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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds meaningful behavioral context by disclosing that the tool combines two independent sources, that RTMA is updated sub-hourly, and that the METAR portion includes raw METAR and flight category. No contradiction with annotations.

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: three sentences and one example, with the core action front-loaded in the first sentence. Every clause contributes information—source types, update cadence, interpretation guidance, and the forecast alternative—without filler or schema repetition.

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 the rich output schema and fully documented parameters, the description covers the remaining contextual needs: what the tool returns conceptually, which source to trust for what purpose, and when to use a sibling tool instead. The example call further reduces ambiguity for an agent.

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 already documents all three parameters at 100% coverage, so the description carries little parameter burden. The example call {'location': 'Pella, IA'} reinforces that free-text location is supported, but it does not materially add meaning beyond the schema descriptions. Baseline 3 is appropriate.

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 first sentence clearly identifies the operation and resource: retrieving current weather conditions at a location, using two independent sources (RTMA gridded analysis and nearest METAR station). It explicitly contrasts with a forecast need via 'For a forecast, use get_forecast,' which distinguishes it from an important sibling tool.

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 states when to use this tool ('Current weather right now at a location') and explicitly routes forecast requests to get_forecast. It also provides internal usage guidance: use the RTMA analysis for point-accurate values and the METAR station for verification, helping the agent interpret the dual-source response.

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