Download Model

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

With no annotations, the description does useful work by disclosing that this fetches from remote mirrors (network access) and writes into a local models directory (a mutation of local state). It stops short of the traits that matter most for a downloader: idempotency/skip-if-present behavior, overwrite semantics, file size or latency expectations, and failure handling.

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 front-loaded sentence with zero filler; source, action and destination all land immediately. Nothing is wasted, though there is no structure beyond a single clause.

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 tool with a full schema and an output schema, the description covers the essential shape of the operation. It is only marginally complete, however, because an agent cannot tell from it whether repeated calls are safe, how long a download takes, or what happens on mirror failure.

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 model_id parameter is already documented with concrete examples in the schema. The description adds no additional meaning about accepted ID formats or validation beyond what the schema provides, 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 specific verb ('Download') and resource ('open-weight model files'), plus the source ('upstream mirrors') and destination ('local models directory'). This clearly separates it from siblings like list_available_models and recommend_model, though it never names them explicitly.

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?

'On demand' hints at a trigger but gives no real when-to-use guidance: no mention of needing a model_id from list_available_models or recommend_model first, no note on whether to check if the file already exists, and no exclusions.

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