diff --git a/client/src/composables/useInvocationMessageStepData.test.ts b/client/src/composables/useInvocationMessageStepData.test.ts
new file mode 100644
index 000000000000..a0375264a138
--- /dev/null
+++ b/client/src/composables/useInvocationMessageStepData.test.ts
@@ -0,0 +1,37 @@
+import { describe, expect, it } from "vitest";
+
+import { generateStepLabel } from "./useInvocationMessageStepData";
+
+describe("generateStepLabel", () => {
+    it("returns basic step label when no additional info available", () => {
+        const step = { type: "tool" };
+        expect(generateStepLabel(0, step)).toBe("Step 1");
+        expect(generateStepLabel(2, step)).toBe("Step 3");
+    });
+
+    it("includes step label when available", () => {
+        const step = { type: "tool", label: "My Step" };
+        expect(generateStepLabel(0, step)).toBe("1:My Step");
+        expect(generateStepLabel(4, step)).toBe("5:My Step");
+    });
+
+    it("extracts last segment from tool_id for tool steps", () => {
+        const step = { type: "tool", tool_id: "toolshed.g2.bx.psu.edu/repos/owner/cat1" };
+        expect(generateStepLabel(0, step)).toBe("1:cat1");
+    });
+
+    it("uses full tool_id when no slash present", () => {
+        const step = { type: "tool", tool_id: "cat1" };
+        expect(generateStepLabel(0, step)).toBe("1:cat1");
+    });
+
+    it("labels subworkflow steps appropriately", () => {
+        const step = { type: "subworkflow" };
+        expect(generateStepLabel(1, step)).toBe("2:subworkflow");
+    });
+
+    it("prefers label over tool_id", () => {
+        const step = { type: "tool", label: "Custom Name", tool_id: "cat1" };
+        expect(generateStepLabel(0, step)).toBe("1:Custom Name");
+    });
+});
diff --git a/client/src/composables/useInvocationMessageStepData.ts b/client/src/composables/useInvocationMessageStepData.ts
index b613c7332e6d..4e151cc985ee 100644
--- a/client/src/composables/useInvocationMessageStepData.ts
+++ b/client/src/composables/useInvocationMessageStepData.ts
@@ -33,7 +33,7 @@ interface WorkflowStep {
 /**
  * Generate a descriptive label for a workflow step
  */
-function generateStepLabel(orderIndex: number, workflowStep: WorkflowStep): string {
+export function generateStepLabel(orderIndex: number, workflowStep: WorkflowStep): string {
     let label = `Step ${orderIndex + 1}`;
     if (workflowStep) {
         // Try to get label from the workflow step