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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=false), so the lower bar applies. The description adds genuine value by enumerating the returned fields (name, category, formula, input names, page URL), which is important given there is no output schema. It says nothing about rate limits or error behavior on an unknown slug.

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?

One sentence with zero filler; the returned fields are front-loaded and the required input is stated at the end. Nothing could be removed without losing information.

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 one-parameter lookup with no output schema, the description supplies the return shape, which is the main thing an agent needs. The remaining gap is the lack of guidance on what happens with an invalid or unknown slug, and on routing to sibling tools.

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% and the single slug parameter is fully documented in the schema with an example. The description only restates 'given its slug' and adds no format, validation, or lookup semantics beyond what the schema already provides, so baseline 3 applies.

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?

States a specific verb ('Returns') and resource (a calculator's name, category, formula, input names, page URL) and the key required input (slug). An agent can tell this is a metadata lookup distinct from 'calculate', but the description never names or contrasts the siblings, so it stops short of a 5.

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 phrase 'given its slug' implies the precondition that the caller already knows the calculator's identifier, which is mild usage guidance. There is no explicit when-to-use, when-not-to-use, or routing to search_calculators (to find a slug) or calculate (to run it).

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