codemagic_start_build

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

No annotations are provided, so the description must carry the burden. It states the tool triggers a build (mutation) and returns a buildId, which is helpful. However, it omits details like idempotency, rate limits, or that builds may be queued, leaving gaps for an agent.

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?

The description is concise: a one-line summary followed by bullet-point parameter explanations. Every sentence provides necessary information without fluff.

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?

Given that an output schema exists (mentioned in context), the description covers the return value (buildId) and refers to a polling tool. It is fairly complete, though it could mention potential error conditions or build queue behavior.

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?

With 0% schema description coverage, the description adds significant meaning via the Args section: it explains each parameter (app_id, workflow_id, branch, tag) and their mutual exclusivity. This goes well beyond the bare schema.

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 'Trigger a new build for an app/workflow on a branch or tag.' This is a specific verb+resource combination that distinguishes it from sibling tools like codemagic_cancel_build (cancel) and codemagic_get_build (get).

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 provides explicit context: 'Provide exactly one of branch or tag.' and 'Returns the new buildId, which you can poll with codemagic_get_build.' It implies when to use (starting a build) but does not explicitly state when not to use or list alternatives, though siblings cover that.

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