Download a free Fab asset file

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

The description adds context beyond annotations: it clarifies the download goes to a 'configured local download directory' and that the operation does not involve purchasing. Annotations indicate idempotentHint true and destructiveHint false, which align with the description.

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?

The description is one sentence, front-loaded with the core action. It is concise but could be more structured by parameter groupings. No wasted words.

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?

Given 3 parameters, annotations, and an output schema, the description explains the download action and clarifies no purchase. However, it omits details about the output schema structure, error conditions, or format variations. Adequate but not comprehensive.

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 only 33% (only acceptFabEula is described). The description mentions 'free Fab file' but does not explain the meaning of format (enum), listingIdOrUrl (which must be a free listing), or the required Eula acceptance. The description fails to compensate for the low schema coverage.

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 clearly states the tool downloads a 'free Fab file' and specifies it never purchases or adds to a library. It distinguishes from siblings like 'fab_search_assets' and 'fab_get_asset' by focusing on download of free files.

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 implies this tool is only for free assets by stating 'free' and 'never purchases'. However, it does not explicitly list when not to use it or suggest alternatives like a purchase tool. Context is clear but lacks explicit exclusions.

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