Stack videos

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

No annotations are provided, so the description carries the burden. It discloses two non-obvious behaviors: clips are normalized to the first clip's size, and audio is taken from the first clip with audio. This is meaningful beyond the schema, though it omits details like output format or overwrite behavior.

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 no filler: the first introduces layouts and use case, the second packs two important behavioral defaults. Every clause earns its place and the most salient information is front-loaded.

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 tool with only three parameters, all schema-documented, and no output schema, the description plus schema cover the core operation: layouts, input order, output path, and key normalization/audio behaviors. Minor gaps like output format or handling of mismatched durations are not essential for basic use.

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 schema describes all three parameters with 100% coverage, including the layout enum and input_paths ordering constraints. The description adds behavioral context about size and audio normalization but does not add new parameter-level syntax or values, so the baseline of 3 is appropriate.

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 stacks videos in horizontal, vertical, or grid layouts, which is specific and goes beyond the bare title. It does not explicitly distinguish from the related picture_in_picture sibling, but the layout vocabulary makes the core purpose unambiguous.

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?

It mentions 'great for comparisons' as a use case, implying when the tool would be useful, but provides no explicit alternatives or exclusions. With siblings like concat_videos and picture_in_picture, a direct contrast would strengthen guidance.

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