ext-apps/examples/system-monitor-server/README.md
Anton Pidkuiko 37aab03de0
docs: add tool visibility and restructure _meta.ui (#131)
* docs: add tool visibility and restructure _meta.ui

- Restructure tool metadata: `_meta["ui/resourceUri"]` → `_meta.ui.resourceUri`
- Add `visibility` array field: ["model"], ["apps"], or ["model", "apps"]
- Default ["model"] preserves standard MCP behavior
- ["apps"] enables widget-only tools hidden from agent
- Add McpUiToolMeta interface for type safety
- Add Design Decision #4 explaining approach vs OpenAI's two-field model

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* address PR review comments

- Change default visibility to ["model", "apps"]
- Add deprecation notice for flat ui/resourceUri format
- Add McpUiToolMeta and McpUiToolVisibility to spec.types.ts
- Improve tools/list and tools/call behavior wording

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: regenerate schemas for McpUiToolMeta types

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* feat: tool visibility and nested _meta.ui format

- Rename visibility "apps" → "app" in McpUiToolVisibility type
- Add _meta.ui.resourceUri nested format (deprecate flat format)
- Add getToolUiResourceUri() utility with backward compatibility
- Add visibility demo to system-monitor-server:
  - get-system-stats: visibility ["model"] with resourceUri
  - refresh-stats: visibility ["app"] (app-only polling)
- Update all example servers to use new _meta.ui format
- Add 11 unit tests for getToolUiResourceUri()

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: regenerate schemas with updated dependencies

* feat: export McpUiToolMeta type and add type annotations

- Export McpUiToolMeta and McpUiToolVisibility types from types.ts
- Export corresponding Zod schemas (McpUiToolMetaSchema, McpUiToolVisibilitySchema)
- Add `as McpUiToolMeta` type annotations to all example servers
- Update docs/quickstart.md with proper typing

Ensures type safety for `_meta.ui` tool metadata across the codebase.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* feat: add server helpers and optional connect() transport

Add `src/server/` with convenience functions for registering MCP App tools
and resources:

- `registerAppTool(server, name, config, handler)`
- `registerAppResource(server, name, uri, config, callback)`

The `transport` parameter in `App.connect()` is now optional, defaulting to
`PostMessageTransport(window.parent)`.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* Update src/server/index.ts

Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>

* feat: update McpUiAppToolConfig to support both _meta.ui and flat formats

* refactor: simplify server helper imports

* docs: add deprecation notice and improve resourceUri documentation

* feat: add backward compat normalization in registerAppTool

- If _meta.ui.resourceUri is set, also set legacy flat key
- If legacy flat key is set, also set _meta.ui.resourceUri
- Preserves existing visibility when merging
- Does not overwrite if both formats already set

* refactor: avoid mutating config arg in registerAppTool

* style: format with prettier

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Olivier Chafik <ochafik@anthropic.com>
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>
2025-12-16 21:47:40 +00:00

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2.4 KiB
Markdown

# Example: System Monitor App
A demo MCP App that displays real-time OS metrics with a stacked area chart for per-core CPU usage and a bar gauge for memory.
<table>
<tr>
<td><a href="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/01-initial-state.png"><img src="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/01-initial-state.png" alt="Initial state" width="100%"></a></td>
<td><a href="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/02-cpu-data-accumulated.png"><img src="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/02-cpu-data-accumulated.png" alt="CPU data accumulated" width="100%"></a></td>
<td><a href="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/03-extended-cpu-history.png"><img src="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/03-extended-cpu-history.png" alt="Extended CPU history" width="100%"></a></td>
</tr>
</table>
## Features
- **Per-Core CPU Monitoring**: Stacked area chart showing individual CPU core utilization over a 1-minute sliding window
- **Memory Usage**: Horizontal bar gauge with color-coded thresholds (green/yellow/red)
- **System Info**: Hostname, platform, and uptime display
- **Auto-Polling**: Automatically starts monitoring on load with 2-second refresh interval
- **Theme Support**: Adapts to light/dark mode preferences
## Running
1. Install dependencies:
```bash
npm install
```
2. Build and start the server:
```bash
npm run start:http # for Streamable HTTP transport
# OR
npm run start:stdio # for stdio transport
```
3. View using the [`basic-host`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) example or another MCP Apps-compatible host.
## Architecture
### Server (`server.ts`)
Exposes a single `get-system-stats` tool that returns:
- Raw per-core CPU timing data (idle/total counters)
- Memory usage (used/total/percentage)
- System info (hostname, platform, uptime)
The tool is linked to a UI resource via `_meta.ui.resourceUri`.
### App (`src/mcp-app.ts`)
- Uses Chart.js for the stacked area chart visualization
- Polls the server tool every 2 seconds
- Computes CPU usage percentages client-side from timing deltas
- Maintains a 30-point history (1 minute at 2s intervals)
- Updates all UI elements on each poll