describe_schema · AWS IoT SiteWise MCP Server MCP

WHAT IT DOES

What describe_schema does on AWS IoT SiteWise MCP Server

AI agents call describe_schema to retrieve information from AWS IoT SiteWise MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

WHY IT NEEDS A POLICY

Why describe_schema needs a policy

The 'describe_schema' operation is a standard read-only action that retrieves schema information. Despite the empty description limiting certainty, the naming convention strongly suggests inspection of existing data structures rather than modification, execution of code, deletion, or financial operations. No side effects are expected.

From the tool's definition Tool name 'describe_schema' indicates a query/retrieval operation following the common 'describe' pattern used for fetching metadata or configuration without modification.

Attacks that exploit this kind of access

Questions about describe_schema

What does the describe_schema tool do? +

describe_schema. It is categorised as a Read tool in the AWS IoT SiteWise MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on describe_schema? +

Register the AWS IoT SiteWise MCP Server MCP server in PolicyLayer and add a rule for describe_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 AWS IoT SiteWise MCP Server. Nothing to install.

What risk level is describe_schema? +

describe_schema is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit describe_schema? +

Yes. Add a rate_limit block to the describe_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 describe_schema completely? +

Set action: deny in the PolicyLayer policy for describe_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 describe_schema? +

describe_schema is provided by the AWS IoT SiteWise MCP Server MCP server (awslabs.aws-iot-sitewise-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.