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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful behavioral details: it returns processing status plus duration and auto-thumbnail, and invalid video_id values produce {'error':'invalid_id'}, which is valuable validation context beyond annotations.

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 front-loaded with the core purpose and then efficiently documents the ready-status meaning, invalid-ID behavior, and optional workspace parameter. Every clause adds actionable information with no waste.

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 that an output schema exists and annotations cover the read-only, open-world nature, the description provides everything needed to call the tool correctly: purpose, workflow relation, parameter formats, optionality, and error behavior.

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 carries the full burden for both parameters. It specifies that video_id must contain only digits and comes from meta_upload_ad_video, and that workspace is the customer workspace slug and optional when only one workspace exists.

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 a specific verb and resource: retrieving the processing status of a Meta ad video, including duration and auto-thumbnail. It also differentiates from siblings by naming meta_upload_ad_video as the source of video_id and meta_create_ad as the consumer when status is 'ready'.

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 clear workflow context: call this after uploading a video via meta_upload_ad_video and before using it with meta_create_ad when status is 'ready'. It does not explicitly list alternatives or when not to use the tool, but the implied usage is strong.

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