A tool for finding standard, ready-made mechanical and electronic parts in the step.parts catalogue and downloading their STEP files, which are 3D CAD models.

Use it to search for items such as screws, bearings, motors, connectors, and standoffs, compare matching records, and save requested STEP models.

It helps locate the correct off-the-shelf part without relying on uncertain names or manually browsing the catalogue.

step-parts — Skill for Codex by earthtojake/step.parts

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add earthtojake/step.parts --skill step-parts

Clone the repo

git clone --depth 1 https://github.com/earthtojake/step.parts

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/earthtojake/step.parts/step-parts/github.svg)](https://agentmods.dev/skills/earthtojake/step.parts/step-parts)

Your own site

<a href="https://agentmods.dev/skills/earthtojake/step.parts/step-parts"><img src="https://agentmods.dev/badge/skills/earthtojake/step.parts/step-parts/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/earthtojake/step.parts/step-parts"><img src="https://agentmods.dev/badge/skills/earthtojake/step.parts/step-parts.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 107 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 973 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00107	$0.00973
Opus 5.5	$0.00043	$0.00389
Sonnet 5.5	$0.00021	$0.00195
Haiku 4.5	$0.00011	$0.00097

Measured 1mo ago against content hash fd4e09751496, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

step-parts scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/download_step_part.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/step-parts/SKILL.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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

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.
Search /v1/parts and inspect items, total, and facets.
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.
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.
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.

Read the full file on GitHub · 60 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago First seen · 60 lines · 107 tokens per session scan A fd4e09751496

Subscribe to this mod's changes

step-parts is a skill published in the GitHub repository earthtojake/step.parts (390 stars, last pushed 4mo ago), licensed MIT. It adds 107 tokens to every session and 973 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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