/token-budget

name: token-budget
description: Token budget tracking and enforcement for Gastown convoy-level execution. Hard limits with pre-execution checking, per-convoy and per-agent tracking, structured stop reasons.
format: 2025-10-02
version: 1.0.0
status: ACTIVE
updated: 2026-04-04
triggers:
  - sizing or enforcing a token budget for a convoy or multi-agent batch
  - pre-execution budget check before dispatching agents
  - need a structured stop reason when a budget limit is reached

Token Budget Enforcement

Pre-execution budget gating for multi-agent convoy execution. Prevents token overspend by checking budgets BEFORE API calls, not after. Identified by the 12 Primitives analysis (Primitive 5) as the #1 actionable improvement.

Activation

This skill activates when:

• A convoy execution starts (mayor creates a convoy)
• Agents are spawned within a convoy
• Any agent is about to make an API call during convoy execution
• Budget reporting is requested during or after execution

Architecture

Budget Hierarchy

Convoy Budget (hard limit, default 500K tokens)
  |
  +-- Agent A budget (hard limit, default 100K tokens)
  +-- Agent B budget (hard limit, default 100K tokens)
  +-- Agent C budget (hard limit, default 100K tokens)

The convoy budget is the aggregate ceiling. Individual agent budgets prevent any single polecat from consuming a disproportionate share.

Check-Before-Execute Pattern

Every API call in a convoy MUST follow this sequence:

1. **Estimate** the projected token cost for the call 2. **Check** `checkBudget(budget, agentId, projectedCost)` — returns `BudgetCheckResult` 3. **If `allowed: false`** — stop immediately, do NOT make the API call 4. **If `reason: 'warning_threshold'`** — proceed but log the warning 5. **If `reason: 'ok'`** — proceed normally 6. **After execution** — `recordUsage(budget, agentId, actualInput, actualOutput)` 7. **Persist** — `saveBudget(budget, budgetDir)` to survive crashes

Structured Stop Reasons

| Reason | Meaning | Action | |--------|---------|--------| | `ok` | Under budget, no concerns | Proceed | | `warning_threshold` | Past warning % but under hard limit | Proceed, log warning | | `convoy_budget_exceeded` | Convoy would exceed hard limit | STOP, do not call API | | `agent_budget_exceeded` | Agent would exceed its limit | STOP, do not call API |

Core API

Types

interface TokenBudget {
  convoyId: string;
  maxTokensPerConvoy: number;      // Hard limit for entire convoy
  maxTokensPerAgent: number;       // Hard limit per polecat
  warningThresholdPercent: number;  // Warn at this % (e.g., 80)
  currentUsage: BudgetUsage;
  createdAt: string;               // ISO 8601
  updatedAt: string;               // ISO 8601
}

interface BudgetCheckResult {
  allowed: boolean;
  reason: 'ok' | 'warning_threshold' | 'convoy_budget_exceeded' | 'agent_budget_exceeded';
  remainingTokens: number;
  usagePercent: number;
}

Functions

| Function | Signature | Description | |----------|-----------|-------------| | `createBudget` | `(convoyId, config?) => TokenBudget` | Initialize a budget for a convoy | | `checkBudget` | `(budget, agentId, projectedCost) => BudgetCheckResult` | Pre-execution gate check | | `recordUsage` | `(budget, agentId, input, output) => void` | Track actual usage after execution | | `getBudgetReport` | `(budget) => BudgetReport` | Summary for logging/display | | `saveBudget` | `(budget, budgetDir) => Promise<void>` | Persist to `.chipset/state/budgets/` | | `loadBudget` | `(convoyId, budgetDir) => Promise<TokenBudget \| null>` | Load from disk | | `deleteBudget` | `(convoyId, budgetDir) => Promise<void>` | Remove budget file | | `listBudgets` | `(budgetDir) => Promise<string[]>` | List all persisted convoy budget IDs |

Default Values

| Parameter | Default | Recalibration note | |-----------|---------|--------------------| | `maxTokensPerConvoy` | 500,000 tokens | Was set conservatively pre-INLINE-SERIAL pattern. v1.49.621 actuals: ~50-300K per convoy under inline-serial Opus/Sonnet authoring (~10-15% of this default). Default retained for safety margin; missions may explicitly cap lower based on convoy shape. | | `maxTokensPerAgent` | 100,000 tokens | Pre-recursive-spawn-block default; with INLINE SERIAL the agent IS the convoy, so per-agent ≈ per-convoy. | | `warningThresholdPercent` | 80% | Unchanged. |

**v1.49.621 retrospective lesson 3 — projection recalibration:** Wave 1+2+3+4 fleet token spend came in at ~26% of projected ceiling under INLINE SERIAL authoring. Future missions should project Opus convoys at ~75-300K and Sonnet convoys at ~30-150K based on output volume × ~1.5K tokens/100-line-of-output heuristic. Reserve 3-5× headroom over the projection for safety; do not 10× as this skill historically did.

State Persistence

**Path:** `.chipset/state/budgets/{convoyId}.json`

Follows the same durability contract as beads-state:

• Atomic writes (write temp -> fsync -> rename)
• JSON with sorted keys for git-friendly diffs
• Filesystem-only, no database dependencies
• Crash-recoverable (partial writes leave only temp files)

Integration Points

Mayor Coordinator

When the mayor creates a convoy, it should also create a token budget:

const convoy = await stateManager.createConvoy('Sprint 1', beadIds);
const budget = createBudget(convoy.id, {
  maxTokensPerConvoy: 500_000,
  maxTokensPerAgent: 100_000,
});
await saveBudget(budget, '.chipset/state/budgets');

Polecat Worker

Before each API call in GUPP autonomous mode:

const budget = await loadBudget(convoyId, '.chipset/state/budgets');
const check = checkBudget(budget!, agentId, estimatedTokens);
if (!check.allowed) {
  // Structured stop — include reason in termination message
  return { stopped: true, reason: check.reason, remaining: check.remainingTokens };
}
// ... make API call ...
recordUsage(budget!, agentId, actualInput, actualOutput);
await saveBudget(budget!