PR-2 of fb-41 multi-hop RAG. Decompose + retrieve + synthesize 3-stage
pipeline가 `opts.multi_hop=true` 일 때 dispatch. Dynamic decide loop
는 PR-3.
- `AskOpts.multi_hop: bool` 필드 추가 + `impl Default for AskOpts`
도입 (HOTFIXES 2026-05-07 의 known limitation 해소). 9 explicit
init site 모두 `multi_hop: false` 추가 — Default 도입으로 향후
`..Default::default()` 점진 migrate 가능.
- `RagPipeline::ask` 의 entry 에 dispatcher 한 줄
(`if opts.multi_hop { return self.ask_multi_hop(...) }`).
- `RagPipeline::ask_multi_hop` 신규 method. 1) decompose LLM call
→ JSON array of strings parse, 2) 각 sub-query 로 retrieve +
chunk_id dedup pool, 3) score gate / no-chunks 가드, 4)
pack_context (single-pass 와 helper 공유), 5) synthesize LLM
call w/ MULTI_HOP_SYNTHESIZE_SYSTEM_PROMPT, 6) citation extract
+ Answer build. `prompt_template_version` = "rag-multi-hop-v1"
로 stamp — eval `compare` 가 single-pass vs multi-hop 분리.
- Prompt const 신규: MULTI_HOP_DECOMPOSE_SYSTEM_PROMPT +
MULTI_HOP_DECOMPOSE_USER_TEMPLATE + MULTI_HOP_SYNTHESIZE_SYSTEM_PROMPT
+ PROMPT_TEMPLATE_VERSION_MULTI_HOP + MULTI_HOP_MAX_SUB_QUERIES_DEFAULT.
- `kebab_core::RefusalReason::MultiHopDecomposeFailed` variant 신규.
Cascade: kebab-store-sqlite `refusal_reason_label` + kebab-tui `ask
refusal render` exhaustive match 갱신.
- `parse_decompose_response` + `strip_markdown_json_fence` helper —
markdown code fence (```json / ```) strip + JSON array of strings
parse + trim + drop empty + cap at MULTI_HOP_MAX_SUB_QUERIES_DEFAULT.
None 반환 시 caller 가 `MultiHopDecomposeFailed` refusal.
Tests (55 passing total, 8 신규):
- 6 unit (parse_decompose_response 의 bare array / fence variants /
garbage / cap / trim 회귀 핀).
- 2 integration: `ask_multi_hop_dispatches_and_decompose_garbage_refuses`
(decompose garbage → MultiHopDecomposeFailed + 정확히 1 LLM call) +
`ask_with_multi_hop_false_keeps_single_pass_path` (회귀 핀, 기존
caller 자동 backwards-compat).
Happy-path multi-hop (decompose 성공 → synthesize) 의 integration
test 는 ScriptedLm helper 가 PR-3 의 decide loop 와 함께 도입될
때 같이 추가. 현 `MockLanguageModel` 는 canned single response 라
2-LLM-call sequence 핀 불가.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Spec PR #59 의 §3.8 multi-turn behaviour 구현. RAG facade 가 prior
turns 받아 prompt 에 prepend, retrieval query expansion 적용,
Answer 에 conversation_id / turn_index 채움.
신규 (kebab-core):
- Answer 에 conversation_id (Option<String>) / turn_index (Option<u32>)
field 추가. serde skip_serializing_if 로 single-shot 의 wire
output 변경 0 (기존 외부 wrapper 영향 없음).
- Turn struct (question + answer + citations + created_at).
- RefusalReason::LlmStreamAborted variant.
신규 (kebab-rag):
- AskOpts 에 history (Vec<Turn>) / conversation_id / turn_index 3 field.
- AskOpts::single_shot(mode) helper.
- RagPipeline::ask_with_history(query, history, conversation_id,
turn_index, opts) — combined opts 로 ask 호출.
- expand_query_with_history: history.last() 의 answer 첫 200 자
concat 해 SearchQuery.text 확장 (spec §3.8 의 \"cheap concat\";
LLM-based standalone-question rewriting 은 P+).
- serialize_history + remaining_history_budget_chars: spec 의 priority
enforcement — system+question 필수, retrieved chunks 가 차지한
뒤 남은 char budget 안에서 newest 우선, oldest drop.
- ask 본문: history 가 비어있지 않으면 [이전 대화] 블록을 user
prompt 위에 prepend. Answer 생성 site 3 곳 (정상 / NoChunks /
ScoreGate refuse) 모두 conversation_id / turn_index 채움.
신규 (kebab-store-sqlite):
- refusal_reason_label 가 LlmStreamAborted → 'llm_stream_aborted'.
기존 caller 변경 (single-shot 동작 동일):
- kebab-cli main.rs Cmd::Ask: AskOpts 에 history=Vec::new(),
conversation_id=None, turn_index=None 명시 (CLI multi-turn 은
p9-fb-18 의 --session/--repl 가 채움).
- kebab-tui src/ask.rs spawn site 동일 (multi-turn UI 는 p9-fb-16).
- kebab-eval runner.rs golden eval 동일 (single-shot per query).
- kebab-app tests/ask_smoke.rs / kebab-tui tests/ask.rs / kebab-rag
tests/pipeline.rs / kebab-eval metrics.rs Answer literal 갱신.
Test:
- 9 신규 lib unit (expand_query 4 / serialize_history 3 / remaining_budget 2).
- 기존 12 PASS 회귀 0.
Plan 갱신:
- p9-fb-15 status planned → in_progress. 머지 후 한 줄 commit
으로 completed flip.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
