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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose that the expression is 'discarded,' which is a meaningful non-persistence trait. However, it does not state whether the tool returns the computed result, a success flag, or an error, and it leaves the overall side-effect and return behavior unclear.

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 concise and front-loaded: 'Evaluate a+b style arithmetic' appears first and states the core purpose. The second sentence is short but meaningful, though it introduces ambiguity about what 'discarded' means. Overall, there is no wasted 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?

This definition is seriously incomplete. There is no output schema, no annotations, and the description fails to explain how the arithmetic expression is supplied among nine unrelated parameters. It also omits return-value behavior and error semantics, leaving an agent unable to use the tool 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 coverage is 100%, which normally supports a baseline of 3. But the description references an 'expression' that does not map to any of the nine schema parameters, which are ref, url, city, feed, host, json, path, and query. The description adds no usable meaning about which parameter should contain the arithmetic expression, so an agent cannot confidently invoke the tool.

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 action and resource: 'Evaluate a+b style arithmetic.' This is clear enough to distinguish calc-eval from its sibling tools, none of which suggest arithmetic evaluation. However, the phrase 'Expression discarded' adds ambiguity, and the tool description never connects the 'expression' to any actual input parameter.

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?

Usage is implied: an agent can infer this tool is for evaluating simple arithmetic expressions. But there is no explicit guidance about when to use it versus alternatives, no prerequisite conditions, and no statement of when not to use it. The lack of any param-to-expression mapping further weakens actionable guidance.

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