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

The only behavioral hint is 'Expression discarded', which suggests the input is not retained, but there is no mention of whether the tool is read-only, whether it performs side effects, or what it returns. Without annotations, this is insufficient.

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 very short at one sentence, but it is also ambiguous and internally inconsistent. The phrase 'Expression discarded' does not add useful structure and makes the concise text misleading.

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?

There is no output schema and no indication of what the tool returns. Given that the parameters are irrelevant to the stated purpose and the expression input is missing, the description is far from complete enough to call correctly.

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?

All nine parameters (ref, url, city, feed, host, json, path, zone, query) have descriptions that are unrelated to arithmetic evaluation—e.g., 'Git ref name', 'Search text'. No parameter is clearly the arithmetic expression, despite the description claiming to evaluate one.

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 says 'Evaluate a+b style arithmetic' but the input schema contains no expression field, and the phrase 'Expression discarded' is confusingly contradictory. It does not clarify how the arithmetic expression is supplied, making the tool's purpose unclear.

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 given for when to use this tool versus any sibling tool. The description mentions no use cases, prerequisites, or alternatives, leaving the agent to guess.

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