diff --git a/packages/api/src/__tests__/assistant-tools-role-delete-success.test.ts b/packages/api/src/__tests__/assistant-tools-role-delete-success.test.ts
new file mode 100644
index 0000000..2b4c574
--- /dev/null
+++ b/packages/api/src/__tests__/assistant-tools-role-delete-success.test.ts
@@ -0,0 +1,61 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { PermissionKey, SystemRole } from "@capakraken/shared";
+
+import {
+  createRoleRecord,
+  createToolContext,
+  executeTool,
+  resetRoleMutationMocks,
+} from "./assistant-tools-role-mutation-test-helpers.js";
+
+describe("assistant role delete tool - success", () => {
+  beforeEach(() => {
+    resetRoleMutationMocks();
+  });
+
+  it("routes deletion through the backing router and returns the expected assistant payload", async () => {
+    const roleRecord = createRoleRecord();
+    const db = {
+      role: {
+        findUnique: vi.fn()
+          .mockResolvedValueOnce(roleRecord)
+          .mockResolvedValueOnce(roleRecord)
+          .mockResolvedValueOnce({
+            id: "role_1",
+            name: "Senior CG Artist",
+            description: "Pipeline lead",
+            color: "#222222",
+            isActive: true,
+            _count: { resourceRoles: 0 },
+          }),
+        delete: vi.fn().mockResolvedValue({ id: "role_1" }),
+      },
+      auditLog: {
+        create: vi.fn().mockResolvedValue({ id: "audit_1" }),
+      },
+      demandRequirement: {
+        groupBy: vi.fn().mockResolvedValue([]),
+      },
+      assignment: {
+        groupBy: vi.fn().mockResolvedValue([]),
+      },
+    };
+    const ctx = createToolContext(db, {
+      userRole: SystemRole.ADMIN,
+      permissions: [PermissionKey.MANAGE_ROLES],
+    });
+
+    const deleteRoleResult = await executeTool(
+      "delete_role",
+      JSON.stringify({ id: "role_1" }),
+      ctx,
+    );
+
+    expect(JSON.parse(deleteRoleResult.content)).toEqual(expect.objectContaining({
+      success: true,
+      message: "Deleted role: Senior CG Artist",
+    }));
+    expect(db.role.delete).toHaveBeenCalledWith({ where: { id: "role_1" } });
+    expect(db.auditLog.create).toHaveBeenCalled();
+  });
+});
diff --git a/packages/api/src/__tests__/assistant-tools-role-mutation-test-helpers.ts b/packages/api/src/__tests__/assistant-tools-role-mutation-test-helpers.ts
new file mode 100644
index 0000000..474b8bb
--- /dev/null
+++ b/packages/api/src/__tests__/assistant-tools-role-mutation-test-helpers.ts
@@ -0,0 +1,37 @@
+import { vi } from "vitest";
+
+vi.mock("@capakraken/application", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@capakraken/application")>();
+  return {
+    ...actual,
+    countPlanningEntries: vi.fn().mockResolvedValue({ countsByRoleId: new Map() }),
+    getDashboardBudgetForecast: vi.fn().mockResolvedValue([]),
+    getDashboardPeakTimes: vi.fn().mockResolvedValue([]),
+    listAssignmentBookings: vi.fn().mockResolvedValue([]),
+  };
+});
+
+import { countPlanningEntries } from "@capakraken/application";
+import { executeTool as executeAssistantTool } from "../router/assistant-tools.js";
+
+export { createToolContext } from "./assistant-tools-master-data-mutation-test-helpers.js";
+
+export function resetRoleMutationMocks() {
+  vi.clearAllMocks();
+  vi.mocked(countPlanningEntries).mockResolvedValue({ countsByRoleId: new Map() });
+}
+
+export function createRoleRecord(overrides: Record<string, unknown> = {}) {
+  return {
+    id: "role_1",
+    name: "Senior CG Artist",
+    description: "Pipeline lead",
+    color: "#222222",
+    isActive: true,
+    _count: { resourceRoles: 0 },
+    resourceRoles: [],
+    ...overrides,
+  };
+}
+
+export const executeTool = executeAssistantTool;
diff --git a/packages/api/src/__tests__/assistant-tools-role-mutations-create-update-success.test.ts b/packages/api/src/__tests__/assistant-tools-role-mutations-create-update-success.test.ts
new file mode 100644
index 0000000..29424db
--- /dev/null
+++ b/packages/api/src/__tests__/assistant-tools-role-mutations-create-update-success.test.ts
@@ -0,0 +1,160 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { PermissionKey, SystemRole } from "@capakraken/shared";
+
+import {
+  createRoleRecord,
+  createToolContext,
+  executeTool,
+  resetRoleMutationMocks,
+} from "./assistant-tools-role-mutation-test-helpers.js";
+
+describe("assistant role create and update tools - success", () => {
+  beforeEach(() => {
+    resetRoleMutationMocks();
+  });
+
+  it("routes create and update role mutations through their backing router", async () => {
+    const db = {
+      role: {
+        findUnique: vi.fn().mockImplementation(async (args?: { where?: { name?: string; id?: string } }) => {
+          if (args?.where?.name === "Pipeline TD") return null;
+          if (args?.where?.name === "Pipeline Lead") return null;
+          if (args?.where?.id === "role_pipeline") {
+            return {
+              id: "role_pipeline",
+              name: "Pipeline TD",
+              description: "Pipeline craft",
+              color: "#123456",
+              isActive: true,
+              _count: { resourceRoles: 0 },
+              resourceRoles: [],
+            };
+          }
+          return null;
+        }),
+        create: vi.fn().mockResolvedValue({
+          id: "role_pipeline",
+          name: "Pipeline TD",
+          description: "Pipeline craft",
+          color: "#123456",
+          isActive: true,
+          _count: { resourceRoles: 0 },
+        }),
+        update: vi.fn().mockResolvedValue({
+          id: "role_pipeline",
+          name: "Pipeline Lead",
+          description: "Lead pipeline craft",
+          color: "#654321",
+          isActive: false,
+          _count: { resourceRoles: 0 },
+        }),
+      },
+      auditLog: {
+        create: vi.fn().mockResolvedValue({ id: "audit_1" }),
+      },
+    };
+    const ctx = createToolContext(db, {
+      userRole: SystemRole.ADMIN,
+      permissions: [PermissionKey.MANAGE_ROLES],
+    });
+
+    const createRoleResult = await executeTool(
+      "create_role",
+      JSON.stringify({ name: "Pipeline TD", description: "Pipeline craft", color: "#123456" }),
+      ctx,
+    );
+    const updateRoleResult = await executeTool(
+      "update_role",
+      JSON.stringify({
+        id: "role_pipeline",
+        name: "Pipeline Lead",
+        description: "Lead pipeline craft",
+        color: "#654321",
+        isActive: false,
+      }),
+      ctx,
+    );
+
+    expect(JSON.parse(createRoleResult.content)).toEqual(expect.objectContaining({
+      success: true,
+      roleId: "role_pipeline",
+      message: "Created role: Pipeline TD",
+    }));
+    expect(JSON.parse(updateRoleResult.content)).toEqual(expect.objectContaining({
+      success: true,
+      roleId: "role_pipeline",
+      message: "Updated role: Pipeline Lead",
+    }));
+
+    expect(db.role.create).toHaveBeenCalled();
+    expect(db.role.update).toHaveBeenCalled();
+    expect(db.auditLog.create).toHaveBeenCalled();
+  });
+
+  it("returns the expected assistant payloads for create and update role mutations", async () => {
+    const roleRecord = createRoleRecord();
+    const db = {
+      role: {
+        findUnique: vi.fn()
+          .mockResolvedValueOnce(null)
+          .mockResolvedValueOnce({ id: "role_1", name: "CG Artist", description: null, color: "#111111", isActive: true })
+          .mockResolvedValueOnce(null)
+          .mockResolvedValueOnce(roleRecord),
+        create: vi.fn().mockResolvedValue({
+          id: "role_1",
+          name: "CG Artist",
+          description: null,
+          color: "#111111",
+          isActive: true,
+          _count: { resourceRoles: 0 },
+        }),
+        update: vi.fn().mockResolvedValue({
+          id: "role_1",
+          name: "Senior CG Artist",
+          description: "Pipeline lead",
+          color: "#222222",
+          isActive: true,
+          _count: { resourceRoles: 0 },
+        }),
+      },
+      auditLog: {
+        create: vi.fn().mockResolvedValue({ id: "audit_1" }),
+      },
+      demandRequirement: {
+        groupBy: vi.fn().mockResolvedValue([]),
+      },
+      assignment: {
+        groupBy: vi.fn().mockResolvedValue([]),
+      },
+    };
+    const ctx = createToolContext(db, {
+      userRole: SystemRole.ADMIN,
+      permissions: [PermissionKey.MANAGE_ROLES],
+    });
+
+    const createRoleResult = await executeTool(
+      "create_role",
+      JSON.stringify({ name: "CG Artist", color: "#111111" }),
+      ctx,
+    );
+    const updateRoleResult = await executeTool(
+      "update_role",
+      JSON.stringify({
+        id: "role_1",
+        name: "Senior CG Artist",
+        description: "Pipeline lead",
+        color: "#222222",
+      }),
+      ctx,
+    );
+
+    expect(JSON.parse(createRoleResult.content)).toEqual(expect.objectContaining({
+      success: true,
+      message: "Created role: CG Artist",
+    }));
+    expect(JSON.parse(updateRoleResult.content)).toEqual(expect.objectContaining({
+      success: true,
+      message: "Updated role: Senior CG Artist",
+    }));
+  });
+});
diff --git a/packages/api/src/__tests__/assistant-tools-role-mutations-errors.test.ts b/packages/api/src/__tests__/assistant-tools-role-mutations-errors.test.ts
new file mode 100644
index 0000000..80f2399
--- /dev/null
+++ b/packages/api/src/__tests__/assistant-tools-role-mutations-errors.test.ts
@@ -0,0 +1,96 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { PermissionKey, SystemRole } from "@capakraken/shared";
+
+import {
+  createRoleRecord,
+  createToolContext,
+  executeTool,
+  resetRoleMutationMocks,
+} from "./assistant-tools-role-mutation-test-helpers.js";
+
+describe("assistant role mutation tools", () => {
+  beforeEach(() => {
+    resetRoleMutationMocks();
+  });
+
+  it("returns a stable error when creating a duplicate role", async () => {
+    const ctx = createToolContext(
+      {
+        role: {
+          findUnique: vi.fn().mockResolvedValue({ id: "role_existing", name: "CG Artist" }),
+        },
+      },
+      {
+        userRole: SystemRole.MANAGER,
+        permissions: [PermissionKey.MANAGE_ROLES],
+      },
+    );
+
+    const result = await executeTool(
+      "create_role",
+      JSON.stringify({ name: "CG Artist" }),
+      ctx,
+    );
+
+    expect(JSON.parse(result.content)).toEqual(expect.objectContaining({
+      error: "A role with this name already exists.",
+    }));
+  });
+
+  it("returns a stable error when updating a missing role", async () => {
+    const ctx = createToolContext(
+      {
+        role: {
+          findUnique: vi.fn().mockResolvedValue(null),
+        },
+      },
+      {
+        userRole: SystemRole.MANAGER,
+        permissions: [PermissionKey.MANAGE_ROLES],
+      },
+    );
+
+    const result = await executeTool(
+      "update_role",
+      JSON.stringify({ id: "role_missing", name: "Senior CG Artist" }),
+      ctx,
+    );
+
+    expect(JSON.parse(result.content)).toEqual(expect.objectContaining({
+      error: "Role not found with the given criteria.",
+    }));
+  });
+
+  it("returns a stable error when deleting an assigned role", async () => {
+    const roleRecord = createRoleRecord({ _count: { resourceRoles: 1 } });
+    const ctx = createToolContext(
+      {
+        role: {
+          findUnique: vi.fn()
+            .mockResolvedValueOnce(roleRecord)
+            .mockResolvedValueOnce(roleRecord),
+        },
+        demandRequirement: {
+          groupBy: vi.fn().mockResolvedValue([]),
+        },
+        assignment: {
+          groupBy: vi.fn().mockResolvedValue([]),
+        },
+      },
+      {
+        userRole: SystemRole.MANAGER,
+        permissions: [PermissionKey.MANAGE_ROLES],
+      },
+    );
+
+    const result = await executeTool(
+      "delete_role",
+      JSON.stringify({ id: "role_1" }),
+      ctx,
+    );
+
+    expect(JSON.parse(result.content)).toEqual(expect.objectContaining({
+      error: "Role cannot be deleted while it is still assigned. Deactivate it instead.",
+    }));
+  });
+});