## 1. Production Harness assembly

- [x] 1.1 Add validated `harness.chat` properties and Spring-managed bounded Chat/model executors with deterministic shutdown and rejection behavior.
- [x] 1.2 Assemble canonical Redis store, ToolBoundary, bounded RAG/log/MySQL adapters and HarnessEvidenceTools without using the application database for query_mysql.
- [x] 1.3 Assemble shared Core/model boundary, Diagnosis Agent, Guards/release, Router, three fixed executors and one ChatApplicationUseCase graph.
- [x] 1.4 Add focused configuration tests for positive defaults, bounded queues, shared dependencies, empty MySQL fail-closed behavior and unambiguous context startup.

## 2. Unique Chat SSE protocol

- [x] 2.1 Add immutable five-event payloads and a first-terminal-wins SSE session enforcing metadata -> status* -> content|failure -> done order, safe fields and exact Run cancellation.
- [x] 2.2 Replace synchronous `/api/chat` with the bounded-worker SSE path, remove `/api/chat_stream`, old Chat response/chunk/history logic and Chat model/tool/service dependencies.
- [x] 2.3 Move legacy AiOps model/Tool acquisition behind AiOpsService while preserving `/api/ai_ops` observable behavior and using a managed executor.
- [x] 2.4 Add focused Controller/protocol tests for validation, one endpoint, event order/schema/mutual exclusion, typed success/fallback, stable failure, saturation and disconnect races.

## 3. Frontend consumer cutover

- [x] 3.1 Remove quick/stream mode state, selector UI, synchronous Chat JSON path, `/chat_stream` and legacy message-wrapper compatibility.
- [x] 3.2 Implement one strict named-event frame parser and typed content renderer that records metadata IDs, shows status, renders content once and requires valid done.
- [x] 3.3 Add static frontend contract tests covering the unique request target, removed legacy tokens and required event/render branches.

## 4. Verification and migration

- [x] 4.1 Run stage 6B focused tests, relevant stage 2-6A and AiOps regressions, Maven compile and Spring context wiring verification.
- [x] 4.2 Validate strict OpenSpec, no `/chat_stream`/sync consumer/controller model/tool dependency, bounded executors, exact SSE safety fields and no unverified/internal content leakage.
- [x] 4.3 Record L4 frontend/API migration and paired rollback evidence; leave live model/Redis/MySQL E2E explicitly deferred to stage 7.