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

There are no annotations, so the description carries the full burden. It discloses that the expression is discarded, but does not state whether a numeric result is returned, how errors are handled, or what side effects occur.

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 text is brief and the main verb is front-loaded, but the second sentence is cryptic and no parameter mapping is included. This is under-specification rather than effective conciseness for a nine-parameter tool.

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 no annotations, no output schema, and nine unrelated optional parameters, a two-sentence description is completely inadequate. The agent cannot tell what input is required, what the call returns, or how arithmetic-related inputs are represented.

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 the nine parameters, but the description's 'a+b expression' maps to none of them; every parameter is optional and marked as a shape-check or discard-only field. An agent cannot identify which parameter to populate to perform arithmetic.

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 first phrase names a concrete operation ('Evaluate a+b style arithmetic'), but the second ('Expression discarded') muddies whether the tool returns a result or is a discard/check helper. With no arithmetic parameter in the input schema, the actual purpose is 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?

No guidance on when to choose this tool over alternatives; sibling tools like domain-shape and validate-json are not referenced. The only context is the operation name, so an agent must infer applicability.

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