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

readOnlyHint=true already tells the agent this is a safe read, and the description only echoes that with the literal 'GET /subscriptions/{id}' path. It adds nothing about auth requirements, error behavior for an unknown id, or what the response contains, so it contributes little beyond the annotation.

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 short, front-loaded sentences with no padding. The API path restates what the verb already conveys, a minor redundancy but not enough to hurt structure.

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 simple id-based read with full schema coverage and readOnlyHint, the description is adequate; return values need not be explained since no output schema is claimed. It could be stronger by noting that the id is a subscription id specifically, not a customer or order id.

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 100%, including the include= sideload syntax, so the schema already carries both parameters. The description adds no format or constraint detail beyond it, making the baseline 3 the right score.

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?

States a specific verb (get), resource (subscription), and scope (single, by id), which implicitly separates it from lemonsqueezy_list_subscriptions. It stops short of naming any sibling explicitly, so an agent must infer the boundary rather than being told it.

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?

There is no explicit when-to-use guidance, no mention of the list vs single-by-id choice, and no prerequisites. The only guidance is implied by 'by id' – an agent must work out for itself that this requires an existing subscription id rather than a customer or order id.

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