kebab/tasks/HOTFIXES.md

title, date

title	date
Post-merge hotfixes log	2026-05-01

Post-merge hotfixes log

Bugs discovered AFTER a phase task was merged, and the small follow-up PRs that close them. Each entry: what broke, how it surfaced, what the fix touched, and which task spec it amends.

The original task specs in tasks/p<N>/p<N>-<M>-*.md stay frozen as the historical contract that was implemented; this file accumulates the deltas so phase 5+ readers can find the live behavior without diffing git history.

2026-05-01 — --config flag silently ignored across all kb-cli subcommands

Discovered: post-P3-5 manual smoke at /tmp/kb-smoke/.

Symptom: kb --config /path/to/config.toml ingest|search|list|inspect|doctor ignored the flag and fell back to ~/.config/kb/config.toml (XDG default). Users had to use KB_* env vars to point at a non-default config.

Root cause: kb-cli read cli.config only inside Cmd::Ingest to build SourceScope, then called bare kb_app::ingest(scope, summary_only) which internally re-loaded Config::load(None) (XDG path). Same pattern in Cmd::Search / List / Inspect / Doctor. P3-5 introduced *_with_config test seams via #[doc(hidden)] pub fn but kb-cli never used them.

Fix (PR #20, fix/cli-config-flag-and-search-output):

• kb-cli now builds the Config once via Config::load(cli.config.as_deref()) at the top of every subcommand and threads it into kb_app::*_with_config(cfg, ...) instead of kb_app::*(...).
• kb_app::doctor() rewritten as doctor_with_config_path(Option<&Path>) that reports the actual path probed and hard-fails when --config <path> doesn't exist (defaults would otherwise mask user intent).
• kb-app module doc-comment updated: #[doc(hidden)] pub fn *_with_config is no longer "test-only seam" — it's the official "config-explicit" API consumed by CLI --config, integration tests, and TUI sessions.
• Same PR also improved kb search printer: {:.4} score formatting (RRF range collapses on {:.2}) and > heading_path suffix so chunks from the same document are visually distinct.

Amends: tasks/p3/p3-5-app-wiring.md (the test seam was always meant to be the config-explicit API; only the doc-comment lied).

2026-05-01 — --config regression in kb ask (P4-3 follow-up)

Discovered: post-P4-3 manual smoke against 192.168.0.47 Ollama with gemma4:26b.

Symptom: kb --config <path> ask returned model.id = qwen2.5:14b-instruct (XDG default model) and score_gate = 0.30 (XDG default), instead of gemma4:26b / 0.05 from the explicit config. P4-3 added the ask body but kb-cli's Cmd::Ask arm still called bare kb_app::ask(query, opts) — same regression class as the P3-5 fix above, just missed when ask was wired.

Fix (PR #24, fix/cli-ask-honor-config-flag):

• kb-cli builds Config::load(cli.config.as_deref()) once at the top of Cmd::Ask and calls kb_app::ask_with_config(cfg, query, opts).

Amends: tasks/p4/p4-3-rag-pipeline.md.

2026-05-01 — RRF fusion_score incompatible with config.rag.score_gate default

Discovered: post-P4-3 manual smoke. Top hybrid result returned fusion_score = 0.0164 against score_gate = 0.05 → ScoreGate refusal on every hybrid query.

Root cause: RRF formula score(c) = Σ 1/(k_rrf + rank_m(c)) produces values bounded by num_retrievers / (k_rrf + 1). With num_retrievers = 2 and the default k_rrf = 60, the upper bound is 2/61 ≈ 0.0328. The default config.rag.score_gate = 0.05 was calibrated for vector / lexical scores already in [0, 1] and silently refused every hybrid query. fusion_score was also incomparable across modes — Lexical / Vector lived in [0, 1], Hybrid lived in (0, 0.033].

Fix (PR #25, fix/rrf-fusion-score-normalize-and-docs):

• crates/kb-search/src/hybrid.rs divides every raw RRF score by 2 / (k_rrf + 1) so fusion_score always lives in [0, 1] regardless of mode. Both retrievers contributing rank 1 normalises to 1.0; chunks present in only one retriever cap around 0.5. RRF's rank-ordering invariants are preserved (same constant divides every score), so sort + tiebreak behaviour is identical.
• One unit test (rrf_formula_matches_known_value) updated to expect the normalised value (1/61 + 1/62) / (2/61) ≈ 0.9919.
• The integration snapshot crates/kb-search/tests/fixtures/search/hybrid/run-1.json already used presence checks (fusion_score_positive: true) rather than absolute values, so it didn't need regeneration.

Why not a per-mode score_gate config: separate lexical_score_gate / vector_score_gate / hybrid_score_gate would force every downstream consumer (CLI, eval, TUI) to know which mode picks which threshold. Normalising the score itself is a one-line change at the source and makes Answer.retrieval.score_gate semantically meaningful without per-mode bookkeeping.

Amends: tasks/p3/p3-4-hybrid-fusion.md (RRF formula now divides by 2/(k_rrf+1) after summation), tasks/phase-3-vector-hybrid.md (RRF section).

Verification: post-fix smoke at /tmp/kb-smoke/ with default score_gate = 0.05 succeeded across four scenarios — Korean→Korean, English→English, cross-language, and out-of-corpus refusal.

How to add an entry

Each fix gets a dated subsection with five fields:

• Discovered: when / how the bug surfaced (smoke, integration test, user report).
• Symptom: what the user saw / what was wrong.
• Root cause: the actual code or design issue.
• Fix: PR number / branch + a one-paragraph summary of the change.
• Amends: which tasks/p<N>/... spec docs the fix retroactively contradicts. Spec text stays frozen; this log is the live source of truth for post-merge deltas.

If a fix is large enough that the original spec is no longer a useful reference, promote the entry into a new task spec (e.g., p<N>-<M+1>-<topic>.md) and link from here.