wren-connection-info

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.

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Supported data sources

Value	Database	Fields reference
POSTGRES	PostgreSQL	databases.md
MYSQL	MySQL / MariaDB	databases.md
MSSQL	SQL Server	databases.md
CLICKHOUSE	ClickHouse	databases.md
ORACLE	Oracle	databases.md
DORIS	Apache Doris	databases.md
REDSHIFT	Amazon Redshift	databases.md
TRINO	Trino	databases.md
BIGQUERY	Google BigQuery	databases.md
SNOWFLAKE	Snowflake	databases.md
DUCKDB	DuckDB	databases.md
ATHENA	AWS Athena	databases.md
DATABRICKS	Databricks	databases.md
SPARK	Apache Spark	databases.md
S3_FILE	Amazon S3	file-sources.md
GCS_FILE	Google Cloud Storage	file-sources.md
MINIO_FILE	MinIO	file-sources.md
LOCAL_FILE	Local files	file-sources.md

Read the linked reference file for the user's data source to get required fields, default ports, and setup notes.

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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.

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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

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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)