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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real value by scoping the payment method to brand, last digits and expiry only, indicating sensitive data is truncated, and it names the underlying endpoint. It says nothing about not-found behavior or error responses for a lookup that can easily miss.

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?

One dense sentence that front-loads the identifier and its source before listing returned fields, with the endpoint appended as a trailing aside. The endpoint reference is arguably redundant given the annotations, but nothing else is wasted.

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?

There is no output schema, so enumerating the returned fields is necessary and done here; combined with the id provenance and endpoint it covers what an agent needs to call this single-parameter lookup. Only the failure mode for an invalid or stale id is left unstated.

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% and the schema already maps the parameter to `shopifyId` in smartrr_list_subscriptions. The description adds a small but real constraint, 'passed exactly as shown', warning against reformatting or extracting the id, so it does more than restate the schema.

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?

Names a specific verb (get) and resource (one subscription) plus the exact identifier that selects it, then enumerates the payload (status, schedule, next billing date, line items, discounts, address, customer, payment method). This clearly separates it from smartrr_list_subscriptions and from the get_subscription_bills/orders/events siblings.

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 tells the agent where to get the argument (the `shopifyId` field from smartrr_list_subscriptions) and that it must be passed verbatim, which is the main usage decision here. It doesn't state exclusions versus siblings like get_subscription_bills, though the field list implies the distinction.

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