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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable context about the output content (segment types, fields, and NZD thousands units), which helps the agent anticipate what the tool returns beyond what the structured annotations provide.

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?

Three sentences with the action and resource front-loaded, followed by return data and usage triggers. Every sentence earns its place with no redundancy, making it appropriately sized and efficiently structured.

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?

With an output schema present and annotations covering safety, the description provides the trigger phrases, return scope, and units. This is complete for an agent to select and invoke the tool correctly without missing prerequisites or caveats.

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 covers all 4 parameters with descriptions (ticker, type, year, limit). The description reinforces the type values and ticker format but adds no new parameter meaning beyond the schema, so the baseline of 3 applies.

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?

Explicitly states the verb 'Get' and the resource 'revenue segment breakdown' for an NZX company, and clarifies the return data (operating/geographic/product segments with revenue, profit, assets). This clearly distinguishes it from siblings like get_financials and get_earnings, which cover broader financial metrics.

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?

Provides explicit trigger phrases ('revenue breakdown', 'business segments', 'divisions', etc.) that signal when to use the tool. However, it does not mention when not to use it or recommend alternative tools, so it lacks exclusion guidance despite clear use-case guidance.

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