commit_transaction · Postgres MCP: Risk & Policy

WHAT IT DOES

What commit_transaction does on Postgres

AI agents use commit_transaction 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.

WHY IT NEEDS A POLICY

Why commit_transaction needs a policy

The tool commits an active transaction, permanently writing all pending changes to the database. While transactions themselves are reversible before commit, the commit action makes changes permanent and irreversible within the transaction's scope. This is more severe than a simple Write (which can often be undone with another Write), but less severe than Destructive (which explicitly deletes/drops data).

From the tool's definition Tool name 'commit_transaction' and description 'making all changes permanent' indicate irreversible finalization of database modifications.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

commit_transaction Rate-limited

commit_transaction 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": {
    "commit_transaction": {
      "limits": [
        {
          "counter": "commit_transaction_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about commit_transaction

What does the commit_transaction tool do? +

Commit an active transaction, making all changes permanent. 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 commit_transaction? +

Register the Postgres MCP server in PolicyLayer and add a rule for commit_transaction: 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 commit_transaction? +

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

Can I rate-limit commit_transaction? +

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

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

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