Create a new database schema.
AI agents use PostgreSQL_create_schema 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.
Creating a schema modifies the database structure but is reversible via DROP SCHEMA, making it a Write operation rather than Destructive. The blast radius is medium because incorrect schema creation could interfere with application functionality and require cleanup, but the change is not irreversible.
From the tool's definition Tool name contains 'create' and description states 'Create a new database schema', indicating reversible data structure creation.
Documented attack patterns abuse exactly the kind of access PostgreSQL_create_schema gives an agent:
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_create_schema:
{
"version": "1",
"default": "deny",
"tools": {
"PostgreSQL_create_schema": {
"limits": [
{
"counter": "postgresql_create_schema_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}PostgreSQL_create_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.
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Create a new database schema. 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.
Register the Postgres MCP server in PolicyLayer and add a rule for PostgreSQL_create_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 Postgres. Nothing to install.
PostgreSQL_create_schema 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 PostgreSQL_create_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.
Set action: deny in the PolicyLayer policy for PostgreSQL_create_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.
PostgreSQL_create_schema 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.
Start from Postgres, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
239 Postgres tools catalogued and risk-classified — across an index of 43,000+ MCP servers.