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

The annotations already declare that the operation is read-only and not destructive, so the safety profile is covered. The description adds useful context by stating the cost is free and no parameters are required, but it does not say whether the list includes all subscriptions or only active ones.

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 compact sentence with a front-loaded category tag, the action, and a cost note; it wastes no words. The bracketed category label is somewhat boilerplate, but it adds navigational context rather than noise.

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 no-argument, read-only list tool with no output schema, the description is technically sufficient to invoke it. It is weaker on the cognitive side: with four or more subscription-related siblings, an agent lacks the information needed to pick this tool confidently over its near-neighbors.

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?

This is a zero-parameter tool, so the baseline is 4. The description correctly states that no parameters are needed, which matches the empty schema and leaves nothing unexplained.

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 states a specific verb and resource ('查询我的订阅列表' — query my subscription list), so its function is clear. However, it does not distinguish this tool from closely related siblings such as platform_user_subscription, platform_subscription_status, or platform_plans, which makes the boundary ambiguous.

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 gives no guidance about when to use this tool or when to use an alternative. '无需参数' addresses calling mechanics, not selection criteria, and it never mentions platform_user_subscription or platform_subscription_status, even though those tools appear to overlap.

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