spec-kit/AGENTS.md

# AGENTS.md

## About Spec Kit and Specify

**GitHub Spec Kit** is a comprehensive toolkit for implementing Spec-Driven Development (SDD) - a methodology that emphasizes creating clear specifications before implementation. The toolkit includes templates, scripts, and workflows that guide development teams through a structured approach to building software.

**Specify CLI** is the command-line interface that bootstraps projects with the Spec Kit framework. It sets up the necessary directory structures, templates, and AI agent integrations to support the Spec-Driven Development workflow.

The toolkit supports multiple AI coding assistants, allowing teams to use their preferred tools while maintaining consistent project structure and development practices.

---

## Integration Architecture

Each AI agent is a self-contained **integration subpackage** under `src/specify_cli/integrations/<key>/`. The subpackage exposes a single class that declares all metadata and inherits setup/teardown logic from a base class. Built-in integrations are then instantiated and added to the global `INTEGRATION_REGISTRY` by `src/specify_cli/integrations/__init__.py` via `_register_builtins()`.

```
src/specify_cli/integrations/
├── __init__.py            # INTEGRATION_REGISTRY + _register_builtins()
├── base.py                # IntegrationBase, MarkdownIntegration, TomlIntegration, YamlIntegration, SkillsIntegration
├── manifest.py            # IntegrationManifest (file tracking)
├── claude/                # Example: SkillsIntegration subclass
│   └── __init__.py        #   ClaudeIntegration class
├── gemini/                # Example: TomlIntegration subclass
│   └── __init__.py
├── windsurf/              # Example: MarkdownIntegration subclass
│   └── __init__.py
├── copilot/               # Example: IntegrationBase subclass (custom setup)
│   └── __init__.py
└── ...                    # One subpackage per supported agent
```

The registry is the **single source of truth for Python integration metadata**. Supported agents, their directories, formats, capabilities, and context files are derived from the integration classes for the Python integration layer.

---

## Adding a New Integration

### 1. Choose a base class

| Your agent needs… | Subclass |
|---|---|
| Standard markdown commands (`.md`) | `MarkdownIntegration` |
| TOML-format commands (`.toml`) | `TomlIntegration` |
| YAML recipe files (`.yaml`) | `YamlIntegration` |
| Skill directories (`speckit-<name>/SKILL.md`) | `SkillsIntegration` |
| Fully custom output (companion files, settings merge, etc.) | `IntegrationBase` directly |

Most agents only need `MarkdownIntegration` — a minimal subclass with zero method overrides.

### 2. Create the subpackage

Create `src/specify_cli/integrations/<package_dir>/__init__.py`, where `<package_dir>` is the Python-safe directory name derived from `<key>`: use the key as-is when it contains no hyphens (e.g., key `"gemini"` → `gemini/`), or replace hyphens with underscores when it does (e.g., key `"kiro-cli"` → `kiro_cli/`). The `IntegrationBase.key` class attribute always retains the original hyphenated value, since that is what the CLI and registry use. For CLI-based integrations (`requires_cli: True`), the `key` should match the actual CLI tool name (the executable users install and run) so CLI checks can resolve it correctly. For IDE-based integrations (`requires_cli: False`), use the canonical integration identifier instead.

**Minimal example — Markdown agent (Windsurf):**

```python
"""Windsurf IDE integration."""

from ..base import MarkdownIntegration


class WindsurfIntegration(MarkdownIntegration):
    key = "windsurf"
    config = {
        "name": "Windsurf",
        "folder": ".windsurf/",
        "commands_subdir": "workflows",
        "install_url": None,
        "requires_cli": False,
    }
    registrar_config = {
        "dir": ".windsurf/workflows",
        "format": "markdown",
        "args": "$ARGUMENTS",
        "extension": ".md",
    }
    context_file = ".windsurf/rules/specify-rules.md"
```

**TOML agent (Gemini):**

```python
"""Gemini CLI integration."""

from ..base import TomlIntegration


class GeminiIntegration(TomlIntegration):
    key = "gemini"
    config = {
        "name": "Gemini CLI",
        "folder": ".gemini/",
        "commands_subdir": "commands",
        "install_url": "https://github.com/google-gemini/gemini-cli",
        "requires_cli": True,
    }
    registrar_config = {
        "dir": ".gemini/commands",
        "format": "toml",
        "args": "{{args}}",
        "extension": ".toml",
    }
    context_file = "GEMINI.md"
```

**Skills agent (Codex):**

```python
"""Codex CLI integration — skills-based agent."""

from __future__ import annotations

from ..base import IntegrationOption, SkillsIntegration


class CodexIntegration(SkillsIntegration):
    key = "codex"
    config = {
        "name": "Codex CLI",
        "folder": ".agents/",
        "commands_subdir": "skills",
        "install_url": "https://github.com/openai/codex",
        "requires_cli": True,
    }
    registrar_config = {
        "dir": ".agents/skills",
        "format": "markdown",
        "args": "$ARGUMENTS",
        "extension": "/SKILL.md",
    }
    context_file = "AGENTS.md"

    @classmethod
    def options(cls) -> list[IntegrationOption]:
        return [
            IntegrationOption(
                "--skills",
                is_flag=True,
                default=True,
                help="Install as agent skills (default for Codex)",
            ),
        ]
```

#### Required fields

| Field | Location | Purpose |
|---|---|---|
| `key` | Class attribute | Unique identifier; for CLI-based integrations (`requires_cli: True`), must match the CLI executable name |
| `config` | Class attribute (dict) | Agent metadata: `name`, `folder`, `commands_subdir`, `install_url`, `requires_cli` |
| `registrar_config` | Class attribute (dict) | Command output config: `dir`, `format`, `args` placeholder, file `extension` |
| `context_file` | Class attribute (str or None) | Path to agent context/instructions file (e.g., `"CLAUDE.md"`, `".github/copilot-instructions.md"`) |

**Key design rule:** For CLI-based integrations (`requires_cli: True`), `key` must be the actual executable name (e.g., `"cursor-agent"` not `"cursor"`). This ensures `shutil.which(key)` works for CLI-tool checks without special-case mappings. IDE-based integrations (`requires_cli: False`) should use their canonical identifier (e.g., `"windsurf"`, `"copilot"`).

### 3. Register it

In `src/specify_cli/integrations/__init__.py`, add one import and one `_register()` call inside `_register_builtins()`. Both lists are alphabetical:

```python
def _register_builtins() -> None:
    # -- Imports (alphabetical) -------------------------------------------
    from .claude import ClaudeIntegration
    # ...
    from .newagent import NewAgentIntegration   # ← add import
    # ...

    # -- Registration (alphabetical) --------------------------------------
    _register(ClaudeIntegration())
    # ...
    _register(NewAgentIntegration())            # ← add registration
    # ...
```

### 4. Context file behavior

Set `context_file` on the integration class. The base integration setup creates or updates the managed Spec Kit section in that file, and uninstall removes the managed section when appropriate.

Only add custom setup logic when the agent needs non-standard behavior. Most integrations do not need wrapper scripts or separate context-update dispatch code.

### 5. Test it

```bash
# Install into a test project
specify init my-project --integration <key>

# Verify files were created in the commands directory configured by
# config["folder"] + config["commands_subdir"] (for example, .windsurf/workflows/)
ls -R my-project/.windsurf/workflows/

# Uninstall cleanly
cd my-project && specify integration uninstall <key>
```

Each integration also has a dedicated test file at `tests/integrations/test_integration_<key>.py`. Note that hyphens in the key are replaced with underscores in the filename (e.g., key `cursor-agent` → `test_integration_cursor_agent.py`, key `kiro-cli` → `test_integration_kiro_cli.py`). Run it with:

```bash
pytest tests/integrations/test_integration_<key_with_underscores>.py -v
```

### 6. Optional overrides

The base classes handle most work automatically. Override only when the agent deviates from standard patterns:

| Override | When to use | Example |
|---|---|---|
| `command_filename(template_name)` | Custom file naming or extension | Copilot → `speckit.{name}.agent.md` |
| `options()` | Integration-specific CLI flags via `--integration-options` | Codex → `--skills` flag, Copilot → `--skills` flag |
| `setup()` | Custom install logic (companion files, settings merge) | Copilot → `.agent.md` + `.prompt.md` + `.vscode/settings.json` (default) or `speckit-<name>/SKILL.md` (skills mode) |
| `teardown()` | Custom uninstall logic | Rarely needed; base handles manifest-tracked files |

**Example — Copilot (fully custom `setup`):**

Copilot extends `IntegrationBase` directly because it creates `.agent.md` commands, companion `.prompt.md` files, and merges `.vscode/settings.json`. It also supports a `--skills` mode that scaffolds `speckit-<name>/SKILL.md` under `.github/skills/` using composition with an internal `_CopilotSkillsHelper`. See `src/specify_cli/integrations/copilot/__init__.py` for the full implementation.

### 7. Update Devcontainer files (Optional)

For agents that have VS Code extensions or require CLI installation, update the devcontainer configuration files:

#### VS Code Extension-based Agents

For agents available as VS Code extensions, add them to `.devcontainer/devcontainer.json`:

```jsonc
{
  "customizations": {
    "vscode": {
      "extensions": [
        // ... existing extensions ...
        "[New Agent Extension ID]"
      ]
    }
  }
}
```

#### CLI-based Agents

For agents that require CLI tools, add installation commands to `.devcontainer/post-create.sh`:

```bash
#!/bin/bash

# Existing installations...

echo -e "\n🤖 Installing [New Agent Name] CLI..."
# run_command "npm install -g [agent-cli-package]@latest"
echo "✅ Done"
```

---

## Command File Formats

### Markdown Format

**Standard format:**

```markdown
---
description: "Command description"
---

Command content with {SCRIPT} and $ARGUMENTS placeholders.
```

**GitHub Copilot Chat Mode format:**

```markdown
---
description: "Command description"
mode: speckit.command-name
---

Command content with {SCRIPT} and $ARGUMENTS placeholders.
```

### TOML Format

```toml
description = "Command description"

prompt = """
Command content with {SCRIPT} and {{args}} placeholders.
"""
```

### YAML Format

Used by: Goose

```yaml
version: 1.0.0
title: "Command Title"
description: "Command description"
author:
  contact: spec-kit
extensions:
  - type: builtin
    name: developer
activities:
  - Spec-Driven Development
prompt: |
  Command content with {SCRIPT} and {{args}} placeholders.
```

## Argument Patterns

Different agents use different argument placeholders. The placeholder used in command files is always taken from `registrar_config["args"]` for each integration — check there first when in doubt:

- **Markdown/prompt-based**: `$ARGUMENTS` (default for most markdown agents)
- **TOML-based**: `{{args}}` (e.g., Gemini)
- **YAML-based**: `{{args}}` (e.g., Goose)
- **Custom**: some agents override the default (e.g., Forge uses `{{parameters}}`)
- **Script placeholders**: `{SCRIPT}` (replaced with actual script path)
- **Agent placeholders**: `__AGENT__` (replaced with agent name)

## Special Processing Requirements

Some agents require custom processing beyond the standard template transformations:

### Copilot Integration

GitHub Copilot has unique requirements:
- Commands use `.agent.md` extension (not `.md`)
- Each command gets a companion `.prompt.md` file in `.github/prompts/`
- Installs `.vscode/settings.json` with prompt file recommendations
- Context file lives at `.github/copilot-instructions.md`

Implementation: Extends `IntegrationBase` with custom `setup()` method that:
1. Processes templates with `process_template()`
2. Generates companion `.prompt.md` files
3. Merges VS Code settings

**Skills mode (`--skills`):** Copilot also supports an alternative skills-based layout
via `--integration-options="--skills"`. When enabled:
- Commands are scaffolded as `speckit-<name>/SKILL.md` under `.github/skills/`
- No companion `.prompt.md` files are generated
- No `.vscode/settings.json` merge
- `post_process_skill_content()` injects a `mode: speckit.<stem>` frontmatter field
- `build_command_invocation()` returns `/speckit-<stem>` instead of bare args

The two modes are mutually exclusive — a project uses one or the other:

```bash
# Default mode: .agent.md agents + .prompt.md companions + settings merge
specify init my-project --integration copilot

# Skills mode: speckit-<name>/SKILL.md under .github/skills/
specify init my-project --integration copilot --integration-options="--skills"
```

### Forge Integration

Forge has special frontmatter and argument requirements:
- Uses `{{parameters}}` instead of `$ARGUMENTS`
- Strips `handoffs` frontmatter key (Forge-specific collaboration feature)
- Injects `name` field into frontmatter when missing

Implementation: Extends `MarkdownIntegration` with custom `setup()` method that:
1. Inherits standard template processing from `MarkdownIntegration`
2. Adds extra `$ARGUMENTS` → `{{parameters}}` replacement after template processing
3. Applies Forge-specific transformations via `_apply_forge_transformations()`
4. Strips `handoffs` frontmatter key
5. Injects missing `name` fields

### Goose Integration

Goose is a YAML-format agent using Block's recipe system:
- Uses `.goose/recipes/` directory for YAML recipe files
- Uses `{{args}}` argument placeholder
- Produces YAML with `prompt: |` block scalar for command content

Implementation: Extends `YamlIntegration` (parallel to `TomlIntegration`):
1. Processes templates through the standard placeholder pipeline
2. Extracts title and description from frontmatter
3. Renders output as Goose recipe YAML (version, title, description, author, extensions, activities, prompt)
4. Uses `yaml.safe_dump()` for header fields to ensure proper escaping
5. Sets `context_file = "AGENTS.md"` so the base setup manages the Spec Kit context section there

## Common Pitfalls

1. **Using shorthand keys for CLI-based integrations**: For CLI-based integrations (`requires_cli: True`), the `key` must match the executable name (e.g., `"cursor-agent"` not `"cursor"`). `shutil.which(key)` is used for CLI tool checks — mismatches require special-case mappings. IDE-based integrations (`requires_cli: False`) are not subject to this constraint.
2. **Forgetting update scripts**: Both bash and PowerShell thin wrappers and the shared context-update scripts must be updated.
3. **Incorrect `requires_cli` value**: Set to `True` only for agents that have a CLI tool; set to `False` for IDE-based agents.
4. **Wrong argument format**: Use `$ARGUMENTS` for Markdown agents, `{{args}}` for TOML agents.
5. **Skipping registration**: The import and `_register()` call in `_register_builtins()` must both be added.

---

*This documentation should be updated whenever new integrations are added to maintain accuracy and completeness.*