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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable context about global station coverage (100K+ stations) and the data source (WeatherAPI.com), which goes beyond the annotations without contradicting them.

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 concise: two sentences that front-load the purpose and output fields, then specify input types. No redundant information; every word 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?

The description, combined with the output schema (which exists but is not shown here) and annotations, provides a complete picture. It explains what the tool returns (specific weather parameters) and how to use it (input types). There are no gaps given the tool's simplicity.

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 provides 100% coverage for the 'q' parameter with examples. The description adds further semantic clarity by explicitly listing allowed input types (city name, coordinates, zip, airport code) and noting the global station count, enriching understanding beyond the schema.

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 tool's purpose: to get current weather conditions for any location worldwide, listing specific data fields (temperature, wind, humidity, etc.) and input types. It distinguishes itself from sibling tools like forecast or astronomy by emphasizing 'current' conditions.

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 specifies acceptable input formats (city name, coordinates, zip code, airport code) and notes global coverage, giving clear context for when to use it. However, it does not explicitly mention when not to use it or alternative tools for non-current data, but the distinction is implicit given the title and sibling context.

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