error-forensics

Error Forensics

Find what's breaking in production — JavaScript errors, network failures, console exceptions — and trace them to root cause using real session evidence.

When to Use

• "Are users hitting JavaScript errors on the settings page?"
• "Find sessions with 504 errors on /api/orders"
• "What's the most common console error right now?"
• "A user reported the checkout broke — find their session and tell me what went wrong"
• "Is the TypeError on /dashboard affecting many users or just one?"
• "What errors started appearing after the last deploy?"

Use free fullstory:discover_groups and fullstory:get_opportunity_stats for live signals. Discovery accepts one scope at a time (page_id, domain, app_name, segment_id, or funnel_id); use a segment for device/user filters and the live schema for time ranges. Use computed metrics for exact custom windows.

Workflow

Step 1: Discover error patterns

Start broad. Call fullstory:discover_groups to surface error-related frustration signals — these will include console errors, network failures, and renderer errors ranked by user count.

If you're investigating a specific error or page, build a metric instead:

fullstory:build_metric(
  query="console errors on /settings",
  output_type="top_n"
)

Step 2: Quantify

Call fullstory:get_opportunity_stats or fullstory:compute_metric to get:

• How many users are affected
• Device/browser breakdown (is it Safari-only? Mobile-only?)
• Page concentration (which pages is it happening on?)
• Trend (is it getting worse? Did it start after a deploy date?)
• Rate vs site average (is this page abnormally error-prone?)

Step 3: Find sessions

Build and compute a metric for the error, then call fullstory:get_sessions(metric_id="<id>") and review 3-5 matching sessions. Stored get_sessions_for_opportunity lookup is an optional StoryAI Premium path, not a prerequisite.

Step 4: Investigate each session

For each session, use the session-context agent with a focused task: