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

No annotations are provided, so the description carries the full burden. It mentions 'activity (sweat/swim)' as an input, but the input schema does not include such a parameter, creating confusion. The description also does not disclose any behavioral traits like side effects or permissions.

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, starting with the purpose and then usage guidance. It is concise and to the point, though it could be more precise about inputs.

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 that the output schema exists (not shown) and parameters are described in schema, the description fails to explain the output format or any edge cases. The mismatch between described inputs and schema inputs reduces completeness.

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 input schema has 100% parameter descriptions already, so the baseline is 3. The description adds little beyond repeating the parameter names; it mentions activity/water exposure which are not in the schema, potentially misleading.

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 verb 'compute' and the resource 'when to reapply sunscreen', and specifies inputs like SPF, skin type, activity, and UV index. While the sibling list is large, this tool's purpose is distinct and well-stated.

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 says 'Use for sun safety' and suggests seeing list_bundles for related calculators, but it does not explicitly state when not to use this tool or compare it to alternatives like other sun exposure calculators.

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