Embedded-AI-Harness: Skill for Claude Code

.claude/skills/testbench-mqtt/SKILL.md

testbench-mqtt is a skill for Claude Code from SensorsIot/Embedded-AI-Harness. It costs 120 tokens per session (1,730 once invoked), scanned B, original, MIT.

A testbench skill for testing MQTT communication with ESP32 devices. MQTT is a messaging system in which devices publish messages to named topics and subscribe to receive them.

In plain words
What is it for?
Use it to start, stop, or check the broker, publish and subscribe to test topics, and verify how an ESP32 MQTT client behaves.
Why use it?
It provides the steps for finding the correct testbench, checking it, and controlling its Mosquitto MQTT broker. This lets devices on the testbench Wi-Fi network communicate during tests without internet access.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: reads .claude/ paths.

This is SensorsIot/Embedded-AI-Harness's own configuration. It tells Claude Code how to work on Embedded-AI-Harness itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Embedded-AI-Harness configures →

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is export TESTBENCH_URL=$(sudo python3 .claude/skills/esp-idf-handling/discover-testbench.py \.

Reuse

Borrowing it

Nothing to install: this file belongs to SensorsIot/Embedded-AI-Harness. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/SensorsIot/Embedded-AI-Harness/main/.claude/skills/testbench-mqtt/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/SensorsIot/Embedded-AI-Harness

Made for: Claude Code.

Wrote this? Show the measurements

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README.md
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Your own site
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agentmods 80×15 button for testbench-mqtt

Your own site · 80×15
<a href="https://agentmods.dev/skills/sensorsiot/embedded-ai-harness/testbench-mqtt"><img src="https://agentmods.dev/badge/skills/sensorsiot/embedded-ai-harness/testbench-mqtt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 120 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,730 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Privilege Escalation · line 17
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00120 $0.01730
Opus 5 $0.00060 $0.00865
Sonnet 5 $0.00024 $0.00346
Haiku 4.5 $0.00012 $0.00173

Measured 12d ago against content hash 17e6d7aaa3b7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade B, and why

testbench-mqtt scanned grade B with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

export TESTBENCH_URL=$(sudo python3 .claude/skills/esp-idf-handling/discover-testbench.py \

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s "$TESTBENCH_URL/api/info" # confirm before anything else
.claude/skills/testbench-mqtt/SKILL.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ESP32 MQTT Broker

Base URL: $TESTBENCH_URL — see Step 0

Step 0: Point at a bench

There are several benches and their addresses move, so nothing here writes one down. $BENCH is not usable either — a container cannot resolve mDNS. Discover the bench and export its URL:

export TESTBENCH_URL=$(sudo python3 .claude/skills/esp-idf-handling/discover-testbench.py \
                         --url --name <bench-hostname>)
curl -s "$TESTBENCH_URL/api/info"        # confirm before anything else

--url refuses to guess when more than one bench answers, so --name is required whenever a second bench is powered on. TESTBENCH_URL is the same variable pytest --wt-url falls back to.

The testbench can run an MQTT broker (mosquitto) for testing ESP32 devices that use MQTT for communication. The broker is accessible to devices connected to the testbench's WiFi AP.

Endpoints

Request and response shapes: FSD Appendix D.12.

Examples

# Start the MQTT broker
curl -X POST $TESTBENCH_URL/api/mqtt/start

# Check broker status
curl $TESTBENCH_URL/api/mqtt/status

# Stop the MQTT broker
curl -X POST $TESTBENCH_URL/api/mqtt/stop

MQTT Broker Details

Property Value
Broker the bench address (from the LAN) or 192.168.4.1 (from the testbench AP)
Default port 1883
Authentication None (open broker for testing)

Common Workflows

  1. Test ESP32 MQTT client:

    • Ensure device is on testbench WiFi (see testbench-wifi)
    • POST /api/mqtt/start — start broker
    • Device connects to 192.168.4.1:1883
    • Monitor device behavior via serial or UDP logs (see testbench-logging)
    • POST /api/mqtt/stop — stop broker when done
  2. Test MQTT disconnect/reconnect:

    • Start broker, let device connect
    • POST /api/mqtt/stop — device loses MQTT
    • Monitor device's reconnection behavior
    • POST /api/mqtt/start — device should reconnect

Read the full file on GitHub · 143 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 12d ago First seen · 143 lines · 120 tokens per session scan B 17e6d7aaa3b7

Subscribe to this mod's changes

testbench-mqtt is a skill published in the GitHub repository SensorsIot/Embedded-AI-Harness (174 stars, last pushed 1mo ago), licensed MIT. It adds 120 tokens to every session and 1,730 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 2 findings (asks for root, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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