**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.
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()`.
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.
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.
| `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:
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.
The managed section is owned by the bundled `agent-context` extension (`extensions/agent-context/`). All configuration flows through the extension's own config file at `.specify/extensions/agent-context/agent-context-config.yml`:
```yaml
# Path to the coding agent context file managed by this extension
context_file:CLAUDE.md
# Delimiters for the managed Spec Kit section
context_markers:
start:"<!-- SPECKIT START -->"
end:"<!-- SPECKIT END -->"
```
-`context_file` is written automatically from the integration's class attribute when `specify init` or `specify integration use` is run.
-`context_markers.{start,end}` defaults to `IntegrationBase.CONTEXT_MARKER_START` / `CONTEXT_MARKER_END`. Users who want custom markers edit `agent-context-config.yml` directly — both the Python layer (`upsert_context_section()` / `remove_context_section()`) and the bundled scripts (`extensions/agent-context/scripts/bash/update-agent-context.sh` and `.ps1`) read from this single source of truth.
Users can opt out entirely with `specify extension disable agent-context`; while disabled, Spec Kit skips context-file creation, updates, and removal (the gates are inside `upsert_context_section()` and `remove_context_section()`).
Only add custom setup logic when the agent needs non-standard behavior. Integrations no longer require per-agent thin wrapper scripts or shared context-update dispatcher scripts — the `agent-context` extension is fully generic.
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:
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.
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:
When an issue exists, include its number immediately after the prefix — this is what makes branches traceable. For small or self-contained changes that go straight to a PR without a tracking issue, omit the number.
- If you are an agent working on behalf of a human, **disclose your identity in your PR comment** — name the agent (and model, if applicable) and the human you are acting for (e.g., "Posted on behalf of @user by GitHub Copilot (model: <name-if-known>)").
- Post **one** top-level summary comment per review round listing what changed and the commit SHA. Do not reply on every individual comment.
- Reply inline only when context is needed (disagreement, deferral, non-obvious fix). Keep it to a sentence or two.
- **Never click "Resolve conversation"** — that belongs to the reviewer or PR author.
- No emoji, no celebratory framing, no checklist mirroring the reviewer's items, no restating what the reviewer wrote.
- Re-request review once per round (when all feedback is addressed), not after every intermediate push.
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 context configuration**: The bundled `agent-context` extension reads from `.specify/extensions/agent-context/agent-context-config.yml`. New integrations only need to set `context_file` on the class — markers and dispatcher scripts are managed centrally.