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

Annotations already declare non-read-only, non-destructive, open-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: uploads are asynchronous ('Processing can take a few minutes') and the call yields a video_id rather than a finished asset. It does not mention format/size limits or permission requirements, which would have earned a 5.

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 short sentences, each carrying distinct information (source, return value, latency), with the core action front-loaded. No filler and nothing redundant with the annotations.

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 output schema, the description correctly discloses the return value, and the latency note covers the async gap. But with six parameters and an empty required list, it never states that one of video_url or media_id must actually be supplied, nor what title/folder do, leaving a real risk of a source-less call.

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%, so the baseline is a 3. The description does add one real constraint the schema lacks: video_url has no schema description at all, and 'from a public URL' is the only statement that the source must be publicly reachable. However, 'title', 'folder', and 'account' get no treatment, and the relationship between media_id and video_url is largely repeated from the schema.

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 ('Upload a video ... to the ad account'), names the destination, and ties the output to a concrete downstream consumer ('returns the video_id for meta_create_ad'). That distinguishes it cleanly from meta_upload_image and tiktok_upload_video without the agent opening any schema.

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 clear context for both input modes: a public URL, or a media_id for a file attached in the Go Shift chat, with the explicit 'Use instead of the URL' rule carried in the schema. It stops short of saying when to pick this over meta_upload_image or media_library, and offers no exclusions, so it is strong context without full routing guidance.

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