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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the description does not need to repeat safety. It adds genuinely new context: the xlsx link requires no sign-in, the online link points to the template page where the sheet can be filled in-browser, and the failure mode ("unknown template id") when the id did not originate from list_templates. Not fully 5 since return shape details (link format, expiration) are not touched.

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 core output is front-loaded in the first sentence, followed by usage rule and error case. The nested parentheticals with extra detail ("the free Excel file to download, no sign-in") are informative but make the sentence dense; still, no sentence is disposable.

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, read-only lookup with no output schema, the description covers what is returned, what each element means, when to prefer it, and the failure condition. Nothing an agent needs in order to call it correctly is missing.

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 parameter already documents its provenance and gives an example id. The description largely echoes that provenance and only adds the error behavior for an invalid id, so it adds marginal meaning beyond the schema. 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?

The description states a specific verb and resource ("Returns two links for one template") and immediately enumerates what each link is (xlsx free Excel file, online browser-fill page). It is clearly distinguishable from siblings such as calculate and list_templates without opening the schema.

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?

It gives an explicit selection rule ("Use it when the user wants the file itself to keep and edit") and names the competing tool with the reason to avoid it ("because calculate saves nothing"). It also states the precondition that the id must come from list_templates, which is a when-to-use constraint in itself.

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