diff --git a/docs/docs.go b/docs/docs.go
index a69b4769..46a64e53 100644
--- a/docs/docs.go
+++ b/docs/docs.go
@@ -41147,6 +41147,12 @@ const docTemplate = `{
                 "due_date": {
                     "type": "string"
                 },
+                "execution_stream_uuid": {
+                    "description": "Computed field (not persisted)",
+                    "type": "string",
+                    "format": "uuid",
+                    "readOnly": true
+                },
                 "failed-at": {
                     "type": "string"
                 },
diff --git a/docs/swagger.json b/docs/swagger.json
index 9f937e1c..6fa337f6 100644
--- a/docs/swagger.json
+++ b/docs/swagger.json
@@ -41141,6 +41141,12 @@
                 "due_date": {
                     "type": "string"
                 },
+                "execution_stream_uuid": {
+                    "description": "Computed field (not persisted)",
+                    "type": "string",
+                    "format": "uuid",
+                    "readOnly": true
+                },
                 "failed-at": {
                     "type": "string"
                 },
diff --git a/docs/swagger.yaml b/docs/swagger.yaml
index 081d2fac..b03b756d 100644
--- a/docs/swagger.yaml
+++ b/docs/swagger.yaml
@@ -9307,6 +9307,11 @@ definitions:
         $ref: '#/definitions/gorm.DeletedAt'
       due_date:
         type: string
+      execution_stream_uuid:
+        description: Computed field (not persisted)
+        format: uuid
+        readOnly: true
+        type: string
       failed-at:
         type: string
       failure_reason:
diff --git a/internal/service/relational/workflows/stream_uuid.go b/internal/service/relational/workflows/stream_uuid.go
new file mode 100644
index 00000000..95d25dbf
--- /dev/null
+++ b/internal/service/relational/workflows/stream_uuid.go
@@ -0,0 +1,24 @@
+package workflows
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/google/uuid"
+)
+
+// ComputeExecutionStreamUUID derives the deterministic evidence stream UUID for a workflow
+// execution. The same seed algorithm is used by EvidenceIntegration so both sides always
+// agree on the UUID without a database round-trip.
+func ComputeExecutionStreamUUID(definitionID, instanceID, executionID uuid.UUID) (uuid.UUID, error) {
+	seed := fmt.Sprintf("execution:%s:%s:%s:%s",
+		definitionID.String(),
+		instanceID.String(),
+		executionID.String(),
+		"v1",
+	)
+	hash := sha256.Sum256([]byte(seed))
+	h := hex.EncodeToString(hash[:16])
+	return uuid.Parse(h[:8] + "-" + h[8:12] + "-" + h[12:16] + "-" + h[16:20] + "-" + h[20:32])
+}
diff --git a/internal/service/relational/workflows/workflow_execution.go b/internal/service/relational/workflows/workflow_execution.go
index fda6a78f..e5078002 100644
--- a/internal/service/relational/workflows/workflow_execution.go
+++ b/internal/service/relational/workflows/workflow_execution.go
@@ -41,6 +41,9 @@ type WorkflowExecution struct {
 	// Relationships
 	WorkflowInstance *WorkflowInstance `gorm:"foreignKey:WorkflowInstanceID" json:"workflow_instance,omitempty"`
 	StepExecutions   []StepExecution   `gorm:"foreignKey:WorkflowExecutionID;constraint:OnDelete:CASCADE" json:"step_executions,omitempty"`
+
+	// Computed field (not persisted)
+	ExecutionStreamUUID *uuid.UUID `gorm:"-" json:"execution_stream_uuid,omitempty" format:"uuid" readonly:"true"`
 }
 
 // TableName specifies the table name for WorkflowExecution
diff --git a/internal/service/relational/workflows/workflow_execution_service.go b/internal/service/relational/workflows/workflow_execution_service.go
index 5cd2a3dc..e166da1e 100644
--- a/internal/service/relational/workflows/workflow_execution_service.go
+++ b/internal/service/relational/workflows/workflow_execution_service.go
@@ -64,6 +64,18 @@ func (s *WorkflowExecutionService) GetByID(id *uuid.UUID) (*WorkflowExecution, e
 	if err != nil {
 		return nil, err
 	}
+	if execution.WorkflowInstance != nil && execution.WorkflowInstance.WorkflowDefinition != nil &&
+		execution.WorkflowInstance.WorkflowDefinition.ID != nil && execution.WorkflowInstanceID != nil && execution.ID != nil {
+		streamUUID, err := ComputeExecutionStreamUUID(
+			*execution.WorkflowInstance.WorkflowDefinition.ID,
+			*execution.WorkflowInstanceID,
+			*execution.ID,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("failed to compute execution stream UUID: %w", err)
+		}
+		execution.ExecutionStreamUUID = &streamUUID
+	}
 	return &execution, nil
 }
 
diff --git a/internal/service/relational/workflows/workflow_execution_service_test.go b/internal/service/relational/workflows/workflow_execution_service_test.go
index 8f911dee..05f96067 100644
--- a/internal/service/relational/workflows/workflow_execution_service_test.go
+++ b/internal/service/relational/workflows/workflow_execution_service_test.go
@@ -97,6 +97,39 @@ func TestWorkflowExecutionService_GetByID(t *testing.T) {
 	assert.Contains(t, err.Error(), "not found")
 }
 
+// TestWorkflowExecutionService_GetByID_PopulatesExecutionStreamUUID tests that GetByID computes
+// and populates ExecutionStreamUUID so callers can link to the evidence stream without extra queries.
+// BCH-1155: terminal evidence is created in a stream but there was no navigable link to it.
+func TestWorkflowExecutionService_GetByID_PopulatesExecutionStreamUUID(t *testing.T) {
+	db := setupTestDB(t)
+	service := NewWorkflowExecutionService(db)
+
+	workflowDef := createTestWorkflowDefinition()
+	require.NoError(t, db.Create(workflowDef).Error)
+
+	instance := createTestWorkflowInstance(workflowDef.ID)
+	require.NoError(t, db.Create(instance).Error)
+
+	execution := createTestWorkflowExecution(instance.ID)
+	require.NoError(t, db.Create(execution).Error)
+
+	retrieved, err := service.GetByID(execution.ID)
+	require.NoError(t, err)
+
+	// ExecutionStreamUUID must equal the value produced by the canonical algorithm
+	// for the same definition/instance/execution IDs.
+	expectedUUID, err := ComputeExecutionStreamUUID(*workflowDef.ID, *instance.ID, *execution.ID)
+	require.NoError(t, err)
+	require.NotNil(t, retrieved.ExecutionStreamUUID)
+	assert.Equal(t, expectedUUID, *retrieved.ExecutionStreamUUID)
+
+	// Calling again must produce the same UUID (determinism check).
+	retrieved2, err := service.GetByID(execution.ID)
+	require.NoError(t, err)
+	require.NotNil(t, retrieved2.ExecutionStreamUUID)
+	assert.Equal(t, expectedUUID, *retrieved2.ExecutionStreamUUID)
+}
+
 // TestWorkflowExecutionService_GetByWorkflowInstanceID tests the GetByWorkflowInstanceID method
 func TestWorkflowExecutionService_GetByWorkflowInstanceID(t *testing.T) {
 	db := setupTestDB(t)