micropython-skills

AI Agent programmable co-processor skill collection. You (the Agent) generate MicroPython code, push it to devices via REPL, parse structured output, and iterate — turning hardware into your extended capability.

Quick Start

Python command: Use python3 on macOS/Linux, python on Windows. On Windows, python3 is often a Microsoft Store stub that silently fails (exit code 49). On macOS/Linux, python may not exist or may point to Python 2.

Every interaction follows this flow:

1. Probe — Run python3 {SKILL_DIR}/scripts/device_probe.py to discover connected devices
   • status: "ok" → Device has MicroPython, proceed to step 2
   • status: "no_firmware" → ESP chip detected but no MicroPython. Ask user to confirm, then flash: python3 {SKILL_DIR}/scripts/firmware_flash.py --port PORT --yes
   • status: "no_device" → No device connected. Guide user to connect hardware.
   • status: "permission_denied" → Serial port not accessible. On Linux: sudo chmod 666 /dev/ttyACM0. On Windows: check Device Manager for driver issues.
2. Connect — Default: USB via mpremote. Optional: WiFi via WebREPL (user must request)
3. Execute — Generate MicroPython code and push to device
4. Parse — Scan stdout for tagged lines (RESULT:/ERROR:/STATUS:/LOG:)
5. Iterate — Adjust code based on results, repeat steps 3-5

Where {SKILL_DIR} is the directory containing this SKILL.md file.

Connection Management

Default: USB (mpremote)

Always start by probing for devices:

python3 {SKILL_DIR}/scripts/device_probe.py

Execute code on device:

mpremote exec "import machine; print('RESULT:' + str(machine.freq()))"

Run a script file:

mpremote run script.py

For multi-line code, write a temporary .py file locally, then mpremote run /path/to/task.py.

Serial port names vary by platform:

The scripts auto-detect the port — you rarely need to specify it manually.

Optional: WiFi (WebREPL)

Only switch to WiFi when the user explicitly requests it. The switch flow:

1. Ask user for WiFi SSID and password
2. Push WiFi + WebREPL config to device via USB:

   python3 {SKILL_DIR}/scripts/wifi_setup.py --ssid "SSID" --password "PASS" --webrepl-password "repl123"
   

3. Note the IP address from the output
4. From now on, execute code over WiFi:

   python3 {SKILL_DIR}/scripts/webrepl_exec.py --host 192.168.1.100 --password repl123 --code "print('hello')"
   

5. USB cable can be disconnected

For detailed command reference, read ./references/connections.md.

Sub-skill Router

Based on user intent, read the corresponding sub-skill for domain-specific templates:

When a task spans multiple domains (e.g., "read sensor and publish via MQTT"), read all relevant sub-skills.

Structured Output Protocol

All MicroPython code you generate for the device MUST use tagged output lines:

Code template — every snippet you generate should follow this pattern:

import json
from machine import Pin
try:
    # ... your operation here ...
    print("RESULT:" + json.dumps({"key": value}))
except Exception as e:
    print("ERROR:" + str(e))

Parse rules:

• Scan device stdout line by line
• Extract lines starting with RESULT:, ERROR:, STATUS:, LOG:
• Ignore all other output (MicroPython boot messages, REPL prompts, etc.)
• If ERROR: is found, diagnose and retry with adjusted code

Safety Rules

Hard constraints:

• Never hardcode WiFi passwords in scripts saved to device — use variables or prompt user
• All loops must have iteration limits or timeouts — never generate infinite loops without exit conditions
• Before overwriting boot.py or main.py, always backup the existing file first
• Before controlling high-current devices (motors, relays), ask user to confirm wiring

For complete recovery procedures, read ./references/safety.md.

Workflow

As the Agent operating this co-processor, follow this mental model:

1. Understand intent — What does the user want to achieve with the hardware?
2. Check connection — Run device_probe.py if you haven't yet. Know your device's platform and capabilities.
3. Route to sub-skill — Read the relevant sub-skill SKILL.md for code templates and domain knowledge
4. Generate code — Write MicroPython code following the output protocol. Adapt pin numbers and parameters to the target platform.
5. Push and capture — Execute via mpremote or WebREPL, capture full stdout
6. Parse results — Extract RESULT:/ERROR: lines, parse JSON data
7. Decide next step — If ERROR, diagnose and adjust. If RESULT, present to user or use for next operation.
8. Maintain state — Remember which pins are in use, which peripherals are initialized, what the device's platform is
9. Offer persistence — After a program runs successfully, ask the user if they want to save it to the device or set it to auto-start on boot

Program Persistence

After a program runs successfully, offer the user two options:

Option 1: Save to Device (for later manual use)

Save the script to the device's filesystem so it can be run anytime without re-uploading:

# Save script to device
mpremote fs cp local_script.py :my_program.py

# List saved scripts on device
mpremote fs ls

# Run a saved script
mpremote exec "exec(open('my_program.py').read())"

This is a Cautious operation — inform the user before writing files to the device.

Option 2: Auto-start on Boot (write to main.py)

If the user wants the program to run automatically every time the device powers on:

1. Always ask first — "要设置为开机自动运行吗？注意：如果程序有问题可能导致设备无法正常连接。"
2. Backup existing main.py (if any):

   mpremote fs cp :main.py ./main.py.bak
   

3. Upload as main.py:

   mpremote fs cp local_script.py :main.py
   

4. Important: For auto-start scripts, wrap the main logic in a try/except and add a short startup delay so the user can interrupt if needed:

   import time
   time.sleep(2)  # 2s window for Ctrl-C interrupt
   # ... main logic ...
   

This is a Dangerous operation — require explicit user confirmation.

Disable Auto-start

If the device becomes hard to access due to a problematic main.py:

# Rename to disable (if mpremote can still connect)
mpremote exec "import os; os.rename('main.py', 'main.py.disabled')"
mpremote reset

# Or delete it
mpremote exec "import os; os.remove('main.py')"
mpremote reset

If the device is completely unresponsive, follow the recovery steps in ./references/safety.md.

Platform Adaptation

After probing, adapt code to the detected platform:

For ESP32-specific pin maps and APIs, read ./references/esp32.md.

Reference Files

Read these on demand — not every interaction needs them:

Dependencies

Agent-side requirements:

• mpremote — pip install mpremote (required for USB connection)
• esptool — pip install esptool (required for chip detection and firmware flashing)
• pyserial — pip install pyserial (required on Windows for COM port auto-detection; recommended on all platforms)
• websocket-client — pip install websocket-client (only needed for WiFi/WebREPL mode)
• Python 3.8+

Windows notes:

• Use python instead of python3 to run scripts. On many Windows systems, python3 is a Microsoft Store stub that returns exit code 49. On macOS/Linux, use python3.
• Without pyserial, the scripts fall back to parsing the mode command output for COM port detection, which provides less detail (no VID/PID info). Install pyserial for best results.

Device-side requirements:

• MicroPython firmware v1.19+ (v1.22+ recommended) — auto-installed by firmware_flash.py if missing
• USB connection or WiFi reachability

External Endpoints

This skill accesses external services during specific operations:

No telemetry, analytics, or data is sent to any external service. The skill operates entirely locally except for firmware downloads.

Security & Privacy

• No data collection: This skill does not collect, transmit, or store any user data
• No telemetry: No usage analytics, crash reports, or tracking of any kind
• Local-only operation: All device communication happens over local USB serial or local WiFi (WebREPL). No cloud relay or proxy is used
• WiFi credentials: When provided by the user, WiFi credentials are passed directly to the device via mpremote and written to the device's boot.py. They are never logged, stored on the host machine, or transmitted to external services
• Firmware source: Firmware binaries are downloaded exclusively from micropython.org, the official MicroPython project site
• File system access: Helper scripts only access serial ports and the system temp directory (for firmware caching). No other host files are read or modified

Trust & Verification

• Open source: Full source code is available at the homepage repository
• No obfuscation: All Python scripts and Markdown files are human-readable
• Auditable: The scripts/ directory contains 4 self-contained Python scripts with no external dependencies beyond mpremote, esptool, pyserial, and websocket-client
• Evals included: The evals/evals.json file contains 5 test scenarios covering device probe, sensor read, actuator control, diagnostics, and recovery