CAD Skills vs Codex CLI: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of CAD Skills and Codex CLI — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
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CAD Skills
earthtojake
Open-source library of agent skills for CAD, robotics, fabrication, and simulation — generate STEP/STL, URDF/SRDF/SDF, DXF, and slicer G-code from prompts.
Key features
- Prompt-to-CAD Generation: The CAD skill creates and edits parametric CAD models from natural language or image requests, exporting to STEP, STL, 3MF, and GLB.
- URDF Robot Description: Writes robot structure files with links, joints, limits, inertials, and meshes ready for ROS-based stacks.
- SRDF for MoveIt2: Adds planning groups, end effectors, named poses, and collision rules on top of a URDF for MoveIt2 planning.
- SDF Simulation Worlds: Creates simulator models and worlds with frames, physics, sensors, and lights.
- 2D DXF Drawings: Produces cut-ready DXF profiles, templates, gaskets, and layouts from Python or CAD geometry.
- G-code Slicing: Slices supported mesh files into validated, printer-profiled FDM G-code using real slicer CLIs.
- Bambu Lab Print Jobs: Dry runs, uploads, and cautiously starts local Bambu Lab prints from validated G-code.
- CAD Viewer Previews: Local browser previews for CAD, G-code, URDF, and other robot files for fast agent iteration.
Best for
- Agentic Mechanical Design: Let a coding agent iterate on brackets, flanges, and enclosures directly from natural-language specs.
- Robot Description Authoring: Generate URDF/SRDF/SDF files for new robot arms or mobile bases without hand-writing XML.
- Rapid Prototyping: Take a CAD model to sliced, printer-ready G-code and kick off a Bambu Lab print from within an agent workflow.
- Custom Part Fabrication: Produce DXF/STEP files pre-checked for SendCutSend, then order laser-cut or CNC parts.
- Simulation Setup: Author SDF worlds for physics simulators with the right frames, sensors, and lighting for robotics research.
- Off-the-Shelf Sourcing: Use step.parts to pull ready-made STEP models for common hardware like screws, bearings, and connectors.
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Codex CLI
OpenAI
Codex CLI is OpenAI's lightweight coding agent that runs locally in your terminal to write, edit, and execute code.
Key features
- Local Terminal Agent: Runs on your own machine and edits files, executes shell commands, and iterates on tasks without leaving the terminal.
- ChatGPT Plan Sign-In: Uses your existing ChatGPT Plus/Pro/Business/Edu/Enterprise subscription for auth, so you don't need a separate API key.
- Approval-Gated Execution: Prompts you before running shell commands or file writes, giving you control over what the agent touches.
- Cross-Platform Binaries: Ships prebuilt binaries for macOS (arm64/x86_64), Linux (x86_64/arm64), and Windows via multiple package managers.
- Companion Products: Interoperates with Codex Web (chatgpt.com/codex), the Codex desktop app, and the Codex IDE extensions for VS Code, Cursor, and Windsurf.
- Open Source Under Apache 2.0: Fully open source on GitHub so teams can inspect, fork, and self-host the CLI.
- API Key Fallback: Optional OpenAI API key authentication for users outside a ChatGPT plan or for CI environments.
Best for
- Terminal-native Pair Programming: Delegate refactors, bug fixes, and small features to Codex while staying in your existing shell workflow.
- Test and Fix Loops: Have Codex run your test suite, read failures, and iterate on patches until green.
- Repository Onboarding: Ask Codex to explore an unfamiliar codebase, summarize modules, and answer 'where is X handled' questions.
- Shell and DevOps Automation: Draft and run shell scripts, containers, and CI recipes with an agent that can execute them locally.
- Cross-Surface Continuation: Start a task in Codex Web or the Codex IDE extension and finish it from the terminal on the same ChatGPT account.