Move a subscription to another offer (write)

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

With no annotations, the description carries full burden. It explicitly marks the operation as 'WRITE', discloses that it terminates the current subscription and creates a new one, that the returned identifier is new, and that customer rights change (advising to re-read usages and stop using the old identifier). It also explains the default end-of-term timing and the immediate override. This is comprehensive behavioral disclosure.

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 three sentences, tightly packed with essential information. It front-loads the 'WRITE' marker and then explains the core behavior, side effects, and timing. There is no fluff or redundant phrasing; every sentence 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 complex write operation with no output schema, the description covers the essential behavioral context: side effects, identifier change, rights change, and timing. It omits edge cases like failure scenarios or engagement bypass details, but those are partly covered by the parameter schema. Overall, it is complete enough for an agent to call the tool correctly without further clarification.

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 provides 100% coverage for all five parameters, each with its own description. The tool description adds minimal parameter-level information beyond what the schema already states—it reinforces the behavior of 'immediate' but does not introduce new semantics for 'bill_now' or 'ignore_engagement'. Since the schema does the heavy lifting, a baseline of 3 is appropriate.

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 ('Moves') and resource ('a ProAbono subscription to another offer'), and clarifies that upgrade and downgrade are the same operation. This clearly distinguishes it from sibling tools like terminate_subscription or create_subscription, which have different intents.

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 explains what the operation does but does not explicitly guide the agent on when to choose it over alternatives like terminate_subscription or create_subscription. It implies usage for changing offers, but there is no explicit 'use this when' or 'do not use when' context. The default timing behavior is noted, but not tool selection.

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