CONTRIBUTING.md

Contributing

With task installed, simply run task to see the list of available commands. For comments, questions, or requests open a GitHub issue.

Setup

1. Clone the repository:

git clone https://github.com/dbt-labs/dbt-mcp.git
cd dbt-mcp

2. Install uv

3. Install Task

4. Run task install

5. Configure environment variables:

   cp .env.example .env

   Then edit .env with your specific environment variables (see our docs to determine the values).

6. Run task client to chat with dbt MCP in your terminal.

Style

Refer to ./cursor/rules for standards and stylistic guidelines.

Testing

Unit Testing

This repo has automated tests which can be run with task test:unit.

Integration Testing

The integration tests exercise system interactions greater than just the unit tests. They require a dbt Platform environment that is setup with semantic layer, developer license, and PAT. These tests can be run with task test:integration.

For dbt Labs employees, a staging environment has been set up. Credentials for this environment can be found by searching for dbt MCP Integration Test Credentials in 1Password.

Manual Testing

To test in a client like Cursor or Claude, use a configuration file like this:

{
  "mcpServers": {
    "dbt": {
      "command": "<path-to-uv>",
      "args": [
        "--directory",
        "<path-to-this-directory>/dbt-mcp",
        "run",
        "dbt-mcp",
        "--env-file",
        "<path-to-this-directory>/dbt-mcp/.env"
      ]
    }
  }
}

Or, if you would like to test with Oauth, use a configuration like this:

{
  "mcpServers": {
    "dbt": {
      "command": "<path-to-uv>",
      "args": [
        "--directory",
        "<path-to-this-directory>/dbt-mcp",
        "run",
        "dbt-mcp",
      ],
      "env": {
        "DBT_HOST": "<dbt-host-with-custom-subdomain>",
      }
    }
  }
}

For improved debugging, you can set the DBT_MCP_SERVER_FILE_LOGGING=true environment variable to log to a ./dbt-mcp.log file.

Adding Tools

Tools are defined using the @dbt_mcp_tool decorator and registered with the MCP server via register_tools().

Steps to add a new tool

1. Add a ToolName entry in src/dbt_mcp/tools/tool_names.py
2. Map it to a toolset in src/dbt_mcp/tools/toolsets.py (e.g., DISCOVERY, SEMANTIC_LAYER, SQL)
3. Write a prompt file in src/dbt_mcp/prompts/<category>/ describing the tool
4. Define the tool function in the appropriate tools.py module:

   @dbt_mcp_tool(
       description=get_prompt("category/tool_name"),
       title="My Tool",
       read_only_hint=True,
       destructive_hint=False,
       idempotent_hint=True,
   )
   async def my_tool(context: MyToolContext, param: str) -> dict:
       return await context.fetcher.do_something(param)

5. Add it to the tool list (e.g., DISCOVERY_TOOLS) in the same module
6. The registration function (e.g., register_discovery_tools) handles context binding and registration

Adding an MCP App tool

MCP Apps are tools that have an associated interactive UI rendered by the host. They build on top of regular tools with two additions:

1. Use structured_output=True and meta to link the tool to a UI resource:

   @dbt_mcp_tool(
       description=get_prompt("category/tool_name"),
       title="My Visualization",
       read_only_hint=True,
       structured_output=True,
       meta={"ui": {"resourceUri": "ui://dbt-mcp/my-app"}},
   )
   async def my_viz_tool(context: MyToolContext, param: str) -> MyResultType:
       ...

   The return type must be a TypedDict when structured_output=True.

2. Register an MCP resource at the matching ui:// URI to serve the HTML app:

   @dbt_mcp.resource(
       uri="ui://dbt-mcp/my-app",
       name="My App",
       mime_type="text/html;profile=mcp-app",
   )
   def get_my_app_ui() -> str:
       return Path("packages/my-app/dist/index.html").read_text()

3. Build a frontend in packages/ using @modelcontextprotocol/ext-apps. The app receives tool results via the ontoolresult callback and must be bundled as a single HTML file (e.g., using vite-plugin-singlefile) or reference external resources via CSP resourceDomains.

The ui:// URI convention is ui://<server-name>/<resource-name>. The meta field is passed through the full tool registration pipeline (@dbt_mcp_tool → GenericToolDefinition → adapt_context → register_tools → FastMCP.add_tool).

Signed Commits

Before committing changes, ensure that you have set up signed commits. This repo requires signing on all commits for PRs.

Changelog

Every PR requires a changelog entry. Install changie and run changie new to create a new changelog entry.

Debugging

The dbt-mcp server runs with stdio transport by default which does not allow for Python debugger support. For debugging with breakpoints, use streamable-http transport.

Option 1: MCP Inspector Only (No Breakpoints)

1. Run task inspector - this starts both the server and inspector automatically
2. Open MCP Inspector UI
3. Use "STDIO" Transport Type to connect
4. Test tools interactively in the inspector UI (uses stdio transport, no debugger support)

Option 2: VS Code Debugger with Breakpoints (Recommended for Debugging)

1. Set breakpoints in your code
2. Press F5 or select "debug dbt-mcp" from the Run menu
3. Open MCP Inspector UI via npx @modelcontextprotocol/inspector
4. Connect to http://localhost:8000/mcp/v1 using "Streamable HTTP" transport and "Via Proxy" connection type
5. Call tools from Inspector - your breakpoints will trigger

Option 3: Manual Debugging with task dev

1. Run task dev - this starts the server with streamable-http transport on http://localhost:8000
2. Set breakpoints in your code
3. Attach your debugger manually (see debugpy documentation for examples)
4. Open MCP Inspector via npx @modelcontextprotocol/inspector
5. Connect to http://localhost:8000/mcp/v1 using "Streamable HTTP" transport and "Via Proxy" connection type
6. Call tools from Inspector - your breakpoints will trigger

Note: task dev uses streamable-http by default. The streamable-http transport allows the debugger and MCP Inspector to work simultaneously without conflicts. To override, use MCP_TRANSPORT=stdio task dev.

If you encounter any problems, you can try running task run to see errors in your terminal.

Release

Only people in the CODEOWNERS file should trigger a new release with these steps:

1. Consider these guidelines when choosing a version number:

• Major
  • Removing a tool or toolset without replacement, or in a way that would result in agents behaving much differently.
  • Changing the behavior of existing environment variables or configurations
• Minor
  • Changes to config system related to the function signature of the register functions (e.g. register_discovery_tools)
  • Adding optional parameters to a tool function signature
  • Adding a new tool or toolset
  • Removing or adding non-optional parameters from tool function signatures
  • Renaming a tool
  • Removing a tool which overlaps or provides similar functionality as other tool(s)
• Patch
  • Bug and security fixes - only major security and bug fixes will be back-ported to prior minor and major versions
  • Dependency updates which don’t change behavior
  • Minor enhancements
  • Editing a tool or parameter description prompt
  • Adding an allowed environment variable with the DBT_MCP_ prefix

2. Trigger the Create release PR Action.

• If the release is NOT a pre-release, select auto (default) to automatically determine the version bump based on changelog entries, or manually pick patch, minor or major if needed
• If the release is a pre-release, set the bump and the pre-release suffix. We support alpha.N, beta.N and rc.N.
  • use alpha for early releases of experimental features that specific people might want to test. Significant changes can be expected between alpha and the official release.
  • use beta for releases that are mostly stable but still in development. It can be used to gather feedback from a group of peopleon how a specific feature should work.
  • use rc for releases that are mostly stable and already feature complete. Only bugfixes and minor changes are expected between rc and the official release.
• Picking the prerelease suffix will depend on whether the last release was the stable release or a pre-release:

Last Stable	Last Pre-release	Bump	Pre-release Suffix	Resulting Version
1.2.0	-	minor	beta.1	1.3.0-beta.1
1.2.0	1.3.0-beta.1	minor	beta.2	1.3.0-beta.2
1.2.0	1.3.0-beta.2	minor	rc.1	1.3.0-rc.1
1.2.0	1.3.0-rc.1	minor		1.3.0
1.2.0	1.3.0-beta.2	minor	-	1.3.0
1.2.0	-	major	rc.1	2.0.0-rc.1
1.2.0	2.0.0-rc.1	major	-	2.0.0

3. Get this PR approved & merged in (if the resulting release name is not the one expected in the PR, just close the PR and try again step 1)
4. This will trigger the Release dbt-mcp Action. On the Summary page of this Action a member of the CODEOWNERS file will have to manually approve the release. The rest of the release process is automated.