Connect to MotherDuck
Source Of Truth
- Prefer current MotherDuck connection, attach-mode, read-scaling, and multithreading docs.
- If the MotherDuck MCP
ask_docs_questiontool is available, use it first for current connection behavior. - When it is unavailable, verify guidance against the public docs before making firm claims about connection strings, token types, or read-scaling behavior.
Default Posture
- Start with the PG endpoint (MotherDuck's Postgres-compatible endpoint) for backend applications, BI tools, and serverless runtimes that want PostgreSQL wire compatibility.
- For BI tools, treat the PG endpoint as the compatibility path for Power BI and Tableau Cloud when current docs list them as supported.
- Use the native DuckDB API when you need local files, hybrid local/cloud execution, or direct DuckDB control.
- Use
md:workspace connections for multi-database exploration, bootstrap flows, and temporary validation environments. - Reuse an existing connection, connector, or environment-managed token when the user's context already provides one; do not ask for secrets that can be discovered from the active workspace.
- Start with one connection. Add pooling or read scaling only when real concurrent-read pressure exists.
- Use native DuckDB
custom_user_agentwhere supported; for PG endpoint clients, prefer the client'sapplication_namesetting when available.
Runtime Selection
Pick the connection method (above) and the runtime separately. The runtime is what actually executes queries: MotherDuck MCP, the MotherDuck CLI, a Python or Node process, or the DuckDB CLI.
For answer, review, or planning requests, inspect the available runtimes and recommend a path without installing anything. Install or configure a runtime only when the user asks to connect, build, or change the application.
Reuse the project’s language, dependencies, and working connection. Prefer MCP for chat-only exploration and the MotherDuck CLI for file-shaped Dive/Flight work or large output. For application code, use its existing runtime; choose a new runtime only when none is established.
Before installing a DuckDB client, check https://motherduck.com/docs/duckdb-versions.json and pin a MotherDuck-supported version. Keep an existing compatible pin unless the task requires an upgrade. See the runtime reference for installation examples.
Workflow
- Choose the connection path for the workload; keep ingestion and serving paths distinct when their needs differ.
- Put the MotherDuck token in environment-managed secrets, not in source code.
- Establish the connection with explicit SSL settings where required.
- Verify the connection with
SELECT 1 AS connectedand then list reachable tables. - If the workload is read-heavy and concurrent, evaluate read scaling and
session_hint.
References
Read only the reference sections needed for the current task.
- Read
references/CONNECTION_GUIDE.mdfor connection-method selection, PG endpoint and native DuckDB examples, token handling, read scaling, attach modes, and common failure modes - Read
references/RUNTIME_SELECTION.mdfor the MCP-vs-Python-vs-Node-vs-CLI decision tree, detection commands, install snippets, and the DuckDB version-pinning workflow
Related Skills
Load related skills only for missing capabilities; reuse established context.
motherduck-explorefor discovering databases, tables, columns, and shares after the connection is establishedmotherduck-queryfor executing DuckDB SQL against the connected databasesmotherduck-duckdb-sqlfor DuckDB syntax and function lookup supportmotherduck-rest-apifor control-plane admin operations; those useMOTHERDUCK_ADMIN_TOKEN, which is never used for database connectionsmotherduck-clifor terminal queries and file-oriented Dive/Flight authoring