fly_create_machine

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

With no annotations, the description should disclose behavioral traits like destructiveness, idempotency, or permissions. It only says 'Create a new machine', omitting that this is a write operation, likely requires authentication, and may have side effects (e.g., starting a machine). Insufficient for a mutation tool.

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 very concise (one sentence), which is positive for brevity, but it omits crucial details needed for correct usage. It could benefit from a structured format listing key capabilities or behavior, while still being succinct.

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 5 parameters, 2 required, and no output schema, the description is too minimal. It does not explain return values, error conditions, prerequisites, or how parameters like api_key should be obtained. The context from sibling tools suggests this is part of a larger system, but the description fails to tie it together.

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 description adds no meaning beyond the input schema. Schema coverage is 60%, but the description does not explain the undocumented parameters (api_key, app_name, env). For required parameters, only image and machine_name have schema descriptions; app_name lacks both schema and description context.

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 the action ('Create'), the resource ('machine'), and the context ('in a Fly.io app'). It effectively distinguishes from sibling tools like fly_list_machines (list) or fly_get_app (get), which have different verbs and resources.

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?

No guidance is provided on when to use this tool versus alternatives, prerequisites (e.g., app must exist), or scenarios to avoid. The single sentence offers no contextual or comparative advice.

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