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

The annotations already declare this as read-only, non-destructive, idempotent, and closed-world. The description adds useful context that only active agents are returned and that real-person agents are prioritized, but it does not cover pagination, response behavior, or rate limits.

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 a single compact sentence with the core operation front-loaded. The parenthetical ordering note is slightly ambiguous, but overall it is efficient and appropriately sized.

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 read-only list tool with full schema coverage, rich annotations, and no output schema, the description is mostly sufficient. It omits details about result ordering and pagination, but those are not essential to invoking the tool correctly.

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?

Schema description coverage is 100%, so the schema already documents city, gender, and api_key. The description adds little beyond repeating the city scope and does not clarify the optional gender filter or API key usage.

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 gives a specific verb and resource: "List active agents" with a city scope. It is clear what the tool does, though it does not explicitly contrast itself with siblings such as register_agent or like_agent.

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?

It states the operation but gives no explicit guidance on when to use this tool versus alternatives, nor any prerequisites or exclusions. The use case is only weakly implied by the purpose statement.

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