# Deterministic Replay Contract (Feed/Tool/Rule Pinning)

## Module
__Libraries

## Status
VERIFIED

## Description
Replay manifests pin feed snapshots, tool versions, rule packs, and scoring inputs with content-addressed hashes. Validation ensures CAS integrity and deterministic sorting.

## Implementation Details
- **ReplayManifest**: `src/__Libraries/StellaOps.Replay.Core/ReplayManifest.cs` -- core manifest model with versioning
- **ReplayManifestValidator**: `src/__Libraries/StellaOps.Replay.Core/ReplayManifestValidator.cs` -- multi-partial validation: `.Cas.cs` (CAS reference integrity), `.Graphs.cs` (graph reference validation), `.Sorting.cs` (deterministic sort verification), `.Traces.cs` (trace reference validation), `.Upgrade.cs`/`.Upgrade.Helpers.cs` (manifest version upgrade paths)
- **ReplayManifestVersions**: `src/__Libraries/StellaOps.Replay.Core/ReplayManifestVersions.cs` -- version constants and migration logic
- **CasReference/ICasValidator/InMemoryCasValidator**: `src/__Libraries/StellaOps.Replay.Core/CasReference.cs`, `ICasValidator.cs`, `InMemoryCasValidator.cs` -- content-addressed storage validation with CasValidationResult/CasValidationError
- **PolicySimulationInputLock**: `src/__Libraries/StellaOps.Replay.Core/PolicySimulationInputLock.cs` -- pins policy simulation inputs with content-addressed hashes
- **PolicySimulationInputLockValidator**: `src/__Libraries/StellaOps.Replay.Core/PolicySimulationInputLockValidator.cs` -- validates pinned input integrity
- **DeterministicHash**: `src/__Libraries/StellaOps.Replay.Core/DeterministicHash.cs` -- deterministic hash computation for replay verification
- **DeterminismManifestValidator**: `src/__Libraries/StellaOps.Replay.Core/Validation/DeterminismManifestValidator.cs` -- comprehensive multi-partial validation: `.Core.cs`, `.Inputs.cs`, `.Artifact.cs`, `.CanonicalHash.cs`, `.Toolchain.cs`, `.Verification.cs`, `.Reproducibility.cs`, `.Required.cs`, `.Parse.cs`, `.Regex.cs`
- **ReplayProof**: `src/__Libraries/StellaOps.Replay.Core/ReplayProof.cs` -- `.Canonical.cs` (canonical serialization), `.Factory.cs` (proof construction), `.Validation.cs` (proof verification)
- **FeedSnapshotCoordinatorService**: `src/__Libraries/StellaOps.Replay.Core/FeedSnapshotCoordinatorService.cs` -- feed snapshot management: `.Create.cs`, `.Export.cs`, `.Import.cs`, `.Validate.cs`, `.Digest.cs`, `.BundleManifest.cs`, with Zstd compression streams
- **Tests**: `src/__Libraries/StellaOps.Replay.Core.Tests/`
- **Source**: Feature matrix scan

## E2E Test Plan
- [ ] Verify replay manifest pins all input hashes (feed, tool, rule, scoring)
- [ ] Test CAS validation detects tampered or missing content-addressed references
- [ ] Verify deterministic sorting produces identical manifest ordering across runs
- [ ] Test manifest version upgrade preserves content integrity
- [ ] Verify PolicySimulationInputLock captures exact policy evaluation parameters
- [ ] Test DeterminismManifestValidator catches non-reproducible manifests
- [ ] Verify ReplayProof canonical serialization produces identical bytes for same inputs
- [ ] Test FeedSnapshotCoordinator export/import round-trip with Zstd compression


## Verification

- **Verified**: 2026-02-13T20:30:00Z
- **Run**: run-001
- **Tier**: Tier 2d (Library/Internal)
- **Verdict**: PASS