Blur / pixelate region

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

No annotations are provided, so the description carries the full burden. It adds that the operation is 'optionally limited to a time range,' which is useful behavioral context not in the schema. However, it does not disclose output behavior (whether input is overwritten or output_path is required), which matters for an edit operation. The description also doesn't mention that mode defaults to blur, though the schema covers that.

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 sentence with an em dash, front-loading the core action and then giving use cases. It is concise and contains no filler. Every word earns its place.

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?

With 10 parameters and no annotations/output schema, this is a moderately complex tool. The description gives a clear high-level purpose and mentions the optional time range, but doesn't cover output-path handling or coordinate/time formats (though schema covers parameter details). For an edit tool, a note on output behavior would enhance completeness.

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 has 100% parameter description coverage, so the schema already documents all 10 parameters. The description adds implicit context by referring to 'rectangle of the frame' (x/y/width/height) and 'time range' (start/end), but doesn't go beyond the schema. With complete schema coverage, 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's function: 'Blur or pixelate a rectangle of the frame' with specific use cases (faces, license plates). This is a specific verb+resource that distinguishes it from sibling tools like crop_video or draw_box, which serve different purposes.

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 clear use-case context: 'for hiding faces, license plates, names, or other sensitive content.' It implies when to use this tool (obscuring sensitive content) but does not explicitly mention alternatives or when not to use it. Given the sibling tools like crop_video and draw_box, explicit exclusions would strengthen it.

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