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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds context that the list is ranked by revenue descending and implies pagination (page parameter description mentions page size of 10). No contradictions.

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?

Two sentences, concise and front-loaded with the core purpose. Every word adds value, 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?

Given the output schema exists (so return values are documented elsewhere), the description covers the use case, ranking criteria, and triggers for use. It could explicitly state that it returns a list of top referrers, but the parameter description covers pagination.

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?

Schema coverage is 100%. The description does not add additional meaning beyond the schema's parameter description for 'page'. No elaboration on parameter semantics is needed beyond what the schema provides.

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 finds 'top-performing referrers' ranked by revenue descending, and includes the verb 'Find' and the resource 'referrers'. It distinguishes from sibling 'cello_get_referrers' by specifying ranking and revenue metric.

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?

Explicitly tells when to use: 'Use when a user asks about top referrers, best performers, or which referrers generate the most revenue.' This directly guides the agent to select this tool over alternatives like 'cello_get_referrers'.

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