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

With no annotations provided, the description carries the full burden of behavioral disclosure. It thoroughly lists the output data fields and accepted input formats, but it does not address error behavior, data source, or any read-only implications. It is adequate but not exhaustive.

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 compact: two sentences with no filler. The first sentence front-loads the tool's core purpose and outputs, while the second covers input formats. Every sentence adds value.

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 there is no output schema, the description compensates by enumerating all returned metrics and the sunniest month, which is crucial for an agent. It also specifies input format variants. It is complete for the tool's apparent simplicity, though it leaves out edge-case handling, which is a minor gap.

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 describes the parameter with 100% coverage, but the description adds concrete examples ('Faro', 'Nice, France', 'FAO') and reiterates the three accepted formats, which helps clarify exactly how to format the destination value. This goes beyond the schema's baseline.

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 unambiguously states the tool provides a 'Full climate card for one destination' and enumerates the specific metrics (Sunshine Score, temperatures, rainfall, UV, sea temperature). It clearly distinguishes from siblings by emphasizing 'one destination' as opposed to comparison or discovery tools.

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 clearly implies usage for a single destination's climate details, effectively distinguishing it from sibling tools like compare_destinations and find_sunny_destinations. However, it does not explicitly mention when to prefer this tool over alternatives or provide explicit exclusions, so it stops short of a 5.

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