arduino-mcp-server

by hardware-mcp

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JavaScript

Local

Ensure Core Installed

ensure_core_installed

DestructiveIdempotent

Checks if the required Arduino core is installed for a board FQBN and auto-installs it if missing using arduino-cli.

Instructions

Ensure the Arduino core required by a board FQBN is installed. Can auto-install via arduino-cli core install.

Input Schema

TableJSON Schema

Name	Required	Description
`fqbn`	No	Board FQBN, e.g. arduino:avr:uno.
`coreId`	No	Core ID, e.g. arduino:avr.
`autoInstall`	No	If true (default), install missing core automatically.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`ok`	Yes
`status`	No
`command`	No
`data`	No
`raw`	No
`rawTail`	No
`stage`	No
`errorCode`	No
`retryable`	No
`reasonCodes`	No
`nextActions`	No
`note`	No
`error`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.8Jun 12, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already provide idempotent and destructive hints. The description adds useful behavioral context by saying it can auto-install via `arduino-cli core install`, making the mutation mechanism explicit. No contradiction with annotations.

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 short sentences convey the action and the installation mechanism without redundancy. The key purpose is front-loaded, and every word adds value.

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

Completeness4/5

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

Given the output schema and annotations, the description sufficiently covers the main behavior. It could mention behavior when `autoInstall` is false or failure modes, but these are not critical for a simple 3-parameter tool.

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

Parameters3/5

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

The input schema already documents all three parameters with 100% coverage, including examples. The description does not add parameter-specific detail, but the schema carries the burden adequately.

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 the tool's purpose: ensuring the Arduino core for a board FQBN is installed. The mention of `arduino-cli core install` differentiates it from sibling `install_arduino_cli`, which installs the CLI itself.

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

Usage Guidelines3/5

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

Usage is implied: run this when a board FQBN might need its core installed before compiling or uploading. However, it does not explicitly say when to prefer this over alternatives or when `autoInstall` should be disabled.

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