A protocol-agnostic Cesium AI control runtime for MCP, WebMCP, function calling, and browser agents
cesium-mcp-bridge is the protocol-agnostic Cesium command executor. Separate adapters expose it to browser-only agents, WebMCP browser agents, function calling, or MCP — your choice.
Four integration paths: Browser Agent (simplest, zero backend) · WebMCP (page-local browser tools) · function calling (embed in your web app) · MCP runtime (Claude Desktop / Cursor / Dify)
The local Runtime is only required for external MCP hosts. Browser Agent, WebMCP, and function-calling integrations execute the same commands directly in the web application.
Try it now — open the live browser demo, no install, no signup.
Website ·
中文 ·
Getting Started ·
API Reference
---
## Cesium Map in Codex
Install the hosted map plugin from this repository's **Cesium Map Community** source:
```text
codex plugin marketplace add gaopengbin/cesium-mcp --ref main
codex plugin add cesium-map@cesium-community
```
Restart Codex and ask “Open a map of Manhattan.” Uses native host chat, with no local map server or separate model API key. Requires a compatible MCP Apps host. This is a community beta, separate from the OpenAI public directory.
[Installation and compatibility](plugins/cesium-map/README.md) · [ZIP download](https://github.com/gaopengbin/cesium-mcp/releases/tag/cesium-map-plugin-v0.1.0) · [Product website](https://laogao.xyz/cesium-map/)
### Continue in native Codex chat
- “Open the New York 3D city blocks scene, change the selected building height to 180 metres, then read it back.”
- “Explain the selected hexagon in the San Francisco city activity scene.”
- “Show the Los Angeles hotspots scene, then zoom in on the route.”
Select a scene in the map, click an object and choose **Ask in Codex** to continue with its map context. The host controls chat placement and map expansion.
### Map previews
Actual running screenshot: the development preview is connected to the hosted HTTPS MCP service. The native conversation UI is provided by Codex; it is not pictured here.
| San Francisco · City activity | New York · 3D city blocks | Los Angeles · Hotspots |
| --- | --- | --- |
|  |  |  |
| Inspect feature values and change classification colors | Select buildings, edit extrusion heights and read back properties | Combine a heatmap, markers and connecting routes |
These covers come from rendered map scenes. Buildings, activity values and heatmap points are demonstration data, not surveyed heights or official statistics. Basemap imagery: Esri and its imagery contributors.
## Demo
https://github.com/user-attachments/assets/8a40565a-fcdd-47bf-ae67-bc870611c908
## Packages & Entry Points
| Module | Role | Status | Links |
|--------|------|--------|-------|
| **cesium-mcp-contracts** | Transport-neutral names, descriptions, and JSON Schemas for browser tools | New shared layer | [source](packages/cesium-mcp-contracts/) |
| **cesium-mcp-bridge** | Protocol- and transport-free Cesium command executor (60+ commands) | Mainline, actively iterated | [](https://www.npmjs.com/package/cesium-mcp-bridge) · [source](packages/cesium-mcp-bridge/) |
| **cesium-mcp-webmcp** | One-package Viewer integration plus the native `document.modelContext` adapter | Browser integration | [source](packages/cesium-mcp-webmcp/) |
| **examples/webmcp-integration** | Focused npm + Vite integration without a chat UI or MCP server | Developer example | [example](examples/webmcp-integration/) |
| **examples/browser-agent** | Browser-only AI agent with automatic WebMCP exposure | Recommended | [example](examples/browser-agent/) · [live demo](https://cesium-browser-agent.pages.dev/) |
| **cesium-mcp-runtime** | MCP server (stdio + HTTP) | Stable MCP SDK v2 | [](https://www.npmjs.com/package/cesium-mcp-runtime) · [source](packages/cesium-mcp-runtime/) |
| **cesium-mcp-dev** | CesiumJS API knowledge base for coding assistants | Maintained | [](https://www.npmjs.com/package/cesium-mcp-dev) · [source](packages/cesium-mcp-dev/) |
> **Which one?** Personal project or quick try → browser-agent. Let a compatible browser agent discover page-local Cesium tools → WebMCP. Existing web app embedding an AI assistant → bridge + your own function calling. Calling from Claude Desktop / Cursor / Dify → MCP runtime.
## Architecture
```mermaid
flowchart LR
subgraph clients ["AI Drivers (pick one)"]
BA["Browser Agent\n(in the same page)"]
WM["WebMCP Agent\n(browser-provided)"]
FC["Your web app\nfunction calling"]
MCP["Claude / Cursor / Dify\nvia MCP runtime"]
end
CONTRACTS["cesium-mcp-contracts\ntool definitions"]
WEBMCP["cesium-mcp-webmcp\nnative adapter"]
subgraph core ["cesium-mcp-bridge (browser)"]
B["60+ tools\nprotocol-agnostic dispatcher"]
C["CesiumJS Viewer"]
end
CONTRACTS -.-> BA
CONTRACTS -.-> WEBMCP
BA -- "in-page call" --> B
WM -- "document.modelContext" --> WEBMCP
WEBMCP --> B
FC -- "in-page call" --> B
MCP -- "WebSocket / JSON-RPC" --> B
B --> C
style clients fill:#1e293b,stroke:#528bff,color:#e2e8f0
style core fill:#1e293b,stroke:#12B76A,color:#e2e8f0
```
The bridge remains the execution core, while contracts and protocol adapters stay separate. Pick whichever driver matches your scenario — they all reach the same Cesium command layer. On WebMCP-capable browsers, `cesium-mcp-webmcp` can expose 61 browser-safe commands in 12 selectable toolsets through `document.modelContext` without adding an MCP transport or backend server.
### Relationship to the CesiumGS AI ecosystem
CesiumGS's newer AI work is split between [`cesiumjs-ai-starter-app`](https://github.com/CesiumGS/cesiumjs-ai-starter-app), a deployable application template, and [`cesiumjs-skills`](https://github.com/CesiumGS/cesiumjs-skills), development-time guidance for coding agents. The earlier [`cesium-ai-integrations`](https://github.com/CesiumGS/cesium-ai-integrations) repository contains the first-generation experiments and community contributions that helped explore this space.
`cesium-mcp` is an independent runtime and integration toolkit, not a continuation of the earlier WebSocket-only reference architecture. Its reusable Bridge and shared contracts work unchanged across browser-only function calling, native WebMCP, standard MCP over stdio/HTTP, and embedded desktop shells. A local WebSocket bridge is used only when an external MCP host needs to reach a live browser Viewer; it is not required for the hosted demo or page-local integrations.
The project author was an early contributor to `CesiumGS/cesium-ai-integrations`, contributing the Imagery server, Terrain server, and unified MCP Gateway. Those experiments informed this project's multi-protocol architecture, while the implementation, release lifecycle, and roadmap remain independent.
## Quick Start
### MCP Apps map panel
Open an interactive Cesium map inside a compatible MCP Apps host with `openCesiumMap`. The panel uses existing MCP tools, publishes camera/layer/selection context, and can send a selected object to the conversation. OpenAI global/thread entrypoint metadata is included; availability depends on the host.
Try the local preview with `npm run app:preview -w packages/cesium-mcp-runtime` after `npm ci` and `npm run build`, then open http://127.0.0.1:19311/. See the [MCP Apps guide](docs/guide/mcp-apps.md) for host configuration and verification boundaries.
### Path 0 — Try in 30 seconds (browser agent, recommended)
Open the [live demo](https://cesium-browser-agent.pages.dev/) and ask—the hosted model is ready without a browser API key:
> *"Fly to the Eiffel Tower and drop a red marker"*
Fork the [examples/browser-agent](examples/browser-agent/) folder to deploy your own.
### Path 1 — Expose Cesium tools through WebMCP (Chrome 149+ experimental)
The browser-agent example automatically registers all 61 browser-safe page tools plus 3 page-local resource tools when `document.modelContext` is available. Its built-in chat uses automatic toolset routing while keeping resource handles available for large GeoJSON/CZML inputs, and still offers explicit core, single-toolset, and all-tools modes:
```bash
npm run build -w packages/cesium-mcp-bridge
npm run build -w packages/cesium-mcp-webmcp
npx serve . -l 4173
```
Open `http://localhost:4173/examples/browser-agent/`, click **Start**, then inspect or execute the tools in DevTools → Application → WebMCP. Enable `#enable-webmcp-testing` and `#devtools-webmcp-support` in `chrome://flags` for local testing.
Application developers install the adapter separately. End users only open the integrated website; they do not install npm packages or run an MCP server.
```bash
npm install cesium-mcp-webmcp
```
```js
import { registerCesiumViewerWebMcp } from 'cesium-mcp-webmcp/viewer'
const registration = await registerCesiumViewerWebMcp(viewer, {
toolsets: 'all',
excludeTools: ['geocode'], // add your own browser geocoder to expose this tool
})
// Later, if the page is unmounted:
registration.unregister()
```
See the [WebMCP adapter API](packages/cesium-mcp-webmcp/README.md) for custom integrations.
For a complete npm + Vite application, start from the [WebMCP integration example](examples/webmcp-integration/).
### Path 2 — Embed in your own web app (function calling)
```bash
npm install cesium-mcp-bridge
```
```js
import { CesiumBridge } from 'cesium-mcp-bridge';
const bridge = new CesiumBridge(viewer);
// Then: send the bridge's tool schema to any LLM that supports function/tool calling,
// route the model's tool calls to bridge.execute(name, params).
```
See [examples/browser-agent/index.html](examples/browser-agent/index.html) for a complete loop with OpenAI-compatible APIs.
### Path 3 — Use from Claude Desktop / Cursor / Dify (MCP)
Ordinary MCP users need only the Runtime package. It includes the browser Bridge bundle and a built-in Viewer at `http://localhost:9100/`; install `cesium-mcp-bridge` separately only when integrating a custom page.
```bash
# Stable channel — npm latest, MCP SDK v2
npx -y cesium-mcp-runtime
# HTTP mode
npx -y cesium-mcp-runtime --transport http --port 3000
```
The stable release serves existing MCP `2025-11-25` clients and the new
`2026-07-28` protocol from the same stdio/HTTP entry. It uses the stable
TypeScript SDK v2 and passes the official `server-stateless` conformance
scenario (28/28).
MCP client config:
```json
{
"mcpServers": {
"cesium": {
"command": "npx",
"args": ["-y", "cesium-mcp-runtime"]
}
}
}
```
## 62 Available Command Tools
Tools are organized into **12 toolsets**. Default mode enables 4 core toolsets (30 tools). Set `CESIUM_TOOLSETS=all` for everything, or let the AI discover and activate toolsets dynamically at runtime.
> **Canonical contracts**: Tool descriptions default to English; set `CESIUM_LOCALE=zh-CN` for Chinese. Titles, behavior annotations, localized descriptions, defaults, input validation, MCP output schemas, and structured results all come from the shared JSON Schemas in `cesium-mcp-contracts`. Text `content` remains available for older clients.
| Toolset | Tools |
|---------|-------|
| **view** (default) | `flyTo`, `setView`, `getView`, `zoomToExtent`, `saveViewpoint`, `loadViewpoint`, `listViewpoints`, `exportScene` |
| **entity** (default) | `addMarker`, `addLabel`, `addModel`, `addPolygon`, `addPolyline`, `updateEntity`, `removeEntity`, `batchAddEntities`, `queryEntities`, `getEntityProperties` |
| **layer** (default) | `addGeoJsonLayer`, `addGeoJsonPrimitive`, `listLayers`, `removeLayer`, `clearAll`, `setLayerVisibility`, `updateLayerStyle`, `getLayerSchema`, `setBasemap` |
| **interaction** (default) | `screenshot`, `highlight`, `measure` |
| camera | `lookAtTransform`, `startOrbit`, `stopOrbit`, `setCameraOptions` |
| entity-ext | `addBillboard`, `addBox`, `addCorridor`, `addCylinder`, `addEllipse`, `addRectangle`, `addWall` |
| animation | `createAnimation`, `controlAnimation`, `removeAnimation`, `listAnimations`, `updateAnimationPath`, `trackEntity`, `controlClock`, `setGlobeLighting` |
| tiles | `load3dTiles`, `load3dGaussianSplat`, `loadTerrain`, `loadImageryService`, `loadCzml`, `loadKml`, `setEdgeDisplayMode` |
| trajectory | `playTrajectory` |
| heatmap | `addHeatmap` |
| scene | `setSceneOptions`, `setPostProcess`, `setIonToken` (Runtime only) |
| geolocation | `geocode` |
## Examples
See [examples/minimal/](examples/minimal/) for a complete working demo.
## Development
```bash
git clone https://github.com/gaopengbin/cesium-mcp.git
cd cesium-mcp
npm install
npm run build
npm test
npm run test:contracts
npm run test:schema-compat
npm run test:routing
npm run test:model-tools
npm run eval:model-tools
npm run test:e2e:packed
```
`test:contracts` is the focused parity gate for MCP Runtime metadata, WebMCP registration, Function Calling definitions, provider Schema portability, and the 60-tool Bridge Executor Registry. Run `test:schema-compat` directly for actionable OpenAI, Azure, VS Code MCP, and WebMCP Schema diagnostics.
`test:routing` evaluates bilingual and multi-intent Browser Agent requests across all 12 toolsets, checking required-tool recall and the 20-tool automatic-routing budget.
`test:model-tools` verifies the provider-neutral multi-turn scoring harness. `eval:model-tools` performs a no-network routing preflight by default; add an explicit provider and `--live` to measure real tool choice, argument validity, and required-tool completion. See [Model Tool Evaluation](docs/guide/model-tool-evaluation.md).
`test:e2e:packed` builds npm tarballs, installs them in a clean temporary project, opens the real Cesium Viewer, and verifies a Runtime-WebSocket-Bridge command round trip.
## Version Policy
Version format: `{CesiumMajor}.{CesiumMinor}.{MCPPatch}`
| Segment | Meaning | Example |
|---------|---------|--------|
| `1.145` | Tracks CesiumJS version — built & tested against Cesium `~1.145.0` | `1.145.0` → Cesium 1.145 |
| `.x` | MCP patch — independent iterations for new tools, bug fixes, docs | `1.145.0` → `1.145.1` |
Official CesiumJS releases are reviewed before the compatibility baseline is bumped; the project does not automatically claim support for a newer release without Bridge verification.
## Related Projects
- [mapbox-mcp](https://github.com/gaopengbin/mapbox-mcp) — AI control for Mapbox GL JS
- [openlayers-mcp](https://github.com/gaopengbin/openlayers-mcp) — AI control for OpenLayers
## Community
This project recognizes [LINUX DO](https://linux.do/) as a community for open-source exchange, technical discussion, and developer feedback.
## Star History
[](https://github.com/gaopengbin/cesium-mcp)
## License
[MIT](LICENSE)