extract_frames

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

With no annotations, the description carries the full behavioral burden. It discloses the output naming convention, but says nothing about overwriting existing files in out_dir, directory creation, codec/quality defaults, or return values - all relevant for a write-heavy export operation.

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?

Two short sentences, zero filler, with the core action and output naming front-loaded ahead of the usage tip. Nothing needs trimming.

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?

A 6-parameter tool with no annotations, no output schema, and 0% schema coverage needs substantially more description than two sentences. The agent lacks guidance on start/duration semantics and on what the export produces or overwrites.

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 description coverage is 0% across 6 parameters, so the description must compensate. It clarifies only 'fps' (thinning rate) and hints at 'ext' via the .jpg example; 'start', 'duration', 'input', and 'out_dir' receive no explanation beyond their bare names.

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 a clear verb+resource ('Export numbered frames') and even gives the naming pattern (00001.jpg). It identifies downstream targets (COLMAP, matting), but does not explicitly differentiate itself from related siblings like impact_frames or on_twos.

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?

Names the intended pipelines ('for COLMAP or matting') and gives one actionable usage tip ('Use fps to thin long clips'), which implies when to set fps. However, it offers no when-not guidance and does not route the agent away from similar frame-producing siblings.

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