# Stack Trace (/academy/stack-trace)



When code dies, it leaves a trail of open doors.

The **stack trace** is that trail: this function called that function called the one that threw. Each line is a frame — a room the program had not left yet. You read from the top until you see *your* file. The rest is libraries yelling because you fed them garbage.

You do not need every frame. You need the first path under `apps/` or `packages/`. That is the line you open. That is the line you paste.

**Not a distributed trace**

A [trace](/academy/trace) follows one request across services and times the hops. A stack trace pulls the other way: the pile of calls *inside one process* at the instant it crashed. One is a map of travel. One is a snapshot of who was still on the line when it dropped.

**The diary vs the last page**

A [log](/academy/log) is the running tape. The stack trace is usually one angry entry on that tape — often a [type error](/academy/type-error) or a null you promised wasn't there. Don't screenshot the whole wall and ask "why." Open the first line that lives in your repo.

**What you hand an agent**

This is the most practical page in debug. An [agent](/academy/agent) that sees "it broke" will [hallucinate](/academy/hallucination) a cause. An agent that sees the full stack — file, line, message — can [patch](/academy/patch) the [bug](/academy/bug). Paste the whole thing from the terminal. The [CLI](/academy/cli) already printed it. That is the artifact.

At a hackathon, the crash during the demo is the same artifact. Don't narrate. Copy the frames.

**What this unlocks**

A stack trace is a map of the last second, not a brick wall. The top line that is yours is the door. Walk through that one.