/recap-doc — Recap Document Generator

Trigger

• Keywords: recap-doc, generate recap, 產出導覽文件, walkthrough doc, 本輪導覽

When NOT to Use

Command Signature

/recap-doc --scope <json-path-or-inline> [--focus <str>] [--depth brief|normal|deep] [--output <path>]

Workflow

sequenceDiagram
    participant U as Caller (user or /post-dev-recap)
    participant D as /recap-doc
    participant S as scripts/detect-scope.js
    participant T as tech-brief-style collection
    participant CE as /codex-explain (Skill)
    participant SR as scripts/security-redact.js
    participant F as Output file

    U->>D: /recap-doc --scope <json> [--depth]
    D->>D: Phase 1: Load & validate ScopeReport
    D->>T: Phase 2: Collect git evidence for scope.files (reuse tech-brief Stage 2)
    D->>D: Phase 3: Cross-reference tech-spec (if feature_context.has_tech_spec)
    D->>CE: Phase 4a: Explain top-N changed files
    D->>D: Phase 4b: Synthesize sections + Blind Spots (Must) + Anticipated Questions
    D->>SR: Phase 5a: Scan output for high/medium-confidence secrets
    SR-->>D: Redacted or AbortError
    D->>F: Phase 5b: Write briefing-recap-<date>.md
    D-->>U: Emit output path + summary

Phase 1 — Scope Load

1. Parse --scope argument: accept file path, - for stdin, or inline JSON (detected by leading {).
2. Validate ScopeReport v1 required fields: version === 1, source, files[], feature_context, fallback_trace.
3. If source === null or files.length === 0 → exit non-zero with message directing user to rerun scripts/detect-scope.js.

Phase 2 — Evidence Collection (reuse tech-brief Stage 2)

See references/source-guide.md for the full strategy. Summary:

• Run git log --oneline -20 -- <path> per scope file (capped at top-N by depth)
• Run git diff --stat <base-ref>..HEAD -- <path> for magnitude
• Read top-N changed files (100 lines each, source files only; exclude docs/test)

Top-N by depth: brief=5, normal=10, deep=15.

Phase 3 — Spec Cross-reference

When scope.feature_context.has_tech_spec === true:

1. Read <docs_path>/2-tech-spec.md
2. Extract section headings + Work Breakdown items
3. Prepare drift-check input: list each tech-spec work item + implementation evidence (changed files overlap)

Phase 4 — AI Synthesis

See references/prompt-template.md for the full prompt. Key behaviors:

1. Per-file explanations (Phase 4a): for each top-N file, invoke /codex-explain (Skill tool call) with --lines scoped to changed hunks. Reuse, not reimplement — this satisfies NFR-5.
2. Section synthesis (Phase 4b): compose §1 Overview through §7 Evidence using the output template (see references/output-template.md).
3. Blind Spots (FR-9, Must — any depth): even if no obvious blind spots are found, emit the §5 heading with the fallback wording 「本輪未偵測到明顯盲點」+ 推論依據.
4. Anticipated Questions (FR-11): present ≥ 3 questions at normal/deep; omit at brief.

Phase 5 — Redaction + Write

1. Load scripts/security-redact.js and invoke redact(text) on the complete markdown output.
2. If AbortError is thrown → do not write; emit stderr with fingerprint and exit non-zero.
3. If redacted successfully → validate output path via fs.realpathSync on the first existing ancestor (must resolve inside repo root or <tmp>; no .. / external symlink).
4. Write file with trailing newline.

Depth Levels

See the full matrix in references/output-template.md. Summary:

Save Behavior

Recap output is ephemeral by default — written to the OS temp directory so the user's project tree stays clean. Callers that want the recap checked in must opt in with --output.

Where <tmp> resolves in this order:

1. $TMPDIR environment variable (honoured on macOS by default).
2. Node's os.tmpdir() (portable fallback — in code this is require('os').tmpdir()).
3. /tmp as the final POSIX fallback.

The directory <tmp>/sd0x-dev-flow-recap/ is created if missing. If the target file already exists the same day, append a numeric suffix: briefing-recap-2026-04-17-r2.md.

Permanent recap: when the user wants the recap stored with the feature docs (e.g. shareable post-mortem), invoke with --output docs/features/<key>/briefing-recap-<YYYY-MM-DD>.md explicitly.

Path Security

Performance

Target: NFR-2 — /recap-doc output generation ≤ 30s (excluding external LLM latency, measured from scope-load start to file-write complete). The Phase 4a per-file explanations should be dispatched in parallel batches to stay within budget.

Output Structure

See references/output-template.md for the canonical markdown template. High-level structure:

# Recap: <feature-key or "session">
> **Scope source**: ...
> **Detected at**: ...
> **Focus**: ...
> **Confidence**: ...

## 1. Overview
## 2. Changed Files (table with file:line references)
## 3. Design Decisions
## 4. Spec vs Implementation Drift    (if has_tech_spec)
## 5. Blind Spots                     (FR-9 Must — any depth)
## 6. Anticipated Questions           (normal/deep only)
## 7. Evidence                         (commit SHAs, file:line index)

Verification

• ScopeReport v1 validated (version + required fields) before any synthesis
• Top-N files aligned with depth (brief=5, normal=10, deep=15)
• §5 Blind Spots heading present regardless of depth; fallback wording when no items
• §6 Anticipated Questions ≥ 3 at normal/deep; omitted at brief
• /codex-explain invoked per top-N file (NFR-5 reuse — not reimplemented)
• security-redact.js invoked before wri