Describe a table: columns, types, nullability, defaults, indexes, and foreign keys.
AI agents call describe_table to retrieve information from PostgreSQL MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns database schema information without modifying or deleting any data. It is a pure read operation that provides introspection capabilities, similar to DESCRIBE or INFORMATION_SCHEMA queries in SQL. The blast radius is minimal—misuse would only expose schema structure.
From the tool's definition Tool name 'describe_table' and description 'Describe a table: columns, types, nullability, defaults, indexes, and foreign keys' indicate retrieval of schema metadata only. No data modification, deletion, or execution of arbitrary code.
Attacks that exploit this kind of access
Describe a table: columns, types, nullability, defaults, indexes, and foreign keys. It is categorised as a Read tool in the PostgreSQL MCP Server MCP Server, which means it retrieves data without modifying state.
Register the PostgreSQL MCP Server MCP server in PolicyLayer and add a rule for describe_table: 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.
describe_table is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the describe_table 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 describe_table. 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.
describe_table is provided by the PostgreSQL MCP Server MCP server (sebivarga/mcp_psql_home). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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