Add beta testers to group

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

Annotations already declare idempotentHint=true and destructiveHint=false, so the safety profile is clear. The description adds the prerequisite about sourcing IDs from list-beta-testers but does not elaborate on edge cases (e.g., duplicates, invalid groups). This is acceptable given annotations coverage.

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?

A single, well-formed sentence with an additional prerequisite note. Every word earns its place; no filler or redundant explanation.

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 two-parameter mutation with full schema coverage and clear safety annotations, the description is sufficiently complete. It states purpose and the source of IDs. It does not describe the return value, but no output schema exists and a success/failure response is typically implied.

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?

Input schema covers 100% of the parameters with descriptions. The tool description repeats the 'come from list-beta-testers' note already in the schema, adding no new semantic value beyond what the schema provides.

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?

The description clearly states the action ('Add one or more beta testers to a TestFlight group') with a specific verb and resource, and naturally distinguishes it from the sibling tool 'remove-beta-testers-from-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?

The description identifies the prerequisite that tester IDs come from 'list-beta-testers', implicitly guiding the user to that tool first. It does not explicitly exclude alternatives like 'remove-beta-testers-from-group', but the add/remove distinction is obvious from the name.

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