video_subtitles

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

With no annotations provided, the description carries the burden of behavioral disclosure. It transparently notes that burning re-encodes the picture, attached subtitles are user-switchable, and limits input types and size (up to 500 MB). This goes beyond the basic schema, though it stops short of detailing output behavior or file handling edge cases.

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 three well-structured sentences. The first states the core action, the second contrasts the two modes, and the final sentence lists accepted formats and the size cap. No wasted words, and the most relevant information is front-loaded.

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?

For a tool with 4 parameters and no output schema, the description covers the essential context: what it does, how the modes differ, accepted file types, and size limits. The schema handles parameter details like outputDir defaults and non-overwriting, so the description is complete for this tool's complexity.

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 coverage is 100%, so the baseline is 3. The description adds genuine meaning to the 'mode' parameter by explaining the real-world consequences of 'burn' vs. 'attach', and it clarifies that 'paths' accepts both video and subtitle file formats. The rest of the parameters (fontSize, outputDir) are adequately described in the schema, so this added context earns a 4.

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 starts with a specific verb+resource ('Add subtitles to video') and clearly distinguishes two modes (burn vs. attach). It differentiates from sibling tools focused on conversion, compression, or thumbnails, so the purpose is unmistakable.

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 explains when to choose burned-in versus attached subtitles by detailing trade-offs (burned-in always visible, attached can be switched off and avoids re-encoding). It does not explicitly compare against 'text_subtitles' or other alternatives, so it stops short of a full 5.

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