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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds value beyond them: it discloses the default ordering ('newest first by default'), names the returned fields in the absence of an output schema, and identifies the underlying endpoint. It omits pagination behavior and any rate-limit or result-cap context, which keeps it below a 5.

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 dense sentences with zero filler; the identity of the resource and the default ordering come first, then the filter set, then the endpoint. Every clause carries information an agent would otherwise have to infer.

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, the description correctly compensates by summarizing return fields, and all 8 optional parameters are covered by the schema. Annotations handle the safety profile. Minor gaps remain around result-set size and paging semantics, but nothing essential to calling it correctly is missing.

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% and every parameter carries its own explanation, including paging via next_offset, so the schema does the heavy lifting. The description restates the filter categories (program, query identity, date range, active/disabled) without adding syntax or edge-case detail. Baseline 3 is appropriate.

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 members'), parenthetically disambiguates what a member is ('the people who refer others'), and enumerates the returned fields (referral code, share URL, counts, rewards, activity dates). That is enough for an agent to distinguish it from list_referrals, list_rewards, or get_member_stats without opening a schema.

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 description does establish usable context by listing the available filter axes (program, email/id/external id/referral code, created date, active vs disabled). However, it never states when to prefer this over sibling tools such as get_member_stats or list_referrals, and offers no exclusions. Usage is implied rather than directed.

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