dsh-turn-budget

When an Agent chain-reactors through model calls, nested tools, and token spend in a single turn with no hard ceiling, one runaway loop can burn through a provider quota or starve downstream services in minutes. dsh-turn-budget is a fail-closed, per-turn resource governor for DeepSeek Harness: it does not estimate currency, rewrite tool arguments, or replace sandboxing; it simply locks each turn to a hard ceiling and rejects anything that exceeds it.

Enforcement works through public Harness extension points at three independent layers. Before the next model request, the plugin checks step count and provider-reported token usage (including cache read/write buckets) and closes the turn as blocked if either ceiling is hit. Before each tool body is dispatched, it tallies root calls and Code Mode nested dispatches; excess calls receive a policy error naming the exceeded budget while the model retains one opportunity to finish without another tool. Token accounting trusts only explicit provider usage reports and never estimates; the tool ledger is process-local, keyed by live Agent identity, and discarded on restart so no stale in-flight state can survive.

Teams running multi-tool orchestrations, heavy Code Mode nesting, or deployments where provider quotas are scarce will benefit most. It slots in front of existing sandboxing and approval layers without replacing them, adding one precise circuit-breaker gate that keeps a single turn from consuming an entire budget.