Clojure Skills for Claude Code

A collection of Claude Code skills for robust Clojure, Babashka, and EDN development.

Available Skills

clojure-discovery

Automatically explore and gather context when writing Clojure code that uses unfamiliar APIs. This skill:

• Looks up documentation and source for Clojure functions and macros via brepl
• Searches for Clojure wrapper libraries before falling back to Java classes
• Prevents bugs by gathering sufficient API context before implementation

Use /clojure-discovery when encountering unfamiliar Clojure functions, macros, Java classes, or any API you're not completely confident about.

clojure-repl-debugging

Debug Clojure code without modifying source files. This skill:

• Uses the REPL for inline inspection of values
• Traces execution and tests hypotheses without adding logging
• Integrates with brepl for efficient debugging

Use /clojure-repl-debugging when encountering bugs, test failures, or unexpected behavior. Load this before adding log statements or modifying code for debugging purposes.

refactor-pm

Identify and improve code design by separating mechanism from policy. This skill:

• Scans files for opportunities to separate concerns
• Suggests refactoring patterns that improve maintainability

Use /refactor-pm to review code for design improvements.

clojure-fast-read

Choose the right strategy for reading Clojure code efficiently. This skill:

• Decides when to use runtime inspection (REPL) vs file reading based on intent
• Uses source-fn, doc, and meta for fast, targeted exploration
• Leverages meta to bridge runtime state and source file locations
• Recommends grep and sed for targeted code extraction without reading full files
• Distinguishes between understanding runtime behavior vs source design

Use /clojure-fast-read whenever you need to inspect Clojure code — whether modifying a function, debugging a production issue, exploring a new codebase, or understanding dependencies. This skill ensures you read efficiently instead of opening entire files.

clj-skill-create-eval

Evaluate Clojure skills through rigorous real-project testing. This skill:

• Creates isolated test projects using Clojure Stack Lite (with/without skills)
• Designs realistic development tasks that showcase skill value
• Executes parallel subagent runs to ensure comparable conditions
• Compares behavioral differences: code quality, exploration patterns, debugging approach
• Analyzes context-logs to identify actual behavior changes vs hypothetical improvements
• Provides structured evaluation reports with quantitative and qualitative metrics

Use /clj-skill-create-eval when you've created or modified a Clojure skill and want to validate its effectiveness through real-world testing. This prevents vague evaluations and ensures skills actually improve development outcomes.

Installation

Install via npx:

npx skills install humorless/clojure-dev

This installs all five skills: clojure-discovery, clojure-repl-debugging, clojure-fast-read, refactor-pm, and clj-skill-create-eval.

Dependencies

• brepl — nREPL client for REPL-based inspection and evaluation

Install and ensure it's on your PATH.

Setup

Start your nREPL server before the session:

# Clojure (deps.edn)
clj -M:nrepl

# Babashka
bb nrepl-server 1667

Claude will detect .nrepl-port automatically.

Credits

• brepl by @licht1stein — https://github.com/licht1stein/brepl
• Improve your code by separating mechanism from policy by Arne Brasseur - https://lambdaisland.com/blog/2022-03-10-mechanism-vs-policy
• "One Year of LLM Usage with Clojure" by Ivan Willig — https://www.iwillig.me/blog/one-year-of-llm-usage-with-clojure/#skills-prompts-and-opencode