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

No annotations are provided, so the description carries the entire behavioral burden, but it only says the expression is discarded—without even naming a parameter that holds the expression. It does not disclose return behavior, side effects, or safety characteristics.

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 short and front-loaded, but the second sentence ('Expression discarded.) is ambiguous rather than clarifying. Brevity is under-specification for a 9-parameter tool, not a model of conciseness.

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 parameters, no annotations, no output schema, and no explanation of which parameter holds the arithmetic expression, the description is seriously incomplete. An agent cannot reliably use or select this tool without guessing.

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?

Every parameter in the schema has a description, and schema description coverage is 100%, so the baseline is 3. The free-text description itself adds no parameter semantics beyond stating that expression evaluation is involved, but the schema already documents each parameter.

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 verb and a resource ('Evaluate a+b style arithmetic'), but no expression parameter exists in the schema; instead, it lists nine unrelated parameters such as ref, url, and city. An agent cannot tell what to pass or how this tool differs from siblings like validate-json or search-query-len.

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 on when to use this tool versus its siblings, no prerequisites, and no alternative tooling such as normalize-url or validate-json. The second sentence, 'Expression discarded., is a behavioral note, not a usage guideline.

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