List library

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

The description discloses key behaviors: it returns assets with kind, model, age, and served URLs, and orders them newest first. It also states it is 'Free, read-only', which aligns with and reinforces the annotations (readOnlyHint, idempotentHint, destructiveHint). It adds value beyond annotations by describing the output content and ordering.

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 a single, efficient sentence that front-loads the purpose and includes all essential details without redundancy. Every clause earns its place, covering scope, ordering, return fields, and a pointer to a related tool.

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 simple listing tool, the description is complete: it explains what is listed, the ordering, what is returned, and how to use the results (open URLs or pass to fetch_asset). Since annotations already cover safety and schema covers parameters, nothing an agent needs to call 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?

The input schema already provides complete descriptions for both parameters (kind with enum and default, limit with default and max). The description does not add new information about the parameters, but given 100% schema coverage, the baseline of 3 is appropriate. It does not need to compensate for any gaps.

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's function: browse the workspace's Library and list image/video assets generated in the Studio, newest first. It is specific about what is returned (URLs, kind, model, age) and distinguishes itself from related tools like fetch_asset by noting it returns served URLs rather than download links.

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 provides clear context on when to use this tool (browsing the Library) and explicitly mentions fetch_asset as the alternative for obtaining download links, which guides the agent on differentiation. It does not explicitly state when not to use it, but the alternative mention and 'read-only' note offer sufficient guidance.

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