phase: 112_honesty_gate_weak_hits

**Phase 112 — final verification pass (all 4 tasks already complete in `complete/`):**

- Verified gate fix: `app/api/chat.py::plan_turn` — HIGH iff `best_cosine >= relevance_threshold` OR (`fts_hits > 0` AND `best_cosine >= lexical_support_floor`); `lexical_support_floor` (default 0.35, `BOR_LEXICAL_SUPPORT_FLOOR`, bounds-validated) in `app/config.py` + `.env.example`; A8 revision note (2026-09-14) in `.agents/PLAN.md`.
- Verified prompt contract: `app/rag/prompts.py` diff is docstring-only (dated owner-decision-iii entry); `tests/unit/test_prompt_lock.py` byte-pins PERSONA/TOOLS_SECTION/DEFLECT body (sha256+length).
- Verified README: L11 + L575 deflection copy refreshed; `grep "haven't done anything" README.md` → no hits; disclosed-answer behavior documented.
- Tests: `uv run pytest --cov=app --cov-report=term-missing` → **2378 passed, 99% coverage (>90%)**; includes Mongolia-quadrant unit pins (fts>0 + cosine<floor → LOW).
- E2E in isolation: `uv run pytest tests/e2e/test_honest_deflection.py -v --no-cov` → **4 passed** (out-of-KB question: `deflected=true`, `sources==[]`, 2–3 suggestions); regression `test_chat_rag.py` + `test_retrieval_quality.py` → **7 passed**.
- Lint/types: `uv run ruff check .` → clean; `uv run pyright` → 0 errors.

**Completion criteria:** weak-FTS→LOW unit-pinned ✅ · no false citations + 2–3 alternatives E2E ✅ · prompts byte-identical (test-pinned) + README matches ✅ · suite/coverage/e2e/lint all green ✅ · commit + phase move → left to harness (no `git commit` run, per rules; changes in working tree).

**Deviations:** none. Next pending phase: `113_source_chip_quality`.

.agents/PLAN.md

@@ -46,7 +46,7 @@ accounts (one admin + hand-out tokens is the model).
 | A5 | LLM backend | OpenAI-compatible self-hosted endpoint `https://aipi.reeseapps.com/v1` via the `openai` async client: **`turbo`** (chat, streams `reasoning_content` thinking), **`embed`** (embeddings), **`lite`** (one-shot: document summaries, KB overview, folder summaries) |
 | A6 | Embedding dim | **768** (verified against the live endpoint); `chunks.embedding` is fixed at table creation — a dim mismatch must **fail loudly**, never silently re-embed |
 | A7 | Retrieval→context | **Hybrid:** cosine top-100 ∪ Postgres FTS top-30 (OR tsquery, `ts_rank`), fused with **RRF (k=60)** → parent docs ranked by best fused chunk → **full text of top-N=2 documents, never truncated** on the retrieval path (owner 2026-08-24: "this should never happen"; the agent `read`-tool cap is a separate owner-permitted path) |
-| A8 | Honesty gate | Deflect (LOW mode) **only when** best cosine < `BOR_RELEVANCE_THRESHOLD` (0.62) **and** zero FTS hits; LOW prompt carries weak-hit *titles only* + the `DEFLECT_MODE` marker (the E2E mock keys on its presence) + the plain-text no-tools line |
+| A8 | Honesty gate | Deflect (LOW mode) **only when** best cosine < `BOR_RELEVANCE_THRESHOLD` (0.62) **and** (zero FTS hits **or** best cosine < `BOR_LEXICAL_SUPPORT_FLOOR` (0.35)); an FTS hit flips HIGH only when `best_cosine >= lexical_support_floor` — the vector signal must corroborate the lexical match (A8 revised 2026-09-14, owner-confirmed, TODO L2a: lexical-only hits without vector support deflect). LOW prompt carries weak-hit *titles only* + the `DEFLECT_MODE` marker (the E2E mock keys on its presence) + the plain-text no-tools line |
 | A9 | Content scope | Default `md, markdown, txt, yaml, yml, json, py` + Podman quadlet family + `j2`; `BOR_IMPORT_EXTENSIONS` may name **any** well-formed extension or narrow the set; hidden (dot) paths + exclusion list + per-source `ignore_paths` (raw prefixes, no globs) always apply |
 | A10 | State & auth | `POST /api/chat` is **stateless** (client-provided `history` only, budget-trimmed — nothing stored per conversation). Auth = single admin, signed `bor_session` cookie (Starlette `SessionMiddleware` + itsdangerous; no server-side session store); admin-issued SHA-256-hashed access tokens are the only other identity; **only** shared chats stay anonymous. Fail-loud at boot while `BOR_ADMIN_PASSWORD`/`BOR_SESSION_SECRET` are empty |
 | A11 | Frontend | Vanilla HTML/CSS/JS in git, **no CDN** — everything served by FastAPI `StaticFiles`; system font stack; the navbar views are views of ONE shell document (`frontend/index.html` + `router.js` deep-links) |