set_style

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

The description provides valuable behavioral context beyond annotations: it explains the unit conventions for outline_width and bottom_margin, warns about usability issues when outline_width exceeds 10, and mentions that changes are saved and immediately reflected. This is more than the idempotentHint/destructiveHint annotations already convey.

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 compact and front-loaded with the overall purpose in the first sentence, followed by targeted clarifications for the two trickiest parameters. Every sentence adds value and there is no filler.

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 9 parameters and no output schema, the description covers the most critical parameter quirks but misses some information like color format or how language is used. It is adequate for basic use but not fully comprehensive for all parameters.

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 thoroughly explains outline_width and bottom_margin, which are non-obvious, but it leaves other parameters (color, font_size, max_lines, font_family, background_alpha, etc.) without explicit semantic detail. The names give some hints, but the description does not fully cover all parameters.

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 states clearly that the tool sets and saves overlay style (font, size, color, outline, bottom position) and immediately applies it to the running overlay. It uses specific verbs and a clear resource, and it is easily distinguished from sibling tools like load_subtitle or start_overlay.

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 whenever you need to change overlay style, but it does not explicitly state when to use this tool versus alternatives. There are no competitor tools for style setting among siblings, but the description also does not mention prerequisites or exclusions.

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