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

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Evaluate a+b style arithmetic. Expression discarded.' which gives no information about side effects, output format, error behavior, or how the parameters relate to the arithmetic. The statement about discarding the expression is vague and not backed by schema details. It does not clarify what happens to the input parameters or what the tool returns.

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) and front-loaded with 'Evaluate a+b style arithmetic', but it is under-specified and not useful. Conciseness is only beneficial when the content is informative; here it omits essential details, making the brevity a drawback rather than a strength.

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, none required, no output schema, and no annotations. The description is utterly inadequate for an agent to call it correctly. It doesn't explain the tool's core function, the role of each parameter, expected input formats, or the return value. Given the complexity, a comprehensive description is necessary, and this one provides almost nothing.

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 the schema already documents each parameter's purpose (e.g., 'Git ref name; discarded after the shape check'). However, the description adds no value beyond that and actually misleads by claiming arithmetic evaluation when the parameters are unrelated. It fails to explain how any parameter contributes to the purported arithmetic, so the description degrades rather than enhances parameter understanding.

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 clear verb and resource ('Evaluate a+b style arithmetic'), but the input schema has no arithmetic parameters (e.g., a, b, expression). It instead contains unrelated fields like ref, url, city, etc. The phrase 'Expression discarded' further confuses the purpose—does it evaluate and return nothing? The description does not align with the schema, making it hard for an agent to know what this tool actually does or how it differs from siblings.

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 alternatives. It does not mention any context, prerequisites, or exclusions. An agent cannot determine if this is appropriate for a given task from the description alone.

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