haabe/mycelium · plugins/mycelium/skills/prompt-optimizer/SKILL.md

prompt-optimizer skillA

prompt-optimizer is agent-read markdown (skill) from haabe/mycelium: A/B test CLAUDE.md instruction changes against eval benchmarks. Capture baselines, test variants, compare results..

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add haabe/mycelium/prompt-optimizer@git:20260704.7639f18
Exact content
mdr add haabe/mycelium/prompt-optimizer@sha256:b253c400e961eaf8

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_koih44n6vip6jczv.svg)](https://markdownregistry.com/a/art_koih44n6vip6jczv)

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Versions

versioncommittedcommitsizeaudit
git:20260704.7639f18 latest2026-07-04 7639f18 2,186 BA view · diff
git:20260525.9fac9422026-05-25 9fac942 2,186 BA view · diff
git:20260522.1825b222026-05-22 1825b22 1,876 BA view · diff
git:20260509.0d172102026-05-09 0d17210 1,862 BA view · diff
git:20260509.46569102026-05-09 4656910 1,826 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (2186 bytes)
  • pass: No zero-width or bidi control characters
  • pass: No instruction hidden inside an HTML comment
  • pass: No link to an exfiltration or paste host
  • pass: No credential-shaped string
  • pass: No instruction to send local credentials anywhere
  • pass: No text hidden with inline styles
  • pass: No prompt-injection phrasing
  • pass: No curl or wget piped into a shell
  • pass: No recursive delete of root, home or parent
  • pass: No instruction to read or print local credentials
  • pass: No base64 blob over 200 characters
  • pass: No link to a raw IP address
  • pass: No script tag

Source

GitHub

haabe/mycelium · 46 stars · license MIT · pushed 2026-09-18 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_koih44n6vip6jczv
GET https://markdownregistry.com/api/v1/resolve?ref=haabe/mycelium/prompt-optimizer
GET https://markdownregistry.com/api/v1/blob/b253c400e961eaf89aca958ee22c389a0de78a74c16703516f6c7f68da7dc8c4

Agents talk at modelranch.com: hand yours the instructions there and it joins the network that reads files like this one.