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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint all false, so the agent knows it's a non-idempotent mutation. The description adds the behavioral trait that the add bypasses invitations, which is useful, but it doesn't disclose side effects (e.g., whether an email is sent, whether the team must exist, or what happens on duplicate adds). The description adds some value beyond annotations but not rich detail.

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, efficient sentence with zero waste. It front-loads the core action (Add) and the key differentiator (directly, no invitation flow) without any filler. Perfect length for an MCP tool definition.

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 simple mutation tool with fully documented parameters and an existing output schema, the description covers the essential behavior (direct add, no invitation). It does not mention prerequisites like team context or error handling, but those are either implicit (team is in the tool name) or handled by the output schema. The description is adequate and nearly complete for an agent to use it correctly.

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 100%, so every parameter (email, status, user_id, username) already has a clear definition. The description does not add any extra meaning beyond what the schema provides, so the baseline score of 3 is appropriate.

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 the specific verb 'Add' with the resource 'team member' and clarifies the mechanism with 'directly (no invitation flow)'. This clearly distinguishes it from sibling tools like team.invitations.create, team.members.delete, etc., so an agent can tell exactly what it does without opening the schema.

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 phrase 'no invitation flow' implicitly contrasts with the invitation-based alternative (team.invitations.create), providing clear context for when to use this tool. However, it does not explicitly state when to prefer invitations over direct adds, so it stops short of explicit exclusions or alternatives.

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