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 formulahendry/agent-skill-code-runner --skill code-runnergit clone --depth 1 https://github.com/formulahendry/agent-skill-code-runnerWrote 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/formulahendry/agent-skill-code-runner/code-runner)<a href="https://agentmods.dev/skills/formulahendry/agent-skill-code-runner/code-runner"><img src="https://agentmods.dev/badge/skills/formulahendry/agent-skill-code-runner/code-runner/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/formulahendry/agent-skill-code-runner/code-runner"><img src="https://agentmods.dev/badge/skills/formulahendry/agent-skill-code-runner/code-runner.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00069 | $0.01521 |
| Opus 5.5 | $0.00028 | $0.00608 |
| Sonnet 5.5 | $0.00014 | $0.00304 |
| Haiku 4.5 | $0.00007 | $0.00152 |
Grade A, and why
code-runner 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.
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 — 190 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Code Runner Skill
This skill enables you to run code snippets in multiple programming languages directly from the command line.
When to Use This Skill
Use this skill when:
- The user wants to run or execute a code snippet
- Testing algorithm implementations or logic
- Verifying expected output of code
- Running quick scripts or one-liners
- Checking syntax or runtime behavior
- Demonstrating code functionality
Supported Languages
The following languages are supported (requires the interpreter/compiler to be installed):
| Language | Command | File Extension |
|---|---|---|
| JavaScript | node |
.js |
| TypeScript | ts-node |
.ts |
| Python | python |
.py |
| Java | java (compile & run) |
.java |
| C | gcc (compile & run) |
.c |
| C++ | g++ (compile & run) |
.cpp |
| Go | go run |
.go |
| Rust | rustc (compile & run) |
.rs |
| Ruby | ruby |
.rb |
| PHP | php |
.php |
| Perl | perl |
.pl |
| Lua | lua |
.lua |
| R | Rscript |
.r |
| Swift | swift |
.swift |
| Kotlin | kotlin |
.kts |
| Scala | scala |
.scala |
| Groovy | groovy |
.groovy |
| Dart | dart |
.dart |
| Julia | julia |
.jl |
| Haskell | runhaskell |
.hs |
| Clojure | clojure |
.clj |
| F# | dotnet fsi |
.fsx |
| C# | dotnet script |
.csx |
| PowerShell | pwsh |
.ps1 |
| Bash | bash |
.sh |
| Batch | cmd /c |
.bat |
| CoffeeScript | coffee |
.coffee |
| Crystal | crystal |
.cr |
| Elixir | elixir |
.exs |
| Nim | nim compile --run |
.nim |
| OCaml | ocaml |
.ml |
| Racket | racket |
.rkt |
| Scheme | scheme |
.scm |
| Lisp | sbcl --script |
.lisp |
See references/LANGUAGES.md for detailed language configuration.
How to Run Code
Step 1: Identify the Language
Determine the programming language from:
- User's explicit request (e.g., "run this Python code")
- File extension if provided
- Code syntax patterns
What ships with it
2 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.
- 1mo ago First seen · 190 lines · 69 tokens per session scan A d5394be8ed89
code-runner is a skill published in the GitHub repository formulahendry/agent-skill-code-runner (16 stars, last pushed 9mo ago), licensed MIT. It adds 69 tokens to every session and 1,521 once invoked, about $0.0003 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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