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 explaining behavior. It reveals only that the expression is 'discarded', but does not state what the tool returns, whether it actually performs computation, whether it has side effects, or how it handles invalid expressions. The schema mismatch further obscures the tool's real behavior.

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 short and front-loaded, with no filler words. However, it is under-specified rather than elegantly concise: two sentences leave the tool's input contract and behavior largely unexplained.

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 9-parameter tool with no annotations and no output schema, this description is critically incomplete. It does not explain which parameter carries the expression, what result shape is returned, or what 'discarded' means for the caller. An agent would have to guess or experiment to use this tool 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?

The schema covers all 9 parameters with individual descriptions, but the tool description does not mention any of them. Worse, the described 'a+b arithmetic expression' has no corresponding parameter, so the description fails to help an agent select or fill the correct input.

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 concrete action ('Evaluate a+b style arithmetic'), so it is not a pure tautology. However, the input schema contains no parameter for an arithmetic expression, making the stated purpose misleading in practice. An agent cannot determine what input actually carries the expression to evaluate.

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 description gives no guidance on when to use this tool instead of related siblings like validate-json, search-query-len, or file-path-ok. It does not mention any conditions, exclusions, or alternative tools.

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