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

With no annotations, the description must carry behavioral disclosure. It does mention 'Expression discarded', which is a behavioral trait, but it doesn't say what is returned, whether side effects occur, or how the tool can both evaluate and discard the expression. The behavior is ambiguous at best.

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?

Two short sentences are concise but under-specified for a tool with nine parameters and no output schema. The sentences also undermine each other ('Evaluate' vs 'discarded'), so brevity is not serving clarity.

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?

This tool has nine parameters, no annotations, and no output schema, yet the description explains neither the return behavior nor which parameter carries the expression. The description leaves too many critical unknowns for an agent to safely call it.

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 descriptions cover all nine parameters, so the baseline is 3, but the description adds no mapping from 'a+b style arithmetic' to any parameter; in fact, no parameter exists for an expression. This leaves an agent unable to know what to pass.

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 names a specific operation, 'Evaluate a+b style arithmetic', and is distinct from sibling validation tools, but it is self-contradictory: 'Expression discarded' suggests no evaluation actually occurs. It also doesn't map to the input schema, which has no arithmetic-expression parameter.

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 on when to use calc-eval versus any sibling tool, and no alternatives or exclusions are mentioned. The only implicit signal is the name and the arithmetic phrase, but the 'discarded' behavior makes even that unreliable.

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