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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context by disclosing the cost and payment mechanism, '$0.01 USDC via x402,' and specifies the response content categories. It does not, however, describe error or rate-limit behavior, though those are less critical for a read-only lookup.

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 a single compact sentence that leads with the core purpose, then lists output fields, then gives cost. Every clause adds useful information and no words are wasted.

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?

For a one-parameter, low-complexity tool with no output schema, the description provides sufficient context: what the tool does, where it applies, what it returns, and that it costs money. It does not detail the exact JSON return shape or error behavior, but the included output fields are enough for an agent to use the result appropriately.

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% coverage: the single 'location' parameter is described with examples. The description reinforces that the location is any city name but does not add meaning beyond what the schema already provides, so the baseline of 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 description begins with a specific action and resource: 'Get current weather for any city worldwide.' It enumerates the key outputs (temperature in F/C, conditions, wind speed), making the tool's function unmistakable. Among the many sibling tools, it is clearly the weather lookup tool, so no confusion remains.

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 phrase 'current weather for any city worldwide' establishes when the tool is appropriate and makes its scope clear. It does not explicitly name alternatives or exclusions, but no sibling tool provides weather data, so the context is sufficient for an agent to select this tool.

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