/motherduck-connect

name: motherduck-connect
description: Connect to MotherDuck from any application. Use when setting up database connectivity via the Postgres endpoint (recommended), pg_duckdb, native DuckDB API, or JDBC. Covers connection strings, authentication, SSL, and environment variable configuration.
license: MIT

Connect to MotherDuck

Use this skill when establishing database connectivity from any application, script, or service to MotherDuck. Start here before running queries or loading data.

Source Of Truth

• Prefer current MotherDuck connection, attach-mode, read-scaling, and multithreading docs.
• If the MotherDuck MCP `ask_docs_question` tool 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 only 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_agent` where supported; for PG endpoint clients, prefer the client's `application_name` setting when available.

Runtime Selection

Pick the connection method (above) and the runtime separately. The runtime is what actually executes queries: an MCP server, a Python script, a Node script, 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.

Classify the workload first:

• **Ad-hoc / exploration**: one-shot, interactive, may be discarded. No artifact ships.
• **Recurring / pipeline**: scheduled, version-controlled, runs unattended. Code is checked into a repo.

Then resolve in this order, stopping at the first match:

1. **MotherDuck MCP available + workload is ad-hoc** → use the MCP tools (`query`, `list_databases`, `list_tables`, `list_columns`, `search_catalog`). No client to install. Stop here. 2. **`uv` is installed** (`command -v uv`) → run scripts via `uv run --with "duckdb==<version>" script.py`. Preferred for both ad-hoc scripts and pipelines because dependencies are declared inline and reproducible. 3. **`python3` + `pip` available** → `pip install "duckdb==<version>"` inside a project-managed venv. 4. **`node` + `npm` available** → `npm install @duckdb/node-api@<version>`. 5. **None of the above** → install the DuckDB CLI: `curl -s https://install.motherduck.com | env -u motherduck_token HOME="$install_home" sh`. Pick `$install_home` as a writable, project-local path (for example `./.duckdb`) rather than polluting the user's home.

If the host project already declares a language (a `pyproject.toml`, `package.json`, or similar lockfile is present), follow that language even if the priority order would suggest otherwise. Do not introduce a second runtime alongside an existing one.

Before any install step, fetch `https://motherduck.com/docs/duckdb-versions.json` and pick the highest MotherDuck-supported DuckDB version. Pin that version explicitly in the install command. Latest upstream DuckDB is **not** automatically supported on MotherDuck.

Workflow

1. Choose one connection method and do not mix methods in the same application. 2. Put the MotherDuck token in environment-managed secrets, not in source code. 3. Establish the connection with explicit SSL settings where required. 4. Verify the connection with `SELECT 1 AS connected` and then list reachable tables. 5. If the workload is read-heavy and concurrent, evaluate read scaling and `session_hint`.

Open Next

• Read `references/CONNECTION_GUIDE.md` for connection-method selection, PG endpoint and native DuckDB examples, token handling, read scaling, attach modes, and common failure modes
• Read `references/RUNTIME_SELECTION.md` for the MCP-vs-Python-vs-Node-vs-CLI decision tree, detection commands, install snippets, and the DuckDB version-pinning workflow

Related Skills

• `motherduck-explore` for discovering databases, tables, columns, and shares after the connection is established
• `motherduck-query` for executing DuckDB SQL against the connected databases
• `motherduck-duckdb-sql` for DuckDB syntax and function lookup support
• `motherduck-rest-api` for control-plane admin operations; those use `MOTHERDUCK_ADMIN_TOKEN`, which is never used for database connections