Serial MCP Server

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serial.readline

Read a line of data from a serial connection until a newline character or maximum bytes limit is reached, with configurable timeout, output format, and line terminator.

Instructions

Read a line from the serial port (reads until the newline character is received or max_bytes is reached). Uses the connection's newline setting by default.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "connection_id": "<connection_id>"
    },
    "name": "serial.readline"
  }
}

Input Schema

Name	Required	Description	Default
`connection_id`	Yes
`timeout_ms`	No	Override read timeout (milliseconds).
`max_bytes`	No	Maximum bytes to read (default 4096).
`newline`	No	Override line terminator (defaults to connection newline).
`as`	No	Output format (default text).	text

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 29, 2026

TDQS

A4.1/5.0

Behavior3/5

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

With no annotations, the description discloses that reading stops at newline or max_bytes and uses connection's newline setting. However, it omits details on blocking, timeout, error handling, or return format beyond the schema.

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?

Two sentences, no redundant information. Every sentence serves a clear purpose: stating the action and highlighting the default newline behavior.

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

Completeness3/5

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

Given 5 parameters and no output schema, the description provides core behavior but lacks details on timeout handling, error conditions, and output format nuances. Moderate completeness for a line-reading tool.

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?

Schema coverage is 80%, and the description adds value by explaining 'reads until the newline character' and 'uses the connection's newline setting', complementing schema descriptions for newline and max_bytes.

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?

The description clearly states 'Read a line from the serial port', specifying the verb and resource. It distinguishes from siblings like serial.read (raw bytes) and serial.read_until (custom terminator) by mentioning newline-based reading.

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?

The description implies usage context (reading a line) and mentions the default newline behavior, but lacks explicit guidance on when to use this tool vs alternatives like serial.read or serial.read_until.

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