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

No annotations are provided, so the description carries full burden. It mentions 'Expression discarded' which hints at non-persistence, but does not disclose the actual behavior—how inputs are processed, what is checked, or what happens to each parameter. The schema descriptions note 'discarded after' for several params, but the main description does not synthesize this. It is not misleading enough to be a contradiction, but it is far from transparent.

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), but it is under-specified rather than concise. It lacks structure, front-loading, or any scoping. Every word is wasted because the core functionality is not conveyed. The brevity is a symptom of missing content, not efficiency.

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, and no annotations, the description is woefully incomplete. It does not explain what the tool returns, how parameters interact, or what 'evaluate' means in this context. An agent would be entirely unable to predict the tool's behavior or craft a valid call. This is critically incomplete.

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 description coverage is 100%—every parameter has a textual description in the schema. The tool description adds no information about parameters, so it meets the baseline of 3. It neither helps nor hurts; the schema already documents the parameters adequately for semantic 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 ('Evaluate') and resource ('arithmetic'), but it is misleading given the schema. The schema contains 9 unrelated parameters (ref, url, city, feed, etc.) with no arithmetic expression field. The description does not clarify what the tool actually does with these parameters, and it does not distinguish from siblings like domain-shape or file-path-ok. The purpose is unclear and potentially deceptive.

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, when not to use it, or which alternatives might be more appropriate. There is no mention of context, prerequisites, or exclusions. An agent would have no basis to select this tool over any of the 28 siblings.

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