video_fade

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 mentions the tool adds effects and auto-generates output paths if omitted, but lacks critical behavioral details: whether it modifies the original video, requires specific file formats, has performance or size limits, or what the output schema returns. For a mutation tool with zero annotation coverage, this is insufficient.

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 well-structured and front-loaded with the purpose, followed by parameter details. It uses bullet-like formatting under 'Args:' for clarity. Every sentence adds value, with no redundant information. It could be slightly more concise by integrating the purpose with parameter explanations, but it's efficient overall.

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?

Given the tool has an output schema, the description doesn't need to explain return values. However, as a mutation tool with no annotations and 4 parameters, it should provide more behavioral context (e.g., side effects, error handling). The parameter explanations help, but overall completeness is adequate only due to the output schema covering returns, leaving other aspects under-specified.

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%, so the description must compensate. It adds meaning by explaining each parameter's purpose (e.g., 'Absolute path to the input video', 'Fade in duration in seconds (from black)'), which clarifies beyond schema titles. However, it doesn't cover constraints like valid ranges for fade durations or path formats, leaving gaps. Baseline would be lower without this info, but the added semantics justify a 3.

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 purpose: 'Add fade in/out effect to a video.' It specifies the verb ('Add'), resource ('video'), and effect type ('fade in/out'), making it distinct from siblings like video_crop or video_rotate. However, it doesn't explicitly differentiate from all siblings (e.g., video_edit might be similar), so it's not a perfect 5.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites, compare to other video editing tools in the sibling list, or specify scenarios where fade effects are appropriate. Usage is implied by the purpose, but explicit guidelines are missing.

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