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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the main safety profile is covered. The description adds meaningful behavioral context by specifying that only confirmed, non-banned accounts are listed, matching the forum's own 'New members' list. This clarifies the filtering behavior beyond the schema.

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 compact and front-loaded with the main purpose; the second sentence adds important filtering context. Every sentence earns its place with no filler or redundancy.

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?

Given the single optional parameter, complete schema coverage, read-only annotations, and the existence of an output schema, the description provides all necessary context: what the tool returns, who is included/excluded, and when to use it. Nothing critical is missing.

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 only parameter, 'limit', is fully documented in the schema with a clear description and default value (schema coverage 100%). The description does not add parameter-level detail, but none is needed since the schema is complete. 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 states a specific verb ('List'), a precise resource ('newest WindowsForum member registrations'), and the intended use cases ('community-growth questions' or 'identify recent joiners'). This clearly differentiates it from sibling tools like get_online_users, get_user, and search_users.

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 clear context for when to use the tool ('community-growth questions' or 'identify recent joiners'). It does not explicitly mention exclusions or alternatives, but the stated purpose is sufficient for an agent to select it appropriately among the sibling tools.

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