DAX Lib MCP server

Local MCP server for DAX Lib, the public gallery of reusable DAX user-defined function (UDF) packages.

It gives an MCP-compatible assistant — such as Claude, GitHub Copilot or Codex — three capabilities:

1. Search the DAX Lib catalog and inspect package metadata, versions and READMEs.
2. Get a package's DAX functions as a DEFINE block, to use them in a DAX query without changing the model.
3. Install a package's DAX functions into a semantic model open in Power BI Desktop.

Requirements

Requirement	Notes
Node.js	Version 18 or later. Used only to launch the server.
Power BI Desktop	Required to install packages. The target model must be at compatibility level 1702 or later. Not required to get a DEFINE block.

Supported platforms

The published package supports Windows x64 (win-x64) with all tools, including installation into a model open in Power BI Desktop. Linux, macOS, Windows ARM64 and other platforms are not currently published.

Installation

Add the server to the MCP client configuration:

{
  "mcpServers": {
    "daxlib-mcp": {
      "command": "npx",
      "args": ["-y", "@daxlib/mcp", "--start"]
    }
  }
}

VS Code and Visual Studio use servers instead of mcpServers. VS Code also supports one-click installation.

No further setup is required. The server has no configuration file, no environment variables and no API keys.

Standalone executable

Each release also provides the executable as a zip archive. Extract it and register daxlib-mcp.exe with the --start argument in place of the npx command shown above. Running daxlib-mcp.exe without arguments prints the configuration snippet with the executable path already set.

Usage

Example requests:

• "Search DAX Lib for packages that generate SVG images."
• "Show the README of DaxLib.SVG."
• "List the Power BI Desktop models currently open."
• "Install DaxLib.SVG into the Sales Report model."
• "Give me the DEFINE block for DaxLib.SVG.Viz.Pill."
• "Write a DAX query that uses DaxLib.FormatString to format the sales amount."

Tools

Tool	Description
search_packages	Searches the DAX Lib catalog by keyword, with paging and optional inclusion of prereleases.
get_package	Returns the description, authors, tags, links, release notes and published versions of a package.
get_package_readme	Returns the README published with a package version.
get_function_definitions	Returns a DAX query DEFINE block with the selected functions of a package and the functions they call.
list_local_instances	Lists the Power BI Desktop instances running on the local machine with their connection details.
install_package	Installs a DAX Lib package into a local Power BI Desktop model.

DAX Lib functions in a DAX query

get_function_definitions returns the functions of a package as a DEFINE block. Paste the block before EVALUATE to use the functions in that query only; the model does not change. The block contains the requested functions and the functions they call, also in the dependency packages that the manifest declares, at the declared versions.

• It needs no Power BI Desktop instance and no installation, and it has no compatibility-level requirement: query-scoped functions depend on the engine, not on the model.
• Supported engines: the Power BI service (also through the XMLA endpoint), Azure Analysis Services, and Power BI Desktop from September 2025 (preview) and June 2026 (general availability).
• A function in the DEFINE block replaces a model function with the same name, for that query only.
• A few functions published before a change of the DAX parser cannot run in a query, because a part of their name is now reserved (for example DaxLib.SVG.Element.Group). The server returns them unchanged; the query error points to the name part.

Command line

daxlib-mcp [--start | --version | --help]

Option	Description
--start	Starts the MCP server on standard input and output. This is the command used by MCP clients.
--version	Prints the version.
--help, -h	Prints the usage information.

Running the executable without arguments prints an overview and the client configuration snippet.

More information

Source code, issue tracking and release information are available at github.com/daxlib/daxlib-mcp. The documentation index lists the available technical documentation.

License

MIT, see LICENSE. Packages published on DAX Lib are contributed by the community under their own licenses.