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

Annotations state idempotentHint=true, but the description's 'Fetches current temperature' implies non-idempotent behavior (results change over time). This contradiction misleads the agent about the tool's repeatability.

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 with one functional sentence, but includes the fluff 'Rigorous methodology' which adds no value and could be removed. Overall efficient but could be tighter.

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?

With an output schema present and the description detailing the algorithm (fetch 10 cities, sum, last two digits), the tool's behavior is fully explained. No additional context is needed.

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?

Schema coverage is 100% with a single optional parameter 'unit' described as 'Temperature unit'. The description adds no additional meaning or context beyond the schema definition, so baseline score 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 clearly states the tool fetches current temperature from 10 cities, sums them, and returns the last two digits. It uses specific verbs and resources and is easily distinguished from sibling tools which are unrelated.

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?

No explicit guidance on when to use or not use this tool versus alternatives. The description implies a unique use case (generating a random-like number from temperature data) but lacks context on appropriate scenarios or limitations.

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