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

Annotations are empty, so description must disclose behavior. It does: returns video id and upload_url, URL expiration (expires_in_seconds), single-PUT upload limit of 5GB, and suggests web uploader for larger files. 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?

Concise yet comprehensive: starts with core purpose, then actionable steps. Every sentence adds value; well-structured for quick comprehension.

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?

Covers all essential aspects: tool purpose, parameter usage, return values, follow-up steps, size constraint, and expiration. Complete for a multi-step upload tool without output schema.

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 100%, baseline 3. Description adds context: filename used for title and extension, size optional but enforced, audio_language as spoken-language code. This enhances meaning beyond 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?

Clearly states it initiates an upload of a LOCAL video file and explicitly distinguishes from sibling tool submit_video (for URLs). The verb 'start an upload' and resource 'local video file' are specific.

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?

Provides explicit guidance: use when file is on disk, not URL; directs to call complete_upload after upload; explains that for files >5GB use web uploader. Also includes detailed steps for the HTTP PUT request with a curl example.

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