list_ports

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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), so the description only needs to add context beyond that. It adds the local-scope detail 'on this machine' but does not disclose return contents, behavior when no ports exist, or whether virtual/composite ports are included. Consistent with annotations, but limited added context.

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?

A single seven-word sentence with the action verb front-loaded and zero filler. Every word earns its place; nothing is redundant or extraneous.

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 zero-parameter read-only tool with full annotation coverage, the description is largely complete. The only gap is the absence of an output schema and no note on what the returned port identifiers look like (e.g., COM3 or /dev/ttyUSB0) or that they can be passed to serial_open — useful for an agent consuming the result.

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?

With zero parameters and 100% schema coverage, the baseline of 4 applies. There is no parameter information for the description to compensate for, and describing the tool as a parameterless query is accurate.

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 uses a specific verb ('List') with a specific resource ('available serial ports on this machine'), making the operation unambiguous. It naturally distinguishes itself from all sibling serial_* operation tools, and the 'on this machine' qualifier clarifies local scope.

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?

No explicit when-to-use guidance, alternatives, or exclusions are given. The intended usage (discover ports before opening one via serial_open or checking serial_status) is implied by the purpose but never stated, so the agent has to infer context from the sibling set.

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