kernelcad-trace-from-image

kernelcad-trace-from-image is a skill for Claude Code, Codex from w1ne/kernelCAD-web. It costs 96 tokens per session (2,282 once invoked), scanned A, original, MIT.

A coordinate-extraction tool for turning features in a reference photo into points that describe curves in a 3D model. It returns normalized image positions and confidence values, which can then be converted to millimetres using a known scale.

In plain words
What is it for?
Use it to trace organic outlines such as eyewear brows, ergonomic handles, or sneaker shapes from photos. It requires an existing blockout, a reference image, and at least one known measurement.
Why use it?
It removes the need to estimate many curve points by eye. The points are a starting point, so the model still needs to be checked against a rendered result.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/w1ne/kernelcad-web/kernelcad-trace-from-image
Any agent
npx skills add w1ne/kernelCAD-web --skill kernelcad-trace-from-image
Clone the repo
git clone --depth 1 https://github.com/w1ne/kernelCAD-web

Made for: Claude Code, 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.

agentmods badge for kernelcad-trace-from-image

README.md
[![agentmods](https://agentmods.dev/badge/skills/w1ne/kernelcad-web/kernelcad-trace-from-image.svg)](https://agentmods.dev/skills/w1ne/kernelcad-web/kernelcad-trace-from-image)
Your own site
<a href="https://agentmods.dev/skills/w1ne/kernelcad-web/kernelcad-trace-from-image"><img src="https://agentmods.dev/badge/skills/w1ne/kernelcad-web/kernelcad-trace-from-image.svg" alt="Measured on agentmods" height="20"></a>
Per session 96 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,282 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00096 $0.02282
Opus 5 $0.00048 $0.01141
Sonnet 5 $0.00019 $0.00456
Haiku 4.5 $0.00010 $0.00228

Measured 4d ago against content hash 8d7b9654711a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

kernelcad-trace-from-image 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 4d 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.

src/agent/skills/kernelcad-from-reference/kernelcad-trace-from-image/SKILL.md · 209 lines

How it starts

The opening of the file, as written. The whole thing — 209 lines — stays where its author put it; the contents beside it link to each section on GitHub.

kernelcad-trace-from-image

Purpose

This is a coord-extractor, not a vision agent. It takes a reference photo plus a list of requested features and returns normalized [0,1] waypoints the agent can convert to mm via a known scale anchor and feed to a path().spline() / path().nurbsSegment() chain.

Accuracy honesty. opencv's contour is geometrically exact on a uniform-bg photo. Claude vision is typically 5–10% off on dense landmarks. Every returned feature carries a per-feature confidence in [0, 1]. Treat the output as better starting-point waypoints, not pixel-perfect coords — the model will still need at least one render→inspect pass before finalizing.

Output replaces the burden of eyeballing dozens of (x, y) pairs off a photo; it does not replace the spec-writer.

Inputs

  • .kcad.ts blockout already in place (from blockout-model/SKILL.md).
  • Reference photo on disk (./reference.jpg typically).
  • A scale anchor from the Real Object Brief — at least one numeric length (mm) over a known fraction of the image width or height. Without a scale anchor the normalized output cannot be lifted to mm.

When to load this skill

Load if all three are true:

  1. The reference image shows an organic curve — brow, knurl, ergonomic contour, sneaker midsole, eyewear front silhouette.
  2. The next authoring step is a path().spline(), path().nurbsSegment(), path().hermiteG2(), or a nurbsCurve(...) ref.
  3. Eyeballing the waypoints would take more than ~60 seconds or the result would be unverifiable (i.e. you could not tell from looking at your own notes whether (12.3, 4.1) was right).

Do not load this skill for:

  • Box / cylinder / rounded-rect blockouts — every primary dimension already lives in a param().
  • References where the brief already enumerates the waypoints.
  • CAD screenshots (vector geometry already, not a photo).

The trace pipeline (4 steps)

Step 1 — Decide features

Pick the smallest set of features that captures the outline you want.

Read the full file on GitHub · 209 lines

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.

  1. 4d ago First seen · 209 lines · 96 tokens per session scan A 8d7b9654711a

Subscribe to this mod's changes

kernelcad-trace-from-image is a skill published in the GitHub repository w1ne/kernelCAD-web (17 stars, last pushed 6d ago), licensed MIT. It adds 96 tokens to every session and 2,282 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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