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

With no annotations, the description carries the full burden of disclosing behavior. The only behavioral hint is 'Expression discarded', which is cryptic and does not explain side effects, return values, or permissions. The description contradicts the schema by implying arithmetic while the schema parameters are unrelated to arithmetic, making it misleading.

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 vague sentence. This is under-specification, not conciseness, and it fails to front-load any useful information for an agent trying to decide whether to invoke the tool.

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 tool has 9 parameters, no output schema, and no annotations. A complete description would explain what the tool does with these parameters, what it returns, and any constraints. This description provides none of that, making it completely inadequate for correct invocation.

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?

Although schema description coverage is 100%, the tool description adds no meaning to any of the 9 parameters. It does not mention them at all, and its claim of 'a+b style arithmetic' does not map to any parameter, actively confusing rather than clarifying.

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 states a verb 'Evaluate' and a resource 'a+b style arithmetic', but this is extremely vague and does not align with the input schema, which lists parameters like ref, url, city, etc. It fails to distinguish the tool from any of the 27 siblings, and the actual function is unclear given the schema.

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 guidance is provided on when to use this tool versus alternatives. There is no mention of exclusions, prerequisites, or scenarios that favor this tool over any of the many sibling tools listed.

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