Create an agent

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

The description discloses that the response contains a credential token that can attach a machine, receive workloads, and read all pipeline secrets — behavior that is not inferable from the annotations or schema. It also emphasizes that the token is only available in this response, which is a critical operational constraint. This goes well beyond the structured metadata.

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 only two sentences and front-loads the core purpose before the high-value security warning. The phrase 'It is part of this answer because it is the only way to get it' is slightly awkward and partially redundant with the surrounding token warning, but every sentence still contributes useful information. A little polish would make it fully crisp.

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 mutating create tool, the description covers the most important non-obvious aspect (token security and uniqueness), while the schema covers all parameters and the output schema covers return values. Permission prerequisites and lifecycle details are not mentioned, but the annotations and schemas carry enough of the remaining burden. The definition is complete for practical agent use.

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?

The input schema has 100% coverage and detailed descriptions for all four parameters, including org_id, no_schedule, and custom_labels. The tool description adds no parameter-level meaning beyond what the schema already provides. Therefore the baseline score of 3 is appropriate.

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 begins with a specific verb ('Registers') and a specific resource ('a new build agent'), and it adds the distinctive outcome 'returns its token.' This makes it unambiguous and easily distinguishable from sibling list/get/update/delete agent tools. There is no tautology or ambiguity.

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 implies this tool is for creating new agents rather than managing existing ones, but it never names an alternative such as update_agent or states when not to use it. The only usage guidance is about token handling after creation, not about tool selection. This is acceptable but leaves selection mostly implicit.

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