# ReachGraph Module Charter

## Mission
- Provide deterministic reachability graph storage and query services with replayable proofs.

## Responsibilities
- Maintain reachability graph schema, canonicalization, and digest computation.
- Provide WebService endpoints for ingest, slice queries, and replay verification.
- Preserve content-addressed storage and DSSE signing hooks.
- Enforce offline-first operation and stable ordering.

## Required Reading
- docs/README.md
- docs/07_HIGH_LEVEL_ARCHITECTURE.md
- docs/modules/platform/architecture-overview.md
- docs/modules/reach-graph/architecture.md
- docs/contracts/richgraph-v1.md

## Working Agreement
- Deterministic outputs: stable ordering, RFC 8785 JSON canonicalization, fixed timestamps via TimeProvider.
- Use DSSE helpers for signing and verification; do not reimplement PAE.
- Use InvariantCulture for parsing or formatting that affects hashes.
- Propagate CancellationToken through all async calls.
- No external network calls beyond configured stores; remain air-gap friendly.

## Testing Strategy
- Unit tests for canonicalization, digests, and slice builders.
- Integration tests for ingest, slice, and replay endpoints.
- Determinism tests: same inputs yield identical digests and slices.