C.E.L_Slide_test2/docs/architecture/IMP-17-CARVE-OUT.md

IMP-17 — AI repair fallback infrastructure (carve-out)

Status: carve-out infra scaffolded under IMP-33 (issue #61, Stage 3 u1~u11). Normal-path AI calls = 0 (PZ-1) — ai_fallback_enabled flag default False in src/config.py. Runtime AI is reachable only via fallback path entry points; Step 12 entry is provisional-gated, Step 17 entry is structurally blocked behind IMP-34 + IMP-35.

Source anchors

• IMP-17 backlog row — PHASE-Z-IMPLEMENTATION-ISSUE-BACKLOG.md:68 (carve-out — normal path 밖, soft link IMP-04 + IMP-05).
• INSIGHT-MAP §3 — PHASE-Q-INSIGHT-TO-22STEP-MAP.md (G3 AI repair fallback infra registry row, normal path = no).
• 22-step pipeline — PHASE-Z-PIPELINE-OVERVIEW.md Step 12 (lines 280-287), Step 16 (lines 318-325), Step 17 (lines 326-333).
• Pattern shape reference (Phase Q Archive — link-only, do not port) — src/content_editor.py:21,318 (httpx + retry shape, imports sse_utils) + src/sse_utils.py:16-50 (SSE token parser).
• Route hint surface (current anchors) — src/phase_z2_pipeline.py:570 (conceptual comment), :572 (_IMP05_ROUTE_HINTS table), :575 (restructure → ai_adaptation_required), :580 (_imp05_route_hint), :664 (candidate_evidence emission). Deterministic emission today; AI consumer deferred to IMP-17 (this carve-out). Anchor pin: tests/orchestrator_unit/test_imp17_comment_anchor.py.

Carve-out boundary

Allowed (fallback path only)

• Step 12: when V4 emits restructure (route hint ai_adaptation_required) AND deterministic mapping cannot satisfy the frame contract, an AI proposal MAY be invoked to map content_object → Internal Region / Frame Slot. Output = placement proposal at content-object granularity. Frame selection, layout selection, zone topology remain deterministic.
• Step 16 / 17: when retry router exhausts deterministic actions (zone_ratio_retry / layout_adjust / frame_reselect / details_popup_escalation / image_fit_candidate / frame_internal_fit_candidate) AND user-approved fallback budget remains, an AI proposal MAY be invoked. Output scope identical to Step 12 — content-object placement only.

Forbidden (any path)

• Normal-path AI calls (Step 12 deterministic mapper, all other steps).
• MDX 원문 요약·삭제·재작성 (Phase Z spacing direction guardrail: never compress text).
• HTML / CSS 직접 생성, frame contract 신설, layout / zone topology 결정 (Layer-A / Layer-B planning은 코드 영역).
• 공통 padding / spacing / tolerance 축소 (PZ-4 — no silent shrink).
• 신규 IMP ID 발급 (이 carve-out 은 IMP-17 슬롯에 영구 귀속).

Activation gate (3-condition AND — all three required)

1. User GO — 명시적 axis activation 요청. carve-out 자체로는 코드 작성 트리거 안 됨.
2. B4 frame_selection evidence integration complete — Step 9 frame_selection 의 evidence trace 가 안정화되어야 fallback proposal 이 어떤 frame contract 안에서 동작해야 하는지 식별 가능.
3. IMP-04 (catalog 확장) + IMP-05 (V4 fallback) live — 카탈로그가 32 frame 으로 확장되고 V4 rank-2/3 fallback 이 활성화돼야 ai_adaptation_required 라우트가 실제 의미를 가짐 (현재는 dead-end route hint).

세 조건 중 하나라도 미충족이면 본 carve-out 은 design-only 상태로 잠겨 있다.

Pattern shape reference (link-only, do not import)

Phase Q content_editor.py 는 Archive Candidate (PHASE-Q-AUDIT.md:660-673) — 포팅 대상 아님. 모양만 참조한다:

• httpx async streaming + retry 구조 — src/content_editor.py:21,318 라인 부근 (import + stream_sse_tokens 호출 site).
• SSE token 파서 분리 모듈 — src/sse_utils.py:16-50 (stream_sse_tokens 본체).
• EDITOR_PROMPT (Kei persona) 및 Kei-API endpoint 는 영구 단절. 재사용 금지.

AI 격리 + Kei persona 단절 contract

• AI 호출은 normal path 에 없다 (Phase Z 원칙, memory feedback_ai_isolation_contract).
• 출력 단위는 항상 content_object / Internal Region / Frame Slot 또는 restructuring proposal — HTML 구조 / 레이아웃 / 프리셋 결정 X.
• Phase Q 자산 (Kei persona prompts, Kei-API endpoint, persona retry semantics) 과 단절. Phase Z 의 fallback runtime 은 별도 prompt / endpoint 설계로 출발한다 (본 carve-out 활성 시).

Runtime module surface (IMP-33 u1~u11 binding)

Axis	Binding
Module path	src/phase_z2_ai_fallback/ (locked by IMP-31-GATE-AUDIT.md:31,50,56).
Step 12 entry	src.phase_z2_ai_fallback.step12.gather_step12_ai_repair_proposals — IMP-30 provisional gate (not_provisional skip) AND reject gate (design_reference_only_no_ai skip) AND non-AI route catch-all run BEFORE route_ai_fallback.
Step 17 entry	src.phase_z2_ai_fallback.step17.gather_step17_ai_repair_proposals — STRUCTURALLY BLOCKED. Every unit returns skip_reason="step17_ai_blocked_imp_34_35_prerequisites_missing". Module does NOT import route_ai_fallback / AiFallbackClient / anthropic.
Cascade order	src.phase_z2_ai_fallback.step17.OVERFLOW_CASCADE_ORDER = (DETERMINISTIC, POPUP, AI_REPAIR, USER_OVERRIDE) — single source of truth for Step 17 consumers. Aligns with line 16 of this doc.
IMP-46 cache gate	src.phase_z2_ai_fallback.cache.save_proposal(..., visual_check_passed, user_approved, auto_cache=False) raises AiFallbackCacheGateError unless visual_check_passed=True AND (user_approved=True OR auto_cache=True). Persistent JSON backend at data/frame_cache/{frame_id}/{signature_hash}.json (u2); cache key = structural signature over 8 axes (u1+u4); read-side fingerprint invalidation via read_proposal(..., fingerprints=...) strict equality (u3); --auto-cache CLI flag + settings.ai_fallback_auto_cache (default False) bypasses ONLY the user_approved gate (u5); repo root tracked via data/frame_cache/.gitkeep with cached payloads git-ignored (u6). read_proposal returns None on missing / corrupt / fingerprint-mismatched entries — cache is a hint, never a hard dependency.
AST isolation	tests/phase_z2_ai_fallback/test_ast_isolation.py parses every *.py under src/phase_z2_ai_fallback/ and forbids Phase Q runtime / Kei client / src.phase_z2_* (non-fallback) imports. Whitelist = src.config + intra-package + stdlib + anthropic + pydantic.