git:20260721.df395b3 to git:20260725.7df3e51

---

name: phx-document

---

# Document

Generate documentation for newly implemented features.

## Usage

```

phx-document .claude/plans/magic-link-auth/plan.md

phx-document magic link authentication

phx-document # Auto-detect from recent plan

```

## Iron Laws

1. **Never remove existing documentation** — Existing docs may reflect design intent that isn't obvious from code alone; update rather than replace

2. **@moduledoc on every public module** — Undocumented modules accumulate quickly and create onboarding friction for new team members

3. **ADRs capture the "why", not the "what"** — Code shows what was built; ADRs explain why this approach was chosen over alternatives

4. **Match @doc to function's public API** — Document parameters, return values, and edge cases; callers shouldn't need to read the implementation

5. **DO NOT add @doc to untested code** — documentation implies a stable contract; document only after tests confirm the function behaves as described

## What Gets Documented

| Output | Description |

|--------|-------------|

| `@moduledoc` | For new modules missing documentation |

| `@doc` | For public functions without docs |

| README section | For user-facing features |

| ADR | For significant architectural decisions |

## Workflow

### Step 0: Pre-check (avoid no-op runs)

Run `git diff --name-only HEAD~5 | grep '\.ex$' | head -20` to check for new `.ex` files.

If NO new `.ex` files were added (only modifications), skip the full

audit and report: "No new modules — documentation coverage unchanged."

This prevents 35-message analysis sessions that conclude "PASS" with

zero output (confirmed: session bb0a0454 wasted ~2K tokens on no-op).

1. **Identify** new modules from recent commits or plan file

2. **Check** documentation coverage (`@moduledoc`, `@doc`)

3. **Generate** missing docs using templates

4. **Add** README section if user-facing feature

5. **Create** ADR if architectural decision was made

6. **Write** report to `.claude/plans/{slug}/reviews/{feature}-docs.md`

## When to Generate ADRs

| Trigger | Create ADR |

|---------|-----------|

| New external dependency | Yes |

| New database table | Maybe (if schema non-obvious) |

| New OTP process | Yes (explain why process needed) |

| New context | Maybe (if boundaries non-obvious) |

| New auth mechanism | Yes |

| Performance optimization | Yes |

## Integration with Workflow

```text

phx-plan → phx-work → phx-review

↓

phx-document ← YOU ARE HERE (optional, suggested after review passes)

```

## References

- `references/doc-templates.md` — @moduledoc, @doc, README, ADR templates

- `references/output-format.md` — Documentation report format

- `references/doc-best-practices.md` — Elixir documentation best practices

- `references/documentation-patterns.md` — Detailed documentation patterns