pricing__get_subscription_price

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

Annotations already declare readOnlyHint and idempotentHint, covering the safety profile. The description adds valuable behavioral context: it returns the effective price, unlike subscriptions__prices__list which returns price-less stubs. This nuance goes beyond the annotations and helps the agent understand the tool's actual 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 four sentences long, front-loaded with the core purpose, and every sentence delivers distinct value: purpose, parameter guidance, alternative advice, and a behavioral caveat. No filler or redundancy.

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 output schema exists, the description does not need to explain return values. It covers purpose, usage scenarios, parameter semantics, and a key behavioral distinction from a sibling tool. It is fully complete for an agent to select and invoke the tool correctly.

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 coverage is 100%, so the baseline is 3. The description adds extra meaning by explaining that the 'app' parameter accepts a name, bundle ID, or Apple ID, providing territory examples, and detailing the optional 'subscription' parameter's behavior with a real-world use case. This enriches the schema definitions.

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: it returns what a subscription costs in a given territory in a single step. It also distinguishes itself from sibling tools by explicitly mentioning the alternative chaining approach and the subscriptions__prices__list stub limitation.

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?

Provides explicit guidance on when to use this tool versus alternatives: 'Use this instead of chaining apps__list / subscription_groups / prices calls.' It also explains when to omit the subscription parameter (to get every subscription) and gives a concrete use case ('what does the weekly one cost').

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