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

Beyond the annotations, the description reveals that the URL records only the next request, expires after 24 hours, and that all sent data becomes publicly readable. It also warns against pointing production webhooks with real data at it, which is critical behavioral context not conveyed by 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 four sentences, each earning its place: what it does, when to use it, authentication-free operation, return values, and a security warning. It is front-loaded and free of 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 zero-parameter tool, the description is complete. It covers purpose, usage, return fields, lifespan, and privacy implications. The output schema exists, so return values are also structured, but the description adds necessary context about the public readability and 24-hour expiry.

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 tool has no parameters, and the description confirms 'Takes no parameters.' This adds no new information beyond the empty schema, but it explicitly states the zero-parameter requirement and outlines return values, which is useful clarity. Baseline for 0 params is 4.

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 clearly states 'Create a throwaway URL that records the next HTTP request anyone sends to it, headers and body included.' This is a specific verb+resource, and it distinguishes itself from sibling tools like generate_uuid or store_temporary_data by focusing on webhook capture.

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?

It explicitly explains when to use this tool: 'Use it to see what a webhook provider, a form or a third party service actually transmits, instead of trusting their documentation, and to prove that an integration fired at all.' It also mentions read_webhook_capture as the companion tool for retrieving captures, providing clear alternatives.

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