Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description reveals critical behavioral details beyond the destructiveHint annotation: the old secret stops working immediately, the receiver must be updated first, and the new secret is returned only once. These are essential for the agent to understand the consequences of the action and are not present in the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three short sentences, each earning its place: purpose, immediate-effect warning, and return behavior. It is front-loaded with the core action and contains no fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter, no-output-schema tool, the description covers the action, the critical ordering requirement, and the return value ('new secret is returned once'). The destructive annotation is supplemented with concrete impact, making the description complete for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides 100% coverage for the single parameter endpoint_id, including its source ('Endpoint id from list_webhook_endpoints'). The description does not add additional parameter-level detail, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Replace') and a specific resource ('the signing secret of one webhook endpoint'), clearly distinguishing it from siblings like create_webhook_endpoint and delete_webhook_endpoint. This leaves no ambiguity about what the tool does.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear operational context: 'old secret stops verifying immediately, so update the receiver first' implies when and how to use it safely. It does not explicitly name alternatives or state when not to use it, but the tool's unique purpose among siblings makes the usage context clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.