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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The description adds the underlying API endpoint and filter-expression mapping, which is useful context, but says nothing about pagination defaults, result ordering, or what the response contains.

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, front-loaded with the capability before the API detail, and no padding. The trailing endpoint/param list is somewhat redundant with the schema but compact enough to keep.

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 nine-parameter list tool with no output schema and no destructive hints, the definition covers filtering well but leaves the return shape and pagination behavior unaddressed. An agent can call it correctly but not predict what comes back.

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%, so all nine parameters are already self-documenting, giving a baseline of 3. The description reinforces this by mapping the friendly parameter names to their API filter expressions (filter[store_id], filter[status], etc.), which is a marginal addition rather than new semantics.

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 (List) and resource (subscriptions) plus the filter dimensions available, so the agent knows exactly what it retrieves. It does not explicitly differentiate itself from the singular lemonsqueezy_get_subscription or from lemonsqueezy_list_subscription_invoices, so it stops short of a 5.

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 enumeration of filter dimensions implies when this tool is the right choice (broad retrieval narrowed by store/status/product/customer/email), but there is no explicit when-to-use statement, no exclusions, and no routing to get_subscription for a single record. Usage is inferable rather than stated.

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