create_api_schema · Postman MCP: Risk & Policy

WHAT IT DOES

What create_api_schema does on Postman

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

WHY IT NEEDS A POLICY

Why create_api_schema needs a policy

This tool creates a new API schema artifact within Postman, which is a write operation that modifies the workspace by adding a resource. While it has side effects, it is not destructive (no deletion), not execution of external code (no Execute category), and not financial.

From the tool's definition Tool name 'create_api_schema' and description 'Create a schema for an API' indicate creation of a new resource without deletion or irreversible data loss. The action is reversible (schemas can be deleted or updated).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_api_schema Rate-limited

create_api_schema 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_api_schema": {
      "limits": [
        {
          "counter": "create_api_schema_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 Postman, so you can run agents against it safely.

FAQ

Questions about create_api_schema

What does the create_api_schema tool do? +

Create a schema for an API. It is categorised as a Write tool in the Postman 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_api_schema? +

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

What risk level is create_api_schema? +

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

Can I rate-limit create_api_schema? +

Yes. Add a rate_limit block to the create_api_schema 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_api_schema completely? +

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

create_api_schema is provided by the Postman MCP server (postmanv3/postman-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.