# Phase 5 — Mode B console (the AI overlay)

**Goal:** a prompt box that streams a short, cited answer and can take over the stage panel. The AI is a second driver for the same panel, not a second site.

**Depends on:** Phase 3 (live URL), Phase 4 (corpus).

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## Work

### 5.1 Query path

```
question
  → rate limit (per IP)
  → CLASSIFY    fast tier   intent · injection score · off-topic · PII
      ├─ refuse  → fixed message, zero model spend
      └─ allow
  → ROUTE       fast tier   which area(s) to search
  → RETRIEVE    Qdrant (payload-filtered) + SQLite FTS5
                → reciprocal rank fusion → cross-encoder rerank top-20 → top-5
  → COMPOSE     mid tier    answer ONLY from context, inline citations
  → VERIFY      citation presence + claim supported by context
  → STREAM      SSE
```

Four nodes. If the graph needs more than four to work, stop and report — complexity growth here is the failure mode this project exists to avoid.

### 5.2 Transport
- `GET /api/ask` as Server-Sent Events.
- Three event types: `token`, `meta` (route, timings, tokens, cost), `done`.
- **Never buffer SSE.** Verify with `flush_interval -1` on the proxy if streams stall. No gzip on the API path.

### 5.3 The console (the only client-side code in the project)
One hand-written TypeScript island, ES modules, no framework, no bundler.

- `xterm.js` console showing the pipeline live: route, retrieval count, timings, tokens, cost.
- Prompt box with submit and stop.
- Stage panel driven by the `token` stream — the driver built in Phase 2 §2.4.
- Panel clears on new response and on navigation.
- Footer strip: model · latency · tokens · cost.

### 5.4 Citations
- Every factual claim carries a citation to a `content/` page or artefact.
- Citation URLs validated against the known-artefact allow-list; unknown URLs dropped, not rendered.
- Answer shape: direct answer → specifics → evidence pointer → optional single suggestion (per `agents/persona.md`).

### 5.5 Persona
- Load `agents/persona.md` at runtime. It is a file, versioned, not a string in code.
- Test the tone: a short answer, an honest "not in the corpus" answer, and a "here's the better example for your role" answer.

---

## Definition of Done

- [ ] First token < 4 s; complete answer < 15 s at p90, measured and recorded.
- [ ] Every claim in ten sample answers resolves to a real page or artefact. No dangling citations.
- [ ] The panel is driven by the SSE stream without changes to layout code (proves Phase 2 §2.4 held).
- [ ] The island is the **only** client-side application code; no framework, no bundler, no `node_modules`.
- [ ] A and B do not drift: for any question, the answer's claims exist on the site.
- [ ] SSE streams untruncated at p90 with no cancellation leak when the client disconnects.
- [ ] All model calls go through OmniRoute; grep proves no direct provider call exists.
- [ ] Asking an off-topic question produces a short refusal and costs nothing.

---

## Out of scope

- Guardrail hardening, cost ceilings and the kill switch — **Phase 6**. Phase 5 runs with a permissive guard and no public traffic.
- Voice input.
- Hub `/ask` registration (a follow-on task, not this phase).

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## Risks

| Risk | Mitigation |
|---|---|
| Graph grows past four nodes | Hard review gate: report and justify before adding a fifth |
| Panel refactor needed | Phase 2 §2.4 contract; if it fails, fix the panel contract, do not fork the UI |
| Streaming stalls behind Caddy | Explicit flush settings; p90 measurement, not a spot check |
| Answers drift from the site | Citation verification is a node, not a hope |