Files
brain-of-reese/.agent/user_stories/chat-rag-answer.md
T
ducoterra 022da8e2bc feat: scaffold Brain of Reese — FastAPI RAG chat over Postgres 17 + pgvector
Foundation (phase 01, verified):
- FastAPI app: /api/health, /api/suggestions, /api/chat (placeholder),
  static frontend served locally (no CDN)
- Postgres 17 + pgvector via db/Containerfile + compose.yaml
  (podman compose up -d db), Alembic initial migration (documents,
  chunks with vector(768), query_log)
- LLM client targeting https://aipi.reeseapps.com/v1 (turbo/embed);
  scripts/llm_probe.py verified models + 768-dim embeddings live
- Conditional debugpy: imported only when DEBUGPY=1 (attach on demand,
  :5678); logging config for clean single-line logs
- Frontend shell: mobile-first chat + Sources pages, tokens, a11y baselines
- Tests: 24 unit+integration (99% coverage on app/), ruff + pyright clean,
  Playwright smoke E2E (3 tests) against a deterministic mock LLM
- Planning: .agent/PLAN.md (architecture + LOCKED decisions), AGENTS.md,
  6 user stories, 7 phase files (one story / one phase / one Playwright
  suite each)
2026-08-21 13:42:21 -04:00

62 lines
3.3 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
# Story: Chat RAG Answer (happy path)
**Phase:** `03_story_chat_rag.md` · **E2E:** `tests/e2e/test_chat_rag.py`
## Narrative
As **a user** (friend, colleague, future me), I want to ask Brain a question
about Reese's setup and get a grounded, chippy answer that points me at the
exact documentation — so I can actually *do* the thing.
- **Given** the knowledge base is imported and I type "How is my Kubernetes
cluster set up?"
- **When** Brain embeds the question, retrieves the top chunks by cosine
similarity, maps them to their parent documents, and feeds the **full
document text** to `turbo`
- **Then** I see a streamed, upbeat answer that cites the source
(`Homelab/kubernetes.md`), grounded in the doc's specifics (Talos,
Cilium, the node list) — and never in anything the docs don't say.
## Acceptance criteria
1. `POST /api/chat` streams SSE: `delta` events then a final `done` event
carrying `{deflected, sources[], suggestions[]}` (PLAN §4).
2. Retrieval: top-4 chunks (`BOR_TOP_K_CHUNKS`), cosine via pgvector
`<=>`, score = 1 − distance.
3. Context assembly: top-2 **distinct documents** by best-chunk score, full
content, capped at `BOR_MAX_CONTEXT_CHARS` with truncation marker.
4. System prompt = locked persona + HONESTY GATE rules (PLAN §6), with
`<relevance>HIGH</relevance>` and `<documents>…</documents>`.
5. The answer arrives **streamed** (multiple deltas), rendered live.
6. Source chips (mono, `source/path`) render under the answer bubble.
7. Per-turn log line emitted (PLAN §9) and a `query_log` row inserted
(`deflected=false`, top_score, sources, latency).
8. LLM/embedding failure → JSON/SSE error the UI turns into the error banner
(no hang, no stale button).
## UI Visualization & Structure
- Chat column centered at 46rem (PLAN §7.1); user bubble right (brand
indigo, white text ≥4.5:1), Brain bubble left (white, ink text, avatar 🧠).
- While generating: typing indicator → live-appended text (see
loading-feedback story for the full state machine — this story only needs
"deltas render as they arrive and the button is busy throughout").
- **Source chips:** pill, `font-family: mono`, `bg --brand-soft`,
`color --brand-ink` (6.3:1), `max-width` + ellipsis; each shows
`Homelab/kubernetes.md`. `aria-label` when truncated.
- Bubble content is safe-rendered markdown (escape-first local renderer —
`<script>` in an LLM answer must NOT execute).
- On mobile the bubbles expand to ~92% width; chips wrap.
## Playwright Mapping Rule
**Test Scenario → `tests/e2e/test_chat_rag.py`** (mock LLM, seeded KB):
1. `test_on_topic_question_streams_grounded_answer` — type "How is my
Kubernetes cluster set up?", submit; assert: answer bubble appears with
streamed content (mock's answer references the question), a `.source-chip`
containing `kubernetes.md` is present, send button returns to enabled
"Send".
2. `test_chat_logs_query` — after the turn, `GET /api/health` is still ok AND
(via a test-only detail: query the DB directly) a `query_log` row exists
with `deflected=false` and sources including `kubernetes.md`.
3. `test_sse_stream_shape` — raw `httpx` streaming request to `/api/chat`:
assert multiple `data:` delta events precede a `done` event with
`deflected: false` and a non-empty `sources` list.