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

No annotations are provided, and the description does not state whether the tool is read-only, whether it has side effects, what it returns, or what 'Expression discarded' means. The repeated 'discarded after...' phrases on parameters imply no persistence, but this is never clearly stated.

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, but brevity is not effective here because it omits essential details and contradicts the parameter schema. A few extra sentences clarifying the actual role of these parameters would be more useful than the current two-sentence text.

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 nine parameters, no required fields, no output schema, and no additional context. The description does not explain why these parameters exist, what the tool actually does with them, what result format is expected, or what error conditions may occur. It is far from complete for an agent to use reliably.

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 the schema covers 100% of parameters with descriptions, the parameter set is entirely mismatched with the stated arithmetic purpose. There is no 'expression' or 'a'/'b' parameter, and the given parameters (url, city, path, etc.) appear borrowed from other tools. Individually they are described, but collectively they do not support the described operation.

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 says 'Evaluate a+b style arithmetic' but none of the nine parameters represent an arithmetic expression. All parameters are named ref, url, city, feed, host, json, path, zone, query, which have no apparent relation to computing a+b. The intended purpose is therefore confusing and internally inconsistent.

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?

No guidance is given about when to use this tool versus alternatives. The sibling tools include timezone, URL, JSON, and search-related tools, but there is no indication of how calc-eval relates to them or what scenarios call for arithmetic evaluation.

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