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

With no annotations, the description carries the full burden. It only says 'Expression discarded', which is cryptic and does not explain what happens to the many parameters, what the tool returns, or any side effects. The schema hints at 'shape check' behaviors, but the description contradicts that by focusing on arithmetic.

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 only one short sentence, but it is not effectively concise – it omits essential information and is under-specified. The structure offers no front-loading of key facts and leaves the agent without a usable understanding.

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?

For a tool with 9 parameters, no output schema, and no annotations, this description is severely incomplete. An agent cannot infer what the tool does, what inputs are meaningful, or what to expect in return, making it nearly impossible to invoke 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%, so the schema documents all 9 parameters, but the description adds no value and even misleads by implying an expression input that does not exist. It fails to clarify the role of the parameters and contradicts their apparent shape-checking 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 states 'Evaluate a+b style arithmetic' which is a specific verb and resource, but it is misleading because the input schema contains no expression parameter – instead it has URL, city, feed, host, etc. This does not match the tool name 'calc-eval' nor the actual parameters, making it unclear what the tool does and failing to distinguish it 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?

No guidance is provided on when to use this tool versus its 28 siblings. The description gives no context for selection, and the misleading arithmetic mention actively confuses rather than clarifies usage.

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