Cesium Mcp Runtime

---

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
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.

Architecture

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, 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.

Quick Start

Path 0 — Try in 30 seconds (browser agent, recommended)

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.

Path 1 — Expose Cesium tools through WebMCP (Chrome 149+ experimental)

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 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.

npm install cesium-mcp-webmcp

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 for custom integrations. For a complete npm + Vite application, start from the WebMCP integration example.

Path 2 — Embed in your own web app (function calling)

npm install cesium-mcp-bridge

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 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.

# 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:

{
  "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/ for a complete working demo.

Development

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. 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
1.143	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.

Related Projects

• mapbox-mcp — AI control for Mapbox GL JS
• openlayers-mcp — AI control for OpenLayers

Community

This project recognizes LINUX DO as a community for open-source exchange, technical discussion, and developer feedback.

Star History

License

MIT