runway_extend

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

No annotations are provided, so the description must fully disclose behavioral traits. It only states the purpose without mentioning whether the operation is destructive, requires authorization, has rate limits, or any side effects. Minimal transparency for a mutation tool.

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 a single, well-formed sentence with no extraneous words. It is front-loaded with the action and resource. Could be slightly more informative but remains concise and clear.

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 the tool has 5 parameters, no output schema, and sibling tools for other platforms, the description is incomplete. It lacks details on return values, error handling, or differentiation from similar extension tools like veo_extend. More information is needed for an agent to use it correctly without confusion.

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?

The input schema already describes most parameters (prompt, task_id, quality, download_dir) with coverage estimated at 60%. The description adds no additional meaning beyond what the schema provides. For filename, the schema lacks description, but the description does not compensate. Baseline of 3 is appropriate given moderate schema coverage.

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 the tool extends an existing Runway Aleph video with continuation content, specifying the verb (extend) and resource (existing video). It distinguishes from sibling tools like generate_video (creation) and veo_extend (Veo platform).

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?

No explicit when-to-use or when-not-to-use guidance is provided. The description implies usage only for extending existing Runway Aleph videos but does not mention alternatives or exclusions. The context of sibling tools helps, but the description itself lacks explicit guidelines.

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