Harlequin CLI
Harlequin provides a terminal SQL editor, while its bundled hsql runs queries and explores database structure for agents.
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- MIT
Extended access
Why this level
- SQL without read-only restrictions can modify data allowed by the connected account.
Install
In your terminal, with SkillFoxx CLI
npx skillfoxx add cli/harlequinDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- SQL without read-only restrictions can modify data allowed by the connected account.
This is third-party code. Review the repository files before installing.
What it does
Harlequin edits and executes SQL in a terminal interface. DuckDB and SQLite adapters are included, with other databases available through separate packages. Users choose connections, browse catalogs and inspect query results. The bundled `hsql` command serves agents and scripts without an interactive screen, sharing the same adapters and profiles. It executes queries, lists schema objects and searches the catalog. Read-only mode and timeouts constrain work when supported by the selected adapter.
Who it is for. SQL analysts needing a manual editor and an agent-friendly command sharing connection profiles.
Good fit when
- Open local DuckDB or SQLite in a terminal editor.
- Let an agent inspect a schema without writing SQL.
- Share a connection profile between manual work and scripts.
- Apply read-only access and a time limit to an exploratory query.
Not a fit when
- The adapter cannot enforce required read-only or timeout constraints.
- You need centralized database-access approval management.
- All external databases must work without extra adapters.
Example request
Inspect the database catalog with read-only hsql and find customer_id columns without fetching user rows.Limitations
Extra adapters must be installed in the same environment as Harlequin; the main CLI does not include every database driver. Given a nonexistent DuckDB file path, the client can create a new database, so check connection strings. Not every adapter can enforce `--read-only` or a timeout; the client refuses to start the query if the adapter cannot enforce the requested protection. Queries without read-only mode use account permissions and can modify data, so prepare a dedicated agent profile.
How to disable. Exit Harlequin or hsql and remove unneeded profiles. Closing the client does not undo completed queries.
FAQ
Is hsql a separate installation?
No. It ships with Harlequin and shares adapters and configuration.
What opens without arguments?
An in-memory DuckDB session. Check paths before using database files.
How do I choose SQLite?
Use `--adapter sqlite` with a file or omit it for an in-memory session.
Can I inspect just the schema?
Yes. `hsql --catalog --path mydb.analytics` lists schema objects, while `hsql --catalog-search customer_id` searches the whole catalog. Substitute your own names.
How do I keep shared profiles free of passwords?
Use configuration environment-variable substitution and store real secrets separately.
Discussion
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README in short
Profiles support environment substitution. hsql can show, validate and describe configuration schemas.