dax-query-mcp 0.2.7

Windows-first DAX and MCP toolkit for Power BI semantic models

dax-query-mcp

MCP server for running DAX queries against Power BI semantic models.

Check out making use of skills and extensions for getting better results since the MCP can't do it all

Features

• Connection-centric MCP server — discover models, query with DAX, inspect schemas
• Relationship-aware context — teach the LLM your model with markdown, structured dictionaries, relationships, and progressive context bundles
• Fuzzy search — search columns and measures across tables by name or description
• Server-authored follow-ups — every query response includes a durable next-step workflow for exports, charts, scaffolds, and workstation saves
• Export anywhere — CSV, clipboard, Power Query M code, Streamlit apps, standalone Python projects
• Query builder — save .dax + .dax.queryBuilder artifacts, open directly in DAX Studio
• Workstation session — save, list, and batch-export queries during an exploration session
• Durable query packs — turn saved DAX into portable packs with a manifest, batch runner, Streamlit explorer, and Power Query files
• Validated query libraries — keep connection-scoped, known-good DAX examples that improve future context without creating a full pack

Prerequisites

1. uv — Python package manager. Install with:

   winget install astral-sh.uv
   

2. For MSOLAP connections: Windows + MSOLAP provider — the default transport uses COM/ADODB. Download from Microsoft — grab the "AMO + ADOMD.NET" or "MSOLAP (OLE DB)" installer. If you already have Power BI Desktop, Excel with Power Pivot, or SSMS installed, you likely have it.

   To check: open PowerShell and run:

   (New-Object System.Data.OleDb.OleDbEnumerator).GetElements() | Where-Object { $_.SOURCES_NAME -like "*MSOLAP*" }
   

   If that returns a row, you're good.

3. For Power BI REST connections: Azure CLI or access token — REST uses the Power BI executeQueries API and does not require Windows or MSOLAP.

   az login --allow-no-subscriptions
   

   On Windows, the standard Azure CLI install path is auto-detected if az is not on PATH. For custom installs, set AZURE_CLI_PATH to the full az.cmd path.

Quick start

1. Install

From PyPI (recommended):

uvx --from dax-query-mcp dax-query-server

From source (for development or latest changes):

git clone https://github.com/wes-stone/dax-query-mcp.git
cd dax-query-mcp
uv sync

2. Add a connection bundle

Each model is represented by a small connection bundle in Connections/. The YAML file provides access to the model; the companion context files are the layer that makes Copilot useful because they explain the model in business terms.

Create Connections/my_model.yaml for the connection string and runtime settings. When transport is omitted, it defaults to msolap, so existing connection files keep working unchanged:

connection_string: |
  Provider=MSOLAP.8;
  Data Source=powerbi://api.powerbi.com/v1.0/myorg/MyWorkspace?readonly;
  Initial Catalog=MySemanticModel

description: "My semantic model"
command_timeout_seconds: 1800

For a REST-backed connection, use transport: powerbi_rest and the Power BI dataset ID instead of an MSOLAP connection string:

transport: powerbi_rest
dataset_id: "00000000-0000-0000-0000-000000000000"
description: "My semantic model via Power BI REST"
auth_mode: azure_cli
command_timeout_seconds: 1800
max_rows: 50000

REST execution always uses the dataset-only executeQueries endpoint: https://api.powerbi.com/v1.0/myorg/datasets/{dataset_id}/executeQueries. Do not put /groups/{workspace_id} in api_base_url; workspace-scoped REST paths can fail for Build-only access even when the dataset-only endpoint works.

Then add context files with the same connection name:

File	Purpose
Connections/my_model.yaml	Required runtime config: MSOLAP connection string or REST dataset ID, plus description, timeouts, and row limits.
Connections/my_model_overview.md	Optional compact overview used first by get_connection_context; include the most important tables, measures, filters, and example queries.
Connections/my_model.md	Optional full model context; include detailed table notes, business definitions, caveats, relationships, and query patterns.
Connections/my_model.data_dictionary.yaml	Optional structured dictionary used by get_data_dictionary, get_schema, search_columns, search_measures, and context detail tools; include tables, columns, measures, filters, relationships, descriptions, and sample values.
Connections/my_model.validated_queries/	Optional validated query library; one metadata file plus one .dax file per reusable known-good query pattern.

Recommended setup flow:

1. Create the .yaml connection file.
2. Add a short _overview.md so Copilot can quickly understand the model before writing DAX.
3. Add the fuller .md context for detailed business logic, naming conventions, and examples.
4. Add or generate the .data_dictionary.yaml so tools can search fields and measures structurally.
5. After real queries work, save repeated patterns to .validated_queries/ so future sessions can reuse known-good DAX.

You can create the dictionary manually or, for MSOLAP connections, scaffold one from the live model with the generate_data_dictionary MCP tool. The generator uses safe MDSCHEMA rowsets for tables, columns, and measures, and includes high-confidence relationships when optional TMSCHEMA rowsets are available. Then fill in business-specific definitions and sample values.

3. Wire up MCP

Add to .copilot/mcp.json (or your MCP client config):

Using PyPI (via uvx):

{
  "mcpServers": {
    "dax-query-server": {
      "command": "uvx",
      "args": ["--from", "dax-query-mcp", "dax-query-server"],
      "env": {
        "DAX_QUERY_MCP_CONNECTIONS_DIR": "C:\\absolute\\path\\to\\Connections"
      }
    }
  }
}

Using a local clone:

{
  "mcpServers": {
    "dax-query-server": {
      "command": "uv",
      "args": ["--directory", "C:\\path\\to\\dax-query-mcp", "run", "--no-sync", "dax-query-server"],
      "env": {
        "DAX_QUERY_MCP_CONNECTIONS_DIR": "C:\\absolute\\path\\to\\Connections"
      }
    }
  }
}

Run uv sync manually after dependency changes. Keep MCP startup on uv run --no-sync so the server does not try to mutate its virtual environment while the executable is already running.

Tip: DAX_QUERY_MCP_CONNECTIONS_DIR lets you share one Connections/ folder across workspaces.

4. Run your first query

Ask Copilot (or any MCP client):

"List connections, then run a DAX query against my model."

The server returns plain markdown — results render as tables directly in chat.

Demo without Power BI: Mock Contoso

The repo includes a safe, deterministic mock_contoso connection for README screenshots, demos, tests, and local development. It uses MOCK://contoso, so it does not require Azure login, Power BI permissions, MSOLAP server access, or private dataset IDs.

Use it to show the full MCP workflow:

Step	Prompt to capture	Feature shown
1	List my DAX connections.	Connection discovery with connection_type
2	Get the connection context for mock_contoso.	Overview/context layer
3	Search measures for sales in mock_contoso.	Structured data dictionary search
4	Search columns for category in mock_contoso.	Column search across model metadata
5	Run the Contoso sales summary query.	DAX execution and markdown result table
6	Inspect the mock_contoso connection.	Live schema inspection via safe MDSCHEMA rowsets
7	Export the Contoso sales summary to CSV.	Export workflow

Mock Contoso context layer

The demo connection is a complete connection bundle. This is the feature worth showing in screenshots: the model is not just a connection string, it includes LLM-readable context and structured metadata.

Connections/
  mock_contoso.yaml
  mock_contoso_overview.md
  mock_contoso.md
  mock_contoso.data_dictionary.yaml

File	Used by	What it teaches the agent
mock_contoso.yaml	list_connections, query execution	Connection name, connection type, runtime settings
mock_contoso_overview.md	get_connection_context(..., detail="overview")	Fast summary: tables, measures, demo queries, screenshot prompts
mock_contoso.md	get_connection_context(..., detail="full")	Deeper guidance and the end-to-end demo walkthrough
mock_contoso.data_dictionary.yaml	get_data_dictionary, get_schema, search_columns, search_measures, context bundle/detail tools	Searchable tables, columns, measures, filters, relationships, descriptions, and sample values

Connection YAML:

connection_string: "MOCK://contoso"
description: "Mock Contoso Sales cube for testing and development"
connection_timeout_seconds: 30
command_timeout_seconds: 300

Overview excerpt:

## Tables

| Table | Purpose | Useful columns |
| --- | --- | --- |
| `Sales` | Transaction fact table | `SalesKey`, `ProductKey`, `DateKey`, `Quantity`, `Amount` |
| `Products` | Product dimension | `ProductKey`, `ProductName`, `Category`, `Price` |
| `Calendar` | Date dimension for 2025 | `DateKey`, `Date`, `Month`, `MonthNum`, `Year`, `Weekday` |

Data dictionary excerpt:

measures:
  - name: Total Sales
    expression: SUM(Sales[Amount])
    description: Sum of all sales amounts
    format_string: "$#,##0.00"
filters:
  - name: Category Filter
    column: Products[Category]
    description: Filter by product category
    suggested_values: ["Bikes", "Accessories"]
relationships:
  - from_table: Sales
    from_column: ProductKey
    to_table: Products
    to_column: ProductKey
    cardinality: many-to-one
    cross_filter_direction: single
    is_active: true
    description: Sales transactions roll up to product attributes through ProductKey
    source: curated
    confidence: high

Good screenshot query:

EVALUATE
SUMMARIZE(
    Sales,
    "Total Sales", [Total Sales],
    "Total Quantity", [Total Quantity]
)

Expected result shape:

Total_Sales	Total_Quantity
178390.0	290

Connection YAML

transport: "msolap" # optional — "msolap" (default) or "powerbi_rest"
connection_string: "..." # required for MSOLAP connections
dataset_id: "..." # required for powerbi_rest connections
description: "..." # human-readable label
auth_mode: "azure_cli" # REST auth: "azure_cli" (default) or "env"
access_token_env: "POWERBI_ACCESS_TOKEN" # env var used when auth_mode="env"
api_base_url: "https://api.powerbi.com/v1.0/myorg" # optional REST override
impersonated_user_name: "..." # optional REST impersonation UPN
command_timeout_seconds: 1800 # DAX query timeout
connection_timeout_seconds: 300 # connection open timeout
max_rows: null # row cap (null = unlimited)
suggested_skill: "..." # optional — hint an MCP client toward a specific skill
suggested_skill_reason: "..." # optional — why that skill is relevant

Connection context layer

The context layer is what turns a raw semantic model connection into an LLM-friendly workspace. Keep the filenames aligned to the connection name:

Connections/
  my_model.yaml
  my_model_overview.md
  my_model.md
  my_model.data_dictionary.yaml

get_connection_context reads the overview first when it exists, falling back to the full markdown context. Use the overview for the shortest useful description: key tables, trusted measures, common filters, grain, date handling, and a few known-good DAX examples.

Use the full .md file for deeper guidance: business definitions, metric caveats, relationship notes, security/filtering assumptions, common query patterns, and examples of what not to do.

Use the data dictionary YAML when you want structured metadata that tools can search and return precisely:

version: "1.0"
tables:
  - name: Sales
    description: Fact table with booked transactions
    columns:
      - name: Amount
        data_type: decimal
        description: Transaction amount in USD
        sample_values: ["100.00", "250.50"]
measures:
  - name: Total Sales
    expression: SUM(Sales[Amount])
    description: Sum of booked sales amount
    format_string: "$#,##0.00"
filters:
  - name: Fiscal Year
    column: Calendar[FiscalYear]
    description: Filter by fiscal year
    suggested_values: ["FY25", "FY26"]
relationships:
  - from_table: Sales
    from_column: DateKey
    to_table: Calendar
    to_column: DateKey
    cardinality: many-to-one
    cross_filter_direction: single
    is_active: true
    description: Sales rows filter through Calendar by date key
    source: curated
    confidence: high

For agent workflows, start with get_connection_context(detail="overview"), then use get_context_bundle(detail="overview") for structured counts and relationship hints. Fetch scoped context only when needed with get_table_detail, get_measure_detail, get_relationships, and get_filter_suggestions. check_context_staleness compares the dictionary to live metadata when the transport supports it; check_ai_readiness highlights missing descriptions, ambiguous columns, undocumented relationships, and other context gaps.

For powerbi_rest connections, the context layer is especially important: Power BI executeQueries supports DAX query execution, but not DMV/MDSCHEMA metadata queries. inspect_connection and live dictionary generation are available for MSOLAP connections; REST connections should rely on the overview, full markdown context, and .data_dictionary.yaml. If a model only works through REST with Build access, document trusted tables/measures and known-good queries in the context layer so agents do not try workspace-scoped metadata paths.

MCP tools

Tool	Purpose
Discovery
list_connections	Discover available connections as a markdown table (output_format="json" for machine-readable output)
get_connection_context	Curated markdown context (tables, columns, measures)
search_connection_context	Search context docs for specific terms
inspect_connection	Live schema via safe MDSCHEMA rowsets
get_context_bundle	Progressive structured context with counts, tables, measures, filters, and relationships
get_table_detail	Scoped table context plus related relationships
get_measure_detail	Scoped measure context
get_relationships	Relationship topology, optionally filtered by table
get_filter_suggestions	Suggested filters and allowed values from the dictionary
check_context_staleness	Compare dictionary names/counts against live metadata
check_ai_readiness	Flag missing/ambiguous context before query writing
probe_tmschema_capabilities	Check optional high-fidelity TMSCHEMA relationship access
Querying
run_connection_query	Run DAX against a named connection
run_ad_hoc_query	Run DAX against a raw connection string
Search
search_columns	Fuzzy-search columns across tables
search_measures	Fuzzy-search measures by name or expression
Export
export_to_csv	Export results to a timestamped CSV
copy_to_clipboard	Copy results to clipboard (TSV or markdown)
scaffold_power_query	Generate Power Query M code for Excel
scaffold_streamlit_app	Generate a live single-query Streamlit explorer
scaffold_dax_workspace	Scaffold a standalone Python project
quick_chart	Render a bar/line/pie chart as PNG
Query builder
save_query_builder	Save .dax + .dax.queryBuilder artifacts
get_query_builder	Load a saved query builder definition
get_query_builder_schema	Get the expected JSON payload shape
Workstation
save_to_workstation	Save a query to the session workstation
list_workstation	List saved workstation queries
export_workstation	Batch-export workstation as scaffold or .dax files
Query packs
create_query_pack	Create an empty durable query-pack folder
save_query_to_pack	Add or update a DAX query in pack.yaml + queries/
list_query_pack	Summarize a saved pack and its query metadata
validate_query_pack	Check manifest shape, safe DAX, parameters, and connections
describe_query_pack	Generate a markdown pack summary for review and sharing
export_query_pack	Generate runner, Streamlit, Power Query, and README artifacts
Validated query libraries
save_validated_query	Save a reusable DAX example under a connection-scoped library
list_validated_queries	List saved examples, tags, parameters, and validation status
search_validated_queries	Retrieve known-good DAX examples for future query authoring
validate_query_library	Smoke-test saved examples and persist status, columns, and row counts

Admin queries are blocked. INFO.*() and $SYSTEM.DISCOVER_* require server admin rights. General query execution only allows safe MDSCHEMA rowsets. Optional TMSCHEMA access is isolated behind dedicated metadata tools and may be unavailable depending on XMLA permissions.

Python scaffolds

scaffold_dax_workspace exports one query as a standalone Python project. export_workstation(format="scaffold") exports every query saved in the session workstation as one multi-query query-pack project.

Generated projects include transport-aware connection config:

Connection type	Generated behavior
msolap	Uses the embedded Power BI / SSAS connection string through ADODB
powerbi_rest	Uses Power BI REST executeQueries with Azure CLI or env-token auth
mock (MOCK://contoso)	Runs the deterministic demo data path without Power BI or ADODB

The generated scripts use a CONNECTION or CONNECTIONS dict instead of a connection-string-only placeholder, so follow-through exports keep dataset ID, auth mode, timeout, and mock/REST metadata aligned with the named connection. Do not commit generated workspaces that contain private dataset IDs, workspace names, connection strings, or tokens.

Query packs

A query pack is a portable, human-editable DAX workspace:

my-query-pack/
  pack.yaml
  connections.json
  queries/
    monthly_arr.dax
  results/
    monthly_arr.csv
    monthly_arr.schema.json
    run_log.json
  power_query/
    monthly_arr.pq
  streamlit_app.py
  run_queries.py
  pyproject.toml
  README.md

Use query packs when an exploration becomes reusable. The in-memory workstation is still best for scratch work; export_workstation(format="scaffold") now makes that scratch work durable as a query pack. For curated projects, use create_query_pack, save_query_to_pack, validate_query_pack, describe_query_pack, and export_query_pack directly.

Generated run_queries.py supports batch execution with --list, --only, --tag, --param name=value, --output, --format csv|json, --max-rows, --continue-on-error, and --fail-fast. Each run writes one result file per query plus schema sidecars and results/run_log.json. Generated workspaces also include pyproject.toml so uv run and uv sync manage the environment from the project manifest.

Generated streamlit_app.py is the full interactive explorer for a pack. It includes query catalog search, tag and connection filters, typed parameter controls, editable rendered DAX, cached execution, an Explore tab that keeps run/results/charts/pivots together, session run history, column filters, drag-and-drop CSV/JSON upload exploration, profiling, and CSV/JSON/schema/DAX downloads. Use it when you want a DAX Studio-like exploration surface over curated queries:

cd .\my-workspace
uv run streamlit run streamlit_app.py

Generated power_query/*.pq is first-class for MSOLAP connections. REST-backed connections produce an explicit stub until Excel Power Query token refresh is safe enough to automate. Query packs never store tokens or passwords.

The project also includes a Copilot CLI extension in .github/extensions/dax-query-pack/extension.mjs. After extensions_reload, it adds dax_pack_* tools that wrap the same query-pack library and return copyable commands for batch execution and Streamlit.

Validated query libraries

Validated query libraries are connection-scoped context artifacts, not runnable workspace projects. Use them for recurring patterns that should guide future DAX generation: common measures, period grains, required filters, and safe SUMMARIZECOLUMNS shapes. Use query packs when you need a shareable project with batch execution, Streamlit, Power Query, and result artifacts.

Each library lives beside the connection config and stores one metadata file plus one DAX file per query:

Connections/
  sales.yaml
  sales.validated_queries/
    monthly_revenue.yaml
    monthly_revenue.dax

The metadata stores intent, tags, declared parameters, sample validation parameters, output defaults, validation status, row count, returned columns, and a rendered DAX hash. It never stores result rows or secrets. If the DAX file changes after validation, list/search/context calls mark the entry as stale.

Typical MCP workflow:

search_validated_queries → run_connection_query → save_validated_query → validate_query_library(max_rows=1)

max_rows caps returned rows but may not make the server-side DAX plan cheap, so keep validation examples intentionally small and well-filtered. Required parameters need defaults or sample_parameters_json before an entry can pass validation.

get_context_bundle includes compact metadata-only summaries from the library so agents can discover that reusable patterns exist without loading every DAX file. Use search_validated_queries or list_validated_queries(include_dax=True) when you need the actual DAX template for query authoring.

CLI usage

# List configured queries
dax-query --list --config-dir queries

# Run a query
dax-query --query my_query --preview --config-dir queries

# Inspect a connection schema
dax-query --inspect-connection my_model --connections-dir Connections

# Save a query builder artifact
dax-query-builder --save-query-builder-from builder.json --config-dir queries

# Create and export a durable query pack
dax-query-pack create --output-dir .\my-pack --name revenue-exploration
dax-query-pack add-query --pack-path .\my-pack --connection-name arr_connection --query "EVALUATE ROW(\"Example\", 1)" --description "Example query"
dax-query-pack validate --pack-path .\my-pack --connections-dir Connections
dax-query-pack describe --pack-path .\my-pack --connections-dir Connections
dax-query-pack export --pack-path .\my-pack --output-dir .\my-workspace --connections-dir Connections

# Get commands to run the generated workspace
dax-query-pack run-command --workspace-dir .\my-workspace --only example-query --format csv
dax-query-pack streamlit-command --workspace-dir .\my-workspace

Saved .dax files open directly in DAX Studio. See docs/ for detailed CLI documentation.

validate_query_pack can also run a live smoke test through the MCP with dry_run=True and a low max_rows cap. Structural validation runs first; live execution is skipped until manifest, query, connection, and parameter checks are clean.

The query result menu preserves the original flat 1-11 compatibility contract and adds option 12 to save successful queries to the Validated query library. Agents that need machine-readable scope can read followup://menu/grouped to separate This query actions from durable Current pack and Validated query library actions.

Copilot guard hook

A pre-commit hook reviews staged changes for private content (real workspace URIs, local paths, non-sample connection files).

Connection files are ignored by default, and the guard blocks likely real Power BI workspace URIs or dataset IDs. Keep real REST dataset IDs in local, untracked connection files; use all-zero sample IDs in docs and tests.

# Install
powershell -ExecutionPolicy Bypass -File .\scripts\install-git-hooks.ps1

# Runs automatically on commit:
dax-query-guard --mode staged

Add repo-specific patterns via .copilot-guard.local.json:

{
  "blocked_content_patterns": [
    {
      "pattern": "PrivateWorkspace|InternalDataset",
      "reason": "Internal identifiers"
    }
  ]
}

Fails closed by default. Set COPILOT_GUARD_FAIL_OPEN=1 to allow commits when Copilot CLI is unavailable.

Requirements

• Windows + MSOLAP for the default msolap transport (COM/ADODB)
• Azure CLI or access token for the optional powerbi_rest transport
• Python 3.12+ (handled automatically by uvx)
• uv (winget install astral-sh.uv)