extend_video

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

With no annotations, description explains duration is for extension only, returns markdown with URL and total duration. Lacks details on side effects or auth needs.

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 with a clear top sentence, followed by a paragraph clarifying duration behavior, then a structured Args list. No wasted words.

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 parameter semantics and return value; lacks error conditions or edge cases, but overall complete for a tool with no 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 0%, but description fully compensates by explaining each parameter's role, constraints (e.g., video_url .mp4 2-15s, duration 2-10, default 6), and behavior.

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 'Extend an existing video with a follow-up prompt' and explains it continues from the last frame, distinguishing it from generate_video which creates new videos.

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?

Clearly indicates when to use (to extend a video) but does not explicitly state when not to use or mention alternatives like generate_video for creation.

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