get_user_profile

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

No annotations are provided, so the description carries the burden of disclosing behavioral traits. It states the tool fetches a 'public profile', implying read-only and no authentication needed, but provides no information about error cases, rate limits, or data freshness. Some transparency is present but lacks depth.

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 one concise sentence that clearly states the action and data included. Every word serves a purpose with no fluff or redundancy. The structure is front-loaded and easy to parse.

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 simple parameter structure and the presence of an output schema, the description adequately covers the tool's purpose and basic return data. It explicitly mentions 'public profile' which is useful context. However, it could mention that the username must be for an existing Reddit user and what happens if not found.

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 input schema has 100% coverage and already describes the 'username' parameter including the note about the 'u/' prefix. The tool description does not add any additional meaning beyond what is in the schema, so baseline score of 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 uses 'Fetch' as a clear action verb and specifies the resource as 'Reddit user's public profile' with specific data included (karma, account age, metadata). This distinguishes it from sibling tools like get_post_thread and get_user_activity which target different resources or data types.

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 provides no guidance on when to use this tool versus alternatives. It does not mention when not to use it, nor does it reference sibling tools or specific contexts. The only usage context implied is that it fetches a public profile.

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