diff --git a/cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/StorageBeanConfig.java b/cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/StorageBeanConfig.java
index 78827a60..001f666e 100644
--- a/cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/StorageBeanConfig.java
+++ b/cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/StorageBeanConfig.java
@@ -107,10 +107,12 @@ public class StorageBeanConfig {
     @ConditionalOnProperty(name = "cameleer.storage.executions", havingValue = "clickhouse", matchIfMissing = true)
     public ChunkAccumulator chunkAccumulator(
             WriteBuffer<MergedExecution> executionBuffer,
-            WriteBuffer<ChunkAccumulator.ProcessorBatch> processorBatchBuffer) {
+            WriteBuffer<ChunkAccumulator.ProcessorBatch> processorBatchBuffer,
+            DiagramStore diagramStore) {
         return new ChunkAccumulator(
                 executionBuffer::offer,
                 processorBatchBuffer::offer,
+                diagramStore,
                 java.time.Duration.ofMinutes(5));
     }
 
diff --git a/cameleer3-server-core/src/main/java/com/cameleer3/server/core/ingestion/ChunkAccumulator.java b/cameleer3-server-core/src/main/java/com/cameleer3/server/core/ingestion/ChunkAccumulator.java
index 9d6ed225..bfbca40d 100644
--- a/cameleer3-server-core/src/main/java/com/cameleer3/server/core/ingestion/ChunkAccumulator.java
+++ b/cameleer3-server-core/src/main/java/com/cameleer3/server/core/ingestion/ChunkAccumulator.java
@@ -2,6 +2,7 @@ package com.cameleer3.server.core.ingestion;
 
 import com.cameleer3.common.model.ExecutionChunk;
 import com.cameleer3.common.model.FlatProcessorRecord;
+import com.cameleer3.server.core.storage.DiagramStore;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.slf4j.Logger;
@@ -29,14 +30,17 @@ public class ChunkAccumulator {
 
     private final Consumer<MergedExecution> executionSink;
     private final Consumer<ProcessorBatch> processorSink;
+    private final DiagramStore diagramStore;
     private final Duration staleThreshold;
     private final ConcurrentHashMap<String, PendingExchange> pending = new ConcurrentHashMap<>();
 
     public ChunkAccumulator(Consumer<MergedExecution> executionSink,
                             Consumer<ProcessorBatch> processorSink,
+                            DiagramStore diagramStore,
                             Duration staleThreshold) {
         this.executionSink = executionSink;
         this.processorSink = processorSink;
+        this.diagramStore = diagramStore;
         this.staleThreshold = staleThreshold;
     }
 
@@ -138,7 +142,15 @@ public class ChunkAccumulator {
 
     // ---- Conversion to MergedExecution ----
 
-    private static MergedExecution toMergedExecution(ExecutionChunk envelope) {
+    private MergedExecution toMergedExecution(ExecutionChunk envelope) {
+        String diagramHash = "";
+        try {
+            diagramHash = diagramStore
+                    .findContentHashForRoute(envelope.getRouteId(), envelope.getAgentId())
+                    .orElse("");
+        } catch (Exception e) {
+            log.debug("Could not resolve diagram hash for route={}", envelope.getRouteId());
+        }
         return new MergedExecution(
                 DEFAULT_TENANT,
                 1L,
@@ -158,7 +170,7 @@ public class ChunkAccumulator {
                 envelope.getErrorCategory(),
                 envelope.getRootCauseType(),
                 envelope.getRootCauseMessage(),
-                "",  // diagramContentHash — server-side lookup, not in chunk
+                diagramHash,
                 envelope.getEngineLevel(),
                 "",  // inputBody — on processor records now
                 "",  // outputBody