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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the detail that the ID is the publicly displayed homepage douyin_id, but discloses no further behavioral traits such as rate limits or response characteristics, which is acceptable but not enriching.

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, front-loaded sentence with no wasted words. It captures both the required input and the resource returned, though it is minimal.

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 lookup with one required parameter, a thorough schema description, an output schema, and read-only/open-world annotations, the definition is largely complete. It does not explicitly mention the alternative sibling tools, but the agent can infer correct usage from the identifier constraint.

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%, and the parameter description already explains the meaning of douyin_id and what not to pass. The tool description restates essentially the same information without adding new semantic detail, so baseline 3 applies.

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?

Description clearly states the operation: retrieve user profile data using the homepage-displayed douyin_id. It identifies the exact identifier type, which helps distinguish it from sec_user_id/profile_url sibling tools, though it does not explicitly name those alternatives.

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?

Usage is implied: use this tool when you have the public douyin_id shown on the user's homepage. However, it does not explicitly state when to prefer this over its sec_user_id or profile_url siblings, leaving the selection guidance mostly to inference.

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