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

With no annotations, the description carries the full behavioral burden and does well: it discloses the return artifact (signed zip URL), the 1-hour validity window, per-call cost, and tier-dependent daily caps. It omits failure conditions (e.g., what happens when the cap is hit) and permission requirements.

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, zero filler, and the most decision-relevant facts — the signed URL and its 1-hour expiry — are front-loaded before the cost and cap details.

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 single-parameter tool with no output schema, the description covers what is returned, how long it is valid, what it costs, and the rate cap — enough to call it correctly. Missing only edge behavior such as cap-exceeded errors or model-availability failures.

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 model_id parameter is fully documented in the schema with its source (search_models). The description adds no syntax, format, or sourcing detail beyond that, so the baseline of 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 precise verb and resource — returns a signed download URL for a model zip — and specifies the artifact format. This distinguishes it from get_model and search_models, which do not produce a downloadable artifact, without needing to name them.

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 conveys cost and rate-limit context (one credit, 100/day cap on subscription plans), which informs the decision to call it, but never states when to choose this over get_model or what conditions block a download. Usage is only implied by the word 'download'.

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