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

Annotations already declare this is a non-read-only, non-idempotent, open-world write. The description adds value beyond that: the owner-only authorization requirement and the fact that re-inviting refreshes the invite link rather than failing. It does not cover whether an email is actually dispatched or what happens on invalid input.

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 compact sentences with the action, roles, and default front-loaded, followed by the permission constraint and the re-invite nuance. No filler.

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 three-parameter write tool with annotations covering the safety profile and no output schema, the description supplies the critical extras (owner-only, default role, re-invite semantics). Minor gaps remain around invitation delivery and failure modes, keeping it just below a 5.

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%, so id, role, and email are already documented, including the enum and the 'default editor' note. The description's role/default mention is essentially a restatement of schema content, so baseline 3 applies.

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 (invite) and resource (site member) by email, and enumerates the three roles with the default. This clearly distinguishes it from siblings like list_site_members and revoke_site_invite without needing their schemas.

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 the key precondition ('Owner-only') and the re-invite behavior, which tells the agent it can call this on an existing member rather than erroring. It does not explicitly name the alternative tools (revoke_site_invite / list_site_members), so it falls short of a full when/when-not routing.

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