create_index · PostgreSQL MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_index does on PostgreSQL MCP Server

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

WHY IT NEEDS A POLICY

Why create_index needs a policy

Creating an index is a reversible write operation that modifies database schema by adding a new index object. While it affects performance and consumes storage, the operation can be undone by dropping the index. It does not delete data, execute arbitrary code, or cause financial impact.

From the tool's definition Tool name is 'create_index' and description states 'Create an index on a table'. This is a schema modification operation that creates a new database object.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_index Rate-limited

create_index 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_index": {
      "limits": [
        {
          "counter": "create_index_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches PostgreSQL MCP Server, so you can run agents against it safely.

FAQ

Questions about create_index

What does the create_index tool do? +

Create an index on a table. It is categorised as a Write tool in the PostgreSQL MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_index? +

Register the PostgreSQL MCP Server MCP server in PolicyLayer and add a rule for create_index: 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 PostgreSQL MCP Server. Nothing to install.

What risk level is create_index? +

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

Can I rate-limit create_index? +

Yes. Add a rate_limit block to the create_index 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 create_index completely? +

Set action: deny in the PolicyLayer policy for create_index. 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 create_index? +

create_index is provided by the PostgreSQL MCP Server MCP server (reckersai/mcpg). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.