builds_start_by_ref_id

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

With no annotations provided, the description discloses a key behavioral trait: it uses a Git reference ID directly and skips resolution, implying it cannot handle branch/tag names. However, it does not elaborate on potential errors or asynchronous behavior, leaving some gaps.

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 compact, front-loaded with the action, and includes only two meaningful sentences. No redundant information, making it easy to parse.

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?

The tool is relatively simple, but the complete absence of parameter descriptions in both schema and text makes the description incomplete for an agent to invoke it correctly. The output schema helps with returns, but input semantics are not adequately covered.

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 0%, so the description must compensate. It only hints at source_ref_id via 'Git reference ID' but does not explain the required workflow_id or pull_request_number. This is insufficient for correct parameter usage.

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 explicitly states the tool starts a new build using a Git reference ID, which is a specific verb+resource. It also distinguishes itself from builds_start by noting that branch/tag names are handled there, making the purpose 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?

It clearly states when to use this tool ('when you already have the Git reference UUID') and explicitly specifies the alternative ('For branch/tag names, use builds_start instead'). This provides excellent guidance on tool selection.

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