generate_video

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

With no annotations provided, the description carries the full burden. It discloses three key behaviors: it requires an API key, it is slow (minutes), and it returns a file path to an MP4. This is meaningful context beyond the schema. It doesn't mention potential failures or whether it's blocking, but covers the most essential behavioral aspects.

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 two sentences with zero filler. The primary action is front-loaded, and each subsequent clause adds critical operational detail (API key, latency, output format). No unnecessary 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?

For a generation tool with four parameters and no output schema, the description covers the essential: what it generates, how (providers), prerequisites (API key), performance (slow), and output (MP4 path). It could mention error handling or asynchronous behavior, but those are minor gaps given the tool's nature.

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% with each parameter described, so baseline is 3. The description adds value by clarifying provider selection ('Omit to use the first configured key') and duration constraints ('Runway snaps to 5 or 10'), which are not fully captured in the schema descriptions. This goes beyond repeating schema info.

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 states a specific verb ('generate'), a resource ('short video from a text description'), and names the providers ('fal or Runway'). This clearly distinguishes it from sibling tools like generate_image, generate_voiceover, or video editing tools, leaving no ambiguity about what the tool does.

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 implicitly indicates when to use it: when you need a video from text, as opposed to image or audio generation. It also notes the requirement of an API key and the slowness, which sets expectations. However, it doesn't explicitly contrast with alternatives like generate_image or explain when NOT to use it, so it lacks explicit exclusions.

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