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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only reveals that the expression is discarded, but says nothing about the return value, side effects, read-only nature, or required permissions. This is too thin 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 two short sentences and front-loads the action immediately. Every word earns its place, and there is no redundant or padding language, though the brevity leaves critical operational details to the schema.

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 9-parameter tool with no annotations and no output schema, this description is severely incomplete. It omits the return format, which parameter receives the expression, side effects, and any disambiguation from siblings, making a correct call nearly impossible to construct reliably.

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 itself has 100% description coverage, so a baseline of 3 is warranted. However, the description's central noun 'expression' matches no schema property, and none of the parameters like ref, url, city, json, or query is identified as the arithmetic expression. An agent cannot tell which field to populate, so the description adds confusion rather than clarifying parameter usage.

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 specific operation ('Evaluate') and a clear resource ('a+b style arithmetic'), so the tool's purpose is immediately recognizable and distinct from the sibling shape-check tools. However, it does not map the expression to any schema parameter, and 'Expression discarded' slightly muddles what is actually being evaluated.

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?

The description gives no explicit when-to-use or when-not-to-use guidance, and it does not name alternatives or exclusions. The intended use is only weakly implied by the phrase 'Evaluate a+b style arithmetic'; there is no context about choosing this tool over a sibling.

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