# Excititor VEX Evidence Chunk Service

## Module
Excititor

## Status
VERIFIED

## Description
Chunked evidence service for VEX data that splits large evidence payloads into manageable chunks for API transport and storage.

## Implementation Details
- **Modules**: `src/Excititor/StellaOps.Excititor.WebService/Services/`, `src/Excititor/StellaOps.Excititor.WebService/Endpoints/`
- **Key Classes**:
  - `VexEvidenceChunkService` (`src/Excititor/StellaOps.Excititor.WebService/Services/VexEvidenceChunkService.cs`) - splits large VEX evidence payloads into chunks for transport
  - `EvidenceEndpoints` (`src/Excititor/StellaOps.Excititor.WebService/Endpoints/EvidenceEndpoints.cs`) - REST endpoints for evidence chunk operations
  - `VexEvidenceChunkContracts` (`src/Excititor/StellaOps.Excititor.WebService/Contracts/VexEvidenceChunkContracts.cs`) - API contracts for evidence chunks
  - `VexEvidenceContracts` (`src/Excititor/StellaOps.Excititor.WebService/Contracts/VexEvidenceContracts.cs`) - API contracts for evidence data
- **Interfaces**: None (uses concrete service)
- **Source**: Sprints 0119 (batch_14/file_19.md)

## E2E Test Plan
- [ ] Submit a large VEX evidence payload and verify `VexEvidenceChunkService` splits it into chunks within size limits
- [ ] Retrieve chunked evidence via `EvidenceEndpoints` and verify all chunks can be reassembled into the original payload
- [ ] Verify chunk ordering is preserved and each chunk includes a sequence number
- [ ] Verify `VexEvidenceChunkContracts` response includes chunk count and total size metadata
- [ ] Verify chunked transport handles partial failures gracefully (retry individual chunks)
- [ ] Verify large evidence payloads (>10MB) are chunked without memory issues

## Verification
- Verified on 2026-02-13 via `run-001`.
- Tier 0: Source files confirmed present on disk.
- Tier 1: `dotnet build` passed (0 errors); 503/504 tests passed (1 env_issue: no local Postgres).
- Tier 2d: `docs/qa/feature-checks/runs/excititor/excititor-vex-evidence-chunk-service/run-001/tier2-integration-check.json`