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

Beyond the readOnlyHint annotation, the description discloses that 'Authenticated user_id is injected server-side' and warns that these are 'FAKE people for demos and testing, not real PII.' This adds meaningful context about the tool's behavior and data nature.

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 efficiently organized: purpose first, then usage, parameters, and a final caveat. Every sentence contributes, and the length is appropriate for the tool's complexity.

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?

The description covers purpose, usage, parameters, authentication context, and data nature, while the output schema handles return values. No significant gaps remain for effective tool invocation.

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 already documents both parameters with descriptions and examples, achieving 100% coverage. The description adds usage nuance, such as 'results' default/minimum and 'isPro' as 0 or 1 'when relevant', which enhances understanding beyond the schema.

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: 'Generate synthetic / fake user profiles' and references the specific API endpoint (POST /mwvideos/api/random_users). It also lists the returned fields, making the purpose unambiguous.

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?

Provides explicit use cases: 'when the user asks for random users, fake people, sample contacts, demo personas, UI fixtures, or test profiles.' It also instructs to 'always call this tool' rather than inventing profiles, giving clear guidance.

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