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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, establishing this as a safe, read-only, idempotent operation. The description adds the context that it should be skipped when the input prompt is already specific, which is useful but not a major behavioral disclosure. Since annotations cover the safety profile, this is adequate.

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 exactly two sentences, front-loaded with the purpose and followed by usage guidance. No redundant phrasing.

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 simple, side-effect-free tool with no required parameters and full schema coverage, the description covers the core purpose and the key decision of when to skip it. It doesn't explicitly state the return format, but the tool name and description imply a prompt string, and annotations cover safety. Complete enough.

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?

All 5 parameters are fully described in the schema (100% coverage), so the description doesn't need to repeat them. The description's mention of 'user's rough description' aligns with the user_text parameter, but the schema already documents each parameter thoroughly. Baseline 3 is appropriate.

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 tool's function: building a highly detailed prompt for avatar/model generation. It distinguishes itself from the sibling generate_avatar by explicitly saying that if the user's prompt is already intentional, the system can skip this and pass wording directly to generate_avatar, making sibling differentiation clear.

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 gives explicit conditions for when to use this tool ('when the user wants help describing a person before image generation') and when to skip it in favor of an alternative ('if the user's prompt is already intentional and specific... pass directly to generate_avatar'). This directly addresses usage vs alternatives.

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