Debug Traces

Debug Coval Traces

Use this skill when a customer expected traces in Coval and they are missing, wrong, sparse, duplicated, or not useful for production debugging.

Read First

Load:

• ../references/debugging-matrix.md
• ../references/coval-tracing-reference.md
• ../references/agent-type-routing.md
• ../references/span-schema.md when trace quality is the problem
• ../references/vapi-artifact-tracing.md when debugging Vapi webhook traces

Phase 1: Identify The Failure Boundary

Separate the problem into one of these boundaries:

• agent never exported spans
• export returned an HTTP error
• export succeeded but targeted the wrong simulation/conversation/org
• spans are stored but the UI route is not where the user looked
• spans exist but are sparse or not useful
• custom trace metrics cannot find spans or attributes

Collect:

• endpoint used
• response status/body from /v1/traces
• whether the export used X-Simulation-Id or X-Conversation-Id
• simulation output ID or conversation ID, not the run ID unless this is a monitoring conversation
• Coval agent type and connection path
• recent trace viewer URL, Trace Search URL, or copied trace dump
• whether spans were sent as OTLP JSON or protobuf

Do not ask for raw API keys. Ask the user to run commands locally with env vars. Redact Coval agent metadata before sharing API responses; provider keys may be stored there.

Phase 2: Run Minimal Checks

Check Coval auth:

coval whoami

Run a standalone connectivity check when useful:

python skills/traces/setup-tracing/scripts/send-test-span.py \
  --api-key "$COVAL_API_KEY" \
  --simulation-id "$SIMULATION_OUTPUT_ID"

Interpretation:

• 200 means Coval accepted and stored the test span for that target.
• 404 for coval-tracing-test or another known-fake ID means auth/connectivity worked but the target ID is not real. Use --allow-not-found for intentional fake-ID checks.
• 404 for a real target usually means wrong ID, wrong org key, or using a run ID instead of a simulation output ID.

For conversation monitoring, use:

python skills/traces/setup-tracing/scripts/send-test-span.py \
  --api-key "$COVAL_API_KEY" \
  --conversation-id "$CONVERSATION_ID"

Phase 3: Apply The Troubleshooting Matrix

Use ../references/debugging-matrix.md to map symptom to cause and fix.

High-probability causes:

• no target header, or both target headers sent
• X-Simulation-Id contains a run ID instead of a simulation output ID
• X-Conversation-Id used for a non-monitoring run
• PSTN phone path expected SIP headers that cannot arrive
• WebSocket initialization payload did not include the simulation output ID
• wrong organization's API key
• payload over roughly 3-4 MB
• retry resent already accepted spans
• only auto-instrumented provider spans exist, so the trace lacks STT/TTS/tool context
• Vapi-hosted PSTN trace uses artifact-derived STT/LLM/TTS marker spans but reports them as measured provider latency
• tracing helper files or OpenTelemetry dependencies were added locally but not copied into the deployed image/bundle
• WebSocket smoke tests sent less audio than the agent's response threshold, or the agent streamed a long canned response after Coval closed the socket
• run progress reached completed_test_cases == total_test_cases, but run status is still non-terminal and metric outputs are still queueing
• older runs reflect stale metric definitions and are being treated as proof of current instrumentation state

For Vapi-hosted PSTN agents, inspect the source of each span before calling it real provider observability. tool-calls webhooks are real tool execution. end-of-call-report.artifact.messages are real transcript/turn evidence. Provider-internal STT/LLM/TTS timing is not real unless the span has measured provider timing or explicit provider fields rather than trace.timing=metadata_marker.

For Vapi-hosted PSTN agents, inspect the source of each span before calling it real provider observability. tool-calls webhooks are real tool execution. end-of-call-report.artifact.messages are real transcript/turn evidence. Provider-internal STT/LLM/TTS timing is not real unless the span has measured provider timing or explicit provider fields rather than trace.timing=metadata_marker.

Phase 4: Verify In Coval UI

Use the right surface:

• simulation result: run result page, OTel Traces card, trace viewer
• cross-call investigation: Trace Search under Observability
• run-level flow failures: Transition Hotspots tab
• conversation monitoring: conversation result/trace search, not simulation-only routes

Trace Search filters that usually isolate issues:

• span name: llm, stt, tts, llm_tool_call
• status: ERROR
• duration greater than expected thresholds
• attribute exists: metrics.ttfb, stt.providerName, function.name, llm.finish_reason
• agent/test set scope

For metric debugging, use the simulation metrics API/CLI output in addition to the run summary:

• run may still show IN PROGRESS while metrics are computing
• each metric output should become terminal (COMPLETED or FAILED)
• treat IN QUEUE / IN PROGRESS metric outputs as pending, not failed

Phase 5: Fix Or Escalate

Fix implementation issues directly when the repo is available and the change is additive. Escalate with exact evidence when:

• the target ID belongs to another org and the user must provide the correct key
• the customer needs SIP provisioning or Coval agent config changes outside the repo
• the Coval API returns repeated 500/503 after valid retries
• the trace exists in storage but the UI cannot load it

End with a short incident-style summary: observed status, root cause, fix applied or required, and the exact command or Coval UI check that proves the current state.