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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the main burden is additional context. The description supplies that context by warning that editing requires a browser session and instructing the agent to send the user to the URL in the response. However, the phrase 'renders spend model credit' is grammatically unclear and weakens the disclosure.

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 definition is short and front-loads the core purpose in the first clause before the caveat and follow-up instruction. It loses one point because the second sentence mixes two ideas (credit spend and browser requirement) in an awkward colon construction.

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 read-only, zero-parameter tool with no output schema, the description explains the high-level return ('what a paid listing returns') and points to the URL in the response. It would be more complete with a clearer statement of what the response literally contains, but the essential agent behavior is covered.

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 zero parameters, and the schema coverage is complete at 100%, so there is no parameter-meaning burden for the description to carry. It appropriately mentions no parameter details, matching the baseline for a no-parameter tool.

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 opens with the resource and return content: 'Duskly's price and what a paid listing returns' and adds a direct trigger: 'Use this when someone asks what it costs or what they get.' It does not name a sibling tool, but the stated scope is specific enough to separate it from checkout, listing, and edit tools.

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 gives an explicit invocation condition ('Use this when someone asks what it costs or what they get') and a clear process limitation ('Editing is not available over MCP... Send the person to the URL in the response'). It stops short of a full 5 because it never names alternatives or states when another sibling should be used instead.

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