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

Beyond noting that the expression is discarded, the description discloses nothing about the tool's actual behavior, side effects, return value, or error conditions. With no annotations to fill the gap, the description fails to provide any meaningful transparency.

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 very brief, but it is not appropriately sized for the tool's complexity: it omits essential information about the 9 parameters and the overall purpose. It is front-loaded in the sense that the first sentence states the supposed action, but the second sentence adds confusion rather than clarity.

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 rich schema (9 optional parameters) and absence of an output schema, the description is grossly incomplete. It does not explain how any of the parameters relate to the tool's function, nor what the tool returns or how to interpret results.

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?

All 9 parameters have generic, unrelated descriptions (e.g., Git ref, URL, city, feed) that have no apparent connection to arithmetic evaluation. The tool description mentions an 'expression' but no such parameter exists in the schema, so parameter semantics are entirely obscure and unhelpful.

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 verb ('Evaluate') and a resource ('a+b style arithmetic'), but it is highly ambiguous because the input schema contains no expression parameter, and the phrase 'Expression discarded' suggests the tool does not actually evaluate anything. This misalignment with the schema severely undermines 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?

The description provides no guidance on when to use this tool versus any of the 28 sibling tools. It only states that the expression is discarded, leaving the intended use case completely unexplained.

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