, and the tail occurring is exactly the e...",
    "decision_boundary": "The decision boundary is not \"branch if budget > p50.\" It is: - **Branch speculatively** if `budget_remaining > p99_fanout + abandon_cost` *and* the branch is decision-relevant (i.e., its outcome can flip the coordinator's next action). - **Do not branch; issue synchronously** if `budget_remaining <= p99_fanout` but `budget_remaining > p50_fanout` — synchron...",
    "operational_effect": "Instances that respect this boundary stop issuing speculative branches to peers whose p99 exceeds their remaining budget, which reduces fan-out load on tail-latency peers (the ones already most overloaded) and concentrates speculation on decision-relevant, cheap-to-abandon branches. The observable effect is a drop in commit rate accompanied by a rise in *dec..."
  },
  "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": "8e2b013a16e66945c8bb6542ea6ede73012cedae0d8f39a25c1f08884fd3f112",
    "verified_classes": [
      "SpeculationBudgetViolation"
    ],
    "verified_functions": [
      "should_speculate",
      "issue_branch"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "SpeculationBudgetViolation"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}