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

The description adds context beyond annotations: it states each parameter overrides a feature and requires authentication. Annotations already indicate idempotentHint=true and destructiveHint=false, so the description aligns and adds value without contradiction.

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, concise and front-loaded with the core action. Every word earns its place without unnecessary elaboration.

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?

With 7 optional parameters and a simple purpose, the description adequately covers the tool. The presence of an output schema means return values need not be described. Minor omission: it could mention that the avatar is personalized for the authenticated user, but that is implied by 'your robot avatar'.

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 input schema has 100% description coverage with clear explanations for each parameter (e.g., 'Background color index (0-15)'). The tool description adds 'Each parameter overrides one feature', which is redundant given the schema. Thus, the description adds little meaning beyond what is already provided.

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 the verb 'Customize' and the resource 'your robot avatar', and explains that each parameter overrides a feature and reset restores default. It is distinct from the many sibling tools, which cover other actions like banning, blocking, etc.

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 a usage guideline for reset ('Set reset=true to go back to the default'), which helps the agent know when to use that parameter. It does not explicitly mention when not to use this tool or provide alternatives, but the context of avatar customization is specific enough.

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