Modeling with coding agents

Smith's inspection tools work in an Elixir process. A coding harness needs shell access to the native toolkit and a way to read files or stdout; Livebook and vision are optional. Start with the inspection guide.

Modeling workflow

1. Read the project's coordinate convention, units, design requirements, and existing source. Preserve user edits and identify unresolved drawing data.
2. Build named immutable stages. Evaluate an expensive stage once, then branch with Smith.from_result/1. Keep its source recipe as the editable design.
3. Query geometry with Smith.Inspection.topology/3 and measure it with Smith.Measure. Refine selectors until they identify the intended feature.
4. Run explicit requirements with Smith.Inspection.run/2. Inspect the report status and each failed check. A successful function call is not a passed check.
5. Write a revision-linked report with Smith.Inspection.write/3. Read the JSON; inspect its PNGs when vision is available. Use sections and stage differences to investigate a failure, then rerun the same requirements after the edit.
6. Export printable geometry with Smith.export/3, which runs mesh and STEP readback checks. A valid CAD solid alone does not establish printability.

Measurements and checks

Without vision, use reports and numerical invariants. Do not claim visual inspection or physical print validation. A dimension copied from an input parameter is a design intention, not a measurement of the result. Equal volumes also do not prove equal shapes. For important revisions, compare the actual added and removed material.

Errors and limitations

Geometry operations return tagged errors. A selector matching multiple features must be refined; do not silently choose its first result. Topology indices belong to one geometry revision and are not semantic names. Explicitly named inspection sources are stable application labels for snapshots, not a face-tracking system.

Use tolerances in the reported units. Containment may report mm³, mm², or mm; clearance is mm with a separate interference tolerance in mm³. The toolkit's numerical tolerance does not replace manufacturing allowances or missing source dimensions. Document an assumption before using it as a target.

Smith.Inspection currently handles material bounds, topology counts, containment, clearance, and measured-value checks. It does not certify production fit or infer all design requirements. Headless images render opaque meshes with flat shading. Drawing dimensions are SVG annotations, not driving constraints or automatic drafting.

Skills and documentation discovery

The package includes skills/smith-cad/SKILL.md. Copy that directory into your harness's skill discovery directory if it supports the SKILL.md convention. For example, a user who uses ~/.agents/skills can copy deps/smith/skills/smith-cad there. Installation is optional; the same workflow is available in this guide and the public Elixir API.

ExDoc generates llms.txt and Markdown pages from the maintained docs and functions. Start at https://hexdocs.pm/smith/llms.txt, then load the relevant module or guide rather than the entire manual. The repository's llms.txt also links to the agent guide, inspection reference, and package skill. These files provide guidance; harnesses decide whether to discover and load them.