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.

The addon exposes 9 tools: one clojure supertool (check, repair, format, eval, discover, wrap), five file tools, todo_write, web_fetch, and web_search. The standalone Babashka server exposes 13 tools: five individual Clojure commands, five file tools, todo_write, web_fetch, and web_search. Web search requires a configured provider; the default searcher returns a configuration error.

The standalone server reads resources/basic-tools-mcp/VERSION from its classpath, so it works from any working directory. This resource mirrors the root VERSION used by releases; the parity test fails if they diverge. config.edn and bb.edn use the same modex-bb tag and commit, also checked by the parity test.

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

Standalone Clojure commands are individual MCP tools; in the addon they are commands of clojure (which also supports wrap).

Standalone tool	Addon command	Description
check	clojure check	Check Clojure code for delimiter errors (mismatched parens/brackets/braces)
repair	clojure repair	Repair delimiter errors using parinfer (edamame + parinferish)
format_code	clojure format	Format Clojure code with cljfmt
eval_code	clojure eval	Evaluate Clojure code via nREPL (requires running nREPL server)
discover	clojure discover	Discover nREPL servers running on this machine
(addon only)	clojure wrap	Wrap a Clojure form at a line in a template (addon only)

check, repair, and format_code accept code (inline string) or file_path (reads from disk; repair/format can write back). eval_code accepts code, port, host, and timeout; discover takes no arguments.

The following tools are exposed separately on both surfaces:

Tool	Description
read_file	Read a file with optional line offset and limit
file_write	Write a file, creating parent directories as needed
edit	Replace an exact substring in a file
glob_files	Find files matching a glob
grep	Search files via ripgrep
todo_write	Replace the agent's session-scoped todo list
web_fetch	Fetch a URL through the configured fetcher (admission-gated in the default runtime)
web_search	Search via the configured searcher (default has no search provider)

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 and eight standalone file/todo/web tools.

(require '[basic-tools-mcp.init :as init])
(init/init-as-addon!)
;; => {:registered ["clojure" "read_file" "file_write" "edit" "glob_files" "grep"
;;                  "todo_write" "web_fetch" "web_search"] :total 9}

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 (13 tools)
  release.clj — reads VERSION for standalone server metadata
  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