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

Far exceeds what annotations convey: it discloses when an email becomes an invite, that an inviteUrl is shareable, inviter naming rules, once-per-hour resend limits, and the exact error semantics (NO_OPERATOR, OPERATOR_AMBIGUOUS, RATE_LIMITED) including which adds are refused vs. proceed without email. This is unusually rich behavioral disclosure for a mutation tool.

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?

Core purpose is front-loaded, but the final rate-limit sentence is a convoluted multi-clause run that is hard to parse, and the emailing rules are restated in several places (invite resend, alias/id email conditions). Dense and informative but overstuffed for a single paragraph.

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 6-parameter mutating tool with an output schema, the description covers permissions, email side effects, defaults, and failure modes thoroughly. Return values are appropriately left to the output schema, though the 'why' requirement (required for workspace writes) is only carried by the schema.

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 the baseline is 3, but the description adds real meaning beyond the schema: it explains the note is refused when no email is sent, the invite-vs-add consequence of an email member, and the default values for membership and role. The 'why' parameter is left entirely to 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?

Opens with a specific verb+resource ('Add or invite someone') and immediately disambiguates what 'member' accepts (email, alias, account id). It also clarifies the add-vs-invite distinction. It doesn't differentiate itself from siblings like team_add_member or workspace_member_set_role, so an agent must infer the boundary.

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 selection guidance: default membership is internal, use external for shared items only; default role is editor; internal admins and editors may add while changing existing access needs an admin. It stops short of explicitly routing to workspace_member_set_role/remove or team_add_member for adjacent operations.

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