storekit__lookup_order

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

readOnlyHint=true already establishes this is a safe read; the description correctly stays consistent with that and adds the source context (App Store Server API, customer receipt). With annotations covering the safety profile, the remaining burden is light, but it doesn't disclose return volume, pagination, or environment behavior nuances beyond what the schema states.

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?

Two tight sentences: the core action first, the usage trigger second, with a bracketed source tag. No filler, and the key information is front-loaded.

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 read-only lookup with no output schema and full schema coverage, the description is largely sufficient: it identifies the input source and scope ('all transactions'). It could note whether results span environments or if pagination applies, but nothing critical for invoking the tool is missing.

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 all three parameters are already documented in the schema. The description reinforces that order_id comes from a customer receipt but adds no format or syntax detail beyond the schema. Baseline 3 is appropriate when the schema carries the parameter documentation.

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+resource: looking up all transactions tied to an order ID from a customer receipt. This clearly differentiates it from sibling tools that key off a transaction ID (get_transaction_info, get_transaction_history). However, it does not explicitly name or contrast any sibling, so the differentiation is implicit rather than stated.

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?

It gives a concrete trigger condition: 'Use when a customer sends you the order number from their email.' This tells the agent when to reach for this tool rather than others. It stops short of naming alternatives or when-not-to-use cases (e.g., vs. transaction-ID lookups), so it lands at a clear context without exclusions.

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