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.
npx skills add earthtojake/step.parts --skill step-partsgit clone --depth 1 https://github.com/earthtojake/step.partsWrote 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.
[](https://agentmods.dev/skills/earthtojake/step.parts/step-parts)<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.
<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>- NVIDIA SkillSpector pass
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 | $0.00053 | $0.00487 |
| Sonnet 5 | $0.00021 | $0.00195 |
| Haiku 4.5 | $0.00011 | $0.00097 |
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 12d ago.
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.
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:
qfor fuzzy tokens, standards, aliases, dimensions, source/product URLs, and attribute names/values.category,family,standard, ortagwhen the user gives an exact facet.
- Search
/v1/partsand inspectitems,total, andfacets. - 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'ssha256when 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: overridehttps://api.step.partsonly 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.
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.
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.
- 12d ago First seen · 60 lines · 107 tokens per session scan A fd4e09751496
step-parts is a skill published in the GitHub repository earthtojake/step.parts (352 stars, last pushed 3mo ago), licensed MIT. It adds 107 tokens to every session and 973 once invoked, about $0.0005 per session on Opus 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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