lights_on

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

With no annotations, description carries full burden. It discloses the underlying set_function call, the F0 convention (not guarantee), and same auto-acquire/no-op-safe behavior. Lacks explicit mention of prerequisites like requiring an acquired throttle, but overall provides substantial behavioral context.

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?

Two short paragraphs with no filler. Front-loaded with primary action, then adds usage distinction. Every sentence earns its place.

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 the tool's simplicity (1 param, no output schema), the description covers purpose, usage guidance, and domain context (F0 convention). Minor gaps in error handling or prerequisites, but sufficient for effective selection and invocation.

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?

Only parameter 'address' is self-explanatory; schema coverage is 0%, so description adds some context (locomotive address, DCC convention) but no format or range. It does not fully compensate for lack of schema descriptions.

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?

Description clearly states 'Turn on a locomotive's headlight(s)' with specific verb and resource. It distinguishes from sibling tools like set_function (by calling it a shortcut) and set_light (for layout lighting). The mention of F0 convention adds precise scope.

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?

Explicitly states when to use: on a plain 'turn the lights on' voice request without asking for function number. Also states when not to use: for layout/scenery lighting, use set_light. References auto-acquire and no-op-safe behavior.

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