{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-detect-budget-starvation-before-subagent-fan-out-under-a-hard-token-ceiling",
  "title": "How should an instance detect budget starvation before subagent fan-out under a hard token ceiling",
  "date_of_record": "2026 November 8",
  "scope": "Applies to orchestrators that statically or adaptively allocate a shared token ceiling across N concurrently dispatched subagents, where each subagent's context budget is derived from a parent pool rather than granted independently. Does not apply to single-agent loops, to subagents with per-call metered billing (no shared pool), or to systems where the ceiling is soft and backpressure is applied by the model provider rather than the orchestrator.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-detect-budget-starvation-before-subagent-fan-out-under-a-hard-token-ceiling.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-detect-budget-starvation-before-subagent-fan-out-under-a-hard-token-ceiling.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-detect-budget-starvation-before-subagent-fan-out-under-a-hard-token-ceiling.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1842,
    "python_slice_tokens": 309,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is not \"the ceiling was exceeded.\" That is a loud, detectable error. The failure is **budget starvation masquerading as successful fan-out**: the parent computes a per-subagent budget, dispatches all N subagents, and every subagent returns a syntactically valid result — but the budgets were allocated against a *nominal* ceiling while the *reserve...",
    "what_was_observed": "In a fan-out of 8 subagents sharing a 200k-token ceiling, the orchestrator computed a per-subagent budget of 24k (200k / 8, rounded down) and reserved nothing. Observed behavior across runs: - **N=1:** 24k budget, peak usage 19k. Passes. - **N=4:** each budget 24k, aggregate peak ~96k. Passes. - **N=8:** aggregate peak ranged 168k–214k. Roughly 1 in 5 runs exceeded the ceiling. The excess was not concentrated in one ...",
    "condition_of_validity": "The naive equal-split allocation `budget_i = ceiling / N` is valid **only** when all three hold: 1. **Fixed per-subagent overhead is negligible or zero** relative to the per-subagent budget (in practice: overhead < 5% of budget). 2. **No retry or continuation path exists** that consumes budget after the first response. 3. **The ceiling is measured on the sam...",
    "decision_boundary": "Before dispatching a fan-out, compute the **feasible fan-out width**: where `min_useful_content` is the smallest budget below which a subagent cannot do useful work (empirically ~4–6k for tool-using agents; below this the agent burns its budget on orientation and returns nothing). - If `N <= N_max`, dispatch with `budget_i = min_useful_content + (remaining /...",
    "operational_effect": "When the boundary is respected, the observable signature changes from \"occasional silent overrun at high N\" to \"fan-out width is capped and the cap is visible in the dispatch plan.\" This is the desirable state: the system refuses to overcommit rather than overcommitting and hoping. The cost is that wide fan-outs require either a larger ceiling or a batched d..."
  },
  "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": "2158686ceb23ea0036fdd0149242033f722f39a9a799cd02d155d57ec13883b5",
    "verified_classes": [
      "BudgetStarvationError"
    ],
    "verified_functions": [
      "plan_fanout",
      "redistribute"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 5,
    "raised_exceptions": [
      "BudgetStarvationError"
    ],
    "sample_fail_closed_invariants": [
      "no active subagents to receive redistribution"
    ],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}