Set lights

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds the useful physical context that the ring has six lights, but says nothing about persistence, whether a light setting survives other commands, or what the optional defaults do when no arguments are supplied.

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?

A single front-loaded sentence with no filler. Everything an agent needs at a glance is in the first clause, and nothing is repeated from the schema or annotations.

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 simple two-parameter tool with full schema coverage, no output schema, and clear annotations, the description is nearly sufficient. The only real gap is that both parameters are optional with defaults, so calling it with no arguments silently sets all six lights green - behavior the description does not surface.

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%: the led enum documents each position (front-left through front-right) and the color parameter lists all accepted colour names plus hex syntax. The description's 'ring of six lights' slightly reinforces how to interpret the led index, but adds no format or constraint detail beyond the schema, so the 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?

The description gives a specific verb ('Set') and resource ('the colour of the robot's ring of six lights'), making it immediately distinguishable from the motion, audio, and vision siblings. It stops short of naming any alternative tool, but none of the siblings overlaps with light control.

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?

There is no guidance on when to use this tool, no prerequisites, and no mention of alternatives. Usage is only implied by the verb itself.

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