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

The readOnlyHint annotation already establishes safety, and the description adds useful behavior beyond that: live availability, mutual-exclusivity rules for lookup identifiers, and the response shape { meta: { next }, entries }. It does not contradict annotations.

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 three tight sentences with no filler. It front-loads the main purpose, then the lookup constraint, then the return shape.

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 a seven-parameter read-only listing tool without an output schema, the description supplies the return shape and a key parameter constraint. The main remaining gap is that the two boolean filtering parameters are undocumented in both schema and description.

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 coverage is 71%, and the description adds a crucial semantic rule not captured by the schema: exactly one of extension, phoneNumber, or ivrKey may be used for lookup. It does not explain includeSuspendedUsers or includeHiddenCallGroups, but it substantially improves understanding of the core lookup parameters.

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 the verb and resource: list or search the unified Spoke directory covering users, teams, and devices, including extensions and live availability. It differentiates itself from narrower list_users/list_teams siblings, but does not explicitly point to get_directory_entry as the alternative for single-entry retrieval.

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 gives an important lookup constraint: exactly one of extension, phoneNumber, or ivrKey may be used to look up an entry. However, it does not explicitly say when to use this tool versus get_directory_entry or the narrower list_user/list_team tools, leaving usage guidance mostly implied.

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