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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds useful behavioral context beyond annotations: it returns photos and videos sorted newest first and includes URLs, which is meaningful for an agent deciding how to use the result.

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 short sentences with no wasted words. The primary content and ordering are front-loaded, and the reuse guidance is a compact, purposeful addition.

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?

With no parameters, strong annotations, and an output schema present, the description fully covers the tool's role and how its results should be used. Nothing required for correct invocation 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 tool has zero parameters, so the schema leaves nothing to explain. The description's mention of URL output effectively covers what an agent needs to know about the tool's interface.

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 specifies a clear resource ('photos and videos uploaded with upload_media'), a clear ordering ('newest first'), and a clear return characteristic ('with their URLs'). It also distinguishes itself from the upload path by naming upload_media as the source.

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 gives concrete downstream guidance: reuse a URL in create_campaign media or a film body. It implies this tool is for retrieving previously uploaded media rather than uploading or listing other entity types, though it does not explicitly exclude sibling list tools.

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