list_serial_ports

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns one entry per port with device name and human description, implying a read-only, safe operation. No mention of side effects or permissions, but the simple nature of the tool makes this 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?

The description is extremely concise—just two sentences and an example line. It front-loads the main action and immediately provides actionable information. Every sentence serves a purpose.

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 lack of parameters and the presence of an output schema (not shown, but mentioned), the description adequately covers what the tool does and its return format. It could mention whether the list is static or can change between calls, but this is minor.

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 schema coverage is 100%. The description adds value by explaining the purpose of the output fields (device name and description), which is helpful despite no parameters.

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 function: 'List the serial ports currently available on this machine.' It provides concrete examples of output (e.g., 'COM5' on Windows) and explains its role as a prerequisite for other tools, distinguishing it from siblings like flash_firmware or read_serial.

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 advises using this tool first to discover the port, and notes that other tools take a `port` parameter. This provides clear context, though it could be more explicit about when not to use it (e.g., if port is already known).

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