# opencode Spec-Driven Development Boilerplate

A spec-driven development boilerplate for [opencode](https://opencode.ai), converted from the
[Claude Code boilerplate](https://git.yasue.org/ken/claudecode-boilerplate) that accompanies the book
*"Practical Claude Code Introduction."*

It gives opencode a structured workflow for turning ideas into production code through persistent design
documents, per-task steering files, AI skills, subagents, and slash commands.

---

## Development Workflow (Step by Step)

How a project goes from idea to working code with this boilerplate:

```
Idea → /setup-project → /define-design → refine design → /generate-app → /plan-milestones → /execute-milestones (phase by phase)
```

### Step 1 — Write down your idea
Put your brainstorming notes, requirements, and constraints into
`docs/ideas/initial-requirements.md` (free-form; replace the sample content with your own).

### Step 2 — Create the specification: `/setup-project`
Automatically creates the six persistent documents that define **what to build**:
PRD, functional design, architecture, repository structure, development guidelines, and glossary
(all under `docs/`). Review them and request edits in normal conversation if needed.

### Step 3 — Define the UI/UX design: `/define-design`
Creates the design specification under `docs/design/`: design brief, design tokens,
**`ui-blueprint.json` (the source of truth for UI generation)**, platform mapping, and SVG
wireframes (visual references only). You'll be asked once about platform, style, screens,
navigation, branding, and accessibility.

### Step 4 — Review and refine the design **before writing any code**
This is the key design-decision gate: iterate on the design while it is still cheap to change.

- `/update-design <change>` — targeted refinements (e.g. `add a profile screen`)
- Re-run `/define-design` — change the overall direction
- Repeat until you approve the design (especially `ui-blueprint.json`)

### Step 5 — Generate the initial app: `/generate-app web | flutter | winui3`
Scaffolds the app shell from the approved design: theme (from tokens), routes, screens, and
reusable components. No feature logic yet.

### Step 6 — Plan milestones: `/plan-milestones`
Breaks the product into **phases** and milestones, and generates `docs/milestones/`:
a `roadmap.md` overview plus **one file per phase** (`phase1-milestones.md`,
`phase2-milestones.md`, …). Each phase file lists its milestones and **the features they
contain** — each feature sized for exactly one `/add-feature` run, with acceptance criteria and a
ready-to-run command. Phase 1 delivers the MVP; later phases build on it by priority and dependency.

### Step 7 — Implement the milestones

Two ways to work through the plan:

**Option A — execute a phase file: `/execute-milestones <phase-file>`**
Requires the phase file to execute, e.g. `/execute-milestones phase1-milestones.md`. Runs that
phase's milestones **one by one, autonomously**. For each milestone it creates a **separate
steering directory** (`.steering/[date]-milestone-[NN]-[name]/`), divides the milestone's
features into concrete tasks grouped by feature, implements them all, validates, tests,
reconciles the docs, and marks the milestone completed — then immediately starts the next
milestone in the file. When the phase completes, run it again with the next phase file.

**Option B — one feature at a time: `/add-feature <feature>`**
A fully autonomous loop, one feature per run. Each run:

1. Creates `.steering/[YYYYMMDD]-[feature]/` (requirements, design, tasklist)
2. Reads the feature's entry in its phase file and the design spec first — and updates the design first if the feature changes the UI
3. Implements every task in `tasklist.md`, checking items off as it goes
4. Validates quality with the `implementation-validator` subagent
5. Writes Playwright E2E tests for the feature's acceptance criteria, then runs `npm test`, `npm run lint`, `npm run typecheck`, and `npm run test:e2e` until green
6. Records a retrospective, reconciles all six `docs/` documents, and checks the feature off in its phase file

### Step 8 — Repeat and maintain
- Remaining phases → `/execute-milestones <next phase file>`, or feature by feature with `/add-feature <feature>`
- UI changes → `/update-design <change>` first, then `/add-feature`
- Re-planning → re-run `/plan-milestones` or edit `docs/milestones/` in conversation
- Document quality checks → `/review-docs <path>`

**A feature is "done" when**: all tasks in its tasklist are `[x]`, validation passes,
test/lint/typecheck and the Playwright E2E suite succeed, and the persistent documents are back
in sync with the code.

---

## Table of Contents

- [Development Workflow (Step by Step)](#development-workflow-step-by-step)
- [What Is Spec-Driven Development?](#what-is-spec-driven-development)
- [Conversion Summary (Claude Code → opencode)](#conversion-summary-claude-code--opencode)
- [Prerequisites](#prerequisites)
- [Quick Start](#quick-start)
- [Directory Structure](#directory-structure)
- [Configuration Overview](#configuration-overview)
- [Usage Workflow](#usage-workflow)
- [Design & App Generation](#design--app-generation)
- [Commands Reference](#commands-reference)
- [Skills Reference](#skills-reference)
- [Agents Reference](#agents-reference)
- [Customizing the Boilerplate](#customizing-the-boilerplate)
- [Troubleshooting](#troubleshooting)
- [License](#license)

---

## What Is Spec-Driven Development?

Spec-driven development separates **"what to build"** from **"how to build it"**:

1. **Persistent documents** (`docs/`) — the north-star design (PRD, functional design, architecture, etc.)
2. **Steering files** (`.steering/`) — per-task plans created fresh for each piece of work
3. **Implementation** — the agent follows `tasklist.md`, updating progress as it goes
4. **Verification** — tests, lint, typecheck, and a retrospective

opencode loads the right skill automatically based on what you're doing, so you don't have to think about
the process — just describe what you want.

---

## Conversion Summary (Claude Code → opencode)

| Claude Code | opencode | Notes |
|---|---|---|
| `CLAUDE.md` | `AGENTS.md` | Referenced via `instructions` in `opencode.json` |
| `.claude/settings.json` | `opencode.json` | Permissions converted to opencode's `permission` schema |
| `.claude/agents/*.md` | `.opencode/agent/*.md` | Added `mode: subagent`; `model: sonnet` removed (inherits default) |
| `.claude/commands/*.md` | `.opencode/command/*.md` | Tool-call syntax (`Bash()`, `Grep()`, `Skill()`) converted to natural instructions; `$ARGUMENTS` added |
| `.claude/skills/*/SKILL.md` | `.opencode/skills/*/SKILL.md` | `allowed-tools` frontmatter removed (not an opencode field) |
| `Skill('steering')` calls | Auto-loaded by description | opencode surfaces skills via `description` matching |
| `TodoWrite` / `Edit` tool refs | `todowrite` / `edit` | Lowercased to match opencode tool names |
| Claude Code devcontainer feature | `curl … opencode.ai/install` | Replaced Anthropic feature with opencode install script |

All skill templates and guides were preserved verbatim except for `.claude/` path references and
"Claude Code" mentions, which were updated to `.opencode/` and "opencode" respectively.

---

## Prerequisites

- **Node.js** v18+ (v24.11.0 recommended)
- **npm**
- **opencode** — install with:
  ```bash
  curl -fsSL https://opencode.ai/install | bash
  ```
  See <https://opencode.ai/docs> for alternatives (npm, Homebrew, etc.)
- **Docker** (only if using the Dev Container)

---

## Quick Start

### Option A — Dev Container (recommended)

1. Open this folder in **VS Code**.
2. When prompted, click **"Reopen in Container"** (or run the command
   *Dev Containers: Reopen in Container*).
3. The container automatically:
   - Installs Node.js LTS
   - Runs `npm install`
   - Installs opencode
4. Open a terminal and start opencode:
   ```bash
   opencode
   ```

### Option B — Manual setup

```bash
# 1. Install dependencies
npm install

# 2. Set up Git hooks
npm run prepare

# 3. Start opencode
opencode
```

---

## Directory Structure

```
.
├── opencode.json              # opencode config (permissions, instructions)
├── AGENTS.md                  # Project instructions (loaded into every session)
├── package.json               # Node.js project + scripts
├── tsconfig.json              # TypeScript config
├── eslint.config.js           # ESLint flat config
├── vitest.config.ts           # Vitest config (80% coverage threshold)
├── .prettierrc / .prettierignore
├── .gitignore
├── .husky/pre-commit          # Runs lint-staged + typecheck before commit
├── .devcontainer/devcontainer.json
├── prompt.md                  # Example MVP prompt
│
├── src/                       # Source code
│   ├── example.ts
│   └── example.test.ts
│
├── docs/                      # Persistent design documents
│   ├── ideas/
│   │   └── initial-requirements.md   # Brainstorming notes (pre-PRD)
│   ├── design/                # UI/UX design spec (created by /define-design)
│   │   ├── design-brief.md
│   │   ├── design-tokens.json
│   │   ├── ui-blueprint.json         # source of truth for UI
│   │   ├── platform-mapping.md
│   │   └── screens/*.svg             # visual references only
│   └── milestones/            # Milestone plan (created by /plan-milestones)
│       ├── roadmap.md                # overview + status
│       └── phaseN-milestones.md      # one per phase: milestones + features
│
├── .steering/                 # Per-task steering files (created by /add-feature)
│   └── .gitkeep
│
└── .opencode/                 # opencode configuration
    ├── agent/                 # Subagent definitions
    │   ├── doc-reviewer.md
    │   └── implementation-validator.md
    ├── command/               # Slash commands
    │   ├── setup-project.md
    │   ├── define-design.md
    │   ├── generate-app.md
    │   ├── update-design.md
    │   ├── plan-milestones.md
    │   ├── execute-milestones.md
    │   ├── add-feature.md
    │   └── review-docs.md
    └── skills/                # Task-specific skills
        ├── prd-writing/           (SKILL.md + template.md)
        ├── functional-design/     (SKILL.md + template.md + guide.md)
        ├── architecture-design/   (SKILL.md + template.md + guide.md)
        ├── repository-structure/  (SKILL.md + template.md + guide.md)
        ├── development-guidelines/(SKILL.md + template.md + guides/)
        ├── glossary-creation/     (SKILL.md + template.md + guide.md)
        ├── ui-design/             (SKILL.md)
        ├── design-tokens/         (SKILL.md)
        ├── platform-ui-generation/(SKILL.md)
        ├── milestone-planning/    (SKILL.md + template.md)
        ├── milestone-execution/   (SKILL.md)
        ├── e2e-testing/           (SKILL.md)
        └── steering/              (SKILL.md + templates/)
```

---

## Configuration Overview

### `opencode.json`

The main configuration file. Key sections:

```jsonc
{
  "$schema": "https://opencode.ai/config.json",
  "instructions": ["AGENTS.md"],     // Loaded into every session
  "permission": {
    "skill": "allow",                // Skills are auto-available
    "bash": {                        // Common dev commands pre-approved
      "*": "ask",
      "npm *": "allow",
      "npx *": "allow",
      "git *": "allow",
      // ...
    }
  }
}
```

> **After editing `opencode.json`, quit and restart opencode** — config is loaded once at startup.

### `AGENTS.md`

The project memory file. opencode reads it on every session. It defines:
- The technology stack
- The spec-driven development principles
- The directory structure
- The development process and workflow

### Agents (`.opencode/agent/`)

Subagents run in isolated contexts via the `task` tool. They don't consume the main session's context.

### Commands (`.opencode/command/`)

Slash commands invoked in the opencode TUI with `/command-name`. Each command is a prompt template
that opencode executes.

### Skills (`.opencode/skills/`)

Skills are loaded automatically based on their `description` field. You don't invoke them by name —
opencode surfaces the right skill when the task matches.

---

## Usage Workflow

### 1. Initial project setup

Run the setup command to automatically create all six persistent design documents:

```
> /setup-project
```

This creates (automatically, end-to-end):
1. `docs/product-requirements.md` (PRD)
2. `docs/functional-design.md`
3. `docs/architecture.md`
4. `docs/repository-structure.md`
5. `docs/development-guidelines.md`
6. `docs/glossary.md`

The PRD is based on the brainstorming notes in `docs/ideas/initial-requirements.md`. Edit that file
first if you have your own idea, or replace it.

### 2. Define the UI/UX design

```
> /define-design
```

Creates the design specification under `docs/design/` (design brief, design tokens, UI blueprint,
platform mapping, and SVG wireframes). You'll be asked about target platform, visual style, main
screens, navigation, branding, and accessibility; if you don't specify, sensible defaults are proposed.

Review and refine the UI/UX **before** generating the app — it is far easier to iterate on the design
than on generated code:

- Re-run `/define-design` to change the overall direction.
- Run `/update-design <change>` for targeted refinements (e.g. `/update-design make the home screen denser`).
- Iterate until the design — especially `docs/design/ui-blueprint.json` — is approved.

**The design source of truth is `docs/design/ui-blueprint.json`.** SVG files are visual references only.

### 3. Generate the app

```
> /generate-app web
> /generate-app flutter
> /generate-app winui3
```

Scaffolds the initial application for the selected target from the design spec — app shell, theme
(from tokens), routes, screens, and reusable components. No feature logic is implemented here.

### 4. Plan milestones

```
> /plan-milestones
> /plan-milestones 2 phases, MVP first
```

Breaks the product into phases and milestones and generates `docs/milestones/`: a `roadmap.md`
overview plus one file per phase (`phase1-milestones.md`, `phase2-milestones.md`, …) listing its
milestones and their features — each feature sized for one `/add-feature` run, with acceptance
criteria and a ready-to-run command. Phase 1 delivers the MVP. You'll be asked once about phase
count, MVP scope, priorities, and constraints; sensible defaults are proposed from the PRD.

### 5. Add a feature

```
> /add-feature User authentication
```

This fully autonomous workflow:
1. Creates `.steering/[YYYYMMDD]-[feature-name]/` with `requirements.md`, `design.md`, `tasklist.md`
2. Reads the feature's milestone document (`docs/milestones/`) for scope and acceptance criteria
3. Reads the design spec (`docs/design/`) and updates it first if the feature changes the UI
4. Generates the steering files (planning mode of the steering skill)
5. Implements every task in `tasklist.md`, marking each `[ ]` → `[x]` as it goes
6. Launches the `implementation-validator` subagent for quality review
7. Writes Playwright E2E tests for the acceptance criteria, then runs `npm test`, `npm run lint`, `npm run typecheck`, `npm run test:e2e`
8. Records a retrospective, reconciles all six persistent docs with the feature, and checks the feature off in its phase file

### 6. Execute a phase file (alternative to per-feature runs)

```
> /execute-milestones phase1-milestones.md
> /execute-milestones docs/milestones/phase2-milestones.md
> /execute-milestones 1                        # shorthand for phase1-milestones.md
```

**The phase file argument is required** — without it the command lists the available phase files
and stops. It then works through that phase's milestones autonomously, one at a time. For each
milestone it creates a **separate steering directory** (`.steering/[date]-milestone-[NN]-[name]/`),
divides the milestone's features into tasks grouped by feature, implements everything, validates,
runs the test suite, reconciles the docs, marks the milestone `Completed` — and immediately starts
the next one. When the last milestone finishes, the phase is marked `Completed` in the roadmap.
It only stops early on a genuine external blocker, which it records in the roadmap.

### 7. Review a document

```
> /review-docs docs/product-requirements.md
```

Launches the `doc-reviewer` subagent to evaluate the document from five perspectives:
completeness, clarity, consistency, implementability, and measurability.

### 8. Day-to-day editing

You don't always need a command — just ask in normal conversation:

```
> Add a new feature to the PRD
> Review the performance requirements in architecture.md
> Add a new domain term to glossary.md
```

opencode loads the appropriate skill automatically.

---

## Design & App Generation

Recommended workflow:

1. Run `/setup-project`
2. Run `/define-design`
3. Review `docs/design/` and refine the UI/UX until approved:
   - Re-run `/define-design` to change direction, or
   - Run `/update-design <change>` for targeted refinements
4. Run `/generate-app web`, `/generate-app flutter`, or `/generate-app winui3`
5. Run `/plan-milestones` to break the product into phases and milestones (one `phaseN-milestones.md` per phase)
6. Use `/execute-milestones phase1-milestones.md` to implement a phase's milestones one by one, or `/add-feature` to go feature by feature
7. Use `/update-design` whenever a feature changes the UI

Source of truth:

- The design source of truth is `docs/design/ui-blueprint.json`.
- SVG files (`docs/design/screens/*.svg`) are only visual references.
- Generated UI should follow `docs/design/design-tokens.json` — no hard-coded values.
- No platform-specific implementation is generated before `/generate-app` is executed.

See [`docs/design/README.md`](docs/design/README.md) for the full structure.

---

## Commands Reference

| Command | Description | Example |
|---|---|---|
| `/setup-project` | Create the six persistent documents automatically | `/setup-project` |
| `/define-design` | Create the UI/UX design spec under `docs/design/` | `/define-design` |
| `/generate-app` | Scaffold the initial app for a target platform | `/generate-app web` |
| `/update-design` | Update the design spec when a feature changes the UI | `/update-design add a profile screen` |
| `/plan-milestones` | Plan phases and milestones; generates one `phase[N]-milestones.md` per phase | `/plan-milestones 2 phases, MVP first` |
| `/execute-milestones` | Execute one phase file: its milestones one by one, with separate steering documents per milestone (file argument required) | `/execute-milestones phase1-milestones.md` |
| `/add-feature` | Implement a feature end-to-end (autonomous) | `/add-feature User profile editing` |
| `/review-docs` | Detailed document review via subagent | `/review-docs docs/architecture.md` |

---

## Skills Reference

| Skill | When it loads | Output |
|---|---|---|
| `prd-writing` | Creating a Product Requirements Document | `docs/product-requirements.md` |
| `functional-design` | Creating a functional design document | `docs/functional-design.md` |
| `architecture-design` | Designing the system architecture | `docs/architecture.md` |
| `repository-structure` | Defining the directory layout | `docs/repository-structure.md` |
| `development-guidelines` | Creating coding conventions / implementing code | `docs/development-guidelines.md` |
| `glossary-creation` | Creating a project glossary | `docs/glossary.md` |
| `ui-design` | Creating the design brief, UI blueprint, and SVG wireframes | `docs/design/` files |
| `design-tokens` | Creating and maintaining design tokens | `docs/design/design-tokens.json` |
| `platform-ui-generation` | Converting design files into Web/Flutter/WinUI 3 code | generated app code |
| `milestone-planning` | Planning phases/milestones and the feature breakdown per milestone | `docs/milestones/` phase files |
| `milestone-execution` | Executing a phase file's milestones one by one with per-milestone steering docs | `.steering/[date]-milestone-NN-[name]/` files |
| `e2e-testing` | Writing and running Playwright E2E tests as part of every verification step | `e2e/*.spec.ts` + `npm run test:e2e` |
| `steering` | Planning, implementing, and retrospecting on a task | `.steering/[date]-[name]/` files |

Each skill folder contains a `SKILL.md` (instructions) plus `template.md` and/or `guide.md` (reference
material the skill points to).

---

## Agents Reference

| Agent | Mode | Purpose |
|---|---|---|
| `doc-reviewer` | subagent | Reviews document quality across 5 dimensions; outputs a scored report with prioritized improvements |
| `implementation-validator` | subagent | Validates code against the spec; checks quality, test coverage, security, performance; runs lint/test/typecheck |

Agents are launched via the `task` tool (e.g., by the `/add-feature` and `/review-docs` commands).
They run in an isolated context window.

---

## Customizing the Boilerplate

### Change the model

Agents inherit the default model from `opencode.json`. To pin a specific model for a subagent, add
`model` to its frontmatter:

```yaml
---
description: ...
mode: subagent
model: anthropic/claude-sonnet-4-6
---
```

Or set a global default in `opencode.json`:

```jsonc
{
  "model": "anthropic/claude-sonnet-4-6"
}
```

> Model IDs use the `provider/model-id` format. See <https://opencode.ai/config.json> for the full schema.

### Adjust permissions

Edit the `permission` block in `opencode.json`. For example, to allow all bash commands:

```jsonc
{
  "permission": { "bash": "allow" }
}
```

### Add a new skill

1. Create `.opencode/skills/my-skill/SKILL.md`
2. Add frontmatter with `name` and `description` (the description controls when opencode loads it)
3. Add any companion `template.md` or `guide.md` files
4. Restart opencode

### Add a new command

1. Create `.opencode/command/my-command.md`
2. Add `description` frontmatter + a prompt body (use `$ARGUMENTS` for user input)
3. Restart opencode

### Add a new agent

1. Create `.opencode/agent/my-agent.md`
2. Add `description` and `mode: subagent` frontmatter + a prompt body
3. Restart opencode

---

## Troubleshooting

### opencode won't start after editing config

opencode validates `opencode.json` strictly and refuses to start on invalid fields. To recover:

```bash
# Skip the project config and start from globals only
OPENCODE_DISABLE_PROJECT_CONFIG=1 opencode
```

Then fix the broken file and restart normally.

### Skills not loading

- Ensure each `SKILL.md` has a `description` in its frontmatter — skills without one are filtered out.
- Ensure the folder name matches the `name` field.
- Restart opencode after adding or changing skills.

### Commands not appearing

- Command files must be directly inside `.opencode/command/` (not in subdirectories).
- Restart opencode after adding commands.

### Dev Container: `opencode` command not found

The install script adds opencode to `~/.opencode/bin/` and updates your shell profile. If the command
isn't found in a new terminal:

```bash
export PATH="$HOME/.opencode/bin:$PATH"
opencode
```

Or create a permanent symlink:

```bash
sudo ln -sf "$HOME/.opencode/bin/opencode" /usr/local/bin/opencode
```

---

## License

MIT — see [LICENSE](LICENSE).