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

Annotations already declare write/non-destructive/non-idempotent/open-world, so the bar is lower. The description still adds real context: an invitation email is sent, the invitee receives their signature, the action consumes the plan's people limit, and it requires owner permissions. It doesn't clarify whether the invitation expires or what happens on duplicate email, but the added side-effect and auth detail is substantial.

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?

Three short sentences, front-loaded with the action and its effect, then prerequisites and alternatives. No filler; every clause carries either behavior, constraint, or routing 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?

No output schema exists, so the description must carry the load, and it does: side effects, permission requirement, plan-limit impact, and sibling routing are all present. An agent has everything needed to call this correctly or route elsewhere.

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%, so 3 is the baseline. The description goes slightly beyond the terse schema labels by explaining that name, title and phone feed 'their signature', giving the fields a purpose rather than restating them, and it clarifies email is the invitation channel.

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/add a person to the company) plus the scope of data supplied. It explicitly names the siblings it is NOT, letting an agent separate it from update_member_field and resend_invite without opening any 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 explicit when-not/alternative routing: 'For someone already in the company, use update_member_field; to send an invitation again, use resend_invite.' It also states the prerequisite 'Company owners only', so both selection and eligibility are covered.

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