cls_describe_index

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does well by explaining what information is returned (full-text index configuration, key-value index configuration, index status), which helps the agent understand the output. However, it doesn't mention important behavioral aspects like whether this is a read-only operation (implied but not stated), error conditions, rate limits, or authentication requirements.

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 well-structured with clear sections (purpose, parameter explanation, return information). It's appropriately sized - every sentence adds value. The only minor issue is some redundancy between the opening statement and the parameter/return sections, but overall it's efficient and front-loaded with the core purpose.

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 that there's an output schema (which handles return values), no annotations, and good parameter coverage in the description, this description is complete enough. It explains the purpose, parameters, and what information will be returned at a high level. The output schema will provide the detailed structure, so the description doesn't need to duplicate that information.

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 0%, so the description must fully compensate. It provides excellent parameter semantics: clearly explains topic_id is required and what it represents, explains region is optional with examples of valid values (ap-guangzhou, na-ashburn), describes the default behavior when region is not provided, and references another tool (cls_describe_regions) for getting all available regions. This adds substantial value beyond the bare schema.

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 tool's purpose as '查询日志主题的索引配置' (query log topic index configuration), specifying both the verb (query) and resource (log topic index configuration). It distinguishes from siblings like cls_describe_topic_detail (which likely describes general topic details) and cls_describe_regions (which lists regions) by focusing specifically on index configuration.

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 clear context for when to use this tool: to query index configuration for log topics. It mentions an alternative tool (cls_describe_regions) for getting available regions, which helps differentiate usage. However, it doesn't explicitly state when NOT to use this tool or compare it to other similar describe tools like cls_describe_topic_detail.

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