List all constraints (primary keys, foreign keys, unique, check) for a table
AI agents call list_constraints to retrieve information from Database MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves schema constraint metadata from a database table. It is a non-mutating query operation analogous to other introspection tools on the server (describe_table, list_columns, list_indexes, list_schemas). It has no side effects, does not execute arbitrary code, and does not modify or delete data.
From the tool's definition Tool name 'list_constraints' and description 'List all constraints (primary keys, foreign keys, unique, check) for a table' indicate a retrieval operation that queries metadata without modifying data or triggering side effects.
Attacks that exploit this kind of access
List all constraints (primary keys, foreign keys, unique, check) for a table. It is categorised as a Read tool in the Database MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Database MCP Server MCP server in PolicyLayer and add a rule for list_constraints: 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 Database MCP Server. Nothing to install.
list_constraints 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 list_constraints 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 list_constraints. 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.
list_constraints is provided by the Database MCP Server MCP server (zeaozhang/database-mcp). 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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