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

Annotations already declare readOnlyHint and idempotentHint. The description adds useful context: browsing is free, requires no key, and returns price and endpoint for each tool. There is no contradiction, and the additional details go beyond the annotations without overexplaining.

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. The primary purpose is front-loaded, followed by use cases and return details. No fluff, no repetition, and it is optimally sized for the tool's simplicity.

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?

Despite lacking an output schema, the description explicitly mentions what is returned (price per call and endpoint) and access requirements (free, no key). The tool is a simple list with three optional filters already documented in the schema. This is sufficient for an agent to invoke it correctly.

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?

All three parameters (search, max_price_usd, verified_only) have schema descriptions, giving 100% coverage. The description does not add extra meaning to these parameters beyond what the schema already provides, 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+resource ('Find a paid tool' / 'Returns every tool on the market'), explains what it provides (price per call and endpoint), and differentiates from siblings focused on earnings, listings, and registration. This is unambiguous and immediately tells the agent 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 explicitly states when to use: when the user needs a capability you lack and is willing to pay, or asks about available paid tools/APIs. It also notes that browsing is free and needs no key. However, it does not mention when not to use it or point to alternatives like get_my_listing or register_server, so it lacks explicit exclusions.

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