# Implementation plan — VEX Consensus Lens

## Delivery phases
- **Phase 1 – Core lens service**  
  Build normalisation pipeline (CSAF/OpenVEX/CycloneDX), product mapping library, trust weighting functions, consensus algorithm, and persistence (`vex_consensus`, history, conflicts).
- **Phase 2 – API & integrations**  
  Expose `/vex/consensus` query/detail/simulate/export endpoints, integrate Policy Engine thresholds, Vuln Explorer UI chips, and VEX Lens change events.
- **Phase 3 – Issuer Directory & signatures**  
  Deliver issuer registry, key management, signature verification, RBAC, audit logs, and tenant overrides.
- **Phase 4 – Console & CLI experiences**  
  Ship Console module (lists, evidence table, quorum bar, conflicts, simulation drawer) and CLI commands (`stella vex consensus ...`) with export support.
- **Phase 5 – Recompute & performance**  
  Implement recompute scheduling (policy activation, Excitator deltas), caching, load tests (10M records/tenant), observability dashboards, and Offline Kit exports.

## Work breakdown
- **VEX Lens service**
  - Normalise VEX payloads, maintain scope scores, compute consensus digest.
  - Trust weighting functions (issuer tier, freshness decay, scope quality).
  - Idempotent workers for consensus projection and history tracking.
  - Conflict handling queue for manual review and notifications.
- **Integrations**
  - Excitator: enrich VEX events with issuer hints, signatures, product trees.
  - Policy Engine: trust knobs, simulation endpoints, policy-driven recompute.
  - Vuln Explorer & Advisory AI: consensus badges, conflict surfacing.
- **Issuer Directory**
  - CRUD for issuers/keys, audit logs, import CSAF publishers, tenant overrides.
  - Signature verification endpoints consumed by Lens.
- **APIs & UX**
  - REST endpoints for query/detail/conflict export, trust weight updates.
  - Console module with filters, saved views, evidence table, simulation drawer.
  - CLI commands for list/show/simulate/export with JSON/CSV output.
- **Observability & Ops**
  - Metrics (consensus latency, conflict rate, signature failures, cache hit rate), logs, traces.
  - Dashboards + runbooks for recompute storms, mapping failures, signature errors, quota breaches.
  - Offline exports for Export Center/Offline Kit.

## Acceptance criteria
- Consensus results reproducible across supported VEX formats with deterministic digests and provenance.
- Signature verification influences trust weights; unverifiable evidence is down-weighted without pipeline failure.
- Policy simulations show quorum shifts without persisting state; Vuln Explorer consumes consensus signals.
- Issuer Directory enforces RBAC, audit logs, and key rotation; CLI & Console parity achieved.
- Recompute pipeline handles Excitator deltas and policy activations with backpressure and incident surfacing.
- Observability dashboards/alerts cover ingestion lag, conflict spikes, signature failures, performance budgets (P95 < 500 ms for 100-row pages at 10M records/tenant).

## Risks & mitigations
- **Product mapping ambiguity:** conservative scope scoring, manual overrides, surfaced warnings, policy review hooks.
- **Issuer compromise:** signature verification, trust weighting, tenant overrides, revocation runbooks.
- **Evidence storms:** batching, worker sharding, orchestrator rate limiting, priority queues.
- **Performance degradation:** caching, indexing, load tests, quota enforcement.
- **Offline gaps:** deterministic exports, manifest hashes, Offline Kit tests.

## Test strategy
- **Unit:** normalisers, mapping, trust weights, consensus lattice, signature verification.
- **Property:** randomised evidence sets verifying lattice commutativity and determinism.
- **Integration:** Excitator → Lens → Policy/Vuln Explorer flow, issuer overrides, simulation.
- **Performance:** large tenant datasets, cache behaviour, concurrency tests.
- **Security:** RBAC, tenant scoping, signature tampering, issuer revocation.
- **Offline:** export/import verification, CLI parity.

## Definition of done
- Lens service, issuer directory, API/CLI/Console components deployed with telemetry and runbooks.
- Documentation set (overview, algorithm, issuer directory, API, console, policy trust) updated with imposed rule statements.
- ./TASKS.md and ../../TASKS.md reflect current status; Offline Kit parity confirmed.