wren-connection-info - Claude MCP Skill

# 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](references/databases.md) |
| `MYSQL` | MySQL / MariaDB | [databases.md](references/databases.md) |
| `MSSQL` | SQL Server | [databases.md](references/databases.md) |
| `CLICKHOUSE` | ClickHouse | [databases.md](references/databases.md) |
| `ORACLE` | Oracle | [databases.md](references/databases.md) |
| `DORIS` | Apache Doris | [databases.md](references/databases.md) |
| `REDSHIFT` | Amazon Redshift | [databases.md](references/databases.md) |
| `TRINO` | Trino | [databases.md](references/databases.md) |
| `BIGQUERY` | Google BigQuery | [databases.md](references/databases.md) |
| `SNOWFLAKE` | Snowflake | [databases.md](references/databases.md) |
| `DUCKDB` | DuckDB | [databases.md](references/databases.md) |
| `ATHENA` | AWS Athena | [databases.md](references/databases.md) |
| `DATABRICKS` | Databricks | [databases.md](references/databases.md) |
| `SPARK` | Apache Spark | [databases.md](references/databases.md) |
| `S3_FILE` | Amazon S3 | [file-sources.md](references/file-sources.md) |
| `GCS_FILE` | Google Cloud Storage | [file-sources.md](references/file-sources.md) |
| `MINIO_FILE` | MinIO | [file-sources.md](references/file-sources.md) |
| `LOCAL_FILE` | Local files | [file-sources.md](references/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](references/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](references/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) |