<instructions>

NOTE: Remove these instructions before submitting the doc for review.

#

Use present tense; describe the shipped state. No TODOs or prior-state notes.

</instructions>

Overview (Required)

• Current behavior and problem the feature solves.
• Key guarantees/invariants callers can rely on (treat as non-negotiable commitments).

Architecture Snapshot (Required)

• Bullet or numbered walkthrough of components and data flow as they exist now (diagrams welcome for pipelines or trust boundaries).
• Extension points or interfaces that allow swapping implementations.

API Surface (Required when public APIs exist)

• Public types and entry points; ownership and lifetime expectations.
• Configuration knobs and default behaviors.

Security and Safety (Required when handling untrusted input or sensitive data)

• Trust boundaries, validation rules, and opaque-forwarding expectations.
• Defensive measures (limits, rate controls) and fuzzing/negative-test hooks.
• Sensitive data handling and any constant-time/side-channel considerations.

Performance Notes (Optional)

• Current performance characteristics, hotspots, and known tuning flags.

Testing and Observability (Required)

• Where unit/integration/golden tests live; how to add new cases.
• Metrics/logging hooks relevant to this feature; what to watch in dashboards/alerts.

Integration Guidance (Optional)

• How to embed or extend the feature (e.g., inject custom engines/backends).
• Compatibility or migration notes for consumers.

Maintainer Checklist (Optional but encouraged)

• Bulleted guarantees and operational checks that must stay true as code evolves.

Limitations and Future Extensions (Optional)

• Known gaps, trade-offs, or planned follow-ups without speculative design detail.