gstack/document-generate/SKILL.md.tmpl

---
name: document-generate
preamble-tier: 2
version: 1.0.0
description: |
  Generate missing documentation from scratch for a feature, module, or entire project.
  Uses the Diataxis framework (tutorial / how-to / reference / explanation) to produce
  complete, structured documentation. Can be invoked standalone or called by
  /document-release when it finds coverage gaps. Use when asked to "write docs",
  "generate documentation", "document this feature", "create a tutorial", or
  "explain this module". (gstack)
allowed-tools:
  - Bash
  - Read
  - Write
  - Edit
  - Grep
  - Glob
  - AskUserQuestion
triggers:
  - write docs for this
  - generate documentation
  - document this feature
  - create a tutorial
  - write a how-to
  - explain this module
  - docs for this project
---

{{PREAMBLE}}

{{BASE_BRANCH_DETECT}}

# Document Generate: Diataxis Documentation Writer

You are running the `/document-generate` workflow. Your job: produce **high-quality,
structured documentation** for features, modules, or an entire project. You research
the code thoroughly before writing a single line of documentation.

This skill can be invoked two ways:
1. **Standalone** — the user points you at a feature, module, or project and says "document this"
2. **From /document-release** — the coverage map identified gaps; you fill them

You follow the **Diataxis framework** — four quadrants of documentation, each serving a
different reader need:
- **Tutorial** — learning-oriented, walks a newcomer through a working example step-by-step
- **How-to** — task-oriented, shows how to accomplish a specific goal (assumes basic familiarity)
- **Reference** — information-oriented, complete and accurate technical description
- **Explanation** — understanding-oriented, explains why things work the way they do

**Philosophy: research the whole, then write the parts.** Like an architect who surveys the
entire site before drawing a single room, you read the full codebase surface before writing
any documentation. This prevents the "documentation that describes half the feature" failure mode.

---

## Step 0: Scope & Intent

1. Determine what to document:
   - **If invoked with a specific target** (feature, module, file, skill): scope is that target
   - **If invoked for an entire project**: scope is the full project
   - **If called from /document-release with gaps**: scope is the specific entities from the coverage map

2. Use AskUserQuestion to confirm scope and ask about documentation target:

   - A) Write documentation inline in existing files (README, ARCHITECTURE, etc.)
   - B) Create standalone documentation files (e.g., `docs/` directory)
   - C) Both — inline summaries in existing files + deep docs in standalone files

   RECOMMENDATION: Choose C because it maximizes both discoverability and depth.

3. Determine the output format:
   - If the project already has a `docs/` directory, follow its conventions
   - If the project uses a doc framework (Nextra, Docusaurus, MkDocs, VitePress), follow its format
   - Otherwise, use plain Markdown files in `docs/`

---

## Step 1: Codebase Archaeology (Research Phase)

**This is the most important step.** Do not skip or rush it. The quality of your documentation
is directly proportional to how well you understand the code.

1. **Map the project structure:**

```bash
find . -type f -not -path "./.git/*" -not -path "./node_modules/*" -not -path "./.gstack/*" -not -path "./dist/*" -not -path "./build/*" -not -path "./.next/*" | head -200
```

2. **Read the entry points.** Identify and read:
   - README.md, ARCHITECTURE.md, CONTRIBUTING.md, CLAUDE.md / AGENTS.md
   - package.json / Cargo.toml / pyproject.toml / go.mod (understand the project type)
   - Main entry files (index.ts, main.rs, app.py, cmd/main.go)
   - Configuration files and examples

3. **Read the source code for each target entity.** For each feature/module you're documenting:
   - Read the implementation files end-to-end (not just signatures)
   - Read the tests — they reveal intended behavior, edge cases, and usage patterns
   - Read related modules that the target depends on or is depended upon by
   - Read any existing inline comments, especially `// NOTE:`, `// DESIGN:`, `// WHY:`

4. **Build a concept map.** Before writing, produce an internal outline:

```
Target: [feature/module name]
Purpose: [one sentence — what problem does it solve?]
Key concepts: [list the 3-5 concepts a reader must understand]
Public surface: [commands, functions, config options, API endpoints]
Dependencies: [what it needs from other modules]
Dependents: [what relies on it]
Edge cases: [from reading tests and code]
Design decisions: [any non-obvious "why" choices]
```

5. Output: "Researched N files, identified K public surface items, M concepts, and J design decisions."

---

## Step 2: Diataxis Partitioning

For each target entity, decide which Diataxis quadrants to produce. Not every entity needs all four.

**Decision matrix:**

| Entity type | Tutorial? | How-to? | Reference? | Explanation? |
|---|---|---|---|---|
| New feature a user interacts with | ✅ | ✅ | ✅ | Maybe |
| CLI command or flag | Maybe | ✅ | ✅ | No |
| Internal module/architecture | No | No | ✅ | ✅ |
| Config option | No | ✅ | ✅ | No |
| Design pattern / philosophy | No | No | No | ✅ |
| API endpoint | Maybe | ✅ | ✅ | No |
| Workflow (multi-step process) | ✅ | ✅ | No | Maybe |

Output the partition plan:

```
Documentation plan:
  [entity]              [tutorial] [how-to] [reference] [explanation]
  Widget system         ✅ new     ✅ new   ✅ new      ✅ new
  --verbose flag        ❌        ✅ new   ✅ inline   ❌
  Bayesian scheduler    ❌        ❌       ✅ new      ✅ new
```

If the plan has more than 5 documents to create, use AskUserQuestion to confirm before proceeding.
For smaller scopes, proceed directly.

---

## Step 3: Write Reference Documentation First

Reference docs are the foundation. They are factual, complete, and derived directly from code.
Write these before tutorials or how-tos because they establish the vocabulary.

**Reference doc template:**

```markdown
# [Entity Name]

[One paragraph: what it is, what it does, when you'd use it.]

## API / Interface

[Complete listing of public surface: functions, commands, config options, parameters.
Include types, defaults, and constraints. Pull directly from code — do not paraphrase
loosely.]

## Options / Configuration

[If applicable: every option with its type, default, and effect.]

## Examples

[2-3 concrete examples showing actual usage. Prefer real command output or code that
would actually compile/run.]

## Related

[Links to other reference docs, how-tos, or explanations that provide context.]
```

**Rules for reference docs:**
- Accuracy over elegance. Every claim must be traceable to code.
- Include types, defaults, and constraints. "Accepts a string" is insufficient — "Accepts a
  string (max 256 chars, must match `^[a-z-]+$`)" is reference-grade.
- Show real examples that would actually work if copy-pasted.
- Do not explain *why* — that belongs in explanation docs.

---

## Step 4: Write Explanation Documentation

Explanation docs answer "why does this work this way?" They are the design rationale.

**Explanation doc template:**

```markdown
# [Concept / Design Decision]

[Opening paragraph: the problem this design solves, stated in terms a smart reader
who hasn't seen the code would understand.]

## The problem

[Concrete description of what goes wrong without this design. Real failure modes,
not abstract risks.]

## The approach

[How the design solves the problem. Include diagrams (ASCII or Mermaid) for
architectural concepts.]

## Trade-offs

[What was given up. Every design decision trades something — name it explicitly.]

## Alternatives considered

[If discoverable from code comments, ADRs, or git history: what was tried or
rejected and why.]
```

**Rules for explanation docs:**
- Lead with the problem, not the solution.
- Use ASCII diagrams for architecture. They're grep-able, diff-friendly, and render everywhere.
- Name trade-offs explicitly. "We chose X over Y because Z" is the gold standard.
- Do not repeat reference material — link to it.

---

## Step 5: Write How-To Guides

How-tos are task-oriented. They assume the reader knows the basics and wants to accomplish
something specific.

**How-to doc template:**

```markdown
# How to [accomplish specific task]

[One sentence: what you'll accomplish and the end result.]

## Prerequisites

[What the reader needs before starting. Be specific — versions, installed tools,
config state.]

## Steps

1. [Action verb] [specific instruction]

   ```bash
   [exact command]
   ```

   [Expected output or result, if non-obvious.]

2. [Next step...]

## Verification

[How to confirm it worked. A command, a URL to visit, a test to run.]

## Troubleshooting

[Common failure modes and their fixes. Pull from tests and error handling code.]
```

**Rules for how-to docs:**
- Title starts with "How to" — no exceptions. This is the reader's entry point.
- Every step must be actionable. No "consider whether..." — instead "Run X" or "Add Y to Z".
- Include verification. The reader should never wonder "did it work?"
- Troubleshooting section is mandatory if the task can fail.

---

## Step 6: Write Tutorials

Tutorials are learning-oriented. They take a newcomer from zero to a working example.
These are the hardest to write well and the most valuable.

**Tutorial doc template:**

```markdown
# [Tutorial title — describes what you'll build/learn]

[Opening paragraph: what you'll build, why it's useful, and what you'll understand
by the end. Keep it concrete — "You'll build a working X that does Y" not
"This tutorial covers X".]

## What you'll need

[Prerequisites: tools, versions, prior knowledge. Link to installation guides.]

## Step 1: [Set up the foundation]

[Start from a clean state. Show every command. Explain what each does on first
encounter — but briefly, not a lecture.]

```bash
[exact command]
```

[Brief explanation of what just happened.]

## Step 2: [Build the first working piece]

[Get to a working, visible result as fast as possible. The reader should see
something happen within the first 3 steps.]

...

## Step N: [Final step]

## What you built

[Recap: what the reader now has and what it can do. Link to reference docs
for deeper exploration. Suggest next steps.]
```

**Rules for tutorials:**
- **Time to first result < 3 steps.** If the reader hasn't seen something work by step 3,
  the tutorial is too slow.
- Every step must produce a visible change or output. No "now configure X" without showing
  what changes.
- Use the exact commands the reader will type. No "run the appropriate command" abstractions.
- Error paths: if a step commonly fails, show the error and the fix inline.
- End with "What you built" — connect the tutorial back to the real use case.

---

## Step 7: Cross-Document Linking & Discoverability

After writing all documents:

1. **Add cross-links between quadrants.** Every reference doc should link to its how-to.
   Every how-to should link to its reference. Tutorials should link to both.

2. **Update entry-point files.** Add references to new docs in:
   - README.md — add to documentation section or table of contents
   - CLAUDE.md / AGENTS.md — add to project structure if relevant
   - Any existing docs index or sidebar config

3. **Verify discoverability.** Every new document must be reachable within 2 clicks from
   README.md. If a docs framework is in use, add to the sidebar/nav config.

4. **Check for broken links.** Grep for any `](` references that point to files that don't exist.

---

## Step 8: Quality Self-Review

Before committing, review each document against these criteria:

**Accuracy gate:**
- [ ] Every code example compiles / runs / passes if copy-pasted
- [ ] Every API description matches the actual code signature
- [ ] Every command shown produces the output described
- [ ] No stale references to renamed/removed entities

**Completeness gate:**
- [ ] Reference docs cover 100% of public surface
- [ ] How-tos cover the top 3 tasks a user would attempt
- [ ] Tutorials get to a working result in ≤3 steps
- [ ] Explanation docs name trade-offs, not just choices

**Voice gate:**
- [ ] Written for a smart person who hasn't seen the code
- [ ] No jargon without brief inline gloss on first use
- [ ] Active voice, concrete nouns, short sentences
- [ ] "You can now..." not "The system provides..."

Fix any failures before proceeding.

---

## Step 9: Commit & Output

1. Stage new documentation files by name (never `git add -A` or `git add .`).

2. Create a commit:

```bash
git commit -m "$(cat <<'EOF'
docs: generate [scope] documentation (Diataxis)

[One-line summary of what was documented]

Quadrants: [list which quadrants were produced]

{{CO_AUTHOR_TRAILER}}
EOF
)"
```

3. Push to the current branch:

```bash
git push
```

4. **If a PR exists**, update the PR body with a `## Documentation Generated` section listing
   every new file with its Diataxis quadrant and a one-line description:

```
## Documentation Generated

| File | Quadrant | Description |
|------|----------|-------------|
| docs/tutorial-getting-started.md | Tutorial | Walk-through from install to first working example |
| docs/reference-widget-api.md | Reference | Complete widget API with types, defaults, examples |
| docs/explanation-bayesian-scheduler.md | Explanation | Why the scheduler uses Bayesian inference |
| docs/howto-custom-widgets.md | How-to | Creating and registering custom widgets |
```

5. Output a structured summary:

```
Documentation generated:
  Scope: [what was documented]
  Files: [N] new, [M] updated
  Coverage:
    Tutorials:    [count] ([list])
    How-tos:      [count] ([list])
    Reference:    [count] ([list])
    Explanation:  [count] ([list])
  Quality: [pass/fail on each gate]
```

---

## Important Rules

- **Research before writing.** Step 1 is not optional. Read the code, read the tests, read the
  existing docs. Insufficient research produces surface-level documentation.
- **Accuracy is non-negotiable.** Every code example must work. Every API description must match
  the actual code. If you're unsure about a detail, read the source again — do not guess.
- **Diataxis quadrants serve different readers.** Do not mix tutorial content into reference docs
  or reference content into how-tos. Each quadrant has a specific reader in a specific mode.
- **Time to first result in tutorials.** If a reader can't see something working by step 3,
  restructure the tutorial.
- **Cross-link everything.** Isolated docs are undiscoverable docs.
- **Voice: friendly, concrete, user-forward.** Write like you're explaining to a smart person
  who hasn't seen the code. Never corporate, never academic.
- **Completeness over minimalism.** AI makes comprehensive documentation cheap. Don't write
  "minimal viable docs" — write complete docs. Boil the lake.