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

No annotations are present, so the description carries the full burden of disclosing behavior. The only behavioral detail is 'Expression discarded,' but the description does not explain return values, side effects, error behavior, or whether evaluation produces any observable result. This is insufficient for a tool with no annotation support.

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 only one sentence and contains no filler, so it is concise and front-loaded. However, wording like 'a+b style' and 'Expression discarded' is terse to the point of ambiguity, preventing a higher score.

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 nine optional parameters, no annotations, and no output schema, the description must explain how to invoke the tool correctly: which parameter receives the expression, what the result looks like, and what 'discarded' means. None of that is provided, so the tool is not reliably callable from the description alone.

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 describes all parameters with 100% coverage, but none of those parameters is described as an arithmetic expression. The description says to evaluate 'a+b style arithmetic' without stating which of the nine parameters should contain the expression, so an agent cannot map the tool's purpose to the available inputs. The description adds no parameter-level clarity and actually creates a disconnect.

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 clear verb and resource: 'Evaluate a+b style arithmetic.' This distinguishes it from sibling validation tools, none of which claim arithmetic evaluation. However, the phrase 'Expression discarded' muddles the purpose: if the expression is discarded, it is unclear what the tool returns or whether it actually computes anything, leaving the core function ambiguous.

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 of the 27 siblings, nor when not to use it. No alternatives, conditions, or prerequisites are mentioned. An agent must guess what input would trigger arithmetic evaluation.

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