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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows this is a safe, external-facing read. The description adds that the set includes Fortune China 500, a useful content hint, but discloses nothing further about scope, pagination, or freshness. With annotations covering the safety profile, a 3 is appropriate.

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?

A single front-loaded sentence that names the resource first and layers the example and cross-reference after. Slightly dense but every clause earns its place with no padding.

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?

An output schema exists, so return values need no explanation, and the description covers the tool's scope plus its relationship to the sibling ranking tools. Complete enough for a zero-parameter discovery tool.

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 takes zero parameters, so per the baseline there is no schema semantics for the description to add. The mention of a 'list parameter' belongs to sibling tools, not this one, so it neither helps nor harms here.

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?

States a specific verb+resource ('List every public ranking Fortune serves') and gives a concrete example (Fortune China 500), which distinguishes it from fortune_ranking/fortune_ranking_years as an enumeration tool. It doesn't explicitly name which sibling to prefer, but the cross-reference to 'the other fortune_ranking tools' list parameter' clarifies its role.

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 phrase 'accepted by the other fortune_ranking tools' list parameter' clearly conveys when to reach for this tool: to discover valid values for the list parameter before calling the ranking tools. It stops short of explicitly saying 'call this first', so it is strong context rather than a hard when/when-not rule.

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