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serial_list_ports

Read-only

List serial ports on this host with by-id paths and USB VID/PID, even without a broker. Use it to pick the correct port before starting a broker or when console output is garbage.

Instructions

List serial ports on this host with by-id paths and USB VID/PID (works without a broker). Use to pick a port before starting a broker, or when output is garbage (wrong port). Bridge chips name the adapter, not the MCU.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
portsYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • changedOutput schema / (root)
      Previous value: -nullNew value: +{
      +  "properties": {
      +    "ports": {
      +      "items": {
      +        "properties": {
      +          "by_id": {
      +            "type": "string"
      +          },
      +          "by_path": {
      +            "type": "string"
      +          },
      +          "identity": {
      +            "enum": [
      +              "STRONG",
      +              "WEAK",
      +              "n/a"
      +            ],
      +            "type": "string"
      +          },
      +          "manufacturer": {
      +            "type": "string"
      +          },
      +          "path": {
      +            "type": "string"
      +          },
      +          "pid": {
      +            "type": "string"
      +          },
      +          "product": {
      +            "type": "string"
      +          },
      +          "vid": {
      +            "type": "string"
      +          }
      +        },
      +        "required": [
      +          "path",
      +          "vid",
      +          "pid",
      +          "identity"
      +        ],
      +        "type": "object"
      +      },
      +      "type": "array"
      +    }
      +  },
      +  "required": [
      +    "ports"
      +  ],
      +  "type": "object"
      +}
  2. First observedv0.4.0

TDQS

A4.5/5.0
Behavior4/5

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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description still adds real behavioral context beyond them: no broker dependency required, and the caveat that bridge chips report the adapter rather than the MCU, which materially affects how an agent interprets the returned names.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences with no filler: purpose and return content first, then usage triggers, then the interpretive caveat. Every clause earns its place and nothing is buried.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and there are no parameters to document. Purpose, invocation timing, and the interpretation caveat are all present, leaving no material gap for an agent deciding to call it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes no parameters, so there is nothing to disambiguate; the description instead spends its words on the returned fields (by-id path, VID/PID), which is the right allocation. Baseline of 4 applies for a zero-parameter tool.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb+resource ('List serial ports on this host') plus the exact payload returned (by-id paths, USB VID/PID), which cleanly separates it from siblings like serial_port_status or serial_read. The parenthetical '(works without a broker)' further scopes it as a standalone discovery tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives two concrete triggering conditions: before starting a broker, and when output is garbage due to a wrong port. No sibling tool is named as an alternative, and there is no explicit 'when not to use', so it falls short of the 5-level routing guidance.

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