AI agents call list_default_constraints to retrieve information from Mssql without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
schema | string | — | Schema name (default: dbo) |
tableName | string | — | Filter by specific table name |
connectionName | string | — | Named connection to use (e.g., 'production', 'staging') |
connectionString | string | — | SQL Server connection string (uses default if not provided) |
Parameters from the server's own tool schema.
This tool retrieves and lists database schema information (default constraints and their definitions) without creating, modifying, deleting, or executing any operations. It is a read-only query operation with no side effects, consistent with similar schema exploration tools on the server like 'describe_table', 'describe_view', and 'describe_trigger'.
From the tool's definition Tool name 'list_default_constraints' and description 'List all default value constraints and their definitions' indicate retrieval of schema metadata with no modification capability.
Attacks that exploit this kind of access
List all default value constraints and their definitions. It is categorised as a Read tool in the Mssql MCP Server, which means it retrieves data without modifying state.
list_default_constraints accepts 4 parameters: schema, tableName, connectionName, connectionString. The full parameter table on this page comes from the server's own tool schema.
Register the Mssql MCP server in PolicyLayer and add a rule for list_default_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 Mssql. Nothing to install.
list_default_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_default_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_default_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_default_constraints is provided by the Mssql MCP server (mssql-mcp-server). 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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