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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds valuable behavioral context: it explicitly states 'Read-only' (consistent with annotations) and clarifies the settlement process ('earnings settle non-custodially to your withdrawal address on release'), which gives the agent deeper understanding of the tool's side effects and data flow. This goes beyond the structured hints.

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 well-structured: it starts with the primary purpose, then lists the return items in a comma-separated sequence, and ends with a concise note about the settlement behavior. It is detailed but not verbose, and every sentence contributes value. The front-loading of the purpose makes it immediately clear what the tool does.

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?

Given the output schema exists and the description already enumerates the key return categories, the tool is adequately specified. It also covers the non-custodial settlement detail, which is a critical behavioral aspect. There is no obvious missing information that an agent would need to correctly invoke this tool, given that it takes no parameters and relies on authentication context.

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 (schema coverage 100%) and the input schema already states that arguments are not needed. According to the baseline rule for 0 parameters, a score of 4 is warranted because there is nothing for the description to add. The description doesn't mention parameters, which is fine; it focuses on the output, which is more relevant.

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 the tool's purpose with a specific verb ('Check') and resource ('earnings'), then enumerates exactly what it returns: lifetime USDC earned, in-flight pending amounts, unclaimed rewards, payout balance, buyer spend summary, and reputation. This level of detail makes the tool's function unambiguous and distinguishes it from any potential sibling tools, even without explicit naming.

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 implies usage via the phrase 'Check how much I have earned and what is pending,' which tells the agent when it's appropriate to call this tool. However, it doesn't explicitly mention alternative tools or provide any exclusion criteria (e.g., 'if you need X, use Y instead'). No sibling tools directly overlap, but the guidance is still only implied, not explicit.

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