list_serial_ports

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

With no annotations provided, the description carries the full behavioral burden. It discloses what the tool returns—system name, human description, USB hardware id—and that already-open ports are marked. This goes well beyond the tool name and gives the agent useful expectations about the output and how to interpret it.

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 compact and front-loaded with the core action, followed by usage guidance and output details. Every sentence adds value, and there is no redundant or filler content. It is appropriately sized for the simplicity of the tool.

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 zero-parameter interface, the available output schema, and the presence of sibling tools, the description provides everything needed to select and invoke the tool correctly. It explains when to call it, what it returns, and how to interpret the results. Nothing critical is missing.

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 baseline is 4; the description accurately reflects that no arguments are needed. It adds context about how the returned values are meant to be used, such as passing the system name to `connect`. No parameter-level documentation is needed here.

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 states a specific verb and resource: 'List every serial port the computer can currently see.' It also differentiates the tool from sibling tools like connect and status by defining its role as the first step before connecting. The purpose is immediately understandable.

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 explicit when-to-use guidance: 'Call this FIRST whenever the user wants to connect to a device but hasn't given an exact port name, or when a connection fails.' It also explains how the returned data supports the next step, making the tool's place in the workflow unambiguous.

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