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
demo.mp4
| Module | Role | Status | Links |
|---|---|---|---|
| cesium-mcp-contracts | Transport-neutral names, descriptions, and JSON Schemas for browser tools | New shared layer | source |
| cesium-mcp-bridge | Protocol- and transport-free Cesium command executor (60+ commands) | Mainline, actively iterated |  · source |
| cesium-mcp-webmcp | One-package Viewer integration plus the native document.modelContext adapter |
Browser integration | source |
| examples/webmcp-integration | Focused npm + Vite integration without a chat UI or MCP server | Developer example | example |
| examples/browser-agent | Browser-only AI agent with automatic WebMCP exposure | Recommended | example · live demo |
| cesium-mcp-runtime | MCP server (stdio + HTTP) | Stable MCP SDK v2 |  · source |
| cesium-mcp-dev | CesiumJS API knowledge base for coding assistants | Maintained |  · source |
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.
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.
CesiumGS's newer AI work is split between cesiumjs-ai-starter-app, a deployable application template, and cesiumjs-skills, development-time guidance for coding agents. The earlier 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.
Open the live demo 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 folder to deploy your own.
The browser-agent example automatically registers all 61 browser-safe page tools when document.modelContext is available. Its built-in chat uses automatic toolset routing to keep each normal request at 20 tools or fewer, while still offering explicit core, single-toolset, and all-61 modes:
npm run build -w packages/cesium-mcp-bridge
npm run build -w packages/cesium-mcp-webmcp
npx serve . -l 4173Open 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.
npm install cesium-mcp-webmcpimport { 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 for custom integrations. For a complete npm + Vite application, start from the WebMCP integration example.
npm install cesium-mcp-bridgeimport { 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 for a complete loop with OpenAI-compatible APIs.
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.
# Stable channel — npm latest, MCP SDK v2
npx -y cesium-mcp-runtime
# HTTP mode
npx -y cesium-mcp-runtime --transport http --port 3000The 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:
{
"mcpServers": {
"cesium": {
"command": "npx",
"args": ["-y", "cesium-mcp-runtime"]
}
}
}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-CNfor Chinese. Titles, behavior annotations, localized descriptions, defaults, input validation, MCP output schemas, and structured results all come from the shared JSON Schemas incesium-mcp-contracts. Textcontentremains 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 |
See examples/minimal/ for a complete working demo.
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:packedtest: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.
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 format: {CesiumMajor}.{CesiumMinor}.{MCPPatch}
| Segment | Meaning | Example |
|---|---|---|
1.143 |
Tracks CesiumJS version — built & tested against Cesium ~1.143.0 |
1.143.0 → Cesium 1.143 |
.x |
MCP patch — independent iterations for new tools, bug fixes, docs | 1.143.0 → 1.143.1 |
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.
- mapbox-mcp — AI control for Mapbox GL JS
- openlayers-mcp — AI control for OpenLayers
This project recognizes LINUX DO as a community for open-source exchange, technical discussion, and developer feedback.
