Register a database connection string and return its connection ID. Args: connection_string: PostgreSQL connection string (required) ctx: Request context (injected by the framework) Returns: Dictionary containing the connection ID
AI agents use connect to create or update resources in Pg — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Pg environment.
This tool registers a new database connection, which is a reversible configuration action that persists state in the MCP server's connection registry. While not directly modifying data in the database itself, it creates a connection object/resource and thus qualifies as Write rather than Read.
From the tool's definition Tool "connect" with description "Register a database connection string and return its connection ID" performs a reversible operation that stores/creates a connection configuration.
Documented attack patterns abuse exactly the kind of access connect gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Pg, and nothing reaches the server without passing your rules. This is the rule we recommend for connect:
{
"version": "1",
"default": "deny",
"tools": {
"connect": {
"limits": [
{
"counter": "connect_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}connect stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Register a database connection string and return its connection ID. Args: connection_string: PostgreSQL connection string (required) ctx: Request context (injected by the framework) Returns: Dictionary containing the connection ID. It is categorised as a Write tool in the Pg MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Pg MCP server in PolicyLayer and add a rule for connect: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Pg. Nothing to install.
connect is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the connect rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for connect. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
connect is provided by the Pg MCP server (stuzero/pg-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 Pg tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
5 Pg tools catalogued and risk-classified — across an index of 42,500+ MCP servers.