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

Annotations declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so this is a write operation. The description adds valuable behavioral context beyond annotations: the invite is not a direct add (async acceptance), and role limitations are explicitly stated. It does not contradict the annotations and enriches the agent's understanding of the side effects and constraints.

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 main action is front-loaded, followed by the crucial behavioral caveat (acceptance required) and a role constraint. Every sentence earns its place with distinct, non-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?

For a simple tool with two parameters and an output schema present, the description covers the essential aspects: the invitation process, the email acceptance flow, and role limitations. It doesn't mention response details or potential errors, but the presence of an output schema and the tool's low complexity make these omissions acceptable. The description is sufficiently complete for an agent to invoke 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% — both parameters have descriptions. The role parameter's description already includes the constraint that owner can't be granted, which is also repeated in the tool description. The email description is standard. Since the schema fully documents parameters, the description adds no significant new semantic value, so a 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 opens with a specific verb+resource: 'Invites someone to the workspace by email.' It clearly distinguishes this from a direct add by stating 'this does not add them directly' and specifies the role limitation. This differentiates it from related membership tools like 'remove_member' and 'update_member_role' without ambiguity.

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 provides clear context on how the invite works (email, acceptance required) and the constraint that only admin/member roles can be granted, with owner excluded. However, it does not explicitly name alternative tools or state when not to use this tool versus others like 'update_member_role' or 'cancel_invite'. The context is clear but no explicit exclusions or alternatives are given.

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