check_subscription

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

No annotations are provided, so the description carries full burden. It states the tool 'Returns: subscription details and usage' which describes output behavior. However, it doesn't disclose authentication requirements, rate limits, error conditions, or whether this is a read-only operation (though 'check' implies non-destructive). The description adds basic behavioral context but lacks completeness for a tool with zero annotation coverage.

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 perfectly concise: two sentences with zero waste. The first states purpose and return values, the second provides usage guidelines. Every word earns its place, and information is front-loaded effectively.

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 zero-parameter tool with no output schema, the description provides adequate coverage of purpose and usage. However, without annotations and with no output schema, it should ideally describe the return format more specifically (what 'subscription details and usage' includes) and mention any authentication or permission requirements. The description is complete enough for basic understanding but has room for improvement.

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?

With 0 parameters and 100% schema description coverage, the baseline is 4. The description doesn't need to explain parameters since there are none, and it appropriately focuses on what the tool does rather than parameter details.

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: 'Checks account subscription' specifies the verb and resource. It distinguishes from siblings like 'list_agents' or 'get_conversation' by focusing on subscription status rather than listing or retrieving specific resources. However, it doesn't explicitly differentiate from potential subscription-related tools that might exist in other contexts.

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 explicit usage context: 'Use when: monitoring API usage and limits.' This gives clear guidance on when to invoke this tool. It doesn't specify when NOT to use it or name alternatives, but the context is sufficiently clear for a zero-parameter tool that returns subscription details.

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