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

Annotations already declare readOnly, idempotent, and non-destructive hints. The description adds valuable behavioral context: teasers are public, full content requires FolioFact Pro, and the report is 'evidence-linked.' This goes beyond the annotations by clarifying access levels and content characteristics.

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 two sentences, front-loaded with the primary purpose, and every sentence contributes useful information. It avoids redundancy with the schema and annotations.

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 tool's simplicity (3 params, output schema present, read-only annotations), the description covers the essential behavior: fetching a single earnings report, teaser vs. Pro full version, and the access requirement. It does not explain 'period' in detail, but the schema covers that, and the description is adequate for an agent to decide whether to invoke it.

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 schema already has 100% parameter documentation, so the baseline is 3. The description adds meaningful semantics for 'include_full' by explaining that it provides the 'complete evidence-linked report' and that this requires Pro access. This clarifies the difference between teaser and full content, which is not fully explicit in the schema alone.

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 retrieves 'the latest cited earnings report for one stock,' which is specific about the resource (earnings report) and scope (one stock). It does not explicitly distinguish it from sibling tools like 'stock_financials' or 'get_stock,' but the focus on 'earnings' is clear enough to infer its primary use.

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 gives implicit usage context: it is for fetching earnings reports, with teasers publicly accessible and full reports requiring Pro. However, it does not explicitly guide when to choose this tool over alternatives such as 'stock_financials' or 'compare_stocks.' The conditional about 'include_full=true' is more about output depth than tool selection.

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