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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: the response is https download URLs, the file type is .xlsx, a filled example file is included only when it exists, and the free-only scoping rule is enforced server-side. It does not cover failure behavior for an unknown id, but that is a minor gap.

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?

Two sentences, no filler, with the return value and the free-only constraint front-loaded. The second sentence is slightly redundant with the first's "free template" framing but reinforces a constraint worth stating.

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?

There is no output schema, so the description carries the burden of describing returns — and it does, naming the URL format, the .xlsx type, and the conditional example file. Combined with a single fully-documented parameter, an agent has what it needs to call this correctly; only error-case behavior is unaddressed.

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% and the single parameter is documented, so the baseline is 3. The description earns extra credit by enumerating concrete accepted value forms — a free template id with the full slug shape, or a trade name like "landlord" or "invoice" — which materially helps an agent construct a valid call.

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 opens with a specific verb and resource: it returns https download URLs (.xlsx plus a filled example) for one free template. Concrete id examples ("free-rental-property-spreadsheet", "landlord", "invoice") make the resource unambiguous. It does not explicitly contrast itself with find_template or list_templates, so sibling differentiation is only implicit in "one free template".

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 rather than stated: the agent can infer it needs a known id or trade name, and the line "Only files already free on tuper.app/templates/free/ are returned; paid files never are" acts as a when-not constraint. However, no alternative is named for the paid-template case or for discovering an id, even though find_template and list_templates exist as siblings.

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