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@procedures/mcp-dev-tools

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 91 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.

When the client closes the input of stdio, the server stops: the calls in flight get their grace time, and then the process ends.

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. @procedures/bundle-assistant adds the tools of the assistant.
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
MCP_TOOL_TIMEOUT_MS	600000	The time limit of a tool call, in milliseconds. 0 turns the limit off.
MCP_READ_ONLY	false	With true, the tools are only the procedures that change nothing
MCP_HTTP_PORT, MCP_HTTP_HOST, MCP_HTTP_TOKEN	not set	The server uses Streamable HTTP on this port, not stdio. The host is 127.0.0.1 by default.
MCP_HTTP_MAX_SESSIONS	256	The most sessions of the Streamable HTTP face at one time (CLI-51). Infinity turns the limit off.
MCP_PROGRAM_CHECK	true	With false, a program starts without the check before the run
MCP_FS_ROOT	not set	The root of the files: each tool keeps its paths in this folder, or the host refuses it. Refer to "The root of the files".

mark mcp starts the same server. Its flags replace the variables: --bundles, --tool-timeout, --read-only, --http, --host, --token, --max-sessions and --fs-root.

The server operates under run() of @mark1russell7/service (CLI-11). The runner owns the signals, the stop in stages and the exit of the process.

• Over stdio, the profile is ephemeral. When the client closes the input, the server stops in stages and the process exits with the code 0. A first Ctrl-C stops the work, and a second one exits at once.
• Over Streamable HTTP, the profile is localDev. A listener of the service answers on the port, and the MCP endpoint is at /mcp.
• In code, runDevToolsServer(config) starts the server under the runner and gives the host, the service, the lifecycle and the URL.

The server serves no remote events (documentation/EVENTS.md). Its transport carries only MCP, and events.subscribe is not a tool. Thus the host has no variable for the topics.

The root of the files

With MCP_FS_ROOT (or mark mcp --fs-root <folder>), the host confines each tool to the folder (roadmap R33):

• The host starts confineToRoot() of @procedures/fs after it builds its registry. The function replaces handlers, and it adds no procedure.
• The list of the tools and tools.snapshot.txt do not change. The host refuses some tools under a root.
• A tool keeps its paths in the root. The host examines the path inputs of its rules (metadata.fsRoot) before it starts. The nested fs.* calls are confined too.
• A path outside the root gives FORBIDDEN with the reason outside-root. A relative path starts at the root. A working folder without a value is the root.
• The host refuses each tool that the root cannot confine, with the same error. At the start, it writes the refused procedures to stderr.
• The host does not start when the folder does not exist.

The tools of bundle-mcp under a root:

Tools	Under a root
cue.*	Confined: cwd
lib.scan, lib.graph, lib.audit, lib.rename	Confined: rootPath. Their nested git calls are refused, and lib.scan gives a warning.
procedure.new	Confined: path
sqlite.*, logs.*	Confined: dbPath, which a call must give, or :memory:
docker.ps, docker.logs, docker.stop, docker.rm, docker.images, docker.inspect, docker.pull, docker.tag, docker.volume.*, docker.network.*	Confined: cwd. Docker runs in a folder of the root.
docker.run, docker.exec, docker.build, docker.compose.*	Refused: a volume, a compose file or a Dockerfile reaches host folders, or runs a program
lib.new, vitest.run, vitest.coverage	Refused: they start code of the project
client.*, json.*, yaml.*, mongo.*, program.*, the other procedure.* tools	Unchanged: they reach no file

The rules and the table of all the procedures are in CAPABILITIES-2026-10.md.

How it selects the tools…