Connect an Agent (Experimental)

You need:

• JetCad3 installed and running;
• Codex, Claude Code, or another MCP-compatible client installed on the same computer; and
• the JetCad3 project you want to use open in its own tab.

Keeping a project open does not give an agent access by itself—the client must connect and explicitly bind that tab. The actions the agent can use still depend on your JetCad3 license and the native features available in the selected workspace.

1. Open Settings → Agentic MCP.
2. Check Enable Agentic MCP.
3. Leave the loopback port at 47330 unless another local program already uses it.
4. Save Settings.
5. Reopen Settings → Agentic MCP and confirm the listener says Running.

The default local endpoint is:

http://127.0.0.1:47330/mcp

Keep JetCad3 running while the agent is connected.

1. In Settings → Agentic MCP, click Copy Codex config.
2. Add the copied block to your Codex configuration file:
   • macOS and Linux: ~/.codex/config.toml
   • Windows: %USERPROFILE%\.codex\config.toml
3. Close the current Codex session and start a fresh one.

The copied block already contains the correct local URL and pairing token. It has this shape:

[mcp_servers.jetcad3]
url = "http://127.0.0.1:47330/mcp"
http_headers = { Authorization = "Bearer <pairing-token>" }

Use the text copied from JetCad3; do not type the token shown above.

1. In Settings → Agentic MCP, click Copy Claude command.
2. Paste and run that command in the terminal where you use Claude Code.
3. Close the current Claude Code session and start a fresh one.

JetCad3 generates a command with the local endpoint and pairing token already included. The connection is registered under the name jetcad3.

Click Copy JSON and paste the result into your client's MCP server settings. The configuration uses Streamable HTTP, the local /mcp endpoint, and an Authorization header containing the pairing token.

If the client asks for the transport separately, choose HTTP or Streamable HTTP. The connection will not work from a different computer because JetCad3 deliberately accepts loopback connections only.

Open the desired project in JetCad3 before starting the agent session. You can then ask the agent plainly:

Use the JetCad3 MCP to inspect the open project and help me model this part.

A correctly connected agent can discover JetCad3, list the open tabs, bind the project you choose, read its Project Memory and geometry, and then ask for any design decisions it still needs. Compact task search points it to the exact native recipe and operation details instead of returning a full manual. Body IDs come from the project geometry query, repeated parts can be created and placed in one recoverable native edit, and ordinary static or joint-motion clearance uses the same project geometry and saved studies as the manual Drafting tools.

The agent should inspect compatible existing feature history before replacing it, carry each returned revision, and use checkpoints, evaluation/render waits, measurements, exports, and current screenshots while it works. If a mutation response is lost, it replays the exact original request with the same key instead of guessing a revision or creating a duplicate edit. If JetCad3 does not advertise a required native capability, the agent should report that specific gap instead of rebuilding a separate copy of the model outside the project.

Only one project tab is bound by a particular document handle. Opening or closing other tabs does not silently redirect the agent to a different design.

Both Agent Tower and an external MCP client use the same supported project actions.

• Design: inspect and edit shapes, nodes, layers, groups, text, images and traces; arrange geometry; import, export, print, and Send To.
• Drafting: create and edit sketches, features, sheet metal, assemblies, JShapes and supported file operations.
• eCAD: work through schematic, PCB, sourcing decisions, checks, review and fabrication preparation.
• Mill: create setups and operations, generate and inspect paths, simulate, review and prepare exact output.
• Plasma and Oxyfuel: manage sheets, exact stock, imports, quantities, placement, nesting, contours, process settings, generation, simulation, quotes and reviewed output.
• Laser: manage Cartesian Laser operations and prepare GRBL or Ruida output. Fiber Galvo supports offline lens/calibration inspection and job preparation.
• Router: use all seven current operation types, their native strategy settings, generation, simulation, quotes and output preparation.
• GcodePilot: inspect passive machine status and saved history, inspect a Project Archive program offline, author PointTrace drawings, and hand completed PointTrace or CamTrace geometry to CAD/CAM.
• Turn: reports unavailable until native turning CAM is implemented.

Machine control stays with the operator. Agents cannot connect or disconnect hardware, jog, home, probe, send MDI, change live offsets or configuration, enable outputs, load or queue a controller program, start or resume a run, Light or Mark a Galvo, install drivers, or flash firmware.

An agent can discover all eight supported Mill operation types, create setups and editable operations, generate paths, and inspect simulation results. Completing generation keeps its result current; later changes to geometry or machining settings still require regeneration and renewed review where applicable.

JShape discovery includes both the installed library and generators stored in the project. Ask the agent to inspect the bundled generator before looking elsewhere for an existing shape. Forking a library generator into a project preserves its source and required helper so that the saved project can reopen with that definition. A generated part still needs the dimensional and machining review appropriate to your job.

Mill references to sketch chains and holes on the standard XY, YZ, and XZ planes survive saving and reopening. Use Project Memory and the Project Archive to retain design decisions, setup intent, and remaining checks for the next session, and review the current toolpaths and simulation before preparing output.

Saved projects retain assembly grounding, linked components, joints, dimensions, 3D sketches, active-component selection, materials, and visibility. Exact STEP, IGES, and BREP component exports use the current evaluated geometry without requiring a dummy edit; stale, incomplete, or not-yet-positioned geometry returns an error instead of an older cached shape. Rigid component moves publish directly to the viewport, picking, measurements, and exports without toggling a feature or forcing an unnecessary solid rebuild. Curved-part measurements use the actual trimmed-solid bounds, not the larger box of an underlying untrimmed surface.

Catalog sourcing distinguishes an empty result from a login or browser challenge. When public McMaster-Carr data is available, agents can verify catalog identity, source dimensions and units, and matching CAD downloads. Incomplete family results still require a selection; a partial list is not treated as an automatic exact match.

Review screenshots wait for a rendered frame and the requested project, revision, workspace, camera, and visibility state. Changing views are reported as stale rather than returned as if current. Operation discovery and recovery guidance use the same supported Drafting tools, bounded edit batches, and refreshed geometry references throughout the workflow.

eCAD automation uses the same import identities, routing geometry, manufacturing rules, DRC and fabrication preflight as the workspace. Long operations are cancellable, and an exact retry after a lost response returns the original committed result instead of duplicating board changes. View and screenshot requests settle on the requested current board before returning.

Design and the sheet-CAM workspaces use their normal ownership, source, stock, nesting, operation, generation, simulation and save behavior. Exact source and library fingerprints prevent an older result from being presented as current. Locked CAM parts remain unchanged until explicitly unlocked. Output is prepared as an inspectable Project Archive artifact and can require current human review.

GcodePilot access is limited to passive diagnostics and preparation. PointTrace capture reads a fresh, idle position without issuing motion. CamTrace results must already exist before an agent can inspect or hand them to another workspace.

On macOS, JetCad3 now shuts down cleanly after automated, development, and packaged workflows that opened tabs or auxiliary views.

The same revision, cancellation, screenshot, save/reopen, and recovery rules apply across the supported workspaces.

The pairing token authorizes local control of JetCad3. Treat copied client configuration like a password:

• do not post it in screenshots, forum messages, or shared project files;
• do not commit it to a repository;
• use Rotate Pairing Token if it may have been exposed; and
• copy a fresh configuration into every client after rotating it.

Rotating the token immediately disconnects existing MCP sessions. Disabling Agentic MCP also closes all connected sessions.

The agent has no JetCad3 tools

Confirm the listener says Running, then start a completely fresh agent session. Most clients load their MCP tool list when a session starts and will not add a newly configured server to a conversation that is already open.

Connection refused or “fetch failed”

JetCad3 is not running, Agentic MCP is disabled, or the configured port does not match. Reopen Settings, confirm the running endpoint, and copy the configuration again.

JetCad3 tools stop working after restarting JetCad3

Restarting JetCad3 ends the agent's old connection, and the agent reconnects on its own the next time it calls a JetCad3 tool. If an older client keeps reporting “MCP session not found”, reconnect the JetCad3 server in that client or start a fresh agent session.

The pairing token is rejected

Use Copy Codex config, Copy Claude command, or Copy JSON again. If necessary, rotate the pairing token and replace the old client configuration.

The agent cannot find the project

Make sure the project is open in JetCad3. Ask the agent to list documents and bind the desired tab again; document handles do not survive closing or replacing a tab.

The listener cannot start

Another local program may already be using the selected port. Choose a different port, save Settings, then copy a new client configuration because the endpoint changed.