tabular-mcp

MCPBI - Tabular Model MCP Server

This is a Model Context Protocol (MCP) server for locally running Tabular Models, i.e. PowerBI models running on PowerBI Desktop.

This server allows MCP-enabled LLM clients to communicate with your tabular models and help you debug, analyse and compose DAX queries.

Example: Copilot querying Tabular Model via MCP

How it works

It connects to a local running instance of Tabular models using the AdomdConnection in ADOMD.NET.

Using this connection, the server then allows clients to execute DAX-queries and retrieve model metadata (using DMV queries) through pre-defined tools for high accuracy, as well as custom DAX queries for debugging and development.

Features

Configuration Options

Port

Specify the Power BI Desktop instance port to connect to (required).

# Example: Connect to Power BI Desktop instance on port 56751
dotnet run -- --port 56751

Obfuscation

Protect sensitive data with configurable encryption strategies:

• None (default): No obfuscation
• All: Mask all values
• Dimensions: Mask only text/date fields (keep numeric data visible)
• Facts: Mask only numeric fields (keep dimensional context)

# Example: Protect customer/product names while keeping sales figures visible
dotnet run -- --port 56751 --obfuscation-strategy dimensions --encryption-key "YourSecureKey123!"

Output Truncation

Automatic row limiting with comprehensive metadata:

• Default 500-row limit (configurable)
• Response includes: totalRows, displayedRows, truncated, hasMore

# Example: Increase row limit for analysis
dotnet run -- --port 56751 --max-rows 2000

Tools

list_objects

• Lists all objects in the model (tables, columns, measures, relationships)
• Returns object type, name, and basic metadata

get_object_details

• Retrieves detailed metadata for a specific object (table, column, measure)
• Returns properties, data types, relationships, and dependencies

list_functions

• Lists available DAX functions with optional filtering by category or origin
• Returns function name, description, interface classification, and origin

get_function_details

• Retrieves comprehensive details for a specific DAX function including full parameter information
• Returns function signature, parameter requirements, return type, and DirectQuery compatibility

run_query

• Executes a custom DAX query against the model
• Returns query results with metadata (total rows, truncated status)

1. Model Discovery

Use [ListTables], [GetTableColumns], and [GetTableRelationships] to quickly understand an unfamiliar model's structure without manually clicking through Power BI Desktop.

2. DAX Assistance

LLM clients can use [ListMeasures] and [GetMeasureDetails] to learn your existing DAX patterns and suggest consistent new measures that follow your naming conventions and calculation styles.

3. Debugging

Combine [RunQuery] with [ValidateDaxSyntax] to iteratively test and refine DAX expressions with immediate feedback on syntax and results.

validate_query

• Validates DAX query syntax without execution
• Returns syntax correctness and error messages if applicable

analyze_query_performance

• Analyzes DAX query performance and provides optimization suggestions
• Returns execution time, resource usage, and improvement recommendations

Installation

Setup Instructions

Requirements

• Power BI Desktop (with a PBIX file open for discovery)
• Windows OS
• Visual Studio Code (for MCP server integration)
• .NET 8.0 Runtime

Setup from Prebuilt Release

1. Download the release from the Releases directory or GitHub releases page and extract to your preferred location.

2. Open Power BI Desktop with a PBIX file you want to work with.

3. Get PowerBI instance information

There are several ways to detect Power BI Desktop instances. The easiest is to open Tabular Editor and check the port in the connection string.

Simply add the port (63717 in example above) to your MCP server configuration in the next step (you can ignore the database ID, as this server connects to the default model).
If you don't have Tabular Editor, you can use the included discovery tool to find the running instance and database.

Open PowerShell, navigate to the release directory, and run:

cd path\to\release
.\pbi-local-mcp.DiscoverCli.exe

Note: In PowerShell, you must use .\ prefix to run executables from the current directory.

Follow the prompts to:

• Select the Power BI Desktop instance (identified by port)
• Choose the database/model to connect to

This creates a .env file with PBI_PORT and PBI_DB_ID in the release directory, which you can reference in your MCP configuration or ignore if you specify the port directly.

4. Configure MCP server in your editor. For VS Code with Roo, create/edit .roo/mcp.json:

   {
     "mcpServers": {
       "MCPBI": {
         "type": "stdio",
         "command": "path\\to\\release\\mcpbi.exe",
         "cwd": "path\\to\\release",
         "args": ["--port", "YOUR_PBI_PORT"],
         "disabled": false,
         "alwaysAllow": [
           "ListTables",
           "GetTableDetails",
           "GetTableColumns",
           "GetTableRelationships",
           "ListMeasures",
           "GetMeasureDetails",
           "PreviewTableData",
           "RunQuery",
           "ValidateDaxSyntax",
           "AnalyzeQueryPerformance",
           "ListFunctions",
           "GetFunctionDetails"
         ]
       }
     }
   }
   

   Replace path\\to\\release with your actual release directory path and YOUR_PBI_PORT with the port number from PBI instance.

Setup from Source (For Development)

1. Clone the repository:

   git clone <repository-url>
   cd MCPBI
   

2. Build the project:

   dotnet build
   

3. Open Power BI Desktop with a PBIX file.

4. Run discovery to create .env file:

   dotnet run --project pbi-local-mcp/pbi-local-mcp.csproj discover-pbi
   

   Follow prompts to select instance and database.

5. Configure MCP server in .roo/mcp.json:

   {
     "mcpServers": {
       "mcpbi-dev": {
         "type": "stdio",
         "command": "dotnet",
         "cwd": "path\\to\\MCPBI",
         "envFile": "path\\to\\MCPBI\\.env",
         "args": [
           "exec",
           "path\\to\\MCPBI\\pbi-local-mcp\\bin\\Debug\\net8.0\\pbi-local-mcp.dll"
         ],
         "disabled": false,
         "alwaysAllow": [
           "ListTables",
           "GetTableDetails",
           "GetTableColumns",
           "GetTableRelationships",
           "ListMeasures",
           "GetMeasureDetails",
           "PreviewTableData",
           "RunQuery",
           "ValidateDaxSyntax",
           "AnalyzeQueryPerformance",
           "ListFunctions",
           "GetFunctionDetails"
         ]
       }
     }
   }
   

   Replace path\\to\\MCPBI with your actual repository path.

Configuration Notes

• Use either port or envFile: You can specify the Power BI port directly in args or use envFile to load from .env.
• Port argument: The --port argument in the release configuration connects to the specific Power BI Desktop instance on that port
• envFile: The development setup uses envFile to automatically load PBI_PORT and PBI_DB_ID from .env
• alwaysAllow: Lists all tools that can be used without requiring user approval for each invocation
• Working directory: The cwd parameter sets the working directory where the .env file is located