| name | wren-connection-info |
| description | Reference guide for Wren Engine connection info — explains required fields for all 18 supported data sources (PostgreSQL, MySQL, BigQuery, Snowflake, ClickHouse, Trino, DuckDB, Databricks, Spark, Athena, Redshift, Oracle, SQL Server, Apache Doris, S3, GCS, MinIO, local files). Covers sensitive field handling, Docker host hints, and BigQuery credential encoding. Use when the user asks how to configure a data source connection or what fields to fill in. |
| license | Apache-2.0 |
| metadata | {"author":"wren-engine","version":"1.5"} |
Wren Connection Info Reference
Connection info can only be configured through the MCP server Web UI at http://localhost:9001. Do not attempt to set it programmatically. Always direct the user to the Web UI.
Supported data sources
Read the linked reference file for the user's data source to get required fields, default ports, and setup notes.
Common patterns
Most database connectors need: host, port, user, password, database.
Exceptions:
- BigQuery — uses
project_id, dataset_id, credentials (base64-encoded). See databases.md for encoding instructions.
- Snowflake — uses
account instead of host, plus schema.
- Trino — needs
catalog and schema instead of database.
- Databricks — uses
serverHostname, httpPath, accessToken (or service principal with clientId, clientSecret).
- Spark — only
host and port (Spark Connect protocol, no auth fields).
- File sources — use
url, format, plus bucket/credentials. See file-sources.md.
Docker host hint
If the database runs on the host machine and Wren Engine runs inside Docker, localhost cannot reach the host. Use host.docker.internal instead:
| Original | Inside Docker |
|---|
localhost | host.docker.internal |
127.0.0.1 | host.docker.internal |
| Cloud/remote hostname | No change needed |
Sensitive fields
Never log, display, or pass sensitive values through the AI agent unnecessarily.
| Connector | Sensitive fields |
|---|
| Postgres / MySQL / MSSQL / ClickHouse / Oracle / Doris / Redshift | password |
| BigQuery | credentials |
| Snowflake | password |
| Athena | aws_access_key_id, aws_secret_access_key |
| Databricks (token) | accessToken |
| Databricks (service principal) | clientId, clientSecret |
| S3 / MinIO | access_key, secret_key |
| GCS | key_id, secret_key, credentials |
| Trino / Spark / Local files | (none) |
