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

Annotations already mark the tool as read-only and non-destructive. The description adds valuable behavioral context: returned media URLs are temporary, content always resolves against the US region, and each successful request costs 0.2 account credits. This goes well beyond the structured annotations and contains no contradictions.

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 four short sentences with the main purpose front-loaded and caveats following in order of importance. Every sentence adds useful information and there is no repetition of schema or annotation content.

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?

An output schema is present, so return value details are already covered. The description supplies the remaining operational knowledge: accepted URL formats, temporary media URLs, regional resolution, and credit cost. An agent has enough context to invoke the tool correctly.

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 0%, so the description must compensate. It clearly explains the URL parameter by noting that canonical and TikTok share URLs are accepted. The region parameter is only indirectly addressed via 'resolves against the US region,' though the schema const/default already clarifies it.

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 opens with a specific verb ('Fetch') and a clear resource: normalized details and current engagement metrics for a TikTok video URL. This distinguishes it from siblings focused on captions, transcripts, or multiple videos, even though it does not explicitly name those alternatives.

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 states which URL forms are accepted and notes the fixed US region, giving implied usage context. However, it does not explicitly tell the agent when to choose this tool over sibling tools like get_tiktok_videos or get_tiktok_video_captions, nor does it mention any exclusions.

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