Agent-skills motherduck-duckdb-sql

DuckDB SQL reference for MotherDuck. Use when you need exact DuckDB syntax, function behavior, supported MotherDuck SQL features, or to resolve whether PostgreSQL-oriented SQL will fail on MotherDuck.

install

source · Clone the upstream repo

git clone https://github.com/motherduckdb/agent-skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/motherduckdb/agent-skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/plugins/motherduck-skills-claude/skills/motherduck-duckdb-sql" ~/.claude/skills/motherduckdb-agent-skills-motherduck-duckdb-sql && rm -rf "$T"

manifest: plugins/motherduck-skills-claude/skills/motherduck-duckdb-sql/SKILL.md

source content

DuckDB SQL Reference for MotherDuck

Use this skill when you need exact DuckDB syntax, function behavior, or a quick sanity check that a statement will actually work on MotherDuck.

Source Of Truth

Prefer current DuckDB SQL docs for language features and function semantics.
Use current MotherDuck SQL docs for MotherDuck-only commands such as shares, secrets, snapshots, and Dive operations.
Check MotherDuck version-lifecycle docs for newly released DuckDB features before promising they are available in MotherDuck.
If the connection path matters, verify behavior against the current Postgres-endpoint docs before promising server-mode support.

Default Posture

Write DuckDB SQL, not PostgreSQL SQL, even when the client connects through the Postgres endpoint.
Use fully qualified
```
"database"."schema"."table"
```
names once more than one database or share is in scope.
Prefer DuckDB-native constructs when they simplify the query:
```
GROUP BY ALL
```
,
```
QUALIFY
```
,
```
UNION BY NAME
```
,
```
arg_max
```
,
```
EXCLUDE
```
, and
```
REPLACE
```
.
For DuckDB 1.5-era syntax such as
```
MERGE INTO
```
,
```
FILL()
```
, or new type support, verify current MotherDuck support before adding it to production guidance.
Check whether the statement depends on local files, extension install/load, temporary-table behavior, or other client-only features before claiming it will work in MotherDuck.
Treat MotherDuck SQL as an additional surface on top of DuckDB SQL, not a replacement for it.

Workflow

Confirm the connection path and whether the question is about syntax, feature support, or a specific error.
Write or repair the statement in DuckDB SQL first.
Verify any MotherDuck-only command or server-mode limitation against the current docs.
If the user needs exact syntax or function details, open
```
references/SYNTAX_REFERENCE.md
```
.

Open Next

```
references/SYNTAX_REFERENCE.md
```
for DuckDB data types, friendly SQL features, functions, complex types, and common MotherDuck-specific gotchas

Related Skills

```
motherduck-query
```
for writing and validating analytical SQL against live MotherDuck data
```
motherduck-connect
```
when syntax support depends on PG endpoint versus native DuckDB behavior
```
motherduck-explore
```
when the problem is really missing schema context rather than missing syntax knowledge