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`@procedures/mcp-dev-tools`

packages/impl-mcp-dev/README.md on GitHub · Package map · Procedures

mcp-dev-tools is the MCP server that gives procedures to Claude as tools. Its folder in the monorepo is packages/impl-mcp-dev. Claude Code (or Claude Desktop) starts it over stdio. By default it loads bundle-mcp, which selects 62 tools.

Set up Claude Code#

Add the server to the MCP configuration of Claude Code. npx gets the package from npm:

{
  "mcpServers": {
    "dev-tools": { "command": "npx", "args": ["-y", "@procedures/mcp-dev-tools"] }
  }
}

From a clone of the monorepo, build it first (pnpm install, then pnpm build). Then give the path of the server file:

{
  "mcpServers": {
    "dev-tools": {
      "command": "node",
      "args": ["/path/to/client/packages/impl-mcp-dev/dist/server.js"]
    }
  }
}

The package has the bin mcp-dev-tools, which starts the same file.

Claude Code starts the server once for each session. After a rebuild, restart the MCP server (or the session) to get the changes.

Configuration#

Environment variable	Default	Function
`MCP_BUNDLES`	`@procedures/bundle-mcp`	The bundles to load, separated by commas. The server imports `<bundle>/register.js` for each one.
`MCP_SERVER_NAME`	`impl-mcp-dev`	The server name in the MCP handshake
`MCP_SERVER_VERSION`	`1.0.0`	The server version in the MCP handshake
`MCP_DEBUG`	`false`	With `true`, the server writes debug lines to stderr

How it selects the tools#

The server loads each bundle. A bundle can export mcpNamespaces and mcpExclude.
A procedure is a tool when its namespace is in mcpNamespaces of a bundle, and its key is not in mcpExclude.
A ProcedureServer serves the registry with that rule as its expose rule. A data-driven procedure (client.chain, client.eval, a procedure of procedure.define) can use only exposed procedures.
McpServerTransport gives the exposed procedures as tools over stdio. It tells Claude when the list of tools changes.

[!WARNING] A bundle without mcpNamespaces exposes every registered procedure, shell.exec too. bundle-dev has no mcpNamespaces. Thus MCP_BUNDLES=@procedures/bundle-dev gives Claude shell access through this server.

The server sends console.log output to stderr, because stdout carries the MCP protocol.

The tool list#

tools.snapshot.txt has the names of the 62 tools. src/tools.test.ts starts the real server over stdio and compares its tools with the file. It also examines that a docker.* tool cannot start a shell command. To change the tools, change bundle-mcp and tools.snapshot.txt in one commit. The bundle-mcp README lists the tools and the reasons for the procedures that stay out.

Troubleshooting#

No tools in Claude. Build the monorepo, and examine the path in the configuration. Start the server with MCP_DEBUG=true and read stderr.
Old tools or old behavior. Restart the MCP server after a rebuild.
A bundle fails to load. The server stops with the message Failed to load bundle. Build the bundle, and examine the name in MCP_BUNDLES.