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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description does add one useful piece of context, that this is the set of devices the backend supports (a static capability list) rather than currently connected hardware, but it says nothing about pagination or refresh behavior.

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 short sentence with the resource stated first and examples in parentheses; nothing is wasted and nothing is buried.

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?

With an output schema present, the description need not enumerate return values, and it correctly identifies the content of that output. For a zero-parameter read-only listing tool this is nearly complete, missing only a one-line pointer to when the list should be consulted.

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 tool takes zero parameters, so there is no parameter semantics to explain and the baseline of 4 applies. The description correctly neither invents inputs nor misleads about filtering options.

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 names the specific resource (EEG devices supported by this backend) and enumerates concrete examples (OpenBCI, Muse, BrainBit, LSL, PiEEG), so an agent can tell it apart from device.test at a glance. It is a noun phrase rather than a verb+resource, but the intent is 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?

There is no when-to-use statement, no mention of prerequisites, and no reference to alternatives such as device.test or stream.start. An agent must infer from the name alone that this is a discovery call made before configuring a stream.

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