Send a build to a TestFlight group

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

Annotations only mark this as non-read-only and destructive; the description goes well beyond that by disclosing that Apple notifies every tester immediately, that the notification cannot be recalled, and that confirm:true is mandatory. It also notes the newest-processed-build default and that the tool is a Pro feature, all of which materially affect whether and how an agent should invoke it.

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?

Two sentences with no filler, front-loaded with the action and immediately followed by the highest-risk consequence. Every clause earns its place; nothing is repeated from the title or annotations.

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 4-parameter mutation tool with no output schema and full schema coverage, the description covers the critical unknowns: irreversibility, the confirm gate, default build selection, and Pro gating. It stops short of explaining what happens to a previously assigned build or error behavior, which would round it out.

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% and each parameter is already documented, including confirm's requirement and build_id's fallback behavior. The description largely restates that (defaults to newest processed build, needs confirm:true) without adding syntax, format, or edge-case detail beyond the schema, so the baseline of 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 and resource (assign a build to a TestFlight beta group) plus the outcome (testers can install it), which is more than a restatement of the name. It does not explicitly differentiate itself from near-siblings in the list such as attach_build or invite_beta_tester, leaving some ambiguity about which tool handles which build-to-group flow.

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 gives a conditional requirement (confirm:true) and states the default build selection, which is real usage guidance. However, it never says when to prefer this over attach_build or how it relates to the surrounding release flow, so the when-to-use-vs-alternative signal is only implied.

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