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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds meaningful behavioral context beyond annotations: what a signed-out visitor would see, profile-limited members getting username-only results, and last seen being omitted when online status is hidden.

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, front-loaded with the core purpose, and each sentence earns its place. It avoids filler while still covering the essential behavior.

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 single-parameter read-only tool with an output schema, the description is complete. It covers the lookup key, the returned profile fields, and the important privacy-driven output variations, leaving nothing an agent needs to invoke it 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 coverage is 100%, with the identifier parameter described as 'Username or user ID'. The description repeats the same meaning without adding extra format, case-sensitivity, or ambiguity guidance, so it stays at the baseline for fully documented parameters.

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?

States a specific verb ('Look up'), a clear resource ('a WindowsForum member's public profile'), and exact lookup keys ('by username or user id'). The listed returned fields and the exact-identifier semantics make it easy to distinguish from sibling search/list tools such as search_users or get_latest_registered_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 implies the intended use: retrieve a public member profile when you have an exact username or user id. It does not explicitly state when not to use it or point to alternatives like search_users, though the visibility caveat provides some context about limitations.

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