lucid-fdn/correlation

Cross-Service Correlation

Correlate errors across services using trace IDs and run IDs to detect cascading failures.

Prerequisites

• Sentry MCP: search_issues, get_issue_details

Correlation Procedure

Step 1: Extract Correlation IDs

From the issue being investigated, look for these tags:

• trace_id — W3C Trace Context ID (32-char hex)
• run_id — Lucid run UUID (links all operations in a single user request)

If neither exists, correlation is not possible. Check that enrichSentryEvent() is called in beforeSend to attach these tags.

Step 2: Search Across All Projects

Use Sentry MCP search_issues with query trace_id:{id} (or run_id:{id}) for each of these projects:

• lucid-web
• lucid-worker
• lucid-l2
• lucid-trustgate
• lucid-mcpgate
• javascript-nextjs

Rate limit strategy: Search 6 projects in a batch (all at once is fine for 6 projects).

Step 3: Deduplicate and Sort

• Deduplicate results by issue ID (same issue may appear in multiple searches)
• Sort by lastSeen descending (newest first)
• Note which services are affected

Step 4: Detect Cascade

If errors appear in more than one service for the same trace:

• Cascade detected — this is a cross-service failure
• Investigate the oldest error first (likely the root cause)
• The error propagation path usually follows the service dependency graph

If errors appear in only one service:

• Isolated failure — no cascade
• Focus diagnosis on that single service

If no errors found:

• Verify enrichSentryEvent() is called in beforeSend to attach trace_id and run_id tags
• The trace may exist in OTel but not have triggered Sentry errors

Step 5: Build Timeline

Present the correlated issues as a timeline:

1. Service name + Sentry project
2. Issue title and severity
3. Event count and user count
4. First seen and last seen timestamps
5. Analysis: which service was the origin, which were downstream effects

Service Dependencies

See references/services.md for the full service topology and dependency graph.

Trace Flow

See references/trace-flow.md for how traces propagate between services.