Invite people to a site

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

Annotations already declare a non-destructive, idempotent, open-world write, but the description adds genuinely new behavioral facts: an email is sent from the account, the operation is atomic ('all or nothing — one bad address, or a list past the plan's limit, adds nobody'), and it does not change site privacy. These are exactly the consequences an agent must anticipate before calling.

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?

Four short sentences, each carrying a distinct payload: effect, provenance rule, role effect, privacy distinction, and atomicity/limit behavior. Nothing is padded and the most important constraint leads.

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 an output schema present, return values need no explanation, and the description covers side effects, atomicity, plan limits and privacy semantics. An agent has everything needed to invoke 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 coverage is 100% and the enum's own description already explains view vs comment, so the description's 'comment lets them comment as well as open it' is largely restatement. It adds only the provenance rule for emails, which the schema already states as 'exactly as the person gave them'.

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 ('Adds email addresses to a site's list') plus the primary side effect ('emails each new one an invitation from the account'). This clearly separates it from list_people, remove_person and update_site without needing 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 precondition ('Use only addresses the person gave you — never guess, infer or look one up') and routes the agent away from a wrong expectation by naming the alternative ('Inviting does not make the site private; update_site's invitedOnly: true does'). It also flags the plan-level constraint that governs whether the call is usable at all.

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