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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds only the free-cost note and the account/quota category; it says nothing about what is returned when the agent has no subscription or whether rate limits apply, which is modest added value over the 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?

Two short clause groups with the category tag and cost note front-loaded, no filler. The only inefficiency is the misleading agentId mention, which costs clarity rather than length.

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 one-parameter, read-only lookup this is close to sufficient, and the absence of an output schema does not require return-value documentation. Still, the alias confusion and the total lack of sibling differentiation leave an agent with open questions about when to prefer platform_user_subscription or platform_subscription_list.

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 coverage is 100% and strategyId is documented as required, so the baseline would be 3. However, the description claims the parameter is 'strategyId 或 agentId' while the schema exposes only strategyId and no agentId property, which could steer an agent to pass an unsupported field — a net information loss rather than an addition.

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?

Uses a specific verb and resource combination ('查询对某 AI 助理的订阅状态') and tags the category as 【账户与额度】, so an agent can tell this is about per-agent subscription state. It does not explicitly distinguish itself from siblings like platform_user_subscription or platform_subscription_list, which query subscription data at other scopes.

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 only implied: the single-strategy scoping implies 'use when you need the subscription status of one specific agent', and no alternative tool or when-not condition is named despite several adjacent subscription tools. 'cost: free' gives a useful hint for choosing this over paid siblings, but there is no real routing guidance.

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