# Common Lisp REPL

> Use this tool when you need to execute Common Lisp code safely and securely, with applications in mathematical calculations, data processing, and symbolic computation tasks. It provides a REPL evaluation interface that takes Lisp code as input and returns the result as printed text, with support for stdio and TCP transport modes. Ideal for AI assistants requiring expressive and secure computation, it disables read-time evaluation to prevent security issues and features structured JSON logging for transparency.

Canonical page: https://skillsregistry.net/skills/cxxxr-common-lisp-repl  
JSON: https://api.skillsregistry.net/v1/skills/cxxxr-common-lisp-repl

## Description

This Common Lisp MCP server by cxxxr provides a REPL evaluation tool that allows AI assistants to execute Lisp code safely with read-time evaluation disabled to prevent security issues from constructs like #.(). Built using ASDF with dependencies on Alexandria, Yason, usocket, and bordeaux-threads, it supports both stdio and TCP transport modes with structured JSON logging and comprehensive test coverage using the Rove framework. The implementation features a single repl-eval tool that evaluates Common Lisp forms sequentially and returns the last value as printed text, making it valuable for AI assistants that need to perform mathematical calculations, data processing, or symbolic computation tasks using the expressive power of Lisp while maintaining security through disabled reader macros.

## Trust

- **Trust score (0–1):** 0.97
- **Verification tier:** verified
- **Last scanned:** 2026-09-19

## Facts

- **Version:** 1.0.0
- **Skill type:** atomic
- **Execution layer:** mcp-remote
- **Runtime environment:** api
- **Category:** monitoring
- **Updated:** 2026-09-19

## Source

- **Source listing:** [PulseMCP](https://www.pulsemcp.com/servers/cxxxr-common-lisp-repl)
- **Repository:** <https://github.com/cl-ai-project/cl-mcp>

## Use it

Resolve this record through the SkillsRegistry MCP server (no auth, read-only):

```
claude mcp add --transport http --scope user skillsregistry https://api.skillsregistry.net/mcp
```

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_skill",
    "arguments": {
      "slug": "cxxxr-common-lisp-repl"
    }
  }
}
```

REST: `GET https://api.skillsregistry.net/v1/skills/cxxxr-common-lisp-repl` · pull for local use: `GET https://api.skillsregistry.net/v1/skills/cxxxr-common-lisp-repl/pull`

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SkillsRegistry indexes agent skills from public registries and GitHub. Skills we have analysed are scanned with Circle-IR and scored on six dimensions; each listing states its scan coverage. More: https://skillsregistry.net/llms.txt