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

Annotations indicate readOnlyHint=false and openWorldHint=true, but the description does not explain the tool's side effects, asynchronous processing, polling behavior, or input/output requirements. It describes interactive previews but not how results are returned or whether it creates files, so an agent lacks behavioral transparency.

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 five-sentence description is promotional and repetitive, using phrases like 'enhance the online experience,' 'effortlessly explore,' and 'streamlines product discovery' that add no operational value. It lacks front-loaded technical summary and every sentence could be cut without losing agent-relevant information.

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 complex tool with a large nested schema, polling flag, and file-reference mechanics, the description provides no invocation guidance, no output explanation, and no mention of the request structure. An agent would have to rely solely on the schema, which is insufficient given the multiple discriminated unions and obscure parameter relationships (sub_type, texture, ref_file_url vs index).

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 50% description coverage and the description adds no parameter semantics; it only generically mentions 'unlimited color and texture options' without explaining the effects array, finger selection, effect_type, or ref_file mechanics. It does not compensate for the undocumented parameters in the large request object.

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 identifies the tool as a nail virtual try-on capability, mentioning nail styles, artificial/acrylic/press-on/gel, and before/after comparisons. It distinguishes from hair/makeup siblings by focusing on nails. However, it uses promotional language ('offers an innovative way to enhance') rather than an explicit verb like 'applies' or 'generates,' making the action less direct.

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 customers exploring nail art should use this tool ('customers interested in nail art'), but it provides no guidance on when to choose this over sibling tools like AI-Makeup-Virtual-Try-On or AI-Look-Virtual-Try-On. No prerequisites, exclusions, or alternative recommendations are given, leaving the agent without selection criteria.

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