Download an asset

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

Adds substantial context beyond the annotations: the signing/expiry window (~30 minutes), the one-time billing model with permanent library ownership, the price-acceptance gate on max_credits, and the connected-account requirement. This is consistent with idempotentHint=true (charge occurs only once) and explains why readOnlyHint is false, so there is no contradiction.

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 compact sentences with the core purpose front-loaded, followed by billing conditions. The parenthetical asides are informative rather than wasteful, though the density of pricing detail in the middle sentence slightly blurs emphasis.

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 three-parameter tool with no output schema, it covers the essentials: what is returned (signed URLs), how long they last, the cost model, the required auth, and the gating condition on max_credits. It omits error/edge behavior such as what happens when a resolution is unavailable or when credits are insufficient, but nothing critical for calling 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 coverage is 67%, and the description supplements the schema by explaining the workflow for max_credits — pass it only after the user accepted the price — which is usage timing the schema does not convey. resolution is left to the schema's own description, so it adds meaning where it matters but not exhaustively.

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 and resource — 'Get signed download URLs for an asset' — with the concrete payoff (a URL valid ~30 minutes). This clearly distinguishes it from siblings like get_asset (metadata) and save_generation_to_library, since it describes retrieval of a downloadable file rather than a record.

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?

Gives concrete conditional guidance: free CC0 assets cost nothing, AI assets charge once and then become free in the user's library, and max_credits should be passed only after the user accepted the price. It also states the prerequisite of a connected account. It does not name sibling alternatives (e.g. get_asset for previewing metadata), so it stops short of explicit routing.

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