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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds value by naming the returned fields (name, email, phone, addresses, total spent) and disclosing that pagination continues via next_page. It does not mention rate limits or permissions, but for a read-only list tool that is a minor gap.

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 resource definition and return fields, with no filler. Minor imprecision in "dates" (which of the four date parameters) is the only rough edge, not verbosity.

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 an 11-parameter, non-destructive read tool with full schema coverage and no output schema, the description covers purpose, population, returned fields and pagination adequately. The remaining gap is guidance on choosing among the many sibling list/get tools rather than factual coverage.

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 11 parameters are documented in structured form and the baseline is 3. The description adds only a coarse summary — "filter by name, email and dates" — and omits any mention of sort_by, sort_key, limit, or the fact that four distinct date ranges (created/updated min/max) exist, so it does not meaningfully enrich 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?

States a specific verb and resource ("List the store's subscribers") and even defines the population — customers with at least one subscription — which an agent can use to distinguish this from a generic customer list. It does not, however, contrast itself with siblings like recurpay_list_subscriptions or recurpay_get_subscriber, so the differentiation is implicit rather than stated.

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?

"Filter by name, email and dates. Page with next_page" gives implied usage of the filter and pagination mechanics, and the parenthetical scope definition hints at what is excluded. There is no explicit statement about when to prefer this over recurpay_list_subscriptions or when to switch to recurpay_get_subscriber for a single record.

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