Extend video (Flow 'Extend')

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

With no formal annotations, the description carries the full burden and excels. It discloses crucial operational behavior, including the 2-day retention limit of remote files and the 720p resolution constraint, which is vital for an agent making quality-sensitive decisions.

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 definition is extremely concise. It front-loads the main function and immediately follows up with essential behavioral constraints (source required, time limit, quality limit) without any unnecessary fluff.

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?

While the core function and the most critical limitations are covered, the lack of semantic guidance on the 3 unspecified parameters ('wait', 'model', 'timeoutSeconds') means the definition is not fully complete for a complex multi-parameter tool.

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 coverage is low at 40%. The description focuses on the overall action and constraints, providing no semantic explanation or context for parameters like 'wait' or 'timeoutSeconds,' forcing the AI agent to rely entirely on schema documentation for the technical parameters.

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 defines the tool's function as continuing a previously generated video asset. By naming it 'Extend,' it distinguishes the action from the 'flow_generate_video' sibling tool. It clearly states the action but could be slightly more explicit about the chain of operation.

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 provides critical usage context: the source video must be generated by this specific server. It also outlines operational constraints regarding file retention and resolution, which dictates the proper use case and expectations for the agent.

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