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

No annotations are provided, so the description carries full responsibility. It only says 'Expression discarded', which hints at a behavior but is ambiguous—no indication of side effects, permissions, return value, or what 'discarded' means operationally. This is insufficient for a tool with 9 parameters and no output schema.

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 a single sentence with no waste, but it is under-specified. It lacks any structure or front-loading of key info. While concise, it fails to convey essential operational details, making it more of an under-specification than a concise, well-structured description.

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?

For a tool with 9 parameters, no output schema, and no annotations, this description is severely incomplete. It does not explain how to use the parameters, what the tool returns, or when to call it. An agent would be completely in the dark about correct 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?

Schema coverage is 100%, so every parameter already has a description. The tool description adds no parameter-specific meaning beyond the schema. Since the schema is complete, the baseline of 3 is appropriate; the description neither enhances nor contradicts the parameter documentation.

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 'Evaluate a+b style arithmetic', which gives a specific action but is vague. It doesn't clarify how the expression is provided, and none of the 9 parameters (ref, url, city, etc.) suggest an arithmetic expression. It does not distinguish this tool from siblings like shape-checkers or fetch tools. The phrase 'Expression discarded' adds confusion rather than clarity.

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 provided on when to use this tool versus any alternative. There is no mention of prerequisites, context, or exclusion criteria. An agent has no basis to decide to call this tool instead of a sibling.

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