SolidCraft is a Rust application for parametric CAD: draw a sketch, constrain its dimensions, turn it into a solid, then change a parameter and rebuild the recorded modelling steps. For developers experimenting with agent-assisted hardware design, its useful distinction is an editable design history—not just an AI-generated picture or mesh.

  • Access: Download Windows, macOS or Linux builds, or try the browser app. The project is open source under a choice of MIT or Apache-2.0 licences; there is no software subscription required. Any paid model you connect brings its own costs. Desktop builds are not yet signed.
  • Agent interface: Install the CLI and expose solidcraft-cli mcp to an MCP client—the standard interface agents use to call tools. For Claude Code, the documented registration is claude mcp add solidcraft -- solidcraft-cli mcp. It can work headless or connect to a running desktop app on the same machine.
  • Useful tools: Agents can create sketches and solid features, change parameters, inspect the design, measure volume and dimensions, obtain screenshots, and export STEP, STL or 3MF files. Command batches roll back on failure by default. Export is not the same thing as slicing a model or controlling a printer.
  • New in 0.8, released October 13: User-defined physical materials, linked components from other designs, named-view control and more reliable face attachments and rounded edges. Compact MCP replies reduce repeated result data; feature replies also expose warnings. Saved designs move to format 16, which older releases cannot open—keep an older-format copy if needed.

Treat this as an experimental modelling tool, not a verified production-CAD replacement. The release notes list unsupported face attachments and hole operations, refused joins, and a cylinder-cut case that can lose some volume. The project’s geometry checks do not establish complete workflow or geometric equivalence. Inspect generated parts and dimensions before fabrication; a successful agent call is not proof that the part is correct or buildable.

The HN discussion adds three practical adoption tests beyond whether an agent can produce a solid:

  • Editability: mijoharas, describing experiments with FreeCAD MCP and agent-generated OpenSCAD rather than SolidCraft, writes: “without being able to edit things generated by the AI myself I wouldn’t want to try it again.” They found the workflows slower than modelling manually, while noting that they were trying something new.
  • Assembly, not just geometry: InsidiousWombat reports using generated FreeCAD Python plus a separate checking program for a workbench they actually built. Their warning is concrete: “it just wasn’t designed to be put together easily”. Passing positional checks did not make the design convenient to fabricate and assemble.
  • Review of the hard maths: phkahler describes Claude-generated fixes to SolveSpace’s NURBS boolean operations: “most of the fixes were accepted after a lot of review by multiple experts on the code.” That is an account of reviewed work on another project, not evidence that SolidCraft’s geometry is reliable. In a follow-up, they report remaining failures where rounded edges intersect.

The unresolved question is whether SolidCraft can deliver editable, buildable parts reliably across those edge cases. These anecdotes do not answer it. This summary is based on the official release and MCP documentation, not hands-on testing.

Handles are pseudonymous; HN exposes no per-comment scores. These comments are arranged for usefulness, not votes, and are a slice of the discussion rather than consensus.