#+TITLE: elisp-dev-mcp: MCP Server for Agentic Elisp Development
[[https://github.com/laurynas-biveinis/elisp-dev-mcp/actions/workflows/elisp-test.yml][https://github.com/laurynas-biveinis/elisp-dev-mcp/actions/workflows/elisp-test.yml/badge.svg]] [[https://github.com/laurynas-biveinis/elisp-dev-mcp/actions/workflows/super-linter.yml][https://github.com/laurynas-biveinis/elisp-dev-mcp/actions/workflows/super-linter.yml/badge.svg]] [[https://melpa.org/#/elisp-dev-mcp][https://melpa.org/packages/elisp-dev-mcp-badge.svg]] [[https://stable.melpa.org/#/elisp-dev-mcp][file:https://stable.melpa.org/packages/elisp-dev-mcp-badge.svg]]
Overview
=elisp-dev-mcp= is an Emacs package that provides an MCP (Machine Code Protocol) server for agentic Elisp development. It enables AI agents to assist with Elisp coding tasks by providing a structured API to interact with Emacs and manipulate Elisp code.
This package leverages [[https://github.com/laurynas-biveinis/mcp-server-lib.el][mcp-server-lib.el]] for the underlying MCP infrastructure.
Installation
From MELPA:
=M-x package-install RET elisp-dev-mcp RET=
Usage
** Registering with an MCP Client
After =mcp-server-lib= has been properly installed (including =M-x mcp-server-lib-install=), register =elisp-dev-mcp= with your MCP client:
#+begin_example claude mcp add -s user -t stdio elisp-dev -- ~/.emacs.d/emacs-mcp-stdio.sh --init-function=elisp-dev-mcp-enable --stop-function=elisp-dev-mcp-disable #+end_example
Before using the MCP server, you must start it in Emacs with =M-x mcp-server-lib-start=. Stop it with =M-x mcp-server-lib-stop= when done.
** Available MCP Handlers
*** Elisp Function Documentation
Name: =elisp-describe-function=
Description: Get full documentation for an Emacs Lisp function
Parameters:
=function=: The name of the function to describe (string)
Returns:
=description=: The function's documentation (string)
or =error=: Error message if something went wrong (string)
*** Elisp Function Definition
Name: =elisp-get-function-definition=
Description: Get the source code definition of an Emacs Lisp function
Parameters:
=function=: The name of the function to retrieve (string)
Returns:
For Elisp functions:
=source=: The function's source code including header comments if present (string)
=file-path=: Path to the file where the function is defined (string)
=start-line=: First line number of the definition including header comments (1-based integer)
=end-line=: Last line number of the definition (1-based integer)
For C-implemented functions:
=is-c-function=: Boolean indicator that this is a C function (always true)
=function-name=: The name of the function (string)
=message=: A message indicating the function is implemented in C source code (string)
*** Elisp Variable Description
Name: =elisp-describe-variable=
Description: Get information about an Emacs Lisp variable without exposing its value
Parameters:
=variable=: The name of the variable to describe (string)
Returns:
=name=: Variable name (string)
=bound=: Whether variable is currently bound (boolean, false for declared but unbound variables)
=value-type=: Type of the value (string, e.g. "cons", "string", "integer")
=documentation=: Variable documentation or null if none (string or null)
=source-file=: Path to the file where the variable is defined (string)
=is-custom=: Whether it's a customizable variable (boolean)
=custom-group=: The custom group this variable belongs to (string, only present for custom variables)
=custom-type=: The custom type specification (string, only present for custom variables)
=is-obsolete=: Whether the variable is marked obsolete (boolean)
=obsolete-since=: Version when the variable became obsolete (string, only present if obsolete)
=obsolete-replacement=: Suggested replacement for the obsolete variable (string, only present if obsolete)
=is-alias=: Whether the variable is an alias for another variable (boolean)
=alias-target=: The variable this is an alias for (string, only present if alias)
=is-special=: Whether the variable is a special (dynamically scoped) variable (boolean)
or =error=: Error message if something went wrong (string)
*** Elisp Info Documentation Lookup
Name: =elisp-info-lookup-symbol=
Description: Look up Elisp symbols in Info documentation and return the complete documentation node
Parameters:
=symbol=: The Elisp symbol to look up (string)
Returns:
=found=: Whether documentation was found (boolean)
=symbol=: The symbol that was looked up (string)
=node=: The Info node name containing the documentation (string, when found)
=manual=: The Info manual name, typically 'elisp' (string, when found)
=content=: The complete Info node content including all examples, cross-references, and related information (string, when found)
=info-ref=: Info reference like '(elisp)Node Name' for direct access (string, when found)
=message=: Error or not-found message (string, when not found)
*** Elisp Source File Reader
Name: =elisp-read-source-file=
Description: Read Elisp source files from Emacs system directories or ELPA packages
Parameters:
=file-path=: Absolute path to =.el= file (string)
Returns:
The complete file contents as a string
or =error=: Error message if file not found, invalid format, or access denied (string)
Examples:
="/opt/homebrew/Cellar/emacs-mac/emacs-29.1-mac-10.0/share/emacs/29.1/lisp/files.el"= - Read system file
="/Users/name/.emacs.d/elpa/package-1.0/package.el"= - Read ELPA package
Security:
Only reads from Emacs system lisp directories and =~/.emacs.d/elpa/=
Rejects paths with =..= traversal
Resolves symlinks to prevent escaping allowed directories
Features:
Transparently handles =.el.gz= compressed files
Works directly with paths from =elisp-get-function-definition=
Returns complete file contents as string
License
This project is licensed under the GNU General Public License v3.0 (GPLv3) - see the LICENSE file for details.
This server cannot be installed
local-only server
The server can only run on the client's local machine because it depends on local resources.
Elisp (Emacs Lisp) development support tools, running in Emacs
Related MCP Servers
- Apache 2.0
- MIT License
- Apache 2.0