basic-tools-mcp

Standalone MCP server for Clojure development tools. Wraps clojure-mcp-light (by Bruce Hauman) as an IAddon. Runs on Babashka via the modex-bb framework.

Provides 5 tools: delimiter error detection/repair, code formatting, nREPL evaluation, and nREPL server discovery.

Requirements

• Babashka v1.3.0+

Quick Start

bb --config bb.edn run server

Claude Code MCP config

Add to ~/.claude/settings.json:

{
  "mcpServers": {
    "basic-tools": {
      "command": "bb",
      "args": ["--config", "/path/to/basic-tools-mcp/bb.edn", "run", "server"]
    }
  }
}

Tools

Tool	Description
check	Check Clojure code for delimiter errors (mismatched parens/brackets/braces)
repair	Repair delimiter errors using parinfer (edamame + parinferish)
format_code	Format Clojure code with cljfmt
eval_code	Evaluate Clojure code via nREPL (requires running nREPL server)
discover	Discover nREPL servers running on this machine

All tools accept either code (inline string) or file_path (reads from disk, writes back for repair/format).

IAddon Integration

basic-tools-mcp implements the IAddon protocol for dynamic registration in hive-mcp. When loaded as an addon, it registers the clojure supertool.

(require '[basic-tools-mcp.init :as init])
(init/init-as-addon!)
;; => {:registered ["clojure"] :total 1}

Direct handler usage:

(require '[basic-tools-mcp.tools :as tools])
(tools/handle-clojure {:command "check" :code "(defn foo [x] (+ x 1)"})
;; => {:content [{:type "text" :text "{:has-error true, :source \"inline\"}"}]}

Upstream

This project wraps clojure-mcp-light v0.2.1, which provides:

• Delimiter repair — edamame parser + parinfer (parinfer-rust when available, parinferish fallback)
• nREPL client — evaluation with timeout handling, persistent sessions, port discovery
• cljfmt — code formatting

Local Development

For local iteration against a clojure-mcp-light checkout, create local.config.edn (gitignored):

{:deps {io.github.bhauman/clojure-mcp-light {:local/root "../clojure-mcp-light"}}}

Project Structure

src/basic_tools_mcp/
  core.clj    — Bridge to clojure-mcp-light (delimiter repair, nREPL eval, formatting)
  tools.clj   — Command handlers + MCP tool schema (IAddon interface)
  init.clj    — IAddon reify + nil-railway registration pipeline
  server.clj  — modex-bb standalone MCP server (5 tools)
  log.clj     — Logging shim (timbre on JVM, stderr on bb)

Dependencies

• modex-bb — MCP server framework
• clojure-mcp-light — Upstream Clojure dev tools

License

MIT