Lambda processing EventBridge voice analytics events fails at the Data Actions CRM enrichment step before DynamoDB writes. The inputs map on POST /api/v2/dataactions/actions/{id}/execute enforces strict string typing, so when the event skips sentimentScore, the payload structure shifts and requests returns a 400 Bad Request. Enforce type defaults or coerce the missing value before serialization.
def lambda_handler(event, context):
sentiment = event.get('sentiment', {})
payload = {"inputs": {"conversationId": event['conversationId'], "sentiment": sentiment.get('score')}}
resp = requests.post(f"{base_url}/api/v2/dataactions/actions/crm_lookup/execute", json=payload, headers=auth)
if resp.status_code == 400:
raise Exception("Enrichment failed")
return resp.json()
The DATA_ACTION execution endpoint enforces strict schema validation, so a missing SENTIMENT_SCORE breaks the payload structure immediately. EventBridge events often lag behind the transcript processing, leaving that field empty until the FLOW tries to push data out to DynamoDB. You’ll want to handle the null check right inside the Set Variable block before the API call runs. Coercing the value to a default string keeps the JSON structure intact and stops the 400 error cold. Just make sure your FLOW defaults to a safe value like “0.5” so the downstream system doesn’t choke on the missing key. The execute call at /api/v2/dataactions/actions/{id}/execute expects every input key to map to a string, so the expression handles the type casting automatically.
{
"inputs": {
"sentimentScore": "${sentimentScore || '0.5'}"
}
}
Cause: EventBridge drops the sentimentScore field when transcription lags, which breaks the strict JSON schema on the Data Actions endpoint.
Solution: genesyscloud-python doesn’t auto-coerce missing floats to strings, so the payload validation fails before it even hits your Lambda. You’ll need to inject a fallback value at the source mapping stage. Leaving it null will trigger repeated 400 retries that’ll quickly exhaust your DynamoDB throughput. Check the Retry-After header or your Lambda will just spin up cold starts for nothing. The event bridge rule also needs a dead letter queue setup, otherwise those failed executions pile up and mask the real routing issue. Honestly, it’s a pain to debug. Just force the string conversion upfront.
payload["inputs"]["sentimentScore"] = str(event.get("sentimentScore") or "0.0")
import os
import requests
BASE_URL = "https://api.genesys.cloud/v2/dataactions/actions"
ACTION_ID = os.getenv("DATA_ACTION_ID")
OAUTH_TOKEN = os.getenv("GENESYS_ACCESS_TOKEN")
headers = {
"Authorization": f"Bearer {OAUTH_TOKEN}",
"Content-Type": "application/json"
}
payload = {
"inputs": {
"conversationId": event["detail"]["conversationId"],
"SENTIMENT_SCORE": str(event["detail"].get("sentimentScore", "0.0")),
"TARGET_QUEUE": os.getenv("WEM_QUEUE_ID")
}
}
response = requests.post(f"{BASE_URL}/{ACTION_ID}/execute", headers=headers, json=payload)
print(response.status_code)
Problem
The EVENTBRIDGE payload drops the SENTIMENT_SCORE field when the transcription engine lags behind the voice stream. The DATA_ACTION endpoint runs strict schema validation, so a missing float breaks the entire JSON structure. You will get a 400 response before the request ever hits DYNAMODB. Honestly, the schema validation is brutal. It happens constantly during peak shift hours in the Pacific timezone. We prefer WEM for tracking these routing gaps anyway, since adherence drops when the flow stalls.
Code
The snippet above forces a string conversion on the missing value. The event["detail"].get("sentimentScore", "0.0") call catches the null state and replaces it with a safe default. The DATA_ACTION_ID must match your configured routing action. Make sure the OAUTH_TOKEN includes the dataactions:execute scope. I keep the payload flat because nested objects trigger extra validation layers that slow down the LAMBDA_FUNCTION execution. You won’t see the 400 error if the types align properly. It’s a small change but it keeps the pipeline moving.
Error
You’ll still see 400 errors if the DATA_ACTION expects a numeric type instead of a string. The Genesys Cloud API strictly enforces the input schema defined in the action designer. If the original configuration uses a NUMBER type, the string coercion will fail. You have to update the DATA_ACTION input mapping to accept TEXT, or cast the fallback to a float before serialization. The platform does not auto-convert types during execution. Don’t forget to check the action version history. Pretty much stalls the flow if you miss that step.
Question
Does your scheduling dashboard show a spike in missed callbacks when this validation fails? We track adherence drops during these exact routing failures. The fallback keeps the queue alive, but the historical accuracy takes a hit. We usually just log the gap and let the WEM engine recalculate overnight. The metric drift stays under 2 percent most days.
Might be worth checking the payload serialization step first.
Cause: The event drops the float field when transcription lags.
Solution: EmbeddableClientAppSDK handles the type coercion after the mapping block failed, so forcing inputs["sentimentScore"] = str(event.get("sentimentScore") or "0.0") stops the schema validator. What’s the exact retry count on your Lambda before it times out?