Report machine status

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

The annotations already declare readOnlyHint and idempotentHint, which are the essential safety traits. The description adds useful context: it mentions that fields are null when hardware doesn't provide them, which is important for handling missing data. It doesn't mention any side effects, but given the read-only and idempotent annotations, this is sufficient. No contradiction.

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 a single, well-structured sentence that front-loads the purpose ('One call for the state of the machine') and then lists the specific fields. It is concise, without redundancy, and every detail adds value.

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 tool with no parameters and no output schema, the description is quite complete: it lists the expected outputs and handles the edge case of null fields. The only gap is that it doesn't describe the output format (e.g., a JSON object or dict), but the list of fields implies the structure. Given the tool's simplicity, this is adequate.

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 description need not explain any. As per the rubric, zero parameters earns a baseline of 4. The description does not add confusion and aligns with the empty schema.

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 purpose: to report the overall state of the machine, and enumerates the specific fields it returns (host name, OS version, idle time, battery, display, wifi, audio). This distinguishes it from sibling tools like hs_audio_volume or hs_brightness which deal with individual settings.

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 implies this is a one-call status check, and the list of returned fields provides clear context for when it would be useful (e.g., checking battery or wifi). It does not explicitly state when not to use it or mention alternatives, but with zero parameters and a broad status purpose, it's clear it should be used when a quick overall snapshot is needed rather than querying individual systems.

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