add_user_to_group

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

With no annotations, the description carries the burden of behavioral disclosure. It does disclose that the operation leaves other members untouched, which is useful, but it does not mention idempotency, what happens if the user is already a member, authorization requirements, or failure modes. This is a minimal but non-empty disclosure.

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 concise and front-loaded. The single-sentence purpose is immediately clear, and the Args section is minimal and directly useful. No unnecessary words or redundant information.

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?

This is a simple tool with an output schema, so detailed return value documentation is unnecessary. However, the description lacks context such as whether the user/group must already exist, what error behavior occurs for duplicates, and how this relates to remove_user_from_group. The basic action is covered, but edge-case context 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 0%, so the description must compensate. However, it merely restates the parameter names ('group_id: group ID', 'user_id: user ID') without adding meaningful detail beyond the schema's integer type and title. It does not clarify formats, constraints, or relationships between 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 uses a specific verb ('Add') with a clear resource ('a user to a group') and adds a meaningful qualifier ('without touching the other members'). This distinguishes it from sibling tools like remove_user_from_group and provides a precise scope of action.

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 implied usage is to add a user to a group, but the description does not explicitly state when to use this tool versus alternatives like remove_user_from_group or update_group. There is no mention of prerequisites or conditions, only the basic action.

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