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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the useful fact that output is the enumerated set of accepted years, but says nothing about the identifier space for 'list', rate limits, or ordering. With annotations carrying the safety burden, a 3 fits.

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 short sentence with no padding and the key noun (years) up front. Slightly ambiguous phrasing ('List every year accepted by') but efficient and appropriately sized for a one-parameter lookup.

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?

The tool is simple (one optional param) and an output schema exists, so return-value explanation is unnecessary. Still, the description leaves the workflow context incomplete: an agent does not learn what valid 'list' values are or how this ties to fortune_ranking, which matters for correct invocation.

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 0% and the single 'list' parameter has no description, so the description must compensate. It does imply that 'list' names a Fortune ranking list and that the tool returns that list's valid years, which is meaningful. It stops short of stating accepted list values or pointing to a sibling for discovering them.

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 and resource: it enumerates the years accepted by a Fortune ranking list. This is clear enough for an agent to know it returns a set of valid year values. However, it does not distinguish itself from nearby siblings like fortune_ranking_lists or fortune_ranking_filters, leaving the boundary to be inferred.

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 no when-to-use guidance, no exclusions, and names no alternative. An agent must infer on its own that this is a discovery helper for populating a year argument elsewhere. No mention of the prerequisite 'list' identifier or where to obtain it.

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