signals-scout-apm

Detects error-rate and latency regressions in OpenTelemetry distributed tracing data.

713|118|Updated Aug 11, 2020
One-click install
npx skills add https://github.com/PostHog/posthog-foss --skill signals-scout-apm
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: signals-scout-apm
Source: https://github.com/PostHog/posthog-foss/tree/main/products/signals/skills/signals-scout-apm
Command: npx skills add https://github.com/PostHog/posthog-foss --skill signals-scout-apm

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Monitoring distributed tracing data manually across many services makes it easy to miss real regressions or to drown in false positives caused by traffic spikes. This Skill watches per-service RED metrics (rate, errors, duration) in PostHog APM span data and files a report only when a validated regression clears the bar.

Core Features & Use Cases

  • Regression Detection: Compares per-(service, operation) error rates and p95 latency against a seasonality-matched baseline from 7 days ago, guarding against volume-driven false positives.
  • Root-Cause Investigation: Pulls representative failing traces, reads exception attributes, breaks down error signatures by attributes like service.version, and localizes latency via span trees and duration histograms.
  • Report Authoring & Memory: Authors or edits inbox reports with evidence and charts, and persists baselines, noise patterns, and dedupe pointers in a scratchpad so future runs stay cheap and non-duplicative.
  • Use Case: A payments service's p95 latency jumps from 320ms to 1.4s while request volume holds steady; the scout confirms the onset bucket, bundles the affected operations into one report, and routes it to the service owner.

Quick Start

Ask the agent to run the APM signals scout against your PostHog project to check for error-rate or latency regressions across your instrumented services.

Frequently Asked Questions about signals-scout-apm

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I detect latency regressions in OpenTelemetry traces?

Compare per-operation p95 latency from the last 24 hours against the same window 7 days ago using span aggregation, keeping only operations where request volume stayed within roughly 2x. Then localize the cause with span trees and duration histograms to separate slower children from uninstrumented work.

How to tell a real error spike from a traffic increase in APM data?

Compute error rate as error_count divided by request count rather than looking at raw totals. If error count rises in lockstep with request volume, the rate is flat and it is a traffic spike, not a regression; only a rate step-up on a steady denominator qualifies.

Does this scout monitor AI observability events or logs?

No, it is scoped strictly to distributed tracing span data. AI observability $ai_* events belong to a separate AI-observability scout, and the logs stream is handled by the logs scout.

Why does a span query return no matching error spans?

The span query tool defaults to root spans only, so a regressed child operation like a DB or client call matches nothing. Set flatSpans to true and rootSpans to false to search child spans with the status_code filter.

When should a regression update an existing report instead of creating one?

When a live inbox report already tracks the same service and operation, the scout edits it by appending the fresh before/after numbers rather than filing a duplicate. A persistent regression stays one report across runs.