List Twinkly devices

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

Annotations already mark readOnlyHint=true, and the description adds that the list comes from configuration and prior discovery (not a live scan), and explains the default device behavior when the `device` argument is omitted. No contradiction with annotations.

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 sentences, front-loaded with the core purpose, followed by return contents and usage instruction. Every sentence contributes value with no fluff or repetition.

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 simplicity of the tool, the output schema, and read-only annotations, the description fully covers what the tool does, what it returns, and how to use the result. It also aligns with the openWorldHint by explicitly stating the list is from configuration and prior discovery.

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?

There are zero parameters, so the baseline is 4. The description adds context about the `device` argument used on other tools, which is helpful even though this tool itself takes no parameters.

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 uses a specific verb ('List') and resource ('the Twinkly devices this server knows about'), clearly distinguishing from sibling discover_devices by noting it draws from configuration and prior discovery. It also states what is returned, making the tool's function unambiguous.

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 gives clear guidance on using the returned names as the `device` argument for other tools, which is actionable. It implies the tool is for listing known devices rather than discovering new ones, but it does not explicitly name discover_devices as the alternative for discovery.

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