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

Goes well beyond the annotations: it discloses that a standard invitation email is sent in the acting user's name, that membership begins only on acceptance, that re-inviting sends a fresh link, and it enumerates the precise refusal codes (SEAT_LIMIT_REACHED, RATE_LIMITED, EMAIL_UNVERIFIED, already-a-member). Seat economics (paid seat vs. guest allowance) and the role-ceiling rule are exactly the kind of non-obvious behavior the annotations cannot express.

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?

Front-loaded with the core action and outcome; the seat, role, refusal and permission details follow in a logical order. It is dense and the refusal/permission sentences are long, but each clause carries actionable information rather than restating the schema.

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?

With no output schema, the description supplies the post-call semantics an agent needs: the invitee is not a member until they accept, a re-invite issues a new link, and the specific failure modes that may come back. Permissions, seat limits and refusal codes complete the picture for a mutation tool with openWorld and destructive hints.

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 coverage is 100% and the enums/defaults are already documented, so the baseline is 3, but the description adds real meaning: MEMBER counts toward the plan's member limit and is a paid seat, GUEST is limited to assigned projects and free within the guest allowance. It also states that role applies only to a MEMBER seat and cannot exceed the caller's own role, a constraint absent from the schema.

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?

States a specific verb and resource ('Invite a person by email to join this organization') and immediately pins the scope to the organization rather than a project, which separates it from siblings like add_project_member and add_ccb_member. An agent can identify the operation 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?

Gives an explicit when-to-use ('Use this after create_project or instantiate_plan to bring the people on the plan into the workspace') plus the permission gate (org.member.invite, default MANAGER+) and the Free-plan exception. It never names the nearest alternative for adding someone only to a project, so the routing is clear but not fully disambiguated.

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