Why Coding Agents Made Reverse-Engineering Your Smart Home Worth It

The undocumented smart-plug API you never bothered reverse-engineering wasn’t beyond your skills. It just wasn’t worth the hours. That math has quietly changed.

How It Works

Simon Willison’s observation starts from anecdotes: people using coding agents to reverse-engineer and automate devices in their own homes — the kind of project that’s always been technically possible but rarely worth starting. The mechanism behind that shift isn’t that agents make reverse-engineering itself easier in some fundamentally new way. It’s that they collapse the cost of the entire project lifecycle: writing the exploratory code, testing hypotheses about an undocumented protocol, throwing away wrong approaches, and trying again.

That last part is the one people underweight. Before agentic coding, the real cost of a home-automation reverse-engineering project was never just the hours to get it working — it was the standing psychological cost of maintaining code you wrote under time pressure, half-understood, for a device that might change its firmware next month and break everything. That maintenance dread was often enough on its own to keep the project in the “someday” pile indefinitely.

Willison’s framing is that agents shrink both halves of that equation at once: the effort to get a simple automation working has dropped, and so has the cost of trying and failing. When failure is cheap, the decision to start stops being a research-project-sized commitment and becomes something closer to “just try it and see.”

What This Means for You

The practical shift is in which projects clear the bar to attempt at all. A huge category of small automations — the one janky smart-device integration, the vendor app you’d rather not open, the API your thermostat obviously has but doesn’t document — sat unattempted for years not because they were hard, but because the effort-to-benefit ratio never quite justified starting. If an agent can produce a working first attempt in an evening instead of a weekend, and abandoning it costs nothing if it doesn’t pan out, the calculus that kept those projects on the shelf stops applying.

This also reframes what “maintenance burden” means for hobbyist code. Willison’s point that abandoning or maintaining agent-assisted code carries “way less psychological baggage” isn’t about the code being disposable in quality — it’s that the sunk-cost anxiety that made people over-invest in fixing brittle scripts, rather than just rewriting them, has less grip when the rewrite itself is cheap.

Source: Simon Willison

Content created with AI assistance and reviewed for accuracy.