Nib Plugin Development: Zero to One

This guide is the shortest complete path from an empty folder to a tested .piplug package. It describes the plugin runtime that Nib ships today. The SDK types, host validators, runtime dispatch, and executable tests are the implementation evidence. The files under docs/spec/07-plugins remain the normative contract when this guide and a specification differ.

1. What a plugin can add

A plugin can contribute one or more of these capabilities:

Capability	Use it for	Main building blocks
Command	An explicit action in global search	contributes.commands, pi.commands.register
Panel	A small isolated HTML interface	ui.panel, ui.panel permission, window.pluginBridge
Floating widget	A transparent, frameless companion window — a round orb, not a rectangle	ui.panel permission, "ui": { "shape": "widget" }, window.pluginBridge
Work panel view	An interface docked in the app's right work panel	contributes.views, ui.view permission, window.pluginBridge
Agent tool	A function the Agent can call	contributes.agentTools, pi.agent.registerTool
OAuth provider	A provider row with host-owned sign-in and encrypted credentials	contributes.providers, provider.oauth, onProviderOAuth
One-shot completion	A host-owned completion against the user's models	pi.models.list, pi.session.getLlmContext, pi.agent.complete
Skill	Instructions loaded by the Agent on demand	contributes.skills, agent.prompt.inject permission
Theme	Design-token overrides	contributes.themes, ui.theme permission
MCP server	Tools discovered from a local or remote MCP server	contributes.mcpServers, an MCP permission
Service	Resident work supervised by the host	contributes.services, background.service permission
Message bus	Typed-by-convention events between plugins	contributes.bus, bus permissions
Renderer slot	UI drawn inside the app's own window: composer controls, message action bars, blocks below a reply, tool cards, code-block renderers, corner layers	renderer, renderer.extension permission, packages/plugin-sdk/src/renderer.ts
Composer suggestion	One dismissible line offered to the input box, taken with Tab	pi.composer.suggest, composer.suggest permission
Provider	API-key, no-auth, or OAuth model service	contributes.providers, provider.register; OAuth also needs provider.oauth
Session import	Import, read, rename, and delete this plugin's own history	contributes.sessionSources, matching session.* grants
Usage facts	Compute your own usage dashboard	pi.usage.listTurns, usage.read
Composer transform	An explicit draft-text action with undo	contributes.composerTransforms, onComposerTransform, composer.transform
Global shortcut	Invoke your command while the app is unfocused	contributes.globalShortcuts, pi.keyboard, keyboard.globalShortcut
Trusted agent extension	pi ExtensionAPI hooks, tools, commands, and custom agents	contributes.agentExtensions, agent.extension
Real-time connection	Host-owned, bounded WebSockets	pi.net.websocket, net.websocket
Browser / desktop control	Reviewed browser or app operations	pi.browser, browser.cdp; pi.desktop, desktop.control
Speech adapter	Add a speech protocol handled by the plugin process	pi.speech, speech.adapter.register

Plugin entry code runs in a dedicated Node process. Panels run in sandboxed, context-isolated Electron windows with no Node integration. Calls from either surface cross a host-owned permission gateway.

Trust boundary: the permission model gates the pi.* host API and panel bridge. It is not yet an operating-system sandbox for raw Node APIs used by a plugin entry process. Load development plugins and third-party packages only when you trust their source, and use the host API instead of direct Node file or network access. See the security specification.

2. Prerequisites

For the recommended app-first path, you need:

• a running Nib build;
• an empty folder for the plugin; and
• a text editor.
• To import a pi extension directory with npm dependencies, a system npm executable must be on PATH. Release builds ship no standalone Node/npm; without it, Nib reports a warning and the imported dependency cannot load.

For the repository CLI path, use the Node.js and pnpm versions declared in the root package.json (engines and packageManager) and a checkout of this repository. The devkit and SDK are currently private workspace packages, so do not assume that npm install @pi-desktop/plugin-devkit works outside this repository.

3. Create the first plugin

Option A: create it in Nib

1. Open Plugins (the Extensions page).
2. Open the header overflow menu and choose New plugin from template.
3. Choose panel-basic.
4. Select an empty folder.

Nib writes the starter files, loads the folder as a development plugin, and opens the folder as the active project. The plugin is live immediately.

The four built-in templates are:

Template	Starts with	Permissions
panel-basic	Command and HTML panel	ui.panel
agent-tool-basic	Agent-callable echo tool	agent.tool.register
skill-pack	One skill document	agent.prompt.inject
full-demo	Command, panel, tool, skill, and setting	The permissions used by those features

Scaffolding refuses a non-empty destination so it cannot silently overwrite an existing project.

Option B: create it with the repository CLI

From the Nib repository root:

pnpm install
pnpm --filter @pi-desktop/plugin-devkit... build
pnpm pi-plugin init panel-basic ../my-first-plugin \
  --id local.my-first-plugin \
  --name "My First Plugin"

Then open Nib, go to Plugins, choose Load development plugin, and select ../my-first-plugin.

Use a reverse-domain id for a published plugin, for example com.example.workspace-summary. The local. prefix is a useful convention for private plugins. Keep the id stable: settings, data, grants, updates, and the package name are keyed by it.

4. Understand the generated files

The panel-basic template produces:

my-first-plugin/
├── manifest.json
├── main.js
├── README.md
└── renderer/
    └── index.html

• manifest.json declares identity, entry points, contributions, and requested permissions.
• main.js runs in the plugin process and exports lifecycle hooks.
• renderer/index.html runs in the isolated panel window.
• README.md explains how to develop and package this particular plugin.

Distribution packages must contain directly executable JavaScript, HTML, CSS, and assets. Nib does not install dependencies or compile TypeScript when it loads a plugin. If you use TypeScript or third-party packages, bundle or compile them into the plugin directory before checking and packing it.

5. Build the minimal plugin by hand

The following three files show the complete command-to-panel path.

manifest.json

{
  "schemaVersion": 1,
  "id": "local.my-first-plugin",
  "name": "My First Plugin",
  "version": "0.1.0",
  "description": "Opens a panel and shows a greeting.",
  "main": "main.js",
  "ui": {
    "panel": "renderer/index.html",
    "title": "My First Plugin",
    "width": 480,
    "height": 360
  },
  "contributes": {
    "commands": [
      {
        "id": "my-first-plugin.open",
        "title": "My First Plugin: Open Panel",
        "keywords": ["hello", "panel"]
      }
    ]
  },
  "permissions": ["ui.panel"],
  "engines": {
    "piDesktop": ">=0.1.0"
  },
  "activationEvents": [
    "onCommand:my-first-plugin.open",
    "onStartup"
  ]
}

schemaVersion, id, name, version, and main are required. Entry, view, and skill paths are relative to the plugin root and must stay inside it. Theme assets have a separately validated external-path route (§6.7). Plugin ids must match ^[a-z0-9]+(\.[a-z0-9_-]+)+$; uppercase and undotted ids are rejected. activationEvents is descriptive metadata today, not a lazy activation scheduler: enabled plugins load at startup or explicit enable/load. Declare only the permissions the plugin actually needs.

main.js

async function onLoad() {
  await pi.commands.register({
    id: "my-first-plugin.open",
    title: "My First Plugin: Open Panel",
    keywords: ["hello", "panel"],
    run: async () => {
      await pi.ui.openPanel({ title: "My First Plugin" });
      await pi.ui.showToast("Hello from My First Plugin");
    },
  });
}

async function onUnload() {
  await pi.commands.unregister("my-first-plugin.open");
}

module.exports = { onLoad, onUnload };

The host injects pi as a global. onLoad and onUnload receive no arguments. CommonJS is the simplest entry format; ESM is also loaded when the entry is an ES module. Module evaluation plus onLoad has a 15-second budget. onUnload has a 5-second budget and is best-effort, so release timers and subscriptions promptly.

Only onLoad and onUnload are lifecycle hooks today. Export them from the entry module; there is no entrypoints manifest dispatcher. onPanelInvoke, onRendererCall, onComposerTransform, and onProviderOAuth are operation callbacks. onInstall, onEnable, onDisable, and onUninstall are not called. During app quit the unload budget is shortened to 1.5 seconds.

onProviderOAuth is a separate operation callback for OAuth provider contributions, not a lifecycle hook. It handles login and refresh only for its own declared provider. The host stores its returned credential encrypted and passes only the access token to model requests; the callback can also use pi.providers.oauth.prompt and .notify for host-rendered login steps. The permission provider.oauth is high risk, and token egress still requires net.fetch plus the manifest's network domains. See the provider OAuth section in the Plugin API.

renderer/index.html

Nib hosts the panel in a frameless window on every platform. The host reserves exactly a transparent 46 CSS px drag band and renders a minimal fixed capsule in the top-right corner with minimize, maximize/restore, and close buttons. The panel title, toolbar, and all other visible UI belong to the plugin. New pages should declare <meta name="pi-plugin-chrome" content="v2"> and apply var(--pi-plugin-titlebar-height, 0px) to their own top spacing once. Without this marker the host retains the legacy additive offset; do not add a second 46px spacer to those pages. The drag band is not clickable outside the capsule; development panels show a reminder for this constraint.

If a panel uses position: fixed or position: sticky for a top toolbar, anchor it below the host drag band instead of using top: 0:

.panel-toolbar {
  position: sticky;
  top: var(--pi-plugin-titlebar-height, 46px);
  -webkit-app-region: drag;
}

.panel-toolbar button {
  -webkit-app-region: no-drag;
}

The host does not inject a panel title. Keep the 46px drag band in mind for viewport-height calculations as well: height: calc(100dvh - var(--pi-plugin-titlebar-height, 46px)).

Floating widgets

A plugin whose whole interface is a small floating shape — a voice orb, a timer, a status light — declares "ui": { "shape": "widget" } in its manifest instead of accepting a rectangle with a toolbar strip. The panel then opens as a transparent, frameless window:

• no 46px drag band and no capsule; --pi-plugin-titlebar-height is 0px
• empty space drags the window, while a standard control — or any element marked data-pi-plugin-no-drag — stays clickable
• right-click on the surface opens the host menu: close, minimize, always on top
• ui.width / ui.height are honoured down to 120×120, and ui.alwaysOnTop pins the widget above other windows
• the page can read document.documentElement.dataset.piPluginPanelShape (panel | widget | view) to style one HTML entry for every placement

Draw the silhouette yourself — border-radius: 50%, your own shadow, a glow that bleeds past the shape — and keep the page background transparent outside it, so the window disappears behind the shape. Everything else, window.pluginBridge, permissions, settings, is identical to a panel.

<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="pi-plugin-chrome" content="v2" />
    <title>My First Plugin</title>
    <style>body { padding-top: var(--pi-plugin-titlebar-height, 0px); }</style>
  </head>
  <body>
    <h1>My First Plugin</h1>
    <button id="hello">Show toast</button>
    <script>
      document.getElementById("hello").addEventListener("click", async () => {
        await window.pluginBridge.invoke("ui.showToast", {
          message: "Hello from the panel",
        });
      });
    </script>
  </body>
</html>

The panel does not receive the global pi object. It receives only window.pluginBridge, and arbitrary Electron IPC channels are unavailable.

6. Add capabilities

6.1 Agent tool

Declare the tool and its permission:

{
  "contributes": {
    "agentTools": [
      {
        "name": "summarize_text",
        "description": "Summarize text supplied by the agent.",
        "risk": "low",
        "schema": {
          "type": "object",
          "properties": {
            "text": { "type": "string" }
          },
          "required": ["text"]
        }
      }
    ]
  },
  "permissions": ["agent.tool.register"]
}

Register the matching handler during onLoad:

await pi.agent.registerTool({
  name: "summarize_text",
  description: "Summarize text supplied by the agent.",
  risk: "low",
  schema: {
    type: "object",
    properties: { text: { type: "string" } },
    required: ["text"],
  },
  execute: async (args, context) => {
    context.log("summarize_text called");
    const text = String(args?.text ?? "");
    return { summary: text.slice(0, 120) };
  },
});

Unregister it in onUnload. The host exposes it to the model under a plugin-namespaced name, applies the normal Agent permission policy, audits execution, and enforces a 110-second plugin-side timeout. Tools are deferred behind ToolSearch. By default they are hidden and denied in Plan/Goal. A tool may opt in with planSafeActions on its runtime registration, naming its read-only action values; keep the manifest descriptor in sync. Registration checks the list against a schema action enum when present, and execution in Plan/Goal requires args.action to be in that list. Risk low, a session grant, or auto cannot substitute for it. See the API contract. Use context.signal for cancellation and context.sessionId / turnId to associate async work with the invoking turn. Never substitute the visible session.

6.2 Skill

Add a file such as skills/release-notes.md:

---
name: Release notes
description: Use when the user asks for release notes or a changelog entry.
---

# Release notes

Write one line per user-visible change. Use imperative mood and put the newest
change first.

Declare it with the required permission:

{
  "contributes": {
    "skills": ["skills/release-notes.md"]
  },
  "permissions": ["agent.prompt.inject"]
}

The prompt receives a short skill catalog; the full body is read on demand. Each plugin may contribute up to 32 skills, each file may be at most 128 KiB, and descriptions are capped at 240 characters. A skill without agent.prompt.inject is ignored rather than loaded.

6.3 Settings and private data

Declare defaults in the manifest:

{
  "contributes": {
    "settings": [
      {
        "key": "greeting",
        "title": "Greeting",
        "type": "string",
        "default": "Hello"
      }
    ]
  }
}

Read and update them from the plugin process:

const settings = await pi.plugin.getSettings();
await pi.plugin.setSettings({ greeting: "Welcome" });
const dataPath = await pi.plugin.getDataPath();

Settings and the data path are private to the plugin id. The installed Plugins page generates controls for string, number, boolean, select, json, and shortcut fields. A shortcut field must name a declared command:

{
  "key": "openShortcut",
  "title": "Open panel shortcut",
  "type": "shortcut",
  "default": "Mod+Shift+H",
  "command": "hello.open",
  "scope": "plugin"
}

Plugin shortcuts run only in the focused Nib window and are checked against the app shortcut map. For OS-global bindings use the separate contributes.globalShortcuts and pi.keyboard surface with keyboard.globalShortcut (§6.17). The plugin receives plugin:settingsChanged after a user edit. Do not put credentials in manifest.json or source control.

6.4 Workspace files, clipboard, network, and notifications

These APIs require explicit permissions:

Permission	Plugin-process API	Panel bridge channel
fs.read	pi.fs.readText, stat, readRange, readPreview, openDefault, openInBrowser, reveal, glob, list, requestDirectory	The same fs.* names; dropped-file grants use fs.registerDropped
fs.write	pi.fs.writeText	fs.writeText
fs.delete	pi.fs.remove	Not exposed
clipboard.read	pi.clipboard.readText, pi.clipboard.getHistory	clipboard.readText, clipboard.getHistory
clipboard.write	pi.clipboard.writeText	clipboard.writeText
net.fetch	pi.net.fetch	net.fetch
shell.openExternal	pi.shell.openExternal	shell.openExternal
notify	pi.ui.notify, pi.ui.getNotificationPermission, pi.ui.requestNotificationPermission, pi.ui.showNativeNotification	ui.notify, ui.getNotificationPermission, ui.requestNotificationPermission, ui.showNativeNotification

Use fs.list rather than fs.glob when you are showing a tree: it returns one directory at a time (name-sorted, directories included), so the user expands what they want instead of waiting on a whole-repo walk that is capped at 500 matches. Both obey the same read scope.

A file permission is only half the declaration: manifest.fs says which paths each mode may touch (see §6.5). Paths are relative to the mode's root. An Agent tool uses its calling session's project root; a panel uses the visible workspace or its view's browsed folder. Registered project-group roots support reviewed absolute-path file actions; this does not make arbitrary absolute paths valid for general file I/O. Absolute paths and .. escapes are rejected, as is a symlink that leaves the root. fs.remove is non-recursive, moves the path to the OS trash, and cannot remove the root itself. net.fetch accepts HTTP(S) and only reaches hosts allowed by manifest.net.domains or the separately reviewed net.anyHost grant; openExternal accepts HTTP(S) and mailto: URLs.

pi.ui.notify shows an in-app Toast. Native notifications are opt-in: call pi.ui.requestNotificationPermission() before pi.ui.showNativeNotification(...). The returned permission is best-effort because Electron does not expose a cross-platform read-only OS permission API; unknown means the platform has not reported a result yet, and unsupported means desktop notifications are unavailable. Native plugin notifications are not added to Nib's durable task notification inbox. Clicking a delivered notification restores and focuses the main window, but does not activate a session.

The panel bridge also exposes ui.showToast, ui.closePanel, plugin.getSettings, and workspace.get. A channel the host does not implement itself is forwarded to your onPanelInvoke(channel, payload), so a panel can talk to its own plugin over channels you define; a plugin that exports no onPanelInvoke gets UNSUPPORTED back.

6.5 File scope

fs.read / fs.write / fs.delete say whether your plugin may touch files. manifest.fs says which ones:

{
  "permissions": ["fs.read", "fs.write", "fs.delete"],
  "fs": {
    "read": { "scope": ["**/*"] },
    "write": { "scope": ["docs/**", "*.md"] },
    "delete": { "own": true, "scope": ["dist/**"] }
  }
}

• scope globs are relative to the root. * matches one segment, ** crosses separators.
• Reading may declare the whole tree. Writing and deleting may not — a whole-tree pattern fails validation, because the egress allowlist is what makes a broad read safe and nothing makes a broad write safe.
• An access outside the declared scope is not an error: Nib asks the user (Deny / Allow once / Allow this session). Declare the scope you need so your plugin does not interrupt them on every call, and expect a refusal to arrive as PERMISSION_DENIED.
• Some paths are refused whatever you declare: .env*, SSH and cloud credentials, *.pem, .git/**, and Nib's own data directory. They do not appear in fs.glob results either.

Deleting. own: true lets you remove files your plugin wrote itself, with no scope and no prompt — the right default for cleaning up your own output. (If the user has edited the file since you wrote it, it stops counting as yours.) Deleting anything else needs a scope. Every delete is non-recursive, goes to the OS trash, and is interrupted once past 50 removals a minute, so batch cleanups should be paced rather than run as a glob plus a loop.

Working outside the workspace. Set "root": "userSelected" on a mode and call pi.fs.requestDirectory(): the user picks a directory and you get full reach inside it with no scope to declare. The handle lives in memory and is gone when the plugin process exits, so ask again each session.

Legacy names. fs.read.workspace, fs.write.workspace and fs.delete.workspace still load, but are cut back — write reaches nothing and delete reaches only your own output — until the manifest declares fs. The Plugins page tells the user this happened.

6.6 Network access

net.fetch lets your plugin make a request; manifest.net.domains says where to:

{
  "permissions": ["net.fetch"],
  "net": { "domains": ["api.example.com", "*.githubusercontent.com"] }
}

Entries are bare hostnames — no scheme, no port, no path — and a leading *. covers the domain and its subdomains. A bare * is refused at install.

The list is the single allowlist for every outbound path the host owns, not only pi.net.fetch: your panel's own fetch, <img>, <script> and stylesheet loads answer to it too (a sandboxed panel still has a network stack), as do remote HTTP MCP servers you declare. window.open from a panel is refused outright.

Without net.anyHost, an omitted or empty net.domains means no egress, even with net.fetch granted; malformed declarations fail validation. net.anyHost is an install-time high-risk exception for user-entered endpoints, not a request-time prompt. It also covers WebSockets, panel traffic, and remote MCP, but still blocks cloud-metadata destinations and grants no fetch/socket API by itself. Redirects are followed by hand and re-checked, so an allowed host cannot bounce a request to one you did not declare. Bundle assets into the plugin rather than loading them from a CDN you would otherwise have to declare.

fetch returns what the server answered, 429 and Retry-After included: the host never retries a request your plugin makes, so backoff after a rate limit is your own policy rather than a hidden host behaviour. A call that comes back >= 400 is still audited, as ok: false with the delay the response advertised.

Fetch redirect policy

Check host support before relying on a policy; old hosts can ignore unknown request fields. Never fall back to a raw network request.

if (typeof pi.net.getCapabilities !== "function") throw new Error("Upgrade Nib");
const capabilities = await pi.net.getCapabilities();
if (!capabilities.fetchRedirectModes.includes("error")) throw new Error("Unsupported host");
const response = await pi.net.fetch({ url: endpoint, redirect: "error" });

error rejects every 3xx with REDIRECT_DISALLOWED before accessing Location. manual returns the original status, headers and body. Omitted/follow retains the existing bounded, per-hop egress-checked behavior. Invalid modes are rejected before I/O. No mode expands network permissions. See the complete contract and the local-only test plugin at examples/plugins/fetch-redirect/README.md in the repository.

6.7 Theme

Declare a CSS file and ui.theme:

{
  "contributes": {
    "themes": [
      {
        "id": "midnight",
        "label": "Midnight",
        "path": "themes/midnight.css",
        "base": "dark",
        "assets": ["themes/background.svg"]
      }
    ],
    "windowAppearance": {
      "backgroundColor": { "dark": "#141a24", "light": "#f5f7fa" }
    }
  },
  "permissions": ["ui.theme", "ui.window.appearance"]
}

base selects the built-in light or dark palette underneath the overrides; omitting it defaults to dark. The user selects the contributed theme in Settings.

Match the base palette's selector when overriding design tokens:

:root[data-theme="dark"] { --ds-bg-primary: #141a24; }
:root[data-theme="light"] { --ds-bg-primary: #f5f7fa; }

The theme stylesheet is appended after the host styles, but later source order wins only when selector specificity is equal. The host palette selectors are :root[data-theme="dark"] and :root[data-theme="light"]; a bare :root has lower specificity and is not sufficient to override those declarations. For a light-base theme, explicitly use :root[data-theme="light"].

The host sanitizes CSS, rejects @import and url() targets other than data: URIs or declared theme assets, caps each stylesheet at 256 KiB, and imposes no per-plugin theme-count cap. Optional assets accepts png, jpg, jpeg, webp, avif, svg, and woff2 files, with a summed limit of 4 MiB. Paths may be package-relative (inside the plugin root, without traversal or node_modules) or absolute. Matching CSS URLs are rewritten to registered, read-only plugin-asset:// URLs; unloading the plugin revokes them. The renderer never receives the raw filesystem path.

Optional contributes.windowAppearance.backgroundColor supplies light/dark colors in #rrggbb or #rrggbbaa form and requires ui.window.appearance in addition to ui.theme. It applies only while that plugin's theme is selected; switching away restores the host background. On macOS the default translucent window ignores the color; turning off Translucent window applies it to the opaque native surface. cornerRadius accepts integer 0..24 DIP: Windows 11 uses square corners for 0 and its system-rounded preference for positive values. macOS keeps native corners. See the manifest contract for all theme and window-appearance fields.

Runtime theme changes do not require reload: pi.themes.upsert, remove, list, and pi.app.setTheme use ui.theme. pi.themes.setVariables(themeId, values) accepts only that theme's declared typed variables (length, number, color, select), not arbitrary CSS or host-reserved tokens. contributes.scenicThemes adds a host-rendered Settings card selector with 1..12 cards and requires both ui.settings and ui.theme. Arbitrary settingsDestinations HTML/JS entries are not a public contribution.

6.8 Work panel view

A view is an interface docked in the app's right work panel, alongside the host's other tool and resource tabs. It is the same isolated page as ui.panel — you can reuse the same HTML — but it is shown inside the main window instead of a separate one, which suits anything the user consults while reading the conversation: a change list, a file tree, an issue queue.

{
  "contributes": {
    "views": [
      {
        "id": "changes",
        "title": { "en": "Changes", "zh-CN": "改动" },
        "icon": "diff",
        "entry": "views/changes.html",
        "order": 10
      }
    ]
  },
  "permissions": ["ui.view"]
}

Declare as many as the plugin needs; each becomes its own row in the panel's header menu. title may be a plain string or an { en, "zh-CN" } object. order sorts the rows and defaults to declaration order.

icon is a token from a fixed list the host draws from its own icon set — bell, book, bot, branch, browser, chat, clock, diff, files, folder, image, key, link, list-checks, palette, plug, pull-request, search, server, shield, sparkles, target, terminal, workflow, wrench. A plugin cannot supply its own SVG, because the icon is drawn inside host chrome. An unknown token is not an error: it renders as a lettered tile, and pi-plugin check warns about it.

Inside the page, window.pluginBridge works exactly as in a panel window. The one difference is the chrome: a docked view has no window controls and no drag band, so read --pi-plugin-titlebar-height instead of hard-coding 46px and the same file lays out correctly in both placements.

body {
  /* 0px docked, 46px in a panel window. */
  padding-top: calc(var(--pi-plugin-titlebar-height, 0px) + 12px);
}

A view is confined the same way a panel window is: sandboxed page, no Node, the plugin's own persisted session partition, and network limited to manifest.net.domains (§6.6). It is also filtered by activation scope — a plugin restricted to certain projects does not offer its views in others.

examples/plugins/hello ships a working view at views/greetings.html, and Nib's own file view is a bundled plugin built the same way — apps/desktop/resources/plugins/pi.file-manager is a complete, non-toy example of a view that reaches the workspace over the public bridge: fs.openDefault and fs.reveal for the two actions only the host can perform, and its plugin-owned onPanelInvoke operations. Custom channels must validate their own payloads; they are not automatically converted into permission-gated pi.fs calls.

6.9 MCP server

MCP servers are declarative. A local server requires mcp.server.local; a remote server requires mcp.server.remote:

{
  "contributes": {
    "settings": [
      { "key": "docsMode", "title": "Docs mode", "type": "string", "default": "public" },
      { "key": "clientName", "title": "Client name", "type": "string", "default": "my-plugin" }
    ],
    "mcpServers": [
      {
        "id": "docs",
        "label": "Documentation tools",
        "transport": "stdio",
        "command": "bin/docs-server",
        "args": ["--stdio"],
        "env": {
          "DOCS_MODE": { "setting": "docsMode" }
        }
      },
      {
        "id": "issues",
        "transport": "http",
        "url": "https://mcp.example.com/tools",
        "headers": {
          "X-Client-Name": { "setting": "clientName" }
        }
      }
    ]
  },
  "permissions": ["mcp.server.local", "mcp.server.remote"],
  "net": { "domains": ["mcp.example.com"] }
}

A stdio command must be a bare command found on PATH or a plugin-relative executable; absolute paths are rejected. npx and uvx are resolved to the real Node.js / uv binaries (PATH, official Node, fnm, nvm, Volta, default uv install). On Windows, python3 and python skip the Microsoft Store alias for a real interpreter on PATH, falling back to py -3. Remote URLs may use HTTP or HTTPS, and the host must be listed in net.domains; non-loopback HTTP is unencrypted, so use it only on a trusted network. Setting references read only this plugin's settings—the host environment and provider secrets are never forwarded. MCP tools follow the same deferred tool catalog and namespacing as hand-written plugin tools. Plugin MCP tools default to medium risk and are not Plan-safe merely because the server describes them as read-only.

6.10 Resident service and message bus

Declare service ids and allowed topics:

{
  "contributes": {
    "services": [
      { "id": "watcher", "label": "Workspace watcher" }
    ],
    "bus": {
      "publish": ["example.index.ready"],
      "subscribe": ["example.build.*"]
    }
  },
  "permissions": [
    "background.service",
    "bus.publish",
    "bus.subscribe"
  ]
}

Register matching handlers:

let unsubscribe;

pi.services.register({
  id: "watcher",
  start: ({ log }) => log("watcher started"),
  stop: () => {},
});

unsubscribe = await pi.bus.subscribe("example.build.*", async (message) => {
  await pi.bus.publish("example.index.ready", {
    source: message.from,
    at: message.at,
  });
});

Call unsubscribe() during unload. A plugin does not receive its own bus messages. Treat topics as public to any installed plugin with a matching subscription; never put secrets in the payload.

6.11 Agent extension (pi ExtensionAPI module)

A plugin can ship code that runs inside the agent process itself: a module written against the pi CLI ExtensionAPI, an explicit subset of the pi extension contract. It registers tools, slash commands, and hooks on every turn, tool call, and provider request. Declare the modules and the agent.extension permission:

{
  "contributes": { "agentExtensions": ["src/index.ts"] },
  "permissions": ["agent.extension"]
}

// src/index.ts
import { Type } from "typebox";
import { defineTool } from "@earendil-works/pi-coding-agent";

export default function (pi) {
  pi.registerTool(defineTool({
    name: "fx_add", label: "Add", description: "Adds two numbers",
    parameters: Type.Object({ a: Type.Number(), b: Type.Number() }),
    async execute(_id, { a, b }) {
      return { content: [{ type: "text", text: String(a + b) }], details: {} };
    },
  }));
  pi.on("tool_call", (event) =>
    event.toolName === "Bash" ? { block: true, reason: "not here" } : undefined,
  );
  pi.registerCommand("greet", {
    description: "Say hello",
    async handler(args, ctx) {
      const name = await ctx.ui.input("Your name?");
      ctx.ui.notify(`Hello ${name} ${args}`);
    },
  });
}

What to know before you use it:

• It is not sandboxed. The module runs in the agent process with the same access as the agent's own tools. agent.extension is a high-risk permission the user confirms explicitly; the manifest is rejected if you list modules without it.
• TypeScript is fine. Modules are loaded with jiti, so .ts needs no build step. typebox, @earendil-works/pi-agent-core, @earendil-works/pi-ai, and @earendil-works/pi-coding-agent resolve to the app's copies; @earendil-works/pi-tui resolves to an inert stub, so terminal-UI calls do nothing and show up as diagnostics.
• Tools are deferred. Like plugin tools, the model activates them through ToolSearch on demand. Names that collide with core or plugin tools are rejected with a diagnostic.
• Slash commands appear in the composer / menu and global search and take the rest of the line as args. ctx.ui.input / select / confirm open native dialogs; ui.notify is a toast.
• Supported members are listed in spec 07-plugins/16 §5. Unsupported ones (setWidget, registerMessageRenderer, navigateTree, and the other terminal-only surfaces) are inert and reported in the plugin row's details, never thrown.
• Import existing pi extensions against the supported-member table in spec 16: Plugins → overflow menu → "Import pi extension" wraps a file or directory in a generated plugin. If the directory declares production or optional dependencies, Nib first runs npm install --package-lock-only --omit=dev --legacy-peer-deps --no-audit --no-fund --ignore-scripts, validates the generated registry-only lockfile, then runs npm ci with the same safety flags. Direct dependency specs are checked across production, optional, dev, and peer fields; git resolution is disabled, and no third-party lifecycle script runs. A native module that needs a build script fails with a diagnostic — rebuild it against Electron headers (npx @electron/rebuild -v <electron version>) inside the plugin directory to fix it. Failed installs clean partial dependencies and report a warning toast without blocking the import; the row shows a load error only if the extension actually fails to load.

6.12 Renderer slots

Every surface above is a window or a page the plugin owns. A renderer module draws inside Nib's own window instead: controls in the composer toolbar, items on a message's action bar, a block below an assistant reply, the card for one of your own Agent tools, a renderer for a fenced code block, or a corner layer you manage yourself.

{
  "permissions": ["renderer.extension"],
  "renderer": "renderer/index.mjs",
  "rendererActions": ["plugin.call", "composer.insertText"],
  "rendererCallMethods": ["openWorkspace"]
}

The entry exports onLoad(pi), the host evaluates it in its own window, and every load is handed a fresh pi. Components read the host through the module's own copy of it, because a component's props carry data and nothing else:

import React from "react";

let host = null;

function InsertButton() {
  return React.createElement(
    "button",
    { onClick: () => host.dispatch("composer.insertText", { text: "hello" }) },
    "Insert",
  );
}

export function onLoad(pi) {
  host = pi;
  pi.slots.register({ slot: "composerControl", component: InsertButton, positions: ["right"] });
}

• composerControl — controls in the composer toolbar; positions: ["left"] or ["right"] selects a side, omitted means both
• composerTrigger — the item list behind one of the composer's trigger symbols: { slot: "composerTrigger", trigger: "#", items }, and the host draws the list
• userAction / assistantAction — items on a message's action bar
• entryExtra — a block below an assistant reply
• toolCard — the card for calls of one of your own Agent tools; toolName names it
• blockRenderer — a fenced block tagged <your-plugin-id>:<lang>; language names the tag

A dialog you draw yourself is not a slot: pi.ui.openLayer() hands you a layer to render into, and the component draws inside it. Styles go through pi.ui.injectStyle, and react, react/jsx-dev-runtime, react/jsx-runtime, react-dom and react-dom/client resolve to the app's copies through the window's import map, so no bundled React is needed.

rendererActions whitelists what a component may dispatch — plugin.call, composer.insertText, composer.readDraft, composer.replaceDraft, attachments.add, attachments.list, attachments.remove, at most 16 — and rendererCallMethods whitelists the method names onRendererCall answers for plugin.call, at most 32. A dispatch outside those lists is refused with PLUGIN_ACTION_UNDECLARED and a word outside the vocabulary with PLUGIN_ACTION_UNKNOWN. The module runs in the app's own document with the app's own React, so renderer.extension is a high-risk permission: grant it only to code you trust.

examples/plugins/ui-slots-lab mounts a sample on every slot. packages/plugin-sdk/src/renderer.ts carries the types and each slot's props, and the manifest side is spec 07-plugins/02 §3.2.

6.13 Model providers and OAuth

Declare providers with provider.register. The host owns the provider row, API-key form, encrypted secret storage, and model requests; a plugin never receives a key entered into Add Service. The provider id becomes plugin:<pluginId>:<id>. Categories and descriptions accept strings or { en, "zh-CN" } labels.

{
  "permissions": ["provider.register"],
  "contributes": {
    "providers": [{
      "id": "example",
      "name": "Example AI",
      "category": "Example services",
      "description": "Models from your Example account.",
      "baseUrl": "https://api.example.com/v1",
      "apiStyle": "chat_completions",
      "authKind": "api_key",
      "models": []
    }]
  }
}

An empty model list is allowed only for an API-key provider with baseUrl: after key save the host discovers the endpoint's models. Otherwise declare 1..64 models per provider. There is no per-plugin provider-count cap. Supported API styles are chat_completions, opencode_go, responses, anthropic_messages, google_generative_ai, openai_codex_responses, and pi_messages; auth kinds are api_key, none, and oauth.

OAuth additionally requires provider.oauth, baseUrl, and onProviderOAuth(request, { signal }). Handle login and refresh, returning { accessToken, refreshToken?, expiresAt?, accountLabel?, headers? }. Only a refresh receives that contribution's existing credential. Use pi.providers.oauth.prompt(loginId, input) / .notify(loginId, event) for host-rendered interaction; respond to cancellation. The host keeps refresh tokens out of the renderer and Agent Runtime. Use the host network gateway with separate net.fetch and egress declarations for token requests. Disabling a plugin retains and disables its provider rows; removing a provider declaration or uninstalling deletes its row and stored credential.

6.14 Follow sessions, import history, and read usage

Use pi.session.getActive() and session:activated for the selected session. No new permission is required, but activation scope still applies. The answer is null away from chat, or { sessionId, projectPath, activeTurn }, where activeTurn is null or { turnId, startedAt }. Treat snapshots as values that can become stale across an await.

session:turnEnded carries { sessionId, turnId, reason } with completed, aborted, or error. Delivery is once per settled host turn to a live plugin, without acknowledgement or replay. It does not prove every late tool has exited. Subscribe and unsubscribe with the same function reference.

function onSession(snapshot) {
  if (!snapshot) return;
  console.log("Selected session", snapshot.sessionId);
}

async function onLoad() {
  pi.events.on("session:activated", onSession);
  onSession(await pi.session.getActive());
}

function onUnload() {
  pi.events.off("session:activated", onSession);
}

module.exports = { onLoad, onUnload };

History management is a separate ownership boundary. Declare contributes.sessionSources: [{ id: "archive", label: "Archive" }], then use:

Task	Methods	Permission
Import history	session.import, session.importBatch	session.import
Read imported history	session.list, get, listMessages	session.read.own
Rename imported session	session.rename	session.update.own
Trash or purge imported session	session.delete	session.delete.own
Create/reuse an explicit project binding	project.create; import with projectId	project.create
Generate a default title	session.getAutoTitleContext, setAutoTitle	session.autoTitle
Read completed-turn usage facts	usage.listTurns	usage.read

Import is idempotent on (pluginId, source, externalId). Use strict RFC3339 timestamps, monotonic message times, and the host-generated ids returned by import. Imported provider/model/path strings are historical metadata, not live bindings. Supply an existing projectId to bind a project; creating it does not activate the workspace. Host-owned sessionsChanged refreshes the UI.

Reads and mutations address only this plugin's imported sessions. Batch skip continues per item; fail is atomic. trash preserves transcript/origin and purge deletes both. There is no general message-mutation or arbitrary session-rebinding API. Auto-title exposes only the bounded first prompt/reply for default-titled sessions and uses compare-and-set expectedTitle; a manual rename wins. Usage facts contain counters and identifiers, never message bodies. See session contracts for payloads and limits.

6.15 Model catalog and one-shot completions

pi.models.list() (models.list) returns ready model bindings without credentials. Pass the returned key unchanged to pi.agent.complete (agent.complete); do not split a model id that may itself contain /.

const models = await pi.models.list();
const model = models.find((item) => item.isDefault) ?? models[0];
if (!model) throw new Error("Configure a model first");
const answer = await pi.agent.complete({
  modelKey: model.key,
  system: "Answer briefly.",
  messages: [{ role: "user", content: "Explain this plugin's purpose." }],
});
await pi.ui.showToast(answer.text);

This spends the user's provider quota and uses no tools. The host owns auth, provider error classification, and bounded provider retries. It enforces a 90s budget and eight calls per plugin per rolling minute. includeSessionContext also needs session.read and an active invocation of this plugin's Agent tool; session.getLlmContext() has the same invocation-only rule. A background service, Composer transform, or selected-session snapshot does not grant a transcript read. Handle TIMEOUT, RATE_LIMITED, and classified provider failures rather than retrying indefinitely.

6.16 Composer transforms and suggestions

A transform is invoked by the user and receives only { id, text, modelKey? }. Declare contributes.composerTransforms and composer.transform, then export:

function onComposerTransform({ id, text }) {
  if (id !== "trim") throw new Error("Unknown transform");
  return text.trim();
}

module.exports = { onComposerTransform };

Declare { "id": "trim", "title": "Trim draft", "undoTitle": "Undo trim" } in that contribution. Input and output each allow 100,000 characters. The host preserves file references, rejects stale edit/session results, and offers undo. The callback gets no transcript, attachment data, or separate file-path metadata.

A suggestion is a separate pi.composer process API with composer.suggest. It offers a placeholder line while the draft is empty; it never sends text.

const active = await pi.session.getActive();
if (active) {
  const result = await pi.composer.suggest({
    sessionId: active.sessionId,
    turnId: active.activeTurn?.turnId,
    text: "Add a regression test for this change",
    ttlMs: 120_000,
  });
  if (!result.shown) console.log("Suggestion refused", result.reason);
}
// On your own cancellation path:
await pi.composer.clearSuggestion();

Text is folded to one line and cut at 200 characters; TTL defaults to 120s and clamps to 1..600s. The user takes it with Tab or dismisses it with Esc. Typing, pasting, adding an attachment, sending, switching session, a new turn, unload, renderer reload, and window close clear it. Normal refusals return { shown: false, reason } (session-not-visible, draft-not-empty, stale-turn, replaced, unsupported); malformed input or a missing grant still throws. For work triggered by session:turnEnded, pass that event's turnId so a late completion cannot suggest for a newer turn.

6.17 Global shortcuts, WebSockets, microphone, and speech

Global shortcuts are separate from app-local shortcut settings. Declare an id and your own command under contributes.globalShortcuts, grant keyboard.globalShortcut, and register the command in onLoad. A default accelerator is registered after load; use pi.keyboard.registerGlobalShortcut for runtime changes. Check registered and error in the result; conflicts are returned as registered: false, not thrown. The host releases bindings on unload, disable, and crash. There are at most eight per plugin.

WebSockets require net.websocket and the same egress policy as fetch. Use pi.net.websocket.connect / send / close and pi.events events net:websocket:open, message, close, error (each with the full prefix and owning socketId). Four sockets, 1 MiB frames, and 4 MiB queued sends are the host bounds. The host closes them with the plugin.

ui.microphone grants audio-only getUserMedia inside an isolated panel; camera remains denied. Background pi.audio.* has types and permission gates but no device backend: authorized calls return/throw UNSUPPORTED. Do not build a working background recorder on that declaration alone.

pi.speech.registerAdapter / unregisterAdapter (speech.adapter.register) adds a protocol handler. Return text, audio, or a host-executed HTTP plan. Built-in ids openai_audio and openai_chat_audio are reserved; a plan carrying a bound provider key must stay on that provider origin.

6.18 Browser and desktop operations

fs.openInBrowser(path) needs only fs.read, opens an existing readable HTML file in a work-panel resource tab, and grants no browser automation. Use browser.cdp only for pi.browser.* automation. Those calls are bound to the invoking tool session; a background session cannot retarget the visible page. CDP is allowlisted, and cookie/storage/target/network-interception methods stay denied. browser.reveal() is explicit presentation and need not precede a background navigation. Full-page captures are scaled to at most 1280×2048 and have a 30s capture deadline.

desktop.control exposes pi.desktop.listOperations() and pi.desktop.invoke({ operation, args, confirm? }) over a reviewed catalog, never arbitrary IPC. Dangerous operations require confirm: true and the user's answer in a host-owned native dialog. Session collaboration spawn and send additionally require an active plugin Agent tool invocation; the host supplies source session/turn identity. Read the desktop-control contract before using operations that create, prompt, cancel, or delete sessions.

7. Permission design

Permissions are both declared in manifest.json and granted by the user. Undeclared or ungranted API calls fail with PERMISSION_DENIED.

Risk	Permissions
Low	ui.panel, ui.view, ui.theme, ui.settings, ui.window.appearance, notify
Medium	ui.microphone, clipboard.read, clipboard.write, fs.read, composer.transform, composer.suggest, models.list, session.read.own, session.update.own, usage.read, shell.openExternal, background.service, bus.publish, bus.subscribe, audio.playback.background, keyboard.globalShortcut
High	fs.write, fs.delete, agent.tool.register, agent.prompt.inject, agent.complete, agent.extension, renderer.extension, provider.register, provider.oauth, desktop.control, project.create, session.read, session.import, session.delete.own, session.autoTitle, net.fetch, net.anyHost, mcp.server.local, mcp.server.remote, browser.cdp, audio.capture.background, speech.adapter.register, net.websocket

keyboard.globalShortcut and net.websocket are implemented. pi.audio.* exists and is callable, and its methods keep their permission gate, but this host has no device backend yet: an authorized call is answered with a coded UNSUPPORTED refusal that is audited, and onInputFrame / offInputFrame throw the same code synchronously, until the device service lands and replaces the refusal with real capture and playback.

Two permissions carry a declared range as well as a name, and the user is shown both: manifest.fs for the file modes (§6.5) and manifest.net.domains for egress (§6.6). Without the separately reviewed net.anyHost exception, an absent network range grants no egress. An absent file scope grants no standing reach; out-of-scope file operations still require host-owned consent.

Ask for the smallest set possible. Adding a permission to a loaded development plugin does not take effect through hot reload: Nib stops automatic reload so the new grant can be reviewed. Use the plugin row's More → Reload action to explicitly review/reload the registered folder, or load the development folder again. Widening manifest.fs counts as adding a permission for this purpose. Removing permissions takes effect on reload.

The complete mapping and policy are in the permission matrix.

8. Develop and debug

Hot reload

Development plugins are watched after the first folder load and across app restarts. Changes reload after a 300 ms debounce. .git, node_modules, dist, target, and common editor scratch files are ignored.

A reload performs unload → validate → load. Panel memory is not preserved. A syntax or manifest error unloads the broken version but keeps the watcher active; save a fix to recover. At most 16 development plugins are watched at once.

Verify each contribution

• Run a command from global search (Cmd/Ctrl+K or Cmd/Ctrl+Shift+P).
• Open a panel from the command or the plugin row.
• Ask the Agent to call the contributed tool while in Agent mode.
• Ask for a task matching the skill description, then inspect whether the skill is selected.
• Select a contributed theme in Settings.
• Inspect the plugin row for service state and restart count.

Logs and failures

Load, crash, permission, tool, network, service, and bus activity is recorded in the application logs. Open Settings → Info → Logs, then search for the plugin id. User-facing load and hot-reload failures also appear as a toast and on the plugin row when a persisted load error is available.

Host API failures throw an Error with a code, commonly PERMISSION_DENIED, NOT_FOUND, INVALID_ARGUMENT, TIMEOUT, UNSUPPORTED, LIMIT_EXCEEDED, or RATE_LIMITED. Catch errors around optional operations and include the code in diagnostics without logging secrets.

9. Check, pack, and install

Run validation from the repository root:

pnpm pi-plugin check ../my-first-plugin

check reports blocking errors and non-blocking warnings. It validates the manifest, referenced files, permissions, path containment, symlinks, package size, and file count before packing. A clean result does not prove runtime loading, compatibility, permission grants, or plugin-center approval; test the packed artifact too. Review warnings too, especially unused and high-risk permissions.

Pack only with the devkit:

pnpm pi-plugin pack ../my-first-plugin

The result is:

../my-first-plugin/dist/local.my-first-plugin-0.1.0.piplug

The command prints the package SHA-256. A .piplug is a store-only (uncompressed) ZIP; normal zip defaults usually produce an archive the installer rejects. The devkit excludes .git, node_modules, and root dist, and omits credential files (.env, .env.*, .npmrc, *.pem, *.key) with a warning. It rejects symlinks, and enforces a maximum of 2,000 files and 50 MiB.

To test the exact artifact users receive:

1. Open Plugins.
2. Choose Install plugin package from the header overflow menu.
3. Select the generated .piplug.
4. Review the permissions and install it.
5. Repeat the contribution checks from the previous section.
6. Disable and re-enable it to verify cleanup and startup behavior.
7. Uninstall it and confirm its contributions disappear.

The Agent can also run PluginCheck in every operating mode. PluginScaffold and PluginPack are Agent-mode tools and are restricted to the current workspace.

Prepare a plugin center submission with pi-plugin publish

publish packs the plugin and pins the package to the git commit it was built from, so the plugin center can rebuild and compare the artifact:

pnpm pi-plugin publish ../my-first-plugin [--out <dir>] [--ref <ref>] [--channel stable|beta] [--allow-dirty]

publish prepares files locally; it does not upload or publish a version. Ignore dist/ in the plugin repository before running it, because packing happens before the clean-worktree check.

The command runs the same check and pack steps, then reads the origin remote and HEAD of the plugin's repository. SSH remotes are rewritten to the canonical https:// form; remotes with embedded credentials or a non-HTTPS scheme are rejected. The working tree must be clean unless you pass --allow-dirty, which produces a submission the center cannot reproduce and prints a warning. The pinned ref is --ref when given, otherwise the tag that points at HEAD as refs/tags/<tag>; without a tag the bare commit is submitted with a warning. The plugin's path relative to the repository root is recorded so a plugin may live in a subdirectory.

The result is dist/<id>-<version>.submission.json (or --out), a schemaVersion: 1 payload with pluginId, version, channel, the source pin (repository, ref, commit, path), the artifact (publisher-release mode, file name, SHA-256, size), the declared permissions, and an idempotencyKey that is stable per plugin, version, commit, and artifact so a retried submission is not a new release. Attach the .piplug to a release on that commit, then submit the payload to the plugin center. The center re-resolves the source from the forge and does not trust the recorded values.

10. Prepare a release

Before sharing a package:

1. Use a stable reverse-domain plugin id.
2. Update version with semantic versioning.
3. Set engines.piDesktop to the versions you actually support.
4. Document every command, setting, tool input, permission, and external service in the plugin README.
5. Add a changelog and a license.
6. Build all generated JavaScript and assets into the plugin folder.
7. Run pi-plugin check and resolve every error and unexpected warning.
8. Run pi-plugin pack and install the resulting package in a clean app state.
9. Record the printed SHA-256 next to the release artifact.

For the official marketplace, publish on the plugin center, plugins.aiuo.net: create the plugin, bind the repository it lives in, tag the version and submit it — from the console, or with the publishing skill over MCP. The center packs the files, audits the source, records the SHA-256 and publishes the version, then mirrors the catalog and packages to AIUO-Net/pi-desktop-plugins for the GitHub backup channel. Plugin sources are never hosted in the distribution repository, and pull requests that add them are closed.

Signatures are not the current trust primitive. Package SHA-256 and explicit permission review are the implemented baseline; follow the signing and updates specification for roadmap details.

11. Troubleshooting

Symptom	Likely cause	Fix
manifest.json is missing	Wrong directory selected	Select the directory whose root contains manifest.json
main entry missing	main points to source that was not built	Compile/bundle first or correct the relative path
Panel does not open	Missing file, ui.panel, or permission	Declare the panel path and ui.panel; reload for a new grant
View is missing from the work panel menu	Missing ui.view, missing entry file, or the plugin's activation scope excludes the open project	Declare ui.view, check views[].entry exists, and set the scope to Global or to this project
View shows a letter tile instead of an icon	Unknown views[].icon token	Use a token from the supported list; pi-plugin check warns about unknown ones
pluginBridge is unavailable	HTML opened in a normal browser	Test bridge calls inside the Nib panel
Tool never appears	Missing contribution, registration, or grant	Align agentTools, registerTool, and agent.tool.register; use Agent mode
Skill never applies	Missing permission or weak metadata	Add agent.prompt.inject and specific name/description front matter
Save reports PERMISSION_DENIED	Manifest widened permissions or file scope	Use More → Reload or load the folder again to review the new grant
Hot reload stops after a syntax error	Broken plugin is unloaded	Save the corrected file; the watcher remains active
Package install rejects compression	Archive was made with a generic ZIP tool	Rebuild it with pi-plugin pack
MCP server does not start	Invalid transport fields, command, URL, setting, or permission	Run pi-plugin check, then inspect logs by plugin id
Service repeatedly restarts	start throws or the plugin process exits	Make start idempotent, clean up in stop, and inspect the restart log

12. Reference map

• Example plugins
• Plugin system overview
• Manifest schema
• Host API
• Lifecycle
• Packaging
• Developer experience
• Permissions
• Hello reference plugin

13. Complete SDK surface and source map

This inventory follows PluginHostApi in packages/plugin-sdk/src/index.ts. It is a method index, not a blanket grant. The permission matrix, invocation context, and availability restrictions above still apply; pi.audio remains unsupported. The panel bridge is a smaller surface listed in API spec §6.

Namespace	Methods
pi.app	getVersion, getLocale, getAppearance, setTheme
pi.themes	upsert, remove, list, setVariables
pi.plugin	getId, getManifest, getSettings, setSettings, getDataPath
pi.commands	register, unregister
pi.speech	registerAdapter, unregisterAdapter
pi.composer	suggest, clearSuggestion
pi.ui	openPanel, closePanel, showToast, notify, getNotificationPermission, requestNotificationPermission, showNativeNotification, revealView
pi.project	create
pi.providers.oauth	prompt, notify
pi.workspace	get
pi.desktop	listOperations, invoke
pi.audio	getInputDevices, openInput, closeInput, getCaptureState, onInputFrame, offInputFrame, openOutput, writeOutput, stopOutput, closeOutput
pi.keyboard	registerGlobalShortcut, unregisterGlobalShortcut, listGlobalShortcuts
pi.fs	readText, stat, readRange, readPreview, openDefault, openInBrowser, reveal, writeText, glob, list, remove, requestDirectory
pi.agent	registerTool, unregisterTool, complete
pi.models	list
pi.session	getLlmContext, getActive, getAutoTitleContext, setAutoTitle, list, get, listMessages, import, importBatch, rename, delete
pi.usage	listTurns
pi.services	register, unregister
pi.bus	publish, subscribe
pi.clipboard	readText, writeText, getHistory
pi.shell	openExternal
pi.browser	reveal, navigate, action, setBounds, setVisible, getState, openExternal, snapshot, screenshot, click, fill, evaluate, console, cdp
pi.net	getCapabilities, fetch
pi.net.websocket	connect, send, close
pi.events	on, off

Renderer modules use a different pi: plugin.id / version, slots.register, ui.injectStyle, ui.openLayer, composer.subscribeDraft, and dispatch. Draft subscriptions require composer.readDraft in rendererActions. Draft replacements use the captured generation as expectedGeneration, require a user input event while the Composer is unfocused, and preserve every host chip; inspect renderer-composer.ts rather than writing host store state. No renderer action sends a message.

Code / tests	What to verify
packages/plugin-sdk/src/index.ts, renderer.ts, renderer-composer.ts	Public types, contributions, permission vocabulary, renderer actions
packages/plugin-sdk/src/{fs-policy,net-policy,theme-css,theme-variables,mcp-config}.ts	Scope, egress, CSS, variable, and MCP validation
packages/plugin-devkit/src/{templates,check,walk,pack,publish,cli}.ts	Template files, checks, exclusions, archive format, submission preparation
crates/host-core/src/plugins/{manifest,validation,install,registry}.rs	Actual install, persistence, compatibility, and uninstall rules
apps/desktop/electron/main/plugin-runtime.ts, plugin-host-process.mjs	Broker dispatch, process callbacks, lifecycle, events, audit, and limits
apps/desktop/electron/preload/plugin-panel.ts	Actual panel bridge and page-owned chrome
apps/desktop/test/plugin-*.test.mjs	Host API, lifecycle, invocation scope, and representative plugin paths
examples/plugins/hello, ui-slots-lab, fetch-redirect, roundtable	Working contributions and focused probes

docs/plugin-plan contains slot/API review pages and proposed runtime hooks. A draft page is not an implemented SDK export. Start with the current SDK and runtime when deciding whether a capability exists. The built-in authoring instructions are shipped at apps/desktop/resources/skills/plugin-development.md.