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

Annotations already declare idempotent/readOnly=false/destructive=false, so the description earns credit for added context instead: the required permission scope, the active-org-member precondition, and the ENTERPRISE+ feature gate. The 'Idempotent' line slightly restates idempotentHint but the auth and eligibility constraints are genuine added value.

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?

Five short telegraphic sentences, front-loaded with the action and scope, then permission, idempotency, eligibility, and tier. Nothing is padded.

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 one-parameter mutation with no output schema, it covers permission, feature tier, and eligibility adequately. It doesn't state what happens on success/failure (e.g. already-a-member response) or the return payload, a minor 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 coverage is 100% with a single well-documented userId, so the baseline is 3. The description adds one eligibility constraint on that parameter's value ('must be an active org member') but no format or sourcing detail beyond what the schema states.

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?

Specific verb+resource+scope: 'Add a user to the org-level Change Control Board.' The 'org-level' qualifier cleanly distinguishes it from sibling add_project_member, so an agent can pick it without opening either 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 concrete preconditions for use: requires org.governance.manage (Admin+), the target must be an active org member, and the changeControl feature at ENTERPRISE+. It never names an alternative tool (e.g. list_ccb_members, update_member_role), so it stops short of explicit when-not guidance.

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