What is cl-mcp-server-dev?

A contributor guide for cl-mcp-server, a Common Lisp server that provides tools for interacting with a Lisp read-eval-print loop (REPL). It covers the server’s structure, commands, tests, and coding rules.

Use it to build, run, test, or modify the server and its 36 Common Lisp REPL tool handlers.

It helps developers understand which code handles communication and which code handles sessions, evaluation, and tools.

How quasi/cl-mcp-server configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to quasi/cl-mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/quasi/cl-mcp-server/main/.claude/skills/dev/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/quasi/cl-mcp-server

Made for: Claude Code.

Wrote 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.

README.md

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Your own site

<a href="https://agentmods.dev/skills/quasi/cl-mcp-server/dev"><img src="https://agentmods.dev/badge/skills/quasi/cl-mcp-server/dev/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.

Your own site · 80×15

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Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,877 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

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	$0.00026	$0.01877
Opus 5.5	$0.00010	$0.00751
Sonnet 5.5	$0.00005	$0.00375
Haiku 4.5	$0.00003	$0.00188

Measured 2mo ago against content hash 1f9fe6587ba4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

cl-mcp-server-dev 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 2mo 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.

.claude/skills/dev/SKILL.md · 178 lines

How it starts

The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cl-mcp-server — Dev Skill

MCP server providing 36 Common Lisp REPL tools to Claude. Thin application layer over the cl-mcp protocol library.

Quick Reference

# Load
sbcl --load cl-mcp-server.asd --eval "(ql:quickload :cl-mcp-server)"

# Run
sbcl --load cl-mcp-server.asd \
     --eval "(ql:quickload :cl-mcp-server)" \
     --eval "(cl-mcp-server:start)"

# Test
sbcl --load cl-mcp-server.asd \
     --eval "(ql:quickload :cl-mcp-server/tests)" \
     --eval "(asdf:test-system :cl-mcp-server)"

Architecture

Dependency graph:

digraph {
  rankdir=LR
  "cl-mcp-server" -> "cl-mcp" [label="protocol"]
  "cl-mcp-server" -> "alexandria"
  "cl-mcp-server" -> "trivial-backtrace"
  "cl-mcp" -> "yason"
  "cl-mcp" -> "opsis/conditions"
}

What cl-mcp owns: JSON-RPC 2.0 framing, stdio transport, MCP handshake, per-server tool registry, error recovery.

What cl-mcp-server owns: Session state, code evaluation, 36 REPL tool handlers.

start reduces to 3 calls:

(cl-mcp:make-server :name "cl-mcp-server" :version "0.3.0")
(cl-mcp-server.tools:define-builtin-tools server session)
(cl-mcp:run-server server)

Package Structure

Package	File	Purpose
`cl-mcp-server.conditions`	`src/conditions.lisp`	REPL conditions + re-exports from `cl-mcp.conditions`
`cl-mcp-server.error-format`	`src/error-format.lisp`	Condition/backtrace formatting
`cl-mcp-server.session`	`src/session.lisp`	Persistent `package` context and state
`cl-mcp-server.evaluator`	`src/evaluator.lisp`	Safe evaluation with stream capture
`cl-mcp-server.introspection`	`src/introspection.lisp`	Symbol/class/method inspection
`cl-mcp-server.asdf-tools`	`src/asdf-tools.lisp`	ASDF/Quicklisp operations
`cl-mcp-server.profiling-tools`	`src/profiling-tools.lisp`	Statistical and deterministic profiling
`cl-mcp-server.telos-tools`	`src/telos-tools.lisp`	Telos intent introspection (graceful degradation; see RULE-007)
`cl-mcp-server.tools`	`src/tools.lisp`	Registers all 36 tools via `cl-mcp:register-tool`
`cl-mcp-server`	`src/server.lisp`	Entry point: `start`

Read the full file on GitHub · 178 lines

Changes

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.

2mo ago First seen · 178 lines · 26 tokens per session scan A 1f9fe6587ba4

Subscribe to this mod's changes

cl-mcp-server-dev is a skill published in the GitHub repository quasi/cl-mcp-server (43 stars, last pushed 8d ago), licensed MIT. It adds 26 tokens to every session and 1,877 once invoked, about $0.0001 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.

Backend and APIs

cl-mcp-server-dev next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
cl-mcp-server-devquasi/cl-mcp-server	Skill	43	8d ago	MIT	A	26	Claude Code
mem0-oss-to-platformmem0ai/mem0	Skill	68k	2d ago	Apache-2.0	A	217	Claude Code, Codex
azure-mgmt-botservice-dotnetmicrosoft/skills	Skill	3.2k	yesterday	MIT	A	78	Claude Code
fastapi-router-pymicrosoft/skills	Skill	3.2k	yesterday	MIT	A	46	Claude Code
dev-runtimelangwatch/langwatch	Skill	5.0k	yesterday	Apache-2.0	A	172	Claude Code
api-designericrisco/rsc-harness	Skill	503	2d ago	MIT	A	105	Claude Code, Codex
migrate-segw-to-raparc-mcp/arc-1	Skill	252	yesterday	MIT	A	106	Claude Code

cl-mcp-server: Skill for Claude Code