Studio Assembly Mediation Error
The error com.workday.esb.mediation.MediationException: unable to mediate message at step 'splitter-1'
What it means
A step in your assembly blew up while processing the message. The assembly itself deployed fine - the data flowing into that step wasn't what the step expected. Empty payload, wrong structure, or an upstream step that silently produced nothing are the usual culprits.
Troubleshooting
- Find the step name from the error (e.g. splitter-1) in the assembly and open the integration event log.
- Check what's going into that step - add a write-to-file or log step just before it in a test run.
- Look for these common causes: upstream component returned zero records, namespace mismatch in XPath, XSLT that emitted nothing.
- Re-run with a small known-good input to separate a data problem from an assembly problem.
⚡ Quick fix
Guard the failing step with a conditional route that skips when the payload is empty, or fix the input data and re-launch.
✓ Permanent fix
Add empty-payload handling and schema/namespace assertions after each transform. Wire in a try/catch mediation that writes a readable error to the integration event so the next failure tells you the cause immediately.
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