video_shape_mask

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

Discloses auto-generated output path and feather effect, but with no annotations, it misses side effects like overwriting behavior or mutation of input. Could be more transparent about file operations.

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?

Description is concise with main action front-loaded. The Args block adds some redundancy but overall efficient.

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?

Covers core functionality and all parameters. Output schema exists so return values are covered. Could add context on file format constraints or destructive 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?

Adds meaning beyond schema by explaining input_path as absolute path, shape options, auto-generation of output_path, and feather radius in pixels. Schema has 0% coverage, so description compensates well.

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?

Clearly states 'Apply a geometric shape mask to a video' with specific shape options (circle, rounded_rect, oval). Distinguishes from sibling 'video_apply_mask' by focusing on geometric shapes.

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?

Implies usage for geometric masks but lacks explicit guidance on when to use versus alternatives like 'video_apply_mask'. No when-not-to or prerequisite information.

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