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. The cryptic statement 'Expression discarded' does not clarify what happens to the expression or the parameters; it only hints that results are not returned, without explaining side effects, output, or error behavior. This is severely inadequate for a tool with 9 parameters.

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 short (one sentence), but it is not concise in a helpful way; it is under-specified. It lacks any structured breakdown of the tool's behavior, parameters, or usage, so the brevity harms clarity rather than aiding it.

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?

Given the tool's complexity (9 optional parameters, no required fields, no output schema) and the lack of annotations, the description is completely inadequate. An agent cannot infer how to invoke the tool correctly, what the parameters mean, what the tool returns, or when to use it. The description covers almost none of the needed context.

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 each parameter has a description, but those descriptions (e.g., 'discarded after the shape check', 'discarded after the call') only state that the parameter is discarded, not what it contributes to the operation. The tool description adds no additional meaning about how parameters are used, and it fails to compensate for the fact that the schema descriptions are uninformative about actual functionality.

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 verb and resource ('Evaluate a+b style arithmetic') but it is misleading because the input schema contains 9 unrelated parameters (ref, url, city, etc.) with no arithmetic-related field. This creates confusion about what the tool actually does, and it does not distinguish it from any of the 28 sibling tools.

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 vs. alternatives. The description gives no context about intended scenarios, prerequisites, or exclusions, leaving the agent with no basis to choose this over siblings like 'normalize-url' or 'validate-json'.

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