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

readOnlyHint=true already covers the safety profile, so the bar is lower. The description still adds useful context beyond the annotations: it discloses the return shape (HAL collection embedding fx:subscriptions) and the underlying read endpoint, which helps an agent anticipate the response envelope.

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?

Three short sentences, front-loaded with the purpose before the return-envelope and endpoint details. Nothing is padded, though the raw endpoint string is marginally redundant for an agent that never calls the HTTP API directly.

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 list tool with full schema coverage, no output schema, and annotations carrying the safety profile, the description supplies the missing return-shape context. Pagination semantics live in the schema, so nothing critical is absent.

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 zoom, limit, offset, store_id and is_active are each documented in the schema with defaults and ranges. The description adds no parameter-level meaning beyond that, which is the expected baseline when the schema does the heavy lifting.

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 (a store's subscriptions / recurring orders), and names the embedding and underlying hAPI endpoint, which pins down exactly what is returned. It differentiates implicitly from foxy_get_subscription by being the collection variant, but never names that sibling explicitly.

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?

Usage is only implied: an agent infers this is the collection-listing counterpart to foxy_get_subscription because of the name and the 'store's subscriptions' phrasing. There is no statement of when to prefer this over foxy_get_subscription, and no prerequisites or exclusions are mentioned.

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