v0.8.1 — Cost & Budget Safety Audit

v0.8.1 — Cost & Budget Safety Audit

🐛 Bugs Found & Fixed

Bug	Severity	Fix
estimateCost() produced negative cost with negative token counts	MEDIUM	Added Math.max(0, ...) guard
BudgetTracker callbacks not wrapped in try/catch — throwing callback corrupted budget accounting	HIGH	Wrapped in try/catch (notification-only semantics)

🛡️ 74 Deep Cost Audit Tests

Area	Tests
Money correctness (NaN, Infinity, negative, floating point)	10
Budget boundary enforcement (exact limits)	8
Session budget enforcement	6
Per-request budget enforcement	4
Model pricing integrity	7
Estimated vs actual cost semantics	3
Callback safety	3
Cost report integrity	5
Client lifecycle	4
Router + cost integration	3
Security	2
Adversarial inputs	7
Determinism	2
Invariant testing	7

7 Invariants Verified

1. totalActual >= 0 for all valid inputs
2. totalActual equals sum of recorded actual costs
3. byProvider totals reconcile with totalActual
4. byPhase totals reconcile with totalActual
5. remainingBudget = sessionBudget - totalActual
6. No NaN in any report field
7. No Infinity in any report field

640 Tests Passing

74 new audit tests added (566 → 640 total).

---

Changelog: https://github.com/Hilbras/Hilbras-ai-sdk/blob/main/CHANGELOG.md