Agent skill

Schemelike Metacircular Eval

by lazyFrogLOL in lazyFrogLOL/Harness_Engineering

Guide for implementing metacircular evaluators—interpreters that can interpret themselves.

No licenceAuto-check passedDevelopment

Install Schemelike Metacircular Eval

skills CLI
$ npx skills add lazyFrogLOL/Harness_Engineering --skill schemelike-metacircular-eval -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install lazyFrogLOL/Harness_Engineering schemelike-metacircular-eval --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/lazyFrogLOL/Harness_Engineering.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/schemelike-metacircular-eval .claude/skills/schemelike-metacircular-eval && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
schemelike-metacircular-eval
GitHub stars
128
Token cost
~2.6k tokens
SKILL.md length
970 words
Files
1
Skills in repo
32
Repo updated
First seen
Licence
None found

At a glance

Guide for implementing metacircular evaluators—interpreters that can interpret themselves.

  • Works in 2 steps: Minimal Self-Interpreting Core → Adding Features Safely
  • Tasks that involve Debugging
  • SKILL.md covers Overview, Critical Success Factors, Implementation Strategy and Environment Implementation, plus 6 more sections
  • Calls python3

What it does

Schemelike Metacircular Eval is an agent skill from lazyFrogLOL/Harness_Engineering. Guide for implementing metacircular evaluators—interpreters that can interpret themselves. This skill should be used when building self-interpreting Scheme-like evaluators, debugging multi-level interpretation issues, or implementing language features like environments, closures, and special forms. Focuses on incremental development, continuous metacircular testing, and systematic debugging of nested interpretation failures.

Its SKILL.md is about 2.6k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development, covering Debugging.

When your agent uses it

  • Tasks that involve Debugging

Example prompts

  • “/schemelike-metacircular-eval”

Requirements

  • Python 3

Workflow steps

2 steps, taken from the step headings in SKILL.md.

  1. Minimal Self-Interpreting Core
  2. Adding Features Safely

What it can do on your machine

Read from SKILL.md and the folder at commit cae3b25. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • python3

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Schemelike Metacircular Eval loads about 2.6k tokens when it runs. Until then it costs about 114 tokens; SKILL.md has 970 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~114
When it runs · the whole SKILL.md, loaded when a task matches
~2.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Without a licence we can't republish the file, so here is its outline and opening line. It has 970 words (~2,576 tokens).

“This skill provides systematic guidance for implementing metacircular evaluators—interpreters written in the language they interpret. The critical challenge is not just building a working interpreter, but building one that can interpret itself (the metacircular property).”

— opening of SKILL.md by lazyFrogLOL
name
schemelike-metacircular-eval

Read the full SKILL.md on GitHub

Files

Just SKILL.md in skills/schemelike-metacircular-eval of lazyFrogLOL/Harness_Engineering.

Open the folder on GitHubat commit cae3b25

Compare with similar skills

Schemelike Metacircular Eval next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Schemelike Metacircular Eval compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Schemelike Metacircular Eval this skilllazyFrogLOL/Harness_Engineering128—~2.6kAutomated safety check: PassNone
Trellis Session Insightmindfold-ai/Trellis15k4 repos~1.7kAutomated safety check: PassAGPL-3.0
Native Data FetchingCherryHQ/cherry-studio-app4k6 repos~2.9kAutomated safety check: NotesMIT
Debugging Executionsn8n-io/n8n207k—~2.6kAutomated safety check: PassCustom licence
Aoti Debugpytorch/pytorch104k1 repos~1.7kAutomated safety check: PassCustom licence
Herdr Throwaway Reproductionherdrdev/herdr43k—~2.4kAutomated safety check: PassApache-2.0

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Categories

Questions about Schemelike Metacircular Eval

What does Schemelike Metacircular Eval do?

Guide for implementing metacircular evaluators—interpreters that can interpret themselves. Schemelike Metacircular Eval is an agent skill from lazyFrogLOL/Harness_Engineering. Guide for implementing metacircular evaluators—interpreters that can interpret themselves.

When should I use Schemelike Metacircular Eval?

Schemelike Metacircular Eval fits situations like: tasks that involve Debugging.

How do I install Schemelike Metacircular Eval in Claude Code?

Run `npx skills add lazyFrogLOL/Harness_Engineering --skill schemelike-metacircular-eval -a claude-code`. Or copy the skill folder (skills/schemelike-metacircular-eval in lazyFrogLOL/Harness_Engineering) into .claude/skills/schemelike-metacircular-eval in your project. Claude Code loads it when a task matches its description.

How do I install Schemelike Metacircular Eval in Codex?

Run `npx skills add lazyFrogLOL/Harness_Engineering --skill schemelike-metacircular-eval -a codex`. Or copy the skill folder (skills/schemelike-metacircular-eval in lazyFrogLOL/Harness_Engineering) into .agents/skills/schemelike-metacircular-eval in your project. Codex loads it when a task matches its description.

Can I use Schemelike Metacircular Eval in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add lazyFrogLOL/Harness_Engineering --skill schemelike-metacircular-eval -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/schemelike-metacircular-eval, .gemini/skills/schemelike-metacircular-eval, .github/skills/schemelike-metacircular-eval and .opencode/skills/schemelike-metacircular-eval in your project.

What does Schemelike Metacircular Eval need to run?

Going by SKILL.md and its folder, Schemelike Metacircular Eval needs the command-line tools its instructions call (python3). Our summary lists: Python 3.

Does Schemelike Metacircular Eval access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Schemelike Metacircular Eval safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Schemelike Metacircular Eval use?

No licence was found for Schemelike Metacircular Eval or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.

How many tokens does Schemelike Metacircular Eval use?

About 2.6k tokens (SKILL.md is roughly 10k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Schemelike Metacircular Eval?

Skills that share tags, products or a category with Schemelike Metacircular Eval: Trellis Session Insight (mindfold-ai/Trellis, 15k stars), Native Data Fetching (CherryHQ/cherry-studio-app, 4k stars), Debugging Executions (n8n-io/n8n, 207k stars) and Aoti Debug (pytorch/pytorch, 104k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Schemelike Metacircular Eval?

lazyFrogLOL (a GitHub user) maintains it in lazyFrogLOL/Harness_Engineering, which has 128 GitHub stars. The repository holds 32 skills in this directory. The repository was last updated on May 18, 2026.

Source: lazyFrogLOL/Harness_Engineering on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.