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

Annotations indicate it is not read-only, not destructive, and idempotent. The description adds valuable behavioral context: 'Humans watching see and hear it change live' describes the real-time effect, and 'Returns the new persona prompt if you changed persona' clarifies the return value. This goes beyond the annotations and does not contradict them.

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 two sentences, front-loaded with the core action and effect. Every sentence serves a purpose: the first states the action and its live consequence, the second notes the return value. There is no filler or redundancy.

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 four parameters and no output schema, the description is fairly complete. It explains the live effect and the return condition for persona changes. However, it is ambiguous what is returned when only look or voice is changed, and it does not mention error conditions or prerequisites beyond being in a room. Given the tool's simplicity and schema coverage, this is adequate but not exhaustive.

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?

The schema has 100% coverage with descriptions for all parameters (look, room, voice, persona). The description does not add significant meaning beyond the schema, only reiterating the parameter names. Since the schema already documents the parameters, the baseline of 3 applies; the description adds minimal extra semantic value.

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 a specific verb and resource: 'Change your look, persona and/or voice while in a room.' It distinguishes itself from sibling tools like list_looks (listing) and reset_style (resetting) by focusing on the act of changing. The added detail about humans seeing and hearing the change live further clarifies the tool's purpose.

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 context by saying 'while in a room', implying the user must be in a room to use it. However, it does not explicitly mention alternatives like reset_style or set_defaults, nor when to choose this tool over them. There is no exclusionary guidance, so usage is implied but not fully specified.

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