Acquire Codebase Knowledge

# Acquire Codebase Knowledge

Produces seven populated documents in `docs/codebase/` covering everything needed to work effectively on the project. Only document what is verifiable from files or terminal output — never infer or assume.

## Output Contract (Required)

Before finishing, all of the following must be true:

1. Exactly these files exist in `docs/codebase/`: `STACK.md`, `STRUCTURE.md`, `ARCHITECTURE.md`, `CONVENTIONS.md`, `INTEGRATIONS.md`, `TESTING.md`, `CONCERNS.md`.
2. Every claim is traceable to source files, config, or terminal output.
3. Unknowns are marked as `[TODO]`; intent-dependent decisions are marked `[ASK USER]`.
4. Every document includes a short "evidence" list with concrete file paths.
5. Final response includes numbered `[ASK USER]` questions and intent-vs-reality divergences.

## Workflow

Copy and track this checklist:

```
- [ ] Phase 1: Run scan, read intent documents
- [ ] Phase 2: Investigate each documentation area
- [ ] Phase 3: Populate all seven docs in docs/codebase/
- [ ] Phase 4: Validate docs, present findings, resolve all [ASK USER] items
```

## Focus Area Mode

If the user supplies a focus area (for example: "architecture only" or "testing and concerns"):

1. Always run Phase 1 in full.
2. Fully complete focus-area documents first.
3. For non-focus documents not yet analyzed, keep required sections present and mark unknowns as `[TODO]`.
4. Still run the Phase 4 validation loop on all seven documents before final output.

### Phase 1: Scan and Read Intent

1. Run the scan script from the target project root:
   ```bash
   python3 "$SKILL_ROOT/scripts/scan.py" --output docs/codebase/.codebase-scan.txt
   ```
   Where `$SKILL_ROOT` is the absolute path to the skill folder. Works on Windows, macOS, and Linux.

   **Quick start:** If you have the path inline:
   ```bash
   python3 /absolute/path/to/skills/acquire-codebase-knowledge/scripts/scan.py --output docs/codebase/.codebase-scan.txt
   ```

2. Search for `PRD`, `TRD`, `README`, `ROADMAP`, `SPEC`, `DESIGN` files and read them.
3. Summarise the stated project intent before reading any source code.

### Phase 2: Investigate

Use the scan output to answer questions for each of the seven templates. Load [`references/inquiry-checkpoints.md`](references/inquiry-checkpoints.md) for the full per-template question list.

If the stack is ambiguous (multiple manifest files, unfamiliar file types, no `package.json`), load [`references/stack-detection.md`](references/stack-detection.md).

### Phase 3: Populate Templates

Copy each template from `assets/templates/` into `docs/codebase/`. Fill in this order:

1. [STACK.md](assets/templates/STACK.md) — language, runtime, frameworks, all dependencies
2. [STRUCTURE.md](assets/templates/STRUCTURE.md) — directory layout, entry points, key files
3. [ARCHITECTURE.md](assets/templates/ARCHITECTURE.md) — layers, patterns, data flow
4. [CONVENTIONS.md](assets/templates/CONVENTIONS.md) — naming, formatting, error handling, imports
5. [INTEGRATIONS.md](assets/templates/INTEGRATIONS.md) — external APIs, databases, auth, monitoring
6. [TESTING.md](assets/templates/TESTING.md) — frameworks, file organization, mocking strategy
7. [CONCERNS.md](assets/templates/CONCERNS.md) — tech debt, bugs, security risks, perf bottlenecks

Use `[TODO]` for anything that cannot be determined from code. Use `[ASK USER]` where the right answer requires team intent.

### Phase 4: Validate, Repair, Verify

Run this mandatory validation loop before finalizing:

1. Validate each doc against `references/inquiry-checkpoints.md`.
2. For each non-trivial claim, confirm at least one evidence reference exists.
3. If any required section is missing or unsupported:
  - Fix the document.
  - Re-run validation.
4. Repeat until all seven docs pass.

Then present a summary of all seven documents, list every `[ASK USER]` item as a numbered question, and highlight any Intent vs. Reality divergences from Phase 1.

Validation pass criteria:

- No unsupported claims.
- No empty required sections.
- Unknowns use `[TODO]` rather than assumptions.
- Team-intent gaps are explicitly marked `[ASK USER]`.

---

## Gotchas

**Monorepos:** Root `package.json` may have no source — check for `workspaces`, `packages/`, or `apps/` directories. Each workspace may have independent dependencies and conventions. Map each sub-package separately.

**Outdated README:** README often describes intended architecture, not the current one. Cross-reference with actual file structure before treating any README claim as fact.

**TypeScript path aliases:** `tsconfig.json` `paths` config means imports like `@/foo` don't map directly to the filesystem. Map aliases to real paths before documenting structure.

**Generated/compiled output:** Never document patterns from `dist/`, `build/`, `generated/`, `.next/`, `out/`, or `__pycache__/`. These are artefacts — document source conventions only.

**`.env.example` reveals required config:** Secrets are never committed. Read `.env.example`, `.env.template`, or `.env.sample` to discover required environment variables.

**`devDependencies` ≠ production stack:** Only `dependencies` (or equivalent, e.g. `[tool.poetry.dependencies]`) runs in production. Document linters, formatters, and test frameworks separately as dev tooling.

**Test TODOs ≠ production debt:** TODOs inside `test/`, `tests/`, `__tests__/`, or `spec/` are coverage gaps, not production technical debt. Separate them in `CONCERNS.md`.

**High-churn files = fragile areas:** Files appearing most in recent git history have the highest modification rate and likely hidden complexity. Always note them in `CONCERNS.md`.

---

## Anti-Patterns

| ❌ Don't | ✅ Do instead |
|---------|--------------|
| "Uses Clean Architecture with Domain/Data layers." (when no such directories exist) | State only what directory structure actually shows. |
| "This is a Next.js project." (without checking `package.json`) | Check `dependencies` first. State what's actually there. |
| Guess the database from a variable name like `dbUrl` | Check manifest for `pg`, `mysql2`, `mongoose`, `prisma`, etc. |
| Document `dist/` or `build/` naming patterns as conventions | Source files only. |

---

## Enhanced Scan Output Sections

The `scan.py` script now produce the following sections in addition to the original output:

- **CODE METRICS** — Total files, lines of code by language, largest files (complexity signals)
- **CI/CD PIPELINES** — Detected GitHub Actions, GitLab CI, Jenkins, CircleCI, etc.
- **CONTAINERS & ORCHESTRATION** — Docker, Docker Compose, Kubernetes, Vagrant configs
- **SECURITY & COMPLIANCE** — Snyk, Dependabot, SECURITY.md, SBOM, security policies
- **PERFORMANCE & TESTING** — Benchmark configs, profiling markers, load testing tools

Use these sections during Phase 2 to inform investigation questions and identify tool-specific patterns.

---

## Bundled Assets

| Asset | When to load |
|-------|-------------|
| [`scripts/scan.py`](scripts/scan.py) | Phase 1 — run first, before reading any code (Python 3.8+ required) |

| [`references/inquiry-checkpoints.md`](references/inquiry-checkpoints.md) | Phase 2 — load for per-template investigation questions |
| [`references/stack-detection.md`](references/stack-detection.md) | Phase 2 — only if stack is ambiguous |
| [`assets/templates/STACK.md`](assets/templates/STACK.md) | Phase 3 step 1 |
| [`assets/templates/STRUCTURE.md`](assets/templates/STRUCTURE.md) | Phase 3 step 2 |
| [`assets/templates/ARCHITECTURE.md`](assets/templates/ARCHITECTURE.md) | Phase 3 step 3 |
| [`assets/templates/CONVENTIONS.md`](assets/templates/CONVENTIONS.md) | Phase 3 step 4 |
| [`assets/templates/INTEGRATIONS.md`](assets/templates/INTEGRATIONS.md) | Phase 3 step 5 |
| [`assets/templates/TESTING.md`](assets/templates/TESTING.md) | Phase 3 step 6 |
| [`assets/templates/CONCERNS.md`](assets/templates/CONCERNS.md) | Phase 3 step 7 |

Template usage mode:

- Default mode: complete only the "Core Sections (Required)" in each template.
- Extended mode: add optional sections only when the repo complexity justifies them.