Simulator Without Side Effects
The policy simulator (hp_guard.simulate) replays JSON Lines traces against policies without:
- Executing tools
- Writing audit records
- Mutating policy state
What This Enables
- Change validation: Replay baseline traces against a candidate policy and see what decisions change
- Test coverage: Deterministic evaluation at specific UTC times (via
resolve_call_at) - Debugging: Trace flow through rules without side effects
Trace Event Requirements
Each trace event requires:
version: 1- A consecutive positive
sequence - A normalized
call
Trace Format
The full JSONL format and stable trace errors are in the spec. The simulator is purely evaluative — it replays and reports decisions without any side effects.