OSCAR_Public
Open-source package for building a localhost MCP server that hands Claude Code full control of Fusion 360.
What it does and how it connects
OSCAR, the Open Source CAD Automation package for Claude Code and Autodesk Fusion 360, is a build package rather than a finished server. The user feeds prompt/MASTER-PROMPT.md to Claude Code, and Claude Code builds the whole system: a Fusion add-in and an MCP server that lets Claude design, model and manipulate 3D geometry through natural conversation. The stated goals are AI-assisted fully parametric design and automatic parameter naming.
The finished system is a two-process bridge on the local computer: a FastMCP Python MCP server over stdio receives tool calls from Claude Code and forwards them as HTTP POST requests to the Fusion add-in on localhost port 45876, with bearer token authentication. The add-in runs inside Fusion 360 and uses Fusion's CustomEvent system to marshal API calls from a background HTTP server thread to the main thread.
The package ships 17 Fusion 360 API reference files, 7 MCP protocol reference files, a 72-rule modeling guide, a testing guide, 36 extended API reference files, and the add-in and server source. An experience layer stores the user's learnings so OSCAR gets faster and better each time it runs. The README states OSCAR is not for someone who does not know Fusion, and that out of the box it is not an expert CAD designer: the user watches it learn. Security is localhost-only binding, a random bearer token per startup, no binaries, no auto-updater and no phone-home.
Alternatives
Compare side by side- autodesk-fusion-mcp
An MCP server that runs inside Autodesk Fusion as an add-in over Streamable HTTP, rather than a build package that hands Claude Code a master prompt to build a Fusion MCP system.
- ipt-mcp
An MCP gateway that drives Autodesk Inventor 2022 to 2027 through a per-version add-in, rather than a build package for a Fusion MCP system.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- Cloud-first file model makes local file control, rename/move/backup workflows feel alien and risky.Error Index
- General UI/UX is described as confusing and hostile for routine work.Error Index
- ChatGPT's Computer Use agent cannot drive Autodesk Fusion 360: selecting Always allow does not stick, a later window-state request fails with 'Computer Use was not approved to use fusion360', and the requested CAD design could not be created. Desktop logs recorded three allow-persist-always approvals with no persisted entry in the config.Error Index
Sources
Not verified
- Pricing: none stated on the repo.
- Real user voices: no real linked post read for this page.
- Related Error Index entries: no matching entry verified (the live error map has no OSCAR entries).
- A named individual builder beyond the Creative-Inertia organization
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.