add_fade

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states the basic operation without mentioning side effects such as overwriting the output file, how zero durations are handled, or whether the source file is modified. Key behavior like the default fade duration of 0 (effectively disabling fades) is not disclosed.

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 concise sentence with no wasted words. It is front-loaded with the core action and targets. While it could be slightly more detailed to cover defaults, the brevity is acceptable for a simple tool and does not hinder clarity.

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 5 parameters (2 required), no output schema, and no annotations, the description is too thin. It does not explain the default behavior of fade_in_duration and fade_out_duration (both 0), the default target ('both'), or the resolution of relative paths beyond what the schema states. The description alone would leave an agent uncertain about how to prevent fades or which target is assumed.

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 high (80%), so a baseline of 3 applies. The description adds little beyond the schema: it echoes 'video, audio, or both' which maps to the target enum, and 'fade-in and/or fade-out' maps to the duration parameters. No additional parameter meaning is provided beyond what the schema already contains.

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 uses a specific verb ('Add') and identifies the resource ('fade-in and/or fade-out') along with target options ('video, audio, or both'). This clearly distinguishes it from sibling tools like trim_video or extract_audio, leaving no ambiguity about its function.

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 implies usage by stating the operation, but it does not explicitly mention when to use this tool versus alternatives or provide exclusions. No sibling comparison or contextual guidance is given, so the agent must infer usage from the name and description.

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