compile-after-changes

A project rule requiring PlatformIO firmware projects to be compiled after significant code changes. PlatformIO is a tool for building embedded-device software.

In plain words
What is it for?
It is for running `pio run` after changes to firmware logic, types, APIs, headers, libraries, or PlatformIO configuration.
Why use it?
It helps catch compilation errors before the change is considered finished.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/jamro/tiny-engineer/compile-after-changes
Clone the repo
git clone --depth 1 https://github.com/jamro/tiny-engineer

Made for: Cursor.

Per session 113 This file is loaded in full into every session.
When invoked 113 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00113 $0.00113
Opus 5 $0.00056 $0.00056
Sonnet 5 $0.00023 $0.00023
Haiku 4.5 $0.00011 $0.00011

Measured 2d ago against content hash 2166a23d7a1b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

compile-after-changes 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 2d 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.

.cursor/rules/compile-after-changes.mdc · 15 lines

What it actually says

Compile after significant changes

After any significant code change, run pio run from the project root and fix failures before considering the work done.

Significant: logic, types, APIs, headers, firmware source (src/, include/, lib/), or platformio.ini.

Skip: comments-only, docs-only, or tiny formatting.

Do not flash (pio run -t upload) unless asked.

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. 2d ago First seen · 15 lines · 113 tokens per session scan A 2166a23d7a1b

Subscribe to this mod's changes

compile-after-changes is a cursor rule published in the GitHub repository jamro/tiny-engineer (117 stars, last pushed 2d ago), licensed MIT. It adds 113 tokens to every session, about $0.0006 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.