A2db MCP server

🗄️ a2db Agent-to-Database Give AI agents safe, read-only access to your databases. One call, multiple queries, clean results. 5 databases · batch queries · pre-configured connections · SQLGlot read-only Quick Start · MCP Tools · Security · Comparison · Setup

Agent: "Show me active users and their recent orders"
  ↓
a2db execute → 2 queries, 1 call, structured results
  ↓
Agent: "Got it — 847 active users, avg order $42.50"

Why a2db?

Most database MCP servers make you run one query at a time, repeat connection details on every call, and return results double-encoded inside JSON strings. a2db fixes all of that:

• Pre-configured connections — define databases in .mcp.json with --register, agent queries immediately
• Batch queries — run multiple named queries in a single tool call
• Default connection — set connection once, use it across all queries in a batch
• Clean output — structured JSON envelope with compact TSV data and per-query timing (see why TSV?)
• Read-only enforced — SQLGlot AST parsing blocks all write operations
• All drivers bundled — pip install a2db and you're done
• Secrets stay in env — ${DB_PASSWORD} in DSNs, expanded only at connection time

Supported Databases

Quick Start

pip install a2db

As an MCP Server (recommended)

Claude Code (with pre-configured connection):

claude mcp add -s user a2db -- a2db-mcp \
  --register myapp/prod/main 'postgresql://user:${DB_PASSWORD}@host/mydb'

Claude Code (minimal — agent calls login on demand):

claude mcp add -s user a2db -- a2db-mcp

Claude Desktop / Cursor / any MCP client (.mcp.json):

{
  "mcpServers": {
    "a2db": {
      "command": "uvx",
      "args": [
        "a2db-mcp",
        "--register", "myapp/prod/main", "postgresql://user:${DB_PASSWORD}@host/mydb"
      ],
      "env": {
        "DB_PASSWORD": "your-password-here"
      }
    }
  }
}

Multiple databases:

{
  "args": [
    "a2db-mcp",
    "--register", "myapp/prod/main", "postgresql://user:${DB_PASSWORD}@host/maindb",
    "--register", "myapp/prod/analytics", "postgresql://user:${DB_PASSWORD}@host/analytics"
  ]
}

--register pre-registers connections at server startup — the agent can query immediately. Passwords use ${ENV_VAR} syntax and are expanded at connection time, never stored in plaintext.

As a CLI

# Save a connection (validates immediately)
a2db login -p myapp -e prod -d main 'postgresql://user:${DB_PASSWORD}@localhost/mydb'

Shortened. The full README is on GitHub.