x_api_get_users_by_usernames

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

With no annotations, the description carries full burden, and it discloses read-only status, required OAuth scopes, and the environment-selection behavior involving scopeTenantId, scopeUserId, and scopeAccountId. It also lists common failure conditions and safety warnings about sensitive data, which goes beyond simple annotations. No contradictions found.

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?

The description is structured into labeled sections, making it scannable, and it includes a wealth of context (failure conditions, example, safety). However, it contains redundancy, such as 'Get Users by usernames.' and 'Use when: Get Users by usernames.' and a long 'Recommended prerequisite and follow-up tools' list that could be trimmed. The example also omits the required 'usernames' parameter, undermining its clarity.

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?

Given no annotations and no output schema, the description provides a detailed response shape, common failures, and auth prerequisites, which is valuable. However, it fails to document all parameters (authorizationKey, preferredAuthType) and the example lacks the required 'usernames' field, leaving gaps for an agent to invoke correctly. The response shape is generic but acceptable for this tool.

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 0%, so the description must compensate. It explains usernames (query, array, required) and the auth/environment parameters via the 'Environment-selection behavior' section (scopeTenantId, scopeUserId, scopeAccountId, credentialKey). However, it does not explain authorizationKey or preferredAuthType, and 'Parameter formats and constraints' only lists usernames, leaving several parameters underdocumented.

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?

The description clearly states 'Get Users by usernames,' identifying the operation and key parameter. It distinguishes from sibling tools like x_api_get_users_by_ids and x_api_get_users_by_username by indicating plural username lookup, though the 'Use when' section repeats the same phrase without adding differentiation.

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 provides explicit 'Do not use when' guidance, advising against use when auth/configuration tools are needed or when exploring, and recommending x_schema_discovery or x_query_suggestion instead. However, the 'Use when' section is tautological ('Get Users by usernames') and does not compare to close siblings like x_api_get_users_by_ids or x_api_get_users_by_username. Prerequisite and follow-up tools are listed, but the primary condition is not well specified.

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