获取直播/回放地址

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is well-covered. The description adds behavioral context beyond annotations by clarifying that omitting classId returns the course live address, and by disclosing the return value is a player URL. It does not contradict annotations.

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 well-structured with a clear purpose statement, parameter list, and return description. Each section earns its place, though the parameter details duplicate the schema descriptions, creating minor redundancy. Overall it is efficient and easy to scan.

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 tool with strong annotations and no output schema, the description is complete enough: it states the return type (播放器URL) and covers parameter semantics. It does not elaborate on potential URL expiry or auth requirements, but these are not critical for safe invocation given the readOnlyHint and simple contract.

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 provides descriptions for all three parameters, including the optional nature of classId and the response_format enum, yielding 100% schema coverage. The description repeats this information without adding new semantics or usage details, so it adds no value beyond what the schema already supplies.

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 '获取课程或课节的直播/回放播放器地址' (get live/replay player URL for a course or class), specifying both the verb and the resource. It distinguishes itself from sibling tools (which are mostly mutations or other getters for different resources) by naming the specific entity being fetched.

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 explains the optional classId behavior ('不传则获取课程直播地址'), giving implicit guidance on when to use the course-level vs class-level functionality. However, it does not explicitly state when to prefer this tool over other sibling getters (e.g., classin_get_cloud_list) or provide alternative scenarios, relying on the agent to infer from the resource type.

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