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

Annotations supply only destructiveHint=true, so the description should carry behavioral context, but it adds only the REST endpoint (POST /builds), which merely restates that this is a write. It discloses nothing about side effects (consumed build minutes/instances), required permissions, concurrency or rate limits, or whether a branch and tag can both be set.

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 short clauses, front-loaded with the action, then the required parameters, then the optional set, plus the endpoint. No filler; every sentence contributes.

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 mutation tool with no output schema and sparse annotations, the definition covers what must be passed but omits consequences of the call: no mention of the returned build identifier (needed for later polling via codemagic_get_build), auth requirements, or side effects. Adequate but with clear gaps.

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 100%, so the schema already documents all seven parameters including the branch/tag alternative and instanceType examples. The description only restates the required pair and lists the optional fields, adding no format, constraint, or precedence detail beyond the schema. Baseline 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 ('Start a new build for an application workflow') and identifies the two required identifiers, so the agent knows exactly what action is performed. It doesn't explicitly name the sibling it contrasts with (e.g. cancel_build), but the action is unambiguous.

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 says what is required and what is optional, but gives no when-to-use/when-not guidance relative to alternatives like codemagic_list_builds or codemagic_get_build, and no prerequisites (auth scope, whether the app/workflow must exist first). Usage is only weakly implied by the purpose sentence.

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