apple_create_intro_offer

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

With no annotations, the description carries the full behavioral burden. It discloses that this is an 'External action' (network call to Apple), that territory is required or Apple refuses, that only one offer per territory can be created, and that paid offer modes are unsupported. It does not mention authentication, rate limits, or idempotency, but the key operational behaviors are covered.

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 front-loaded with the core purpose and then uses clear, separated lines for each parameter's semantics. It is appropriately sized and every sentence adds value. Minor redundancy exists (e.g., 'free trial' appears in both the opening and offer_mode), but overall structure is efficient.

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?

Given the tool's complexity (creating a subscription intro offer via external API), the description is largely complete: it covers purpose, key parameters, limitations, and territory handling. The presence of an output schema means return values need not be explained. The main gaps are the unmentioned 'number_of_periods' parameter and the schema/description conflict about territory being required.

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 0%, so the description must explain parameters. It thoroughly enumerates duration values and offer_mode options, and explains territory requirements. However, it completely omits the 'number_of_periods' parameter and does not explicitly define 'subscription_id'. Additionally, it claims territory is REQUIRED while the schema lists only subscription_id as required and gives territory a default, creating a semantic conflict.

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 opens with a specific verb+resource: 'Create the subscription's introductory offer (free trial).' It clearly distinguishes from sibling tools like apple_set_subscription_price and apple_create_subscription by focusing on the introductory offer creation. The parenthetical '(free trial)' further narrows the scope.

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 clear context for use: it notes that the tool is an 'External action' and explains the territory requirement ('one offer per country: Apple refuses to create the offer without it. To apply in several countries, call once per territory'). It also states that PAY_AS_YOU_GO and PAY_UP_FRONT modes are not covered, implying when not to use. However, it does not explicitly compare to alternative tools or state when to choose this over other subscription-related tools.

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