/step-parts

name: step-parts
description: Find, evaluate, and download low-level common standard CAD parts from step.parts, such as screws, bolts, nuts, washers, bearings, standoffs, electronics parts, motors, connectors, and other off-the-shelf components. Use when Codex needs to search the hosted step.parts catalog, resolve fuzzy part names, standards, aliases, or dimensions, choose a matching part, fetch a canonical .step file, verify checksums, or use the step.parts API/OpenAPI/catalog endpoints for standard part discovery.

CAD Parts

Overview

Use the hosted step.parts machine endpoints instead of scraping HTML or relying on local repository files. Treat `https://api.step.parts` as the canonical API origin and `https://www.step.parts` as the site/static-asset origin unless the user provides a different hosted mirror. If the domain does not resolve or the API is unavailable, report that the hosted service is not reachable yet instead of falling back to repo-specific assumptions.

Quick Workflow

1. Interpret the requested part into search terms and optional facets:

• `q` for fuzzy tokens, standards, aliases, dimensions, source/product URLs, and attribute names/values.
• `category`, `family`, `standard`, or `tag` when the user gives an exact facet.

2. Search `/v1/parts` and inspect `items`, `total`, and `facets`. 3. If results are ambiguous, present the best few options with `id`, `name`, `standard`, and key attributes before choosing. If one result clearly matches, return the selected record details without downloading unless the user asked for a local STEP file. 4. When the user asks to download or save a STEP file, download its `stepUrl`, then verify the file with the record's `sha256` when present. 5. Return the local path when downloaded, plus the selected part id and page/API URLs so the user can trace provenance.

Bundled Downloader

Use `scripts/download_step_part.py` for deterministic search, download, and checksum verification:

python skills/step-parts/scripts/download_step_part.py "M3 socket head 12" --download --out-dir /tmp/step-parts
python skills/step-parts/scripts/download_step_part.py --id iso4762_socket_head_cap_screw_m3x12 --download --out-dir /tmp/step-parts
python skills/step-parts/scripts/download_step_part.py "bearing 608zz" --limit 5

Useful options:

• `--origin`: override `https://api.step.parts` only when the user provides another hosted API origin.
• `--tag`, `--category`, `--family`, `--standard`: repeatable facet filters.
• `--out-dir`: directory for downloaded STEP files. Defaults to `/tmp/step-parts`.
• `--all`: with `--download`, download every result on the returned page as individual STEP downloads.
• `--overwrite`: replace an existing output file.

The script prints JSON to stdout. For searches, it prints matched records. For downloads, it prints saved file paths, checksums, and source URLs.

API Reference

Read `references/step-parts-api.md` when you need endpoint details, field meanings, or query semantics. Prefer:

• `/v1/parts` for filtered search with absolute asset URLs.
• `/v1/parts/{id}` for one enriched record.
• Returned `stepUrl` for STEP downloads.
• `/v1/catalog/parts.index.json` for a compact discovery index.
• `/v1/catalog/schema` for field and family attribute meanings.
• `/v1/openapi.json` when generating a client or tool.

Search Guidance

• Query tokens are ANDed by the API, so start specific but not overconstrained. For example, use `M3 SHCS 12` before adding exact family and standard filters.
• Values within one facet are ORed together, and selected `tag`, `category`, `family`, and `standard` fields are ANDed together. Use exact facets to narrow within known categories, then rank manually by name and attributes.
• Standards can be queried as `ISO 4762`, `ISO4762`, or the exact `standard.designation`.
• The `attributes` object contains family-specific facts such as `thread`, `lengthMm`, `bore1Mm`, `material`, `profileSeries`, `slotSizeMm`, and dimensions in millimeters.
• Part, GLB, and PNG URL patterns are predictable on `https://www.step.parts`; STEP URLs are environment-aware and may resolve to GitHub LFS media in production. Use catalog/API `stepUrl` for downloads.