Invite a TestFlight tester

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

Annotations already declare destructiveHint=true and readOnlyHint=false, and the description adds the crucial why: Apple sends a real email from the user's account and the action cannot be recalled. This irreversible side effect plus the confirm:true safety gate is exactly the behavioral context an agent needs beyond the flags.

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 tight sentences, front-loaded with the action, then the safety requirement and consequence, then the Pro gating. No filler and every clause carries 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, and the description covers the irreversibility, the mandatory confirm flag, and the Pro requirement for a 5-param mutation. Nothing needed to call it safely and correctly is missing.

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 all five parameters are already documented, and the description largely reinforces that (confirm required, email consequence). It adds the rationale for confirm but no new syntax or value semantics beyond the schema, so the 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 (external tester by email) plus the second effect of adding them to a beta group. It also implicitly distinguishes this from build/version siblings by naming the beta-group target that the schema links to list_beta_groups, so an agent can tell it apart from assign_build_to_group.

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 use (inviting an external tester) and a precondition (confirm:true) plus a gating note (Pro feature). It does not name an alternative tool or state when-not-to-use, but the surrounding conditions are explicit enough to route correctly.

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