list_ports

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It reveals that on macOS, /dev/cu.* ports are prioritized and /dev/tty.* is excluded, and it details the exact output structure (device, description, hwid), going beyond a basic statement of function.

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 succinct and well-structured: a one-sentence purpose, a usage directive, a platform nuance, and a Returns block. Each sentence earns its place with no redundancy, and the most critical information is front-loaded.

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 zero-parameter tool with an output schema, the description is complete. It covers purpose, usage, platform behavior, and return format, providing the agent with all necessary context to select and invoke the tool correctly. No gaps are evident.

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 input schema is empty. Per the rubric, a baseline of 4 is appropriate when no parameters exist, and the description does not need to add any parameter semantics beyond what the schema already covers (100% coverage).

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 returns information about all connected serial ports, using the specific verb '返す' (returns) and resource 'シリアルポート' (serial ports). It is unambiguous and distinct from sibling tools like connect and write_and_read, which perform actions rather than listing ports.

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 explicitly instructs users to run this tool before calling connect ('connect の呼び出し前に必ず実行し'), providing clear when-to-use guidance. It also adds platform-specific behavior for macOS, enhancing the agent's ability to invoke it correctly.

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