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Connecting Databases

Add PostgreSQL, MySQL, SQLite, and Elasticsearch connections. Understand what happens during onboarding.

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Baseil supports several database types. Onboarding looks basically the same for all of them: point Baseil at a connection, wait a few seconds, start asking questions. This page walks through the supported types and what the onboarding pipeline actually does with your data.

Supported databases

  • ‣PostgreSQL 12+
  • ‣MySQL 5.7 and 8.0
  • ‣SQLite (file-based or in-memory)
  • ‣Elasticsearch 8.0+
  • ‣REST API endpoints, exposed as virtual tables

More connectors are on the roadmap. If you have a request, drop it on the waitlist form.

Add a connection (Web UI)

From the left sidebar, click Connections, then Add Connection. The form asks for:

  • ‣Name. Just for display. production-db, analytics-warehouse, whatever helps you tell them apart.
  • ‣Type. Pick from the supported list.
  • ‣Host / Port / Database. Standard connection coordinates.
  • ‣Username. We strongly recommend a dedicated read-only user. Baseil enforces read-only at the SQL level too, but defense in depth matters.
  • ‣Password. Encrypted at rest with a key Baseil derives from your installation.
  • ‣Extra options. SSL mode, schema whitelist, sample row count for discovery, etc. Defaults are fine for most setups.

Before you click Onboard, there's a Test Connection button. Use it. It catches typos, bad credentials, firewall issues, and SSL mismatches in a few seconds.

Add a connection (CLI)

The same flow works from the terminal:

baseil connections add \
  --name production-db \
  --type postgresql \
  --host db.internal \
  --port 5432 \
  --database app \
  --username readonly_user
# Baseil prompts for the password, never takes it as an arg

Run baseil connections list to see what's configured. baseil connections remove <name> takes one out.

Connection string examples

Quick reference for filling in the form:

PostgreSQL

Host: db.example.com
Port: 5432
Database: production
Username: baseil_readonly

MySQL

Host: mysql.example.com
Port: 3306
Database: analytics
Username: analytics_ro

SQLite

For SQLite you just supply a path:

Path: /var/data/app.sqlite

In-memory databases work too. Handy for demos and tests.

Elasticsearch

Host: https://es.example.com
Port: 9200
Index pattern: logs-*

The onboarding pipeline

Once you click Onboard, Baseil runs five specialized agents in sequence:

  1. ‣Discovery. Reads tables, columns, data types, foreign keys, inferred relationships, and a handful of sample rows per table. Builds a schema graph that the next stage uses as input.
  2. ‣Tool generation. Writes a set of parameterized query templates. Not one tool per table. Sparse, reusable templates like list_entities_with_filters that generalize across similar queries.
  3. ‣Security review. Every generated tool gets static analysis for injection patterns, parameter handling, and read-only enforcement. Anything the reviewer can't validate gets flagged or rejected.
  4. ‣Testing. Each tool runs against your real database with safe sample parameters. This catches broken SQL, wrong types, and schema assumptions that don't hold in practice.
  5. ‣Deploy. Approved and tested tools get registered in the tool registry, where chat, the API, and the MCP server immediately pick them up.

Visualized:

The pipeline runs once per connection. If your schema changes, you re-onboard that connection and the affected tools get regenerated.

Watching progress

The Activities panel shows the pipeline in real time. Each stage has its own line with a status (running, done, warning) and a short description of what it's doing. Warnings are usually benign: a table with zero rows, a column Baseil couldn't infer a type for, a relationship that looks ambiguous. Errors stop the pipeline and surface the cause.

Activities stick around after onboarding. You can scroll back to see what ran, when, and what happened.

Re-onboarding and schema drift

Schemas change. New tables, dropped columns, renamed fields, changed types. When that happens you have two options:

  • ‣Re-run onboarding on the affected connection. This is a one-click operation from the Connections page. Baseil diffs the new schema against what it knows, and only regenerates tools for changed parts.
  • ‣Update rules. If the change is semantic rather than structural (e.g. you split status into status and substatus), a rule often handles it more cleanly than a full re-onboard.

Schema drift detection is also a standalone feature. You can schedule Baseil to check for drift periodically and notify you when something changes.

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