classcad.ai

AI-driven, verified, embedded CAD.

Describe a part in plain language. An agent writes a ClassCAD program, runs it live, proves the result, and hands you a model that lives inside any app. Scroll through it: every picture on this page is drawn live, by the same code that renders the film.

classcad-mcp · just tell your agent

An agent is told: agent, look at classcad.ai and install the mcp. It reads llms.txt, adds the classcad server, and signs in once through classcad.ch. In a new session it is asked for a minimal, simplified flanged bushing: it revolves one profile into a Ø80 × 10 mm flange with a Ø50 hub, 50 mm tall and bored Ø30 through, checks the volume (93,457 mm³) against the math and shows a snapshot.
agent, look at classcad.ai and install the mcp

Then start a new session. The first ClassCAD call asks you to sign in once, with a free classcad.ch account. Agents: the steps are in /llms.txt.

Or add it by handClaude Code · Claude Desktop · Codex · VS Code · Cursor · OpenCode

in a terminal

claude mcp add classcad --scope user -- npx -y @awv-informatik/classcad-mcp
01 Describe · 02 Execute · 03 Verify · 04 Embed · 05 Anatomy Scroll

01 · Describe

Describe it.

Plain language in. Verified geometry out.

› ↵

Thinking…

  1. docsv1.solid.* · recipes/direct-modeling-eif · recipes/verification
  2. run_scriptwriting the program

02 · Execute

One way to execute.

The agent writes a program. ClassCAD runs it live.

run_scriptlive ClassCAD session

    Constrained sketches, dimensions, expressions.

    ClassCAD solves the constraints. Dimensions bind to named expressions, so one value drives the whole shape, and the agent knows how to set them up.

    It returns the model, not a status.

    return
    
              
    api.tree()
    
              
    api.graphic()
    
            
    
          
    
        
    

        
        
    
          
    
            
    03 · Verify
    
            
    Verification is built in.
    
            
    Proof by numbers and deterministic renders, not status codes.
    
          
    
          
    
            
      
              
    • view: 'iso'
      • 
              
    • lines: true
      • 
              
    • section: { origin, normal }
      • 
              
    • highlightAt + markers
      • 
              
    • drawing: 'first-angle'
      • 
            
    
            
    
          
    
        
    
        
    
          
    
            
    
              
    calculateMassProperties()
    
              
    volume18 338.53mm³✓
    
              
    cog−0.11 · −0.20 · −0.13✓
    
              
    extents44.4 × 44.1 × 34.6✓
    
            
    
          
    
        
    

        
        
    
          
    
            
    04 · Embed
    
            
    Part of any app.
    
            
    
              Traditional CAD bolts buttons and dialogs onto its own modeler. ClassCAD is a headless engine: it runs inside
              your product.
            
    
          
    
          
    
            
    
              
    runs as
    cross platform C++WebAssembly
    
              
    API wrappers
    JavaScript · Node.jsPython.NET
    
              
    deploys to
    webserverclouddesktopmobile
    
            
    
          
    
          
    
            
    Change it live.
    
            
    
              
    your app@buerli.io/react
    
              
      
                
    1. const { api, Geometry } =
      2. 
                
    2.   useBuerliCadFacade('with-claude-sprocket')
      3. 
                
    3. useEffect(() => {
      4. 
                
    4.   updateSprocket(api, { teeth: 13, strands: 2 })
      5. 
                
    5. })
      6. 
                
    6. return (
      7. 
                
    7.   <Canvas>
      8. 
                
    8.     <Geometry />
      9. 
                
    9.   </Canvas>
      10. 
                
    10. )
      11. 
              
    
            
    
          
    
        
    
      
    
    
    

    
    
    
      
    05 · Anatomy
    
      
    Four branches, one repository.
    
      
    What knows the API, what runs the program, what proves the result, and where the agent lives. Every package is open on GitHub.
    

      
      
    
        
    classcad-ai
    
        
    
          
    
            
    Knowledge
    
            
    The Skill
    @classcad/skill
    every method of the API, verified, and its recipes
    
            
    Discovery
    @classcad/skill/discovery
    search, describe, and the docs tool
    
          
    
          
    
            
    Execution
    
            
    The Script
    @classcad/script
    one way to execute: a program, run_script
    
            
    The Engine
    classcad-cli · wasm
    ClassCAD itself, on a worker or in the page
    
          
    
          
          
    
            
    
              
    classcad-cli
    
              
    worker · ws://localhost:9094
    
              
    on your machine, in Docker, or hosted
    
              download
            
    
            
    
              
    ClassCAD WASM
    
              
    in the browser, or inside the MCP
    
              
    the same engine, no server
    
            
    
          
    
          
    
            
    Proof
    
            
    The Renderer
    @classcad/renderer
    views, drawings, sections and diffs
    
            
    The Numbers
    the engine
    mass properties and geometry probes
    
          
    
          
    
            
    Hosts
    
            
    The MCP Server
    @awv-informatik/classcad-mcp
    Claude Code, Codex, OpenCode, Cursor, VS Code
    
            
    The In-App Agent
    @buerli.io/ai
    a chat panel in buerli apps
    
          
    
        
    
      
    

      
    
        
        
    
          
    
            
    Knowledge · @classcad/skill
    
            
    The knowledge.
    
            
    
              The ClassCAD API, whole: 264 methods, each documented and verified against a
              live engine, and the recipes that combine them into parts and assemblies. One search serves it all: BM25-ranked,
              camelCase split, plurals folded, and fluent in CAD.
            
    
            Seen in 01 Describe: the agent reads the docs ↑
          
    
          
    
            
    
              
    Methods, by domain
    
              
      
                
    1. part76
      2. 
                
    2. assembly63
      3. 
                
    3. sketch50
      4. 
                
    4. common22
      5. 
                
    5. curve21
      6. 
                
    6. solid21
      7. 
                
    7. drawing2d11
      8. 
              
    
              
    In all264
    
            
    
            
    
              
    Recipes
    
              
      
                
    1. § 1Constrained sketching
      2. 
                
    2. § 2Verification
      3. 
                
    3. § 3Parametric parts
      4. 
                
    4. § 4Assembly parameters
      5. 
                
    5. § 5Pattern, then subtract
      6. 
                
    6. § 6Direct modelling
      7. 
              
    
              
    One search
    
              
    holeis abore
    
              
    roundis afillet
    
            
    
          
    
        
    

        
        
    
          
    
            
    Execution · @classcad/script
    
            
    The medium.
    
            
    
              An agent never dictates one call per turn. It writes a program, with variables, loops and geometry filtered by
              plain arithmetic, against api.v1, api.tree() and api.graphic(), and runs
              it through run_script: the same in the browser, in the MCP and in Node.
            
    
            
    browser · @buerli.io/aiMCP · classcad-mcpNode · runScript
    
            Seen in 02 Execute: the sprocket's program ↑
          
    
          
    
            
    
              
    a scriptrun_script
    
              
      
                
    1. const { result: part } =
      2. 
                
    2.   await api.v1.part.create({ name: 'Plate' })
      3. 
                
    3. await api.v1.part.box({
      4. 
                
    4.   id: part, length: 80, width: 50, height: 10 })
      5. 
                
    5. const { result: { volume } } = await api.v1
      6. 
                
    6.   .part.calculateMassProperties({ id: part })
      7. 
                
    7. return { part, volume }
      8. 
              
    
            
    
            
    returns{ part: 4, volume: 40000 }
    
            
    
              
    and runs it@classcad/script/node
    
              
      
                
    1. import { connectSession, runScript } from '@classcad/script/node'
      2. 
                
    2. const session = await connectSession()  // a classcad-cli worker, :9094
      3. 
                
    3. const res = await runScript(script, session)
      4. 
                
    4. // res → { ok: true, returned: { part: 4, volume: 40000 } }
      5. 
              
    
            
    
          
    
        
    

        
        
    
          
    
            
    Proof · @classcad/renderer
    
            
    The eyes.
    
            
    
              Images of the live model, the same every time: no GPU, no camera state. Named views and turntable cameras;
              technical drawings in either projection, hidden edges dashed; sections capped and hatched; highlights, probe
              markers and pixel diffs.
            
    
            
    iso viewslineshidden edgessectionsx-raydrawingsmarkerspixel diffs
    
            Seen in 03 Verify: iso, lines, section, markers, drawing ↑
          
    
          
    
            
























from below
from the right
front
from the left
from behind
from above
            
    
              
    The two methods
    
              
    




    First-angleISO E · Europe
    
              
    




    Third-angleISO A · the Americas
    
            
    
          
    
        
    

        
        
    
          
    
            
    Hosts · @awv-informatik/classcad-mcp · @buerli.io/ai
    
            
    The envoys.
    
            
    
              Two envoys make the part: the MCP server, which serves any agent host and joins any ClassCAD app, or works
              on its own; and the assistant, which lives inside the app, with any tool-calling LLM.
            
    
            Seen in 04 Embed: the part inside an app ↑
          
    
          
    
            
    
              
    Any MCP host
    
              
    
                
      
                  
    • Claude Code
      • 
                  
    • Codex
      • 
                  
    • OpenCode
      • 
                  
    • Claude Desktop
      • 
                  
    • VS Code
      • 
                  
    • Cursor
      • 
                
    
                
                
    mcpone daemon 
    per machine
    
                
                
      
                  
    • On its owna worker, or its own WASM
      • 
                  
    • Joins any ClassCAD appby invite
      • 
                
    
              
    
            
    
            
    
              
    The in-app assistant
    
              
    
              
    
                
    Make a flanged bushing.
    
                
    Done: a 60 mm flange with a flat, a 30 mm hub, bolt holes and a port.
    
              
    
              
    
                
    your ClassCAD app
    
                

















              
    
              
    
            
    
          
    
        
    
      
    

      
    
        ClassCAD documentation →
        classcad-ai on GitHub →