Control Device

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

Annotations already state readOnlyHint=false and idempotentHint=true. The description adds behavioral context by explaining capability value types (boolean for onoff, number ranges for dim/volume_set) and directing users to inspect current values via get_device. It does not contradict annotations and provides useful usage context beyond the schema.

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 two sentences, front-loaded with the primary action and immediately followed by actionable examples and a usage hint. No wasted words; 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?

For a simple set operation with three parameters and no output schema, the description covers the essentials: what it does, common capabilities, value types, and how to discover available capabilities. It lacks explicit error-handling details, but these are not critical for this tool's basic use case.

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 coverage is 100%, so baseline is 3. The description adds value beyond the schema by mapping capabilities to concrete value types and ranges (boolean for onoff, number 0-1 for dim, target_temperature as number), enriching the meaning of the 'value' parameter.

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 tool's function: 'Control a device by setting a capability value.' It names specific capability examples (onoff, dim, target_temperature, volume_set) and provides value types, distinguishing it from siblings like get_device (read) and set_variable (variables).

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 provides explicit guidance: 'Use get_device first to see available capabilities and their current values.' This establishes a clear prerequisite. It does not explicitly contrast with alternatives like set_variable, but the domain-specific focus and the get_device hint make the intended use clear.

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