group_addMember

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

Without annotations, the description carries the full burden and partially succeeds by disclosing the side effect (task assignment eligibility). However, it omits critical operational details: whether the operation is idempotent, what happens if the user is already a member, error conditions, or authorization requirements.

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?

Two sentences with zero waste: the first states the operation and identifiers, the second explains the business consequence. Every element earns its place and is appropriately front-loaded.

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?

As a mutation tool with no annotations and no output schema, the description should provide comprehensive safety and contract details. It explains the business logic but leaves critical technical boundaries undefined, particularly regarding the missing parameter definitions and error handling.

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?

While the description mentions 'user ID and group ID,' the input schema defines zero properties (empty object). This creates a serious mismatch—the description references parameters the schema doesn't allow, confusing how to actually invoke the tool. The baseline for 0 params is 4, but this contradiction significantly reduces the score.

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 identifies the action (Add), resource (user to group), and required identifiers (user ID and group ID), distinguishing it from sibling tools like group_removeMember and group_create. However, the mismatch with the empty input schema creates slight ambiguity about where these IDs come from.

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 explains the downstream effect (user receives task assignments) which provides implicit usage context, but fails to explicitly state when to use this tool versus alternatives like group_removeMember, or prerequisites such as group/user existence.

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