paseo/docs/plugins.md

# Local plugins

Local plugins contribute daemon RPCs, native app surfaces, and composer attachment sources from one
`index.tsx`. Paseo executes the server contribution in a subprocess and evaluates the client
contribution in the app runtime. Plugin code is trusted code; this first slice does not sandbox it.

## Install a directory source

Create a typecheckable plugin project, install its development dependencies, then install it into
the daemon. `init` only writes the project files; it does not run the package manager.

```bash
paseo plugin init /absolute/path/to/my-plugin
cd /absolute/path/to/my-plugin
npm install
npm run typecheck
paseo plugin install /absolute/path/to/my-plugin
paseo plugin install /absolute/path/to/my-plugin --id another-runtime-id
paseo plugin ls
```

The daemon stores directory sources under the root `plugins` object:

```json
{
  "pluginsEnabled": true,
  "plugins": {
    "my-plugin": {
      "source": "directory",
      "path": "/absolute/path/to/my-plugin",
      "enabled": true
    }
  }
}
```

The plugin system is disabled unless `pluginsEnabled` is `true`.

The directory contains an identity-only manifest, one entry point, and local typechecking support:

```text
my-plugin/
  paseo-plugin.json
  index.tsx
  paseo-plugin.d.ts
  package.json
  tsconfig.json
```

Paseo compiles TSX when loading the plugin, so these packages are development dependencies only.
The generated declaration file supplies `@paseo/plugin` types until the SDK is distributed as a
public package. Regenerate new plugins with the matching Paseo CLI when the SDK contract changes.

```json
{
  "id": "my-plugin"
}
```

The config key is the runtime plugin ID. The manifest ID is the default selected during install;
`--id` overrides it. Existing configuration is not renamed when the manifest changes, and the
runtime does not compare the two IDs. The same directory can be installed under several config
keys.

Source changes are explicit. Run `paseo plugin reload <id>` to stop and fully tear down the old
plugin before compiling and starting from disk. A failed reload stays failed; Paseo does not restore
the old code. Use `enable`, `disable`, and `remove` to manage one plugin. Remove deletes only its
configuration, never its source directory. The global `pluginsEnabled` switch remains available.

## Contribute behavior and UI

Default export one contribution function. Paseo calls it with a plugin-scoped context. The compiler
removes UI registrations from the server bundle and RPC registrations from the client bundle before
resolving dependencies.

```tsx
import { Text } from "react-native";
import { useQuery } from "@tanstack/react-query";
import { z } from "zod";
import { defineRpc, type PluginContext, useRpc } from "@paseo/plugin";

const greetRpc = defineRpc({
  name: "greet",
  input: z.object({ name: z.string() }),
  output: z.object({ message: z.string() }),
});

function Greeting() {
  const greet = useRpc(greetRpc);
  const query = useQuery({
    queryKey: ["greeting", "Paseo"],
    queryFn: () => greet({ name: "Paseo" }),
  });
  return <Text>{query.data?.message}</Text>;
}

export default function contribute(plugin: PluginContext) {
  plugin.handle(greetRpc, async ({ name }) => ({ message: `Hello, ${name}` }));
  plugin.addSurface("main", Greeting);
  plugin.addSidebarItem({
    id: "main",
    title: "Greeting",
    icon: "MessageCircle",
    surface: "main",
  });
  return () => undefined;
}
```

The contribution function must return cleanup. Paseo invokes it once when the plugin is reloaded,
disabled, removed, disconnected, or shut down. Cleanup is for resources created by plugin code.
Paseo removes registered contributions, unmounts surfaces, clears query state, rejects pending RPCs,
and stops the subprocess. Cleanup errors are logged and do not interrupt host teardown.

Paseo owns the route, screen header, Lucide icon validation, close action, theme DTO, layout facts,
and render error boundary. The contributed component owns the complete body below the header.

RPC contracts validate inputs and outputs in both the app and plugin subprocess. `useRpc` returns a
typed async function. Use the host-provided `@tanstack/react-query` for request state and caching;
Paseo gives each plugin installation its own query client.

When the same plugin contribution exists on multiple hosts, Paseo shows it once in the sidebar and
adds a host picker to the screen header. The selected host supplies the bundle, RPC transport, and
query cache. Plugin code cannot address another host.

## Contribute composer attachments

Register a declarative attachment source backed by a plugin RPC. Paseo owns the attachment menu,
search picker, drafts, selected pill, and submission. The plugin returns complete text snapshots;
credentials and vendor API calls stay in the daemon handler.

```tsx
const searchIssues = defineRpc({
  name: "issues.search",
  input: z.object({ query: z.string() }),
  output: z.object({
    items: z.array(
      z.object({
        id: z.string(),
        identifier: z.string(),
        title: z.string(),
        subtitle: z.string().optional(),
        url: z.string().url(),
        text: z.string(),
        resourceType: z.string(),
      }),
    ),
  }),
});

const issues = defineAttachmentSource({
  id: "issues",
  title: "Acme issue",
  icon: "CircleDot",
  pickerTitle: "Attach Acme issue",
  searchPlaceholder: "Search by identifier or title",
  search: searchIssues,
});

export default function contribute(plugin: PluginContext) {
  plugin.handle(searchIssues, ({ query }) => searchAcmeIssues(query));
  plugin.addAttachmentSource(issues);
  return () => undefined;
}
```

Attachment sources stay scoped to the composer's host. Unlike sidebar contributions, equal sources
on several hosts are not coalesced. The selected snapshot submits as a text attachment with neutral
external-resource presentation, so it remains readable if the plugin is removed or an older peer
drops the optional presentation fields.

See `plugin-examples/local-plugin` for a native surface and `plugin-examples/linear` for a complete
attachment-source example.