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

Annotations already claim destructiveHint, and the description reinforces this by stating 'This changes billing state.' It also adds the meaningful resume/cancel-on-zero behavior without contradicting the annotation.

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?

Three concise sentences carry real load: the action, the special parameter semantics, and the underlying API endpoint. No filler or redundant restatement.

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 low-complexity write operation with two well-documented required params and a destructive annotation, the description covers the behavior and the key edge case. It omits return-value or permission detail, but the ansent can invoke it correctly from this description.

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 already documents both parameters at 100% coverage, so the baseline is a 3. The description adds extra value by explaining that remaining_pause_cycles=0 resumes/cancels an existing pause, which is not fully captured by the schema alone.

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?

States a specific action: pause a subscription for a defined number of billing cycles. The endpoint reference and the resume semantics distinguish it clearly from recurly_cancel_subscription.

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 clear usage context, especially the conditional behavior of setting remaining_pause_cycles to 0 to resume/cancel an existing pause. It does not explicitly point to recurly_cancel_subscription for permanent cancellation, but the contrast is implied by the tool name.

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