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

The annotations already establish that this is a non-read-only, non-destructive mutation, and the description adds meaningful behavioral context: partial updates are supported, colors must be in #RRGGBB format, and invalid font or color choices are either corrected or rejected with a reason. It does not cover permissions, reversibility, or success behavior, but it adds substantial value beyond the annotations.

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 compact sentences, front-loads the core mutation purpose, and each sentence adds useful information: scope, partial-update behavior, formatting, and validation. 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?

For a nested, mutation-style tool with no output schema, the description covers the essential behavior, partial-update semantics, and validation. It leaves some context implicit, such as how the 'current' style is selected and how this relates to choose_style, but it is largely sufficient.

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 moderate at 50%, and the description adds important meaning beyond the schema by clarifying that changes is a patch-style object where only fields to change should be sent. It also reinforces color formatting and validation behavior, though it does not explain every nested parameter.

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 a specific verb and resource: it changes the look of the current lyric video style, and it enumerates the affected areas such as layout, animation, colors, font, background, and chorus emphasis. It clearly implies an update operation on an existing style, though it does not explicitly distinguish itself from the sibling choose_style tool.

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?

It gives a useful partial-update instruction, "Send only the fields to change," and frames the operation around the current style. However, it does not state when to use this versus choose_style or create_lyric_video, nor does it mention prerequisites such as needing an existing style.

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