add_user_to_group

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

With no annotations, the description carries full responsibility for behavioral disclosure. It only restates the basic action and provides no information about side effects, permissions, error semantics, or whether the operation is idempotent. This is a minimal disclosure, falling below even the 'update_drive' example which listed specific fields.

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 a single, front-loaded sentence with no wasted words. It is concise and easy to parse. However, it is so brief that it borders on under-specification, though for a simple action it remains appropriately compact.

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?

The tool is a simple mutation with two required params and an output schema, but the description provides no context about preconditions, return values, or failure modes. It lacks sufficient detail to fully understand the tool's behavior in context, though the simplicity of the operation slightly mitigates the gap.

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 does not explain what user_id or group_id refer to, whether they must correspond to existing entities, or any constraints. The description adds no semantic value beyond the schema's field names and types.

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 action: 'Add a user to a group.' It uses a specific verb and resource, distinguishing it from siblings like 'remove_user_from_group' and 'create_group'. However, it doesn't explicitly call out alternatives or edge cases, so it falls slightly short of a 5.

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?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., user and group must exist), idempotency, or when not to use it. The description simply states the action without contextual usage advice.

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