Start or restart a subscription (write)

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

With no annotations, the description carries the full burden. It discloses the write nature ('WRITE') and explains the effect: it grants rights and transitions a draft or suspended subscription to active. It also notes that rights only exist after starting, which is a valuable behavioral nuance. It does not cover side effects like billing when bill_now is true, but that is parameter-specific, not core behavior.

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 efficient and front-loaded with 'WRITE'. Every sentence adds value: the purpose, the state transition, the lack of an alternative, and the follow-up action. It is slightly longer than necessary but each part earns its place.

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 write tool with no output schema, the description covers the main use case and post-condition (rights granted, re-read with get_usages). It does not discuss errors or prerequisites, but those are not critical for correct invocation. The core behavior is sufficiently explained.

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 description coverage is 100%, so the schema already explains all three parameters. The description does not add any parameter-specific meaning beyond what the schema provides, so the baseline of 3 applies. It mentions the overall purpose but not parameter interactions.

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 ('activates'/'restarts') and resource ('subscription'), and clearly differentiates from siblings like suspend_subscription and create_subscription by explaining the same transition covers draft and suspended states. It also clarifies there is no separate resume operation, making it unambiguous.

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?

Explicitly identifies this as the tool to unsuspend a subscription and notes there is no alternative operation ('no separate resume or unsuspend operation'). It also implies when to use it (draft or suspended states) and suggests a follow-up action with get_usages, giving clear selection guidance.

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