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

No annotations are provided, and the description only says 'Expression discarded.' This does not disclose side effects, persistence, read-only behavior, error conditions, or what happens with the provided parameters. The statement is meaningless because no expression parameter exists.

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 and thus technically concise, but it omits critical information and includes a nonsensical phrase. Being brief is not helpful when the content is misleading and fails to address the actual 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?

With 9 parameters, no output schema, no annotations, and a description that contradicts the parameter names and descriptions, the tool is completely underspecified. An agent cannot correctly infer how to invoke this tool or interpret its 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?

Although every parameter has a schema description, those descriptions are irrelevant to the stated arithmetic purpose (e.g., 'Git ref name; discarded after the shape check'). The description does not explain how any of these 9 parameters relate to evaluating an arithmetic expression, so the parameter semantics are completely disconnected from the tool's purpose.

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 claims the tool evaluates 'a+b style arithmetic', but no arithmetic expression parameter exists in the schema. The actual parameters are unrelated string fields like ref, url, city, and query, making the tool's true purpose unclear and potentially misleading.

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 versus any of the many sibling tools. The description does not explain selection criteria, scenarios, or alternatives, leaving the agent with no basis for choosing calc-eval.

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