Live Diagnostics (LSP)
The tightest feedback loop doesn't wait for you to run the code — it catches mistakes the moment they're typed. That's what the Language Server Protocol () provides: the live "smarts" behind your editor, including real-time errors, type information, go-to-definition, and autocomplete. A language server reads your code as it changes and reports problems before anything runs.
The leverage for vibe coding is to feed those diagnostics back to the AI. Without it, the loop is slow: the AI writes code, you run it, it crashes on a typo or a type error, and you paste the message back by hand. With diagnostics wired in, the sees the same red squiggle you do the instant it writes the line — and fixes the type or lint error as it goes, before the code ever runs.
You can give the agent this sight in a few ways:
- Run the language server for your stack (tsserver, rust-analyzer, pyright, and so on) — most AI-native editors do this for you.
- Have the agent run a typecheck or lint command and read the output, or expose diagnostics through an server.
- Treat a clean diagnostics report as part of "done," not an afterthought.
Wired this way, the agent runs the same self-correcting cycle on its own — edit, run, read the failure, fix, and run again until the diagnostics come back clean:
┌──────────┐ ┌──────────┐ ┌──────────────┐
│ EDIT │ ───▶ │ RUN │ ───▶ │ READ FAILURE │
└──────────┘ └──────────┘ └──────┬───────┘
▲ │
│ ▼
│ ┌──────────┐ ┌──────────┐
│ │ PASS │ ◀──── │ FIX │
│ │ (done) │ no └──────────┘
│ └────┬─────┘
└─────────────────┘
still failing
This is also why a typed language can be a quiet superpower for vibe coding: every type annotation is a tiny, machine-checked spec that catches the AI's mistakes before they ever run. A run-crash-paste cycle becomes a quiet, self-correcting one. The AI grinds less and converges faster.