Start Xcode Cloud Build

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

Annotations already declare readOnly=false, idempotent=false and openWorld=true, so the safety profile is covered. The description goes further by disclosing that repeat invocations create additional build runs and that individual build-run cancellation is not supported by Apple's public API – a real operational consequence the agent cannot infer from structured fields.

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 sentences, front-loaded with the core action, each carrying useful information. Mild redundancy between 'creates a new build run' and 'repeating the same call can create another build', but nothing is wasted overall.

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 non-idempotent mutation with no output schema, the description omits what a successful call returns (build-run identifier for follow-up polling via get_build_issues/get_build_logs) and any authentication or permission requirements. The cancellation limitation is a strong addition, but the picture remains incomplete for an agent planning a full build-then-inspect loop.

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 80%, so the schema does the heavy lifting (buildRunId, pullRequestId, sourceBranchOrTagId are well documented). The description adds nothing about parameters, and workflowId – the sole required field – carries no schema description to compensate.

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 ('Start exactly one new Xcode Cloud build') and pins the scope to a single build run. No sibling tool starts builds, so the agent can disambiguate immediately from list_workflows, get_build_logs, or update_workflow_* without opening a 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?

The description never says when to call this versus other tools, nor what preconditions must hold (e.g. the workflow must exist and be enabled via set_workflow_enabled, or a workflowId must be obtained from list_workflows). The repetition caveat hints at usage but no genuine when-to-use guidance is offered.

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