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

Annotations already declare the safety profile (non-read-only, non-destructive, open-world, non-idempotent), so the bar is lower. The description adds real behavioral context beyond that: it sends an invitation email, takes one seat of the plan, and falls back to returning invite_link when email delivery fails — the kind of side-effect and failure-mode detail annotations cannot convey.

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?

Front-loaded with the core action, then role semantics, then side effects and the email-failure fallback. Dense but every clause carries information; the parenthetical role glosses are useful rather than 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 3-param mutation tool with no output schema, it covers the important gaps: side effects (email sent, seat consumed) and the conditional invite_link return value. The locale parameter is only covered by the schema, but that is acceptable given full schema coverage.

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 baseline is 3. The description goes beyond the schema's terse 'App role' by explaining what each role actually means (admin manages team/billing-free settings, member is a manager working in the app, viewer is read-only), giving the agent operational meaning it couldn't get from the enum alone.

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 someone by email to the app dashboard') and explicitly distinguishes the target from sibling concepts — 'an account with a login, unlike creators and crew who work through a private link'. An agent can tell this apart from create_creator / create_crew_member 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 clear context for when this applies: it's for full app accounts, not for creators/crew (private link), and it consumes a plan seat. It does not, however, explicitly contrast with sibling tools like create_crew_member or get_member_link by name, so routing is inferred rather than prescribed.

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