List contact groups

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

Beyond the readOnlyHint and idempotentHint annotations, the description discloses important behavior: the return envelope, the distinction between user-created and system-fixed groups, default group_fields behavior, page_size limits, and sync_token expiration semantics (410). This gives an agent a strong model of what will happen.

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?

Four dense sentences cover return format, group taxonomy, field defaults, pagination, and sync behavior without fluff. Key information is front-loaded (what is returned), and every sentence earns its place.

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 fully compensates by enumerating the response fields and edge cases. It covers pagination, sync tokens, group types, and field customization, leaving little for an agent to guess.

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 already 100%, but the description adds substantial value beyond the schema. It explains the default group_fields, warns that memberCount must be explicitly included if narrowing fields, and clarifies page_size limits and sync_token expiration behavior. This is more than the schema alone provides.

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 tool lists the account's contact groups and specifies the exact response fields (contactGroups[], resourceName, name, groupType, memberCount, nextPageToken, totalItems). It also distinguishes the two group kinds (USER_CONTACT_GROUP vs SYSTEM_CONTACT_GROUP), which sets it apart from related siblings like get_contact_group or list_contacts.

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 verb 'Lists' makes the primary use case obvious, and the description adds useful context about when you would care about member counts or sync tokens. It references list_contacts for sync_token behavior but does not explicitly state when to choose this tool over siblings like get_contact_group or list_contacts, so it falls short of a full 5.

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