Distribute a TestFlight build

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

Beyond the annotations (idempotentHint/destructiveHint/readOnlyHint), it discloses the required environment flag (ASC_WRITE=1), that it mutates App Store Connect, and the mechanism behind idempotency: every step checks current state first, so already-done steps are skipped on re-run. It also explains the resume behavior when Apple processing exceeds wait_minutes. This is context an agent cannot get from the annotations alone.

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 the operational caveats (auth flag, safe re-run) in a short second paragraph. The first sentence is a long comma-chained list of steps, which is dense but still scannable; nothing is wasted.

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 an 11-parameter mutation with no output schema, the description covers the workflow, auth prerequisite, idempotency, and partial-failure resume path, which is most of what an agent needs. It stops short of describing the shape of the returned plan/result (relevant for dry_run), leaving that to inference.

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 91%, so the schema already documents nearly every parameter; per the rubric the baseline is 3. The description adds only marginal framing (that the export-compliance answer is used "only if the build is waiting on it", and the conditional default for beta review), and does not address the undocumented notes_locale parameter.

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 names a specific verb+resource ("Ships a build to TestFlight testers") and then enumerates the exact sub-steps performed in the call: wait for processing, export compliance, What to Test notes, beta group assignment, beta app review submission. This clearly distinguishes it from siblings like upload_build (which only uploads) and submit_for_review (which only submits).

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?

It states the conditions under which optional steps fire ("answers export compliance if you say how", "submits it for beta app review when an external group needs it") and explicitly endorses re-running after a timeout or error. It never names a sibling alternative or an explicit when-not-to-use case, so it falls short of a 5.

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