xhs_get_user_id_by_encrypted_user_id

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

The annotations already declare readOnlyHint=true and openWorldHint=true, indicating a safe read operation. The description, though brief, adds valuable context by specifying the required format of the encrypted user ID (29-bit lowercase hex). However, it doesn't disclose potential failure cases or error behavior, but given the annotations, the bar is lowered and this additional format detail justifies a 4.

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 concise sentence with no unnecessary words. It is front-loaded with the main action and outcome, and the parameter schema handles all additional details, making it optimally concise.

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 tool has one parameter with a rich schema description and an output schema (as indicated by context signals), the description is sufficient for understanding the input and expected result. It doesn't describe return values, but since an output schema exists, that is not required. The main missing piece is explicit mention of use-cases or limitations, but it's still complete enough for an agent to call 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?

The schema description coverage is 100%, so the schema already documents the parameter thoroughly. The description does not add further semantics beyond what the schema provides, so a 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 clearly states the verb '获取' (get) and the resource 'user_id' derived from an encrypted user ID, which is distinct from other tools that fetch user info by profile URL or user ID. It precisely identifies the input and output, making it easy for an agent to understand its purpose.

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?

While the description doesn't explicitly mention when to use this tool over alternatives, the parameter schema provides strong guidance by explicitly stating what not to pass (24-bit user_id, nickname, etc.). This is clear context but lacks an explicit alternative tool reference, so it doesn't fully reach a 5.

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