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

There are no annotations, so the description carries the full burden of behavioral disclosure. It does disclose that the expression is discarded, which gives some transparency, but it fails to mention side effects, return value, mutation, permissions, or any other expected behavior beyond the fact the expression is 'discarded.'

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 (two sentences), but this is under-specification rather than conciseness. It omits crucial information about how to invoke the tool and what to expect, so the brevity detracts from usefulness.

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?

The tool has 9 parameters, 0 required, no output schema, and no annotations. The description fails to explain how to construct a valid call, what result to expect, or what operation is performed on which parameter. It is not complete enough for an agent to use correctly.

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 description coverage is 100%, so the baseline is 3. The description itself does not clarify how any of the 9 parameters map to arithmetic evaluation, but because the schema already describes each parameter's purpose (somewhat at odds with the tool name), no extra meaning is required. The lack of contradiction with schema descriptions keeps this at the baseline.

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 operation ('Evaluate a+b style arithmetic') but provides no mechanism for mapping this to the tool's parameters. An agent cannot tell which input contains the expression, and the schema lists only unrelated strings (ref, url, city, etc.) with 'discarded after' semantics. This makes the actual purpose unclear and barely distinguishable from a generic shape-check tool.

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 guidance on when to use this tool vs alternatives, and no example or prerequisite. It vaguely implies using it for arithmetic, but it does not explain how to pass the expression, what the output is, or when not to use it.

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