Medium Risk

PostgreSQL_grant_privileges

PostgreSQL_grant_privileges

How to control PostgreSQL_grant_privileges ↓

What PostgreSQL_grant_privileges does on Postgres

AI agents use PostgreSQL_grant_privileges to create or update resources in Postgres — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Postgres environment.

Medium Risk

Why PostgreSQL_grant_privileges needs a policy

Granting privileges modifies access control settings in PostgreSQL, which is a write/modification operation. It is reversible (privileges can be revoked), but misuse could allow unauthorized users to gain elevated access to the database, making the blast radius high. The description is empty, so confidence is reduced, but the tool name strongly implies privilege assignment.

From the tool's definition Tool name 'PostgreSQL_grant_privileges' — the word 'grant' implies assigning permissions/privileges to database users or roles.

Documented attack patterns abuse exactly the kind of access PostgreSQL_grant_privileges gives an agent:

How to control PostgreSQL_grant_privileges

PolicyLayer is an MCP gateway — it sits between your AI agents and Postgres, and nothing reaches the server without passing your rules. This is the rule we recommend for PostgreSQL_grant_privileges:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "PostgreSQL_grant_privileges": {
      "limits": [
        {
          "counter": "postgresql_grant_privileges_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

PostgreSQL_grant_privileges 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.

  1. Create a free account and register Postgres — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
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Related tools and policies

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Questions about PostgreSQL_grant_privileges

What does the PostgreSQL_grant_privileges tool do? +

PostgreSQL_grant_privileges. It is categorised as a Write tool in the Postgres MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on PostgreSQL_grant_privileges? +

Register the Postgres MCP server in PolicyLayer and add a rule for PostgreSQL_grant_privileges: 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 Postgres. Nothing to install.

What risk level is PostgreSQL_grant_privileges? +

PostgreSQL_grant_privileges is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit PostgreSQL_grant_privileges? +

Yes. Add a rate_limit block to the PostgreSQL_grant_privileges 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.

How do I block PostgreSQL_grant_privileges completely? +

Set action: deny in the PolicyLayer policy for PostgreSQL_grant_privileges. 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.

What MCP server provides PostgreSQL_grant_privileges? +

PostgreSQL_grant_privileges is provided by the Postgres MCP server (mukul975/postgres-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Postgres tool call.

Start from Postgres, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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239 Postgres tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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