# OpenCode

> Set up the Comity plugin and MCP server for OpenCode.

OpenCode has no command-hook config, so Comity integrates through an OpenCode plugin: a TypeScript module that OpenCode loads from `.opencode/plugins/` at startup and that forwards its events to `comity hook`.

## Set up

```sh
cd your-repo
comity init --tools opencode
git add .opencode/plugins/comity.ts opencode.json
git commit -m "Set up Comity for OpenCode"
```

Start `opencode` from the repository root. There is no token in the repo: `comity login` is enough.

## What init writes

### `.opencode/plugins/comity.ts`

The bridge plugin (first line `// comity-opencode-bridge v1 (comity hook)`). It:

- reports `session.created`, every prompt (`chat.message`), `tool.execute.before` and `tool.execute.after` for `bash`, `edit`, `multiedit`, `write` and `apply_patch`, `session.idle` (end of a turn) and `session.deleted`;
- blocks a tool call Comity denies (OpenCode cancels a tool whose plugin hook throws) and shows Comity's reason to the model;
- adds the session briefing and prompt context to the next system prompt, and appends post-tool context to the tool's output;
- runs `comity hook --tool opencode` per event and allows after 5 seconds or when the CLI is missing.

Reads and searches never leave the process. The file holds no token and no machine path; re-running init rewrites it and `comity doctor` warns when it is from another CLI version.

### `opencode.json`

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "comity": {
      "type": "local",
      "command": ["node", "-e", "<launcher>", "mcp"],
      "enabled": true
    }
  }
}
```

OpenCode starts `comity mcp`, a local proxy to the Comity server that authenticates with your `comity login` (or `COMITY_TOKEN`). The entry is the same on every OS, so the committed file never changes between teammates; it needs Node on `PATH` (the CLI needs it anyway). `<launcher>` stands for a one-line Node script that starts `comity mcp` through your shell, so it finds the npm `comity` shim on every OS. Your other settings and servers are kept. If the repo only has `opencode.jsonc`, init writes there.

## Verify

```sh
comity doctor
opencode mcp list
```

Expect `opencode plugin  .opencode/plugins/comity.ts is current` and `opencode mcp  comity server in opencode.json`; `opencode mcp list` should show `comity` connected.

## Limits

- The prompt context uses OpenCode's `experimental.chat.system.transform` hook; it may change between OpenCode releases.
- Re-writing `opencode.jsonc` drops its comments.