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

Annotations already provide readOnlyHint=true, destructiveHint=false, and idempotenceHint=true, covering the safety profile. The description adds the behavioral trait that the expression is discarded, which is useful context beyond the annotations. No contradiction is present.

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 concise, with two short sentences and no wasted words. It front-loads the core action. However, the terseness leaves out important output details, slightly reducing the 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?

There is no output schema and the description does not state what the tool returns (e.g., a boolean shape-check result or a numeric evaluation). With a large parameter list and no guidance on which parameters are relevant, the description is incomplete for reliable invocation.

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 parameters already have schema descriptions, giving 100% coverage, so the baseline is 3. The description adds minimal extra meaning—'a+b style' hints at the expected expression syntax—but does not clarify the roles of the many other unrelated parameters.

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 specific action ('Evaluate a+b style arithmetic') and resource (arithmetic expressions), which distinguishes it from sibling shape-check tools like domain-shape or validate-json. However, 'Expression discarded' is ambiguous about whether the result is returned, preventing a perfect score.

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 about when to use this tool versus alternatives. It does not mention any sibling tools or describe the context in which arithmetic evaluation should be chosen over other shape-check or validation tools.

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