List attached hardware

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

Annotations already declare readOnlyHint and idempotentHint, covering safety. The description adds specific behavioral details not in annotations, such as listing free space for volumes and whether a camera is in use. It lacks discussion of permissions or latency, but for a read-only list operation, this is sufficient.

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, fully front-loaded with the core action in the first sentence, and the second provides illustrative use cases. No redundant wording or filler.

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 (no parameters, no output schema, read-only), the description fully covers what the tool does and what it returns. It even anticipates common questions, making it self-contained for an agent.

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 has zero parameters, so the schema trivially covers everything. The description explains what will be returned, which serves as the semantic content. Baseline for 0 params is 4, and the description adds value by specifying the output categories.

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 lists USB devices, cameras (including usage status), and mounted volumes with free space, and provides concrete example questions it answers. This distinctly differentiates it from sibling tools like hs_machine_status or hs_network.

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 practical use cases ('Answers questions like whether an external drive is mounted or whether the webcam is active'), which implies when to use it. It doesn't explicitly mention alternatives, but the examples provide sufficient context for typical scenarios.

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