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 pagination behavior (50 per page) and notes that items and billing attempts can be included, which affects response size, but says nothing about auth requirements, rate limits, or ordering of results.

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 but well-ordered sentence: purpose first, returned fields second, then search, filter and expansion options, with the endpoint last. Every clause carries information; the field enumeration is slightly long but justified since no output schema exists.

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?

With no output schema, listing the returned fields is valuable and the description does it. For a read-only, zero-required-parameter list tool this is nearly complete; only result ordering and pagination navigation beyond the schema's own note are unaddressed.

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 the schema already documents all five parameters including defaults and the next_page hint. The description mirrors the searchable fields and filters but adds no extra syntax or format detail beyond the schema, so baseline 3 applies.

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?

Clear verb (list/search) plus resource (shop's subscriptions) and it enumerates the fields returned, so an agent knows exactly what comes back. It does not name the near-twin sibling sealsubscriptions_list_subscriptions_by_billing_date, which is the main confusion risk among 25 siblings, so it falls short of the top score.

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 explains how to use the tool (search by email/first/last name, filter by status, opt into items and billing attempts), which implies the intended use cases. But there is no explicit when-not guidance or pointer to alternatives such as get_subscription for a single record or list_subscriptions_by_billing_date for date-ordered listing.

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