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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and scope are covered structurally. The description adds the shape of returned records, but says nothing about pagination behavior, result-set size, or that deleted fields are hidden by default — context that would matter for a listing call.

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?

A single sentence with the verb and resource front-loaded and the parenthetical earning its place by previewing the returned attributes. Nothing is padded or repeated.

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?

There is no output schema, and the parenthetical partially compensates by naming the fields returned. Pagination and soft-delete behavior live entirely in the schema, which is adequate for a simple zero-required-parameter read tool; only the return envelope (paging metadata) is left unstated.

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%: limit, start, and include_deleted are each documented with ranges and defaults, including the 'use next_start from the previous reply' hint. The description adds no parameter meaning beyond the schema, so the 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?

Names a specific verb and resource ('List the custom member fields of the account') and the parenthetical enumerates what each field record contains (shortcut names, display names, types). The resource is distinct from every sibling, which all operate on members, groups, mailings, searches, or imports, so an agent can route here without ambiguity even though no sibling is named.

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 can infer this is the discovery call for custom-field definitions, but the description never states when to call it (e.g. before reading or filtering members by custom field) or how it relates to emma_list_members. No exclusions or prerequisites are given.

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