refactor(api): modularize assistant router workflow

packages/api/src/__tests__/assistant-tool-results.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+import { readToolError, readToolSuccessMessage } from "../router/assistant-tool-results.js";
+
+describe("assistant tool results", () => {
+  it("reads structured tool errors from result data or JSON content", () => {
+    expect(readToolError({
+      content: "",
+      data: { error: "Forbidden" },
+    })).toBe("Forbidden");
+
+    expect(readToolError({
+      content: JSON.stringify({ error: "Validation failed" }),
+    })).toBe("Validation failed");
+
+    expect(readToolError({
+      content: "plain text",
+      data: { ok: true },
+    })).toBeNull();
+  });
+
+  it("prefers structured success messages and falls back to plain content", () => {
+    expect(readToolSuccessMessage({
+      content: "",
+      data: { message: "Created project Apollo" },
+    })).toBe("Created project Apollo");
+
+    expect(readToolSuccessMessage({
+      content: JSON.stringify({ description: "Updated allocation" }),
+    })).toBe("Updated allocation");
+
+    expect(readToolSuccessMessage({
+      content: "Fallback tool response",
+    })).toBe("Fallback tool response");
+  });
+});