Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add alexex1993/mcu-skills --skill nrf52840-promicrogit clone --depth 1 https://github.com/alexex1993/mcu-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/alexex1993/mcu-skills/nrf52840-promicro)<a href="https://agentmods.dev/skills/alexex1993/mcu-skills/nrf52840-promicro"><img src="https://agentmods.dev/badge/skills/alexex1993/mcu-skills/nrf52840-promicro/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/alexex1993/mcu-skills/nrf52840-promicro"><img src="https://agentmods.dev/badge/skills/alexex1993/mcu-skills/nrf52840-promicro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
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 Rogue Agent · line 111 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00251 | $0.04916 |
| Opus 5.5 | $0.00100 | $0.01966 |
| Sonnet 5.5 | $0.00050 | $0.00983 |
| Haiku 4.5 | $0.00025 | $0.00492 |
Grade A, and why
nrf52840-promicro scanned grade A with 0 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 6d 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 259 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ProMicro nRF52840 (V1940)
A nice!nano v2 clone: nRF52840 module on a Pro Micro footprint, USB-C, factory Adafruit UF2 bootloader with SoftDevice S140 6.1.1. Sold as ProMicro nRF52840, SuperMini nRF52840, nRF52840 Pro Micro; the ZMK/QMK wireless keyboard crowd is where most of the documentation lives.
Its failure modes are quiet and all look like "the board is dead": the board
is in neither PlatformIO's board list nor the Arduino core's variant list, so
half of what a tutorial tells you to type does not apply; a missing 32.768 kHz
crystal hangs the SoftDevice with USB still enumerated; and Serial does not
exist until you include a library that the code never otherwise mentions.
reference/board-hardware.md— the complete board reference: full pin map (silkscreen → Arduino number → P0.xx/P1.xx → peripheral), power, flash and RAM maps, bootloader layout, clocks, plus a development guide (Part II: §7 toolchain, §8 peripheral cookbook, §9 flashing and recovery, §10 the Zephyr board target, §11 symptom → cause → fix table).reference/recipes.md— copy-paste code:platformio.ini, the board JSON,variant.h/variant.cppexcerpts, USB CDC +Serial1, SAADC with the gain math,Wire/SPI, BLE UART, InternalFS, deep sleep, UF2 conversion.template/— a project that builds clean, in three variants, plus a scaffold script. Seetemplate/README.md.
Orientation
| MCU | nRF52840 QIAA (aQFN73 module) — ARM Cortex-M4F @ 64 MHz, fixed; no PLL to configure |
| Memory | 1 MB internal flash, 256 KB RAM. With S140 6.1.1 + UF2 bootloader the app gets 815,104 B flash (0x26000–0xED000) and 237,568 B RAM (0x20006000–0x20040000) |
| LED | P0.15 = Arduino pin 11 (LED_BUILTIN), active HIGH, not on the header. P0.26/P0.30 are the fallback candidates on other clone revisions |
| Button | RESET only — no user button. Double-tap it to reach the bootloader |
| USB | USB-C, native FS device (no USB-serial chip). Serial = USB CDC via TinyUSB; bootloader enumerates as a NICENANO/PROMICRO mass-storage drive |
| Radio | BLE 5 / 802.15.4 / ANT via SoftDevice S140 6.1.1 already on the board; Bluefruit is the Arduino API |
| LF clock | 32.768 kHz crystal is often NOT populated on clones. USE_LFRC in variant.h (internal RC) is the safe default; USE_LFXO hangs a board without the crystal |
| ADC | SAADC, 14-bit max, 10-bit by default, internal 0.6 V ref + 1/6 gain = 0–3.6 V full scale. Channels only on P0.02–P0.05, P0.28–P0.31 — A0 (P1.15) has no ADC |
| Bus defaults | Wire = D2/D3 (P0.17/P0.20) · SPI = D14/D15/D16 + SS D10 (P1.11/P1.13/P0.10, P0.09) · Serial1 = D0/D1 (P0.08/P0.06) |
| Logic | 3.3 V, not 5 V tolerant; 15 mA per pin (high-drive), 0.5 mA standard drive |
| Power | USB 5 V → on-board 3.3 V regulator; battery pads on the underside on most revisions. No published schematic for V1940 — treat battery-sense and charger claims as unverified |
| Debug | SWDIO/SWCLK pads on the back, no header. J-Link, CMSIS-DAP or a WCH-LinkE in ARM mode |
| Toolchain | PlatformIO + nordicnrf52 10.11.0 + framework-arduinoadafruitnrf52 1.10700.0 (Adafruit core 1.7.0). Zephyr also supports it as promicro_nrf52840/nrf52840/uf2 |
What ships with it
14 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- assets/IMAGE.md 467 B
- reference/board-hardware.md 21 KB
- reference/recipes.md 12 KB
- template/.gitignore 13 B
- template/boards/promicro_nrf52840.json 1.4 KB
- template/boards/variants/promicro_nrf52840/variant.cpp 1.4 KB
- template/boards/variants/promicro_nrf52840/variant.h 4.1 KB
- template/include/board.h 3.6 KB
- template/platformio.ini 1.3 KB
- template/README.md 5.2 KB
- template/src/main.cpp 2.4 KB
- template/variants/ble/main.cpp 2.3 KB
- template/variants/minimal/main.cpp 937 B
- template/variants/new-project.sh 1.7 KB runs code
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.
- 6d ago Changed · +2 lines · +251 tokens per session 4ff1f4497148
- 2mo ago First seen · 257 lines · 0 tokens per session scan A 2db1c7e835e8
nrf52840-promicro is a skill published in the GitHub repository alexex1993/mcu-skills (25 stars, last pushed 7d ago), licensed MIT. It adds 251 tokens to every session and 4,916 once invoked, about $0.0010 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
nrf52840-promicro compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| nrf52840-promicroalexex1993/mcu-skills | Skill | 25 | 7d ago | MIT | A | 251 | Claude Code, Codex |
| holoscan-install-wheelNVIDIA/skills | Skill | 3.9k | yesterday | Apache-2.0 | A | 34 | Claude Code, Codex |
| doca-argpNVIDIA/skills | Skill | 3.9k | yesterday | Apache-2.0 | A | 277 | Claude Code, Codex |
| holoscan-module-lifecycleNVIDIA/skills | Skill | 3.9k | yesterday | Apache-2.0 | A | 47 | Claude Code, Codex |
| mspm0-skillIbook000/mspm0-skill | Skill | 13 | 1mo ago | MIT | A | 76 | Claude Code, Codex |
| keymap-aijohncattrall/keymap-ai | Skill | 24 | 1mo ago | MIT | A | 146 | Claude Code, Codex |
| arduino-code-generatorwedsamuel1230/arduino-skills | Skill | 24 | 2mo ago | MIT | A | 86 | Claude Code |