Dev & Engineering

step.parts Catalog Skill

Give your agent the ability to search the step.parts hosted catalog and download real off-the-shelf STEP parts — screws, bearings, motors, servos — instead of sketching crude placeholder geometry.

55/ 100
Use with care

Useful, but reliability, evidence or controls still have material gaps.

See how it was scored ↓
Works as-is in
Codex · Claude Code
Stars
★ 19k
Last updated
1d ago
License
MIT
step-filescad-partsmechanical-engineeringparts-catalog
+4rest-apichecksum-verificationfastenersactuators

What does this skill do, and when should you use it?

step-parts is one of 13 skills bundled in the earthtojake/text-to-cad collection. It teaches a coding agent how to find, evaluate, and download purchasable CAD parts through the hosted step.parts API, covering off-the-shelf actuators, servos, motors, electronics boards, connectors, screws, bolts, nuts, washers, and bearings. It ships a deterministic Python downloader with fuzzy search, facet filtering, and SHA-256 checksum verification, and enforces a strict rule that network failures trigger a retry before any part is declared unavailable. When no match exists, the skill records the miss and falls back to a documented envelope rather than pretending the part was found.

  • Interprets a request into search terms and optional facets (category, family, standard, tag) and queries /v1/parts
  • Retries aliases, dropped letters, vendor spellings, and family facets for named actuator models like STS3215 before declaring a miss
  • Downloads the selected part's stepUrl STEP file and verifies it against the record's sha256
  • Runs scripts/download_step_part.py for deterministic search, download, and checksum verification with flags like --download, --tag, --limit, --all
  • Returns the local path, part id, and page/API URLs so provenance is traceable
  • Exposes catalog discovery endpoints (/v1/catalog/parts.index., /v1/catalog/schema, /v1/openapi.) for field semantics and client generation
Good fit
  • A mechanical engineer needs a real M3x12 socket head cap screw in an assembly and asks the agent to search ISO 4762 and download the official STEP file
  • A robotics developer wants a Feetech STS3215 servo in their model and needs the agent to try aliases until it finds the exact part's CAD file
  • A designer looking for catalog parts like a 608ZZ bearing wants facet-filtered candidates compared side by side with provenance links
  • An automated agent workflow needs to batch-fetch a full page of search results as individual STEP downloads, each checksum-verified
Not a fit
  • Users who need a self-hosted or offline parts library — the skill depends on the hosted api.step.parts catalog and cannot work without network access
  • Users who want to generate custom part geometry from scratch — that is the CAD skill's job in this collection; this skill only searches and downloads catalog components

How do you install this skill?

Before you use it
  • Core function depends entirely on the overseas-hosted api.step.parts; mainland-China reachability is undeclared and no mirror is offered, so verify connectivity yourself.
  • Downloads default to the system temp directory; pass --out-dir explicitly for persistence, and manually confirm the selected part before downloading.
  • Static review executed nothing: API behavior, catalog coverage, and the checksum mechanism are unverified by execution.
  • The skill has no independent version number or changelog; updates require tracking the upstream repository.
  • Publisher is not verified by the FollowSkills registry and is treated as unknown.
Before you start
Your agent needs
  • Shell / CLI
  • Network access
  • Local filesystem
Install first
  • Python 3 (for scripts/download_step_part.py)
  • Network access to api.step.parts

This skill ships as part of the earthtojake/text-to-cad collection (13 skills); installing the collection brings it in. The README documents no command for installing this skill alone.

Claude Code

claude plugin marketplace add earthtojake/text-to-cad#latest
claude plugin install text-to-cad@earthtojake

Codex

codex plugin marketplace add earthtojake/text-to-cad --ref latest
codex plugin add text-to-cad@earthtojake

Cursor

git clone --depth 1 --branch latest https://github.com/earthtojake/text-to-cad ~/.cursor/plugins/local/text-to-cad

Grok Build

grok plugin install earthtojake/text-to-cad@latest --trust
grok plugin enable text-to-cad

Gemini

gemini extensions install https://github.com/earthtojake/text-to-cad --ref latest --consent --auto-update

Other agents (Skills CLI)

npx skills add earthtojake/text-to-cad#latest

How do you use this skill?

Try saying

Once installed, send your agent any of these to trigger it:

  • Add an M3x12 socket head cap screw to my assembly — find it on step.parts and download the STEP file into the project directory
  • Search step.parts for the Feetech STS3215 servo and download its STEP file with checksum verification if you find it
  • Find 608ZZ bearings on step.parts and list the top five candidates with standard, name, and key dimensions
  • Download the STEP file for every nut on the current results page, without overwriting any existing files

The skill is triggered by the model from the SKILL.md description: when an assembly includes a named off-the-shelf part, the agent should search step.parts before creating placeholder geometry. The flow is: parse search terms → call /v1/parts and inspect items/total/facets → present candidates when ambiguous → download stepUrl and verify sha256 → return the local path plus provenance URLs. You can also drive the bundled downloader directly:

python scripts/download_step_part.py "M3 socket head 12" --download
python scripts/download_step_part.py --id iso4762_socket_head_cap_screw_m3x12 --download
python scripts/download_step_part.py "bearing 608zz" --limit 5

Useful options: --origin to override the API origin, repeatable --tag/--category/--family/--standard facet filters, --out-dir for a persistent destination (defaults to the system temp directory), --filename to rename (incompatible with --all), --limit/--page for pagination (default 10, API cap 500), --all to download every result on a page, and --overwrite to replace existing files. The script prints JSON to stdout; failures print one line to stderr and exit 1. Endpoint details live in references/step-parts-api.md.

What are this skill's strengths and limitations?

Pros
  • Targets real purchasable parts and delivers usable STEP files instead of simplified stand-in geometry
  • Built-in sha256 verification and a deterministic downloader make results reproducible and provenance traceable
  • Thoughtful handling of fuzzy model names: aliases, vendor spellings, and family facets all have explicit retry strategies
  • Clear discipline around network failures: one retry before a miss is reported, so parts are never falsely declared unavailable
Limitations
  • Entirely dependent on api.step.parts availability — there is no offline or local catalog fallback
  • The README does not verify this individual skill on every host beyond the plugin install paths; plugin telemetry is on by default (disable with uvx cadgen telemetry off)
  • STEP downloads rely on a Python script; without the plugin you must install uv and use the Skills CLI yourself

How does this skill compare with similar options?

Side by side with related skills; every score comes from the same FSRS standard.

Skill FS score Stars Last updated License
step.parts Catalog Skill this page 55 · Use with care ★ 19k 1d ago MIT
FreeHire Tech Job Search Skill 63 · Recommended ★ 45k 3d ago MIT
AMC Sample Dataset Calibration ✓ NVIDIA · Official 55 · Use with care ★ 3.5k 3d ago Apache-2.0
AutoMagicCalib Video Calibration ✓ NVIDIA · Official 53 · Use with care ★ 3.5k 3d ago Apache-2.0
Xberg API Server & MCP Protocol Integration 52 · Use with care ★ 9.4k 3d ago MIT

The sibling CAD skill in the same repository generates and edits 3D models from natural language or images (exporting STEP/STL/3MF/GLB); this skill is complementary — the CAD skill makes geometry, while this skill retrieves real off-the-shelf parts before geometry is built, so standard components don't get remodeled by hand.

How did FollowSkills review this skill?

FollowSkills review · FSRS-2.0
Use with care
55/ 100 5-point scale 2.8 / 5
1Trust17 / 25 · 3.4/5

Script hits only the user/default API origin, verifies sha256, refuses silent overwrite, treats catalog records as data not instructions, and outputs transparent provenance (stdout JSON with source URLs). Deductions: downloads default to a system temp dir without explicit confirmation, stepUrl may resolve to external GitHub LFS/Vercel Blob with checksums only as self-consistent as the record itself, publisher identity unverified, and rollback/isolation guidance is thin.

2Reliability9 / 20 · 2.3/5

SKILL.md, API reference and script are mutually consistent; argument validation, one-line stderr failures with exit 1, adjustable timeout, and a clear alias-retry policy. Deductions: static review cannot reproduce key paths; no committed tests covering this skill path were shown; edge semantics (pagination, --all/--filename conflicts) rest on inference despite documented network-failure semantics.

3Adaptability9 / 15 · 3.0/5

Scenario (finding purchasable standard parts by name/standard and downloading STEP) is clear; trigger description is specific (aliases, standard numbers, facets) and fallback to placeholder geometry is defined. Deductions: core function depends entirely on the overseas-hosted api.step.parts with no declared mainland-China reachability or mirror; non-fit boundaries (private/custom parts) only implied.

4Convention10 / 15 · 3.3/5

Well-layered docs (SKILL.md → references/api.md → script), MIT license, provenance statement, and install caveats (default temp out-dir). Deductions: no skill-level version/changelog, maintenance responsibility rests on an individual repo, no FAQ or known-limitations list.

5Effectiveness6 / 15 · 2.0/5

Clear value claim (avoid placeholder geometry, canonical checksummed STEP files) with marginal value over manual search and directly usable output. Deductions: static review cannot verify actual output or API behavior; benefit depends on third-party catalog coverage; no representative output evidence.

6Verifiability4 / 10 · 2.0/5

Auditable primary material exists (script, API reference, OpenAPI pointer, checksum mechanism) with facts mostly separated from inference. Deductions: below the static ceiling, no third-party execution evidence or committed tests for the skill's key paths; corroboration is thin.

1 2 3 4 5 6

Open a dimension to read why it scored that way

Reviewed Oct 10, 2026 Reviewed revision b48ff49e0096 Review evidence[1][2][3][4][5][6][7][8][9][10][11][12][13]

Evidence confidence:Low — Mostly static review, author material or a limited demo; useful for discovery, not high-risk decisions.

See the full review method →

FAQ

Does this skill cost anything?
The skill itself is MIT-licensed open source. The source material does not state the pricing or rate-limit policy of the step.parts API — check the service's terms before adopting it in production.
What happens if api.step.parts is unreachable?
The skill requires one retry (requesting network permission if needed) before concluding anything; only if the API was reachable and returned no candidates does the agent record a miss and fall back to a documented envelope — never treating a network failure as evidence a part doesn't exist.
Where do downloaded files go?
The script defaults to the system temp directory; pass --out-dir whenever the file must survive in your project, and use --overwrite to replace an existing destination (otherwise it is refused).
Can I use it alongside other text-to-cad skills?
Yes — they belong to the same collection and are complementary. Just don't install both the plugin and the standalone skills in one agent app, or every skill will exist twice.

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