> AI agents: this is one page from PostHog's docs. Full index of Markdown docs for LLMs: https://posthog.com/llms.txt

# Catch error spikes and stuck loops – Error Tracking pocket guide

Canonical URL: https://posthog.com/learn/error-tracking/pocket-guide/spikes-and-stuck-loops

> **Cloud region:** This page uses US Cloud hosts. For an EU Cloud project, use `https://eu.posthog.com` instead of `https://app.posthog.com` (app host for links).

## On this page

- [What the scout looks at](#what-the-scout-looks-at)
- [The report in your inbox](#the-report-in-your-inbox)
- [The scout itself](#the-scout-itself)
- [Add this to your scout troop](#add-this-to-your-scout-troop)

This [scout](https://posthog.com/docs/self-driving/scouts.md) reports error spikes and ranks them by how many guests they affect. A bug that breaks booking for hundreds of guests ranks above a few browsers stuck in a retry loop.

## What the scout looks at

The scout reports an issue when its exceptions jump well above the issue's own baseline. It sets the priority by comparing exceptions with distinct users:

-   **Both climb.** Many guests hit a regression. The report is P1, or P2 when the reach is moderate.
-   **Exceptions climb, users stay flat.** A few browsers are stuck in a loop Fig. 1. The report is P3, or P2 when it's fresh and in the thousands.
-   **A resolved issue fires again.** The report is P1.

02:10

Distinct users

flat at 4

Exceptions

~20/hour → ~240/hour

Fig. 1 – What the scout saw: At 02:10, exceptions on Twig's Trip details issue jumped from about 20 an hour to about 240 an hour. Distinct users held at four the whole time.

The scout files new issues with overlapping stack traces as one report, and skips one-off exceptions and known upstream errors.

## The report in your inbox

Each spike becomes a [report](https://posthog.com/docs/self-driving/reports.md) in the team's [inbox](https://posthog.com/docs/self-driving/inbox.md), with exceptions, distinct users, and an hourly chart against the issue's baseline Fig. 2. From the report, the engineers can [ask AI](https://posthog.com/docs/self-driving/reports.md#ask-ai-about-a-report) who else is affected or what to do next.

P31Trip details retries loop on the same TypeError, ~240 exceptions an hour from 4 guests 2Exceptions jumped to ~240 an hour at 02:10 while distinct users held at 4, because four guests keep clicking Try again on a Trip details page that throws every time3Scout · error tracking4ReadyActionable53h ago

ArchiveReview6

Fig. 2 – The report card in your inbox shows the scout's claim and triage. The full evidence is inside the report.Hover over the figure to learn about each element.

## The scout itself

PostHog maintains this scout, listed as **Error tracking** in the project's scouts. Its [skill file](https://github.com/PostHog/posthog/blob/master/products/signals/skills/signals-scout-error-tracking/SKILL.md) is on GitHub. Each run queries Twig's issues and `$exception` events through the [PostHog MCP](https://posthog.com/learn/error-tracking/agent-prompts-and-mcp.md), and checks its notes and the team's inbox so it doesn't report the same spike twice. It runs every 24 hours by default and stays quiet unless something needs the team's attention.

## Add this to your scout troop

The engineers turn it on for each project. It needs exceptions reaching PostHog.

[Open your scouts](https://app.posthog.com/inbox/scouts)Find Error tracking in the list and switch it on.

See also: [Scouts](https://posthog.com/docs/self-driving/scouts.md) · [Scout examples](https://posthog.com/docs/self-driving/scout-examples.md) · [Reports](https://posthog.com/docs/self-driving/reports.md) · [Signal sources](https://posthog.com/docs/self-driving/inbox/sources.md) · [Detect spikes](https://posthog.com/docs/error-tracking/spikes.md)