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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only says the expression is discarded, but it does not explain what is returned, whether there are side effects, what failure modes exist, or how the tool behaves with no arguments.

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 extremely short and front-loads the primary action in the first sentence. There is no filler or repetition, though the brevity comes at the cost of completeness.

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 no annotations, no output schema, no required parameters, and nine largely unrelated optional properties, this description is severely incomplete. An agent cannot determine what input to send, how to interpret the result, or whether the tool is appropriate for the task.

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 description coverage is 100%, so the baseline is 3 even without parameter details in the description. However, the description does not map 'a+b arithmetic' to any of the nine schema properties, so it adds no semantic value beyond what the schema already provides.

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 'Evaluate a+b style arithmetic,' which names a verb and a task, but the input schema exposes no field for an arithmetic expression. The nine properties (ref, url, city, feed, host, json, path, query) are unrelated to 'a+b' arithmetic, so the description is misleading rather than actionable.

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?

There is no guidance about when to use this tool versus any sibling. It does not mention alternatives, exclusions, prerequisites, or a triggering condition. 'Expression discarded' is a behavioral note, not usage guidance.

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