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

With no annotations, the description carries the full disclosure burden and does well: it reveals the 7-day expiry, the credit cost, and the ownership exemption that makes re-download free. It omits error behavior (e.g., what happens with insufficient credits) and any auth requirements, keeping it short of a 5.

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?

Three tight sentences, ~20 words, with the core outcome and validity front-loaded and the pricing caveats after. No filler and nothing redundant.

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?

Absent an output schema, the description usefully explains what is returned (a signed URL) and its lifetime, plus the credit model. Failure modes and permission requirements are unaddressed, but for a one-parameter download helper this is close to sufficient.

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?

The single parameter has 100% schema description coverage and even cross-references search_models as its source, so the schema does the heavy lifting. The description adds no additional meaning about the identifier's format or origin — the baseline 3 for high-coverage schemas.

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 ("Return a signed download URL") and resource ("model zip") with an exact validity window, so an agent knows precisely what it gets back. It never names or contrasts sibling tools such as get_model or get_model_preview, so sibling differentiation is left to inference.

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?

Cost information ("Consumes one credit", owned models are free again) is decision-relevant guidance, but there is no explicit when-to-use statement, no prerequisites, and no routing among the many siblings (get_model, get_model_preview, generate_model).

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