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 wedsamuel1230/arduino-skills --skill hardware-tddgit clone --depth 1 https://github.com/wedsamuel1230/arduino-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/wedsamuel1230/arduino-skills/hardware-tdd)<a href="https://agentmods.dev/skills/wedsamuel1230/arduino-skills/hardware-tdd"><img src="https://agentmods.dev/badge/skills/wedsamuel1230/arduino-skills/hardware-tdd/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/wedsamuel1230/arduino-skills/hardware-tdd"><img src="https://agentmods.dev/badge/skills/wedsamuel1230/arduino-skills/hardware-tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00059 | $0.00712 |
| Opus 5 | $0.00030 | $0.00356 |
| Sonnet 5 | $0.00012 | $0.00142 |
| Haiku 4.5 | $0.00006 | $0.00071 |
Grade A, and why
hardware-tdd 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 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.
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 — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Hardware TDD
Build the test ladder before claiming a feature is complete. Pure behavior can often be tested off-target; voltage, pin mux, timing under load, and physical assembly still require target evidence.
Intake
Record exact board/revision, framework/toolchain, hardware invariants, safety inhibits, simulator model, available instruments, test fixtures, and the proof stage required by the user.
Process
- Turn requirements into observable behavior and safety invariants.
- Write host tests for pure C/C++ logic using fakes for time, serial, sensors, and actuators. Keep hardware adapters thin.
- Use Wokwi or another simulator only for peripherals and timing that its model actually represents; record model limitations.
- Run an exact-board compile and static checks with the selected toolchain.
- Create a one-change target checklist: power-off continuity, controlled power-up, input observation, output inhibit, reset/recovery, and logs.
- Ask a physical gate for measurements, photos, or serial output. Do not infer target success from a host test or compile log.
- Record failures as evidence and keep the next test bounded.
Test matrix
| Layer | Example | Proves | Does not prove |
|---|---|---|---|
| Host | debounce/state/packet parser | deterministic logic | pin voltage or wiring |
| Simulation | modeled sensor/LED/UART | modeled interactions | regulator, clone, EMI, thermal behavior |
| Build | exact FQBN/environment | source and dependency compile | upload or behavior |
| Target | serial, meter, scope, photo | observed hardware behavior | field reliability unless loaded |
| System | integrated load/failure case | requirement under scenario | future deployment safety |
Anti-rationalization
| Shortcut | Response |
|---|---|
| "The unit test passed." | Keep all physical and system stages open. |
| "Wokwi matches the board." | List what the model omits and verify those items on hardware. |
| "The sketch compiled." | Require upload identity and target observations separately. |
| "The photo proves it works." | Require board identity, measurement context, and observed result. |
| "Mark it done and test later." | Keep the loop item blocked or needs-review until evidence exists. |
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.
- 12d ago First seen · 68 lines · 59 tokens per session scan A 2509249477f4
hardware-tdd is a skill published in the GitHub repository wedsamuel1230/arduino-skills (21 stars, last pushed 23d ago), licensed MIT. It adds 59 tokens to every session and 712 once invoked, about $0.0003 per session on Opus 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.
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