List Serial Ports

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

Annotations already declare readOnlyHint=true, indicating a safe read operation. The description adds that the tool uses arduino-cli and is cross-platform, which are minor behavioral traits. No additional details about side effects, permissions, or error conditions are provided.

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 extremely concise—two short sentences—and front-loads the core purpose. Every sentence adds value: the first states the action and result, the second confirms platform compatibility. No unnecessary words.

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 tool has no parameters and an output schema exists, the description is largely complete for a simple list operation. It covers the action, tool dependency, and platform support. However, it does not hint at what the output schema contains (e.g., fields like port name, board type).

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, and the schema coverage is 100%, so the description does not need to add parameter details. The baseline for no parameters is 4, and the description adequately covers the tool's general functionality.

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 verb 'list' and the resource 'serial ports', specifying that it also retrieves detected board metadata using arduino-cli. This effectively distinguishes it from sibling tools like list_connected_boards which list boards, not 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?

While the description notes cross-platform support (Windows/macOS/Linux), it does not provide guidance on when to use this tool versus alternatives such as list_connected_boards or serial-related tools. The context of platform compatibility is helpful but insufficient for distinguishing usage scenarios.

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