feat(api): add terminal session persistence with Prisma model and CRUD service

Adds database-backed TerminalSession model with ACTIVE/CLOSED status enum,
migration SQL, TerminalSessionService (create/findByWorkspace/close/findById),
DTO file with class-validator decorators, unit tests (12 tests), and module
registration. Workspace relation and indexed columns enable efficient session
listing and recovery.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/prisma/migrations/20260225000000_add_terminal_sessions/migration.sql

@@ -0,0 +1,23 @@
+-- CreateEnum
+CREATE TYPE "TerminalSessionStatus" AS ENUM ('ACTIVE', 'CLOSED');
+
+-- CreateTable
+CREATE TABLE "terminal_sessions" (
+    "id" UUID NOT NULL,
+    "workspace_id" UUID NOT NULL,
+    "name" TEXT NOT NULL DEFAULT 'Terminal',
+    "status" "TerminalSessionStatus" NOT NULL DEFAULT 'ACTIVE',
+    "created_at" TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "closed_at" TIMESTAMPTZ,
+
+    CONSTRAINT "terminal_sessions_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "terminal_sessions_workspace_id_idx" ON "terminal_sessions"("workspace_id");
+
+-- CreateIndex
+CREATE INDEX "terminal_sessions_workspace_id_status_idx" ON "terminal_sessions"("workspace_id", "status");
+
+-- AddForeignKey
+ALTER TABLE "terminal_sessions" ADD CONSTRAINT "terminal_sessions_workspace_id_fkey" FOREIGN KEY ("workspace_id") REFERENCES "workspaces"("id") ON DELETE CASCADE ON UPDATE CASCADE;

apps/api/prisma/schema.prisma

@@ -206,6 +206,11 @@ enum CredentialScope {
   SYSTEM
 }
 
+enum TerminalSessionStatus {
+  ACTIVE
+  CLOSED
+}
+
 // ============================================
 // MODELS
 // ============================================
@@ -297,6 +302,7 @@ model Workspace {
   federationEventSubscriptions FederationEventSubscription[]
   llmUsageLogs                 LlmUsageLog[]
   userCredentials              UserCredential[]
+  terminalSessions             TerminalSession[]
 
   @@index([ownerId])
   @@map("workspaces")
@@ -1507,3 +1513,23 @@ model LlmUsageLog {
   @@index([conversationId])
   @@map("llm_usage_logs")
 }
+
+// ============================================
+// TERMINAL MODULE
+// ============================================
+
+model TerminalSession {
+  id          String                @id @default(uuid()) @db.Uuid
+  workspaceId String                @map("workspace_id") @db.Uuid
+  name        String                @default("Terminal")
+  status      TerminalSessionStatus @default(ACTIVE)
+  createdAt   DateTime              @default(now()) @map("created_at") @db.Timestamptz
+  closedAt    DateTime?             @map("closed_at") @db.Timestamptz
+
+  // Relations
+  workspace Workspace @relation(fields: [workspaceId], references: [id], onDelete: Cascade)
+
+  @@index([workspaceId])
+  @@index([workspaceId, status])
+  @@map("terminal_sessions")
+}

apps/api/src/terminal/terminal-session.dto.ts

@@ -0,0 +1,53 @@
+/**
+ * Terminal Session DTOs
+ *
+ * Data Transfer Objects for terminal session persistence endpoints.
+ * Validated using class-validator decorators.
+ */
+
+import { IsString, IsOptional, MaxLength, IsEnum, IsUUID } from "class-validator";
+import { TerminalSessionStatus } from "@prisma/client";
+
+/**
+ * DTO for creating a new terminal session record.
+ */
+export class CreateTerminalSessionDto {
+  @IsString()
+  @IsUUID()
+  workspaceId!: string;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(128)
+  name?: string;
+}
+
+/**
+ * DTO for querying terminal sessions by workspace.
+ */
+export class FindTerminalSessionsByWorkspaceDto {
+  @IsString()
+  @IsUUID()
+  workspaceId!: string;
+}
+
+/**
+ * Response shape for a terminal session.
+ */
+export class TerminalSessionResponseDto {
+  id!: string;
+  workspaceId!: string;
+  name!: string;
+  status!: TerminalSessionStatus;
+  createdAt!: Date;
+  closedAt!: Date | null;
+}
+
+/**
+ * DTO for filtering terminal sessions by status.
+ */
+export class TerminalSessionStatusFilterDto {
+  @IsOptional()
+  @IsEnum(TerminalSessionStatus)
+  status?: TerminalSessionStatus;
+}

apps/api/src/terminal/terminal-session.service.spec.ts

@@ -0,0 +1,229 @@
+/**
+ * TerminalSessionService Tests
+ *
+ * Unit tests for database-backed terminal session CRUD:
+ * create, findByWorkspace, close, and findById.
+ * PrismaService is mocked to isolate the service logic.
+ */
+
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { NotFoundException } from "@nestjs/common";
+import { TerminalSessionStatus } from "@prisma/client";
+import type { TerminalSession } from "@prisma/client";
+import { TerminalSessionService } from "./terminal-session.service";
+
+// ==========================================
+// Helpers
+// ==========================================
+
+function makeSession(overrides: Partial<TerminalSession> = {}): TerminalSession {
+  return {
+    id: "session-uuid-1",
+    workspaceId: "workspace-uuid-1",
+    name: "Terminal",
+    status: TerminalSessionStatus.ACTIVE,
+    createdAt: new Date("2026-02-25T00:00:00Z"),
+    closedAt: null,
+    ...overrides,
+  };
+}
+
+// ==========================================
+// Mock PrismaService
+// ==========================================
+
+function makeMockPrisma() {
+  return {
+    terminalSession: {
+      create: vi.fn(),
+      findMany: vi.fn(),
+      findUnique: vi.fn(),
+      update: vi.fn(),
+    },
+  };
+}
+
+// ==========================================
+// Tests
+// ==========================================
+
+describe("TerminalSessionService", () => {
+  let service: TerminalSessionService;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  let mockPrisma: any;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockPrisma = makeMockPrisma();
+    service = new TerminalSessionService(mockPrisma);
+  });
+
+  // ==========================================
+  // create
+  // ==========================================
+  describe("create", () => {
+    it("should call prisma.terminalSession.create with workspaceId only when no name provided", async () => {
+      const session = makeSession();
+      mockPrisma.terminalSession.create.mockResolvedValueOnce(session);
+
+      const result = await service.create("workspace-uuid-1");
+
+      expect(mockPrisma.terminalSession.create).toHaveBeenCalledWith({
+        data: { workspaceId: "workspace-uuid-1" },
+      });
+      expect(result).toEqual(session);
+    });
+
+    it("should include name in create data when name is provided", async () => {
+      const session = makeSession({ name: "My Terminal" });
+      mockPrisma.terminalSession.create.mockResolvedValueOnce(session);
+
+      const result = await service.create("workspace-uuid-1", "My Terminal");
+
+      expect(mockPrisma.terminalSession.create).toHaveBeenCalledWith({
+        data: { workspaceId: "workspace-uuid-1", name: "My Terminal" },
+      });
+      expect(result).toEqual(session);
+    });
+
+    it("should return the created session", async () => {
+      const session = makeSession();
+      mockPrisma.terminalSession.create.mockResolvedValueOnce(session);
+
+      const result = await service.create("workspace-uuid-1");
+
+      expect(result.id).toBe("session-uuid-1");
+      expect(result.status).toBe(TerminalSessionStatus.ACTIVE);
+    });
+  });
+
+  // ==========================================
+  // findByWorkspace
+  // ==========================================
+  describe("findByWorkspace", () => {
+    it("should query for ACTIVE sessions in the given workspace, ordered by createdAt desc", async () => {
+      const sessions = [makeSession(), makeSession({ id: "session-uuid-2" })];
+      mockPrisma.terminalSession.findMany.mockResolvedValueOnce(sessions);
+
+      const result = await service.findByWorkspace("workspace-uuid-1");
+
+      expect(mockPrisma.terminalSession.findMany).toHaveBeenCalledWith({
+        where: {
+          workspaceId: "workspace-uuid-1",
+          status: TerminalSessionStatus.ACTIVE,
+        },
+        orderBy: { createdAt: "desc" },
+      });
+      expect(result).toHaveLength(2);
+    });
+
+    it("should return an empty array when no active sessions exist", async () => {
+      mockPrisma.terminalSession.findMany.mockResolvedValueOnce([]);
+
+      const result = await service.findByWorkspace("workspace-uuid-empty");
+
+      expect(result).toEqual([]);
+    });
+
+    it("should not include CLOSED sessions", async () => {
+      // The where clause enforces ACTIVE status — verify it is present
+      mockPrisma.terminalSession.findMany.mockResolvedValueOnce([]);
+
+      await service.findByWorkspace("workspace-uuid-1");
+
+      const callArgs = mockPrisma.terminalSession.findMany.mock.calls[0][0] as {
+        where: { status: TerminalSessionStatus };
+      };
+      expect(callArgs.where.status).toBe(TerminalSessionStatus.ACTIVE);
+    });
+  });
+
+  // ==========================================
+  // close
+  // ==========================================
+  describe("close", () => {
+    it("should set status to CLOSED and set closedAt when session exists", async () => {
+      const existingSession = makeSession();
+      const closedSession = makeSession({
+        status: TerminalSessionStatus.CLOSED,
+        closedAt: new Date("2026-02-25T01:00:00Z"),
+      });
+
+      mockPrisma.terminalSession.findUnique.mockResolvedValueOnce(existingSession);
+      mockPrisma.terminalSession.update.mockResolvedValueOnce(closedSession);
+
+      const result = await service.close("session-uuid-1");
+
+      expect(mockPrisma.terminalSession.findUnique).toHaveBeenCalledWith({
+        where: { id: "session-uuid-1" },
+      });
+      expect(mockPrisma.terminalSession.update).toHaveBeenCalledWith({
+        where: { id: "session-uuid-1" },
+        data: {
+          status: TerminalSessionStatus.CLOSED,
+          closedAt: expect.any(Date),
+        },
+      });
+      expect(result.status).toBe(TerminalSessionStatus.CLOSED);
+    });
+
+    it("should throw NotFoundException when session does not exist", async () => {
+      mockPrisma.terminalSession.findUnique.mockResolvedValueOnce(null);
+
+      await expect(service.close("nonexistent-id")).rejects.toThrow(NotFoundException);
+      expect(mockPrisma.terminalSession.update).not.toHaveBeenCalled();
+    });
+
+    it("should include a non-null closedAt timestamp on close", async () => {
+      const existingSession = makeSession();
+      const closedSession = makeSession({
+        status: TerminalSessionStatus.CLOSED,
+        closedAt: new Date(),
+      });
+
+      mockPrisma.terminalSession.findUnique.mockResolvedValueOnce(existingSession);
+      mockPrisma.terminalSession.update.mockResolvedValueOnce(closedSession);
+
+      const result = await service.close("session-uuid-1");
+
+      expect(result.closedAt).not.toBeNull();
+    });
+  });
+
+  // ==========================================
+  // findById
+  // ==========================================
+  describe("findById", () => {
+    it("should return the session when it exists", async () => {
+      const session = makeSession();
+      mockPrisma.terminalSession.findUnique.mockResolvedValueOnce(session);
+
+      const result = await service.findById("session-uuid-1");
+
+      expect(mockPrisma.terminalSession.findUnique).toHaveBeenCalledWith({
+        where: { id: "session-uuid-1" },
+      });
+      expect(result).toEqual(session);
+    });
+
+    it("should return null when session does not exist", async () => {
+      mockPrisma.terminalSession.findUnique.mockResolvedValueOnce(null);
+
+      const result = await service.findById("no-such-id");
+
+      expect(result).toBeNull();
+    });
+
+    it("should find CLOSED sessions as well as ACTIVE ones", async () => {
+      const closedSession = makeSession({
+        status: TerminalSessionStatus.CLOSED,
+        closedAt: new Date(),
+      });
+      mockPrisma.terminalSession.findUnique.mockResolvedValueOnce(closedSession);
+
+      const result = await service.findById("session-uuid-1");
+
+      expect(result?.status).toBe(TerminalSessionStatus.CLOSED);
+    });
+  });
+});

apps/api/src/terminal/terminal-session.service.ts

@@ -0,0 +1,96 @@
+/**
+ * TerminalSessionService
+ *
+ * Manages database persistence for terminal sessions.
+ * Provides CRUD operations on the TerminalSession model,
+ * enabling session tracking, recovery, and workspace-level listing.
+ *
+ * Session lifecycle:
+ * - create: record a new terminal session with ACTIVE status
+ * - findByWorkspace: return all ACTIVE sessions for a workspace
+ * - close: mark a session as CLOSED, set closedAt timestamp
+ * - findById: retrieve a single session by ID
+ */
+
+import { Injectable, NotFoundException, Logger } from "@nestjs/common";
+import { TerminalSessionStatus } from "@prisma/client";
+import type { TerminalSession } from "@prisma/client";
+import { PrismaService } from "../prisma/prisma.service";
+
+@Injectable()
+export class TerminalSessionService {
+  private readonly logger = new Logger(TerminalSessionService.name);
+
+  constructor(private readonly prisma: PrismaService) {}
+
+  /**
+   * Create a new terminal session record in the database.
+   *
+   * @param workspaceId - The workspace this session belongs to
+   * @param name - Optional display name for the session (defaults to "Terminal")
+   * @returns The created TerminalSession record
+   */
+  async create(workspaceId: string, name?: string): Promise<TerminalSession> {
+    this.logger.log(
+      `Creating terminal session for workspace ${workspaceId}${name !== undefined ? ` (name: ${name})` : ""}`
+    );
+
+    const data: { workspaceId: string; name?: string } = { workspaceId };
+    if (name !== undefined) {
+      data.name = name;
+    }
+
+    return this.prisma.terminalSession.create({ data });
+  }
+
+  /**
+   * Find all ACTIVE terminal sessions for a workspace.
+   *
+   * @param workspaceId - The workspace to query
+   * @returns Array of active TerminalSession records, ordered by creation time (newest first)
+   */
+  async findByWorkspace(workspaceId: string): Promise<TerminalSession[]> {
+    return this.prisma.terminalSession.findMany({
+      where: {
+        workspaceId,
+        status: TerminalSessionStatus.ACTIVE,
+      },
+      orderBy: { createdAt: "desc" },
+    });
+  }
+
+  /**
+   * Close a terminal session by setting its status to CLOSED and recording closedAt.
+   *
+   * @param id - The session ID to close
+   * @returns The updated TerminalSession record
+   * @throws NotFoundException if the session does not exist
+   */
+  async close(id: string): Promise<TerminalSession> {
+    const existing = await this.prisma.terminalSession.findUnique({ where: { id } });
+
+    if (!existing) {
+      throw new NotFoundException(`Terminal session ${id} not found`);
+    }
+
+    this.logger.log(`Closing terminal session ${id} (workspace: ${existing.workspaceId})`);
+
+    return this.prisma.terminalSession.update({
+      where: { id },
+      data: {
+        status: TerminalSessionStatus.CLOSED,
+        closedAt: new Date(),
+      },
+    });
+  }
+
+  /**
+   * Find a terminal session by ID.
+   *
+   * @param id - The session ID to retrieve
+   * @returns The TerminalSession record, or null if not found
+   */
+  async findById(id: string): Promise<TerminalSession | null> {
+    return this.prisma.terminalSession.findUnique({ where: { id } });
+  }
+}

apps/api/src/terminal/terminal.module.ts

@@ -5,10 +5,11 @@
  *
  * Imports:
  * - AuthModule for WebSocket authentication (verifySession)
- * - PrismaModule for workspace membership queries
+ * - PrismaModule for workspace membership queries and session persistence
  *
  * Providers:
- * - TerminalService: manages PTY session lifecycle
+ * - TerminalService: manages PTY session lifecycle (in-memory)
+ * - TerminalSessionService: persists session records to the database
  * - TerminalGateway: WebSocket gateway on /terminal namespace
  *
  * The module does not export providers; terminal sessions are
@@ -18,11 +19,13 @@
 import { Module } from "@nestjs/common";
 import { TerminalGateway } from "./terminal.gateway";
 import { TerminalService } from "./terminal.service";
+import { TerminalSessionService } from "./terminal-session.service";
 import { AuthModule } from "../auth/auth.module";
 import { PrismaModule } from "../prisma/prisma.module";
 
 @Module({
   imports: [AuthModule, PrismaModule],
-  providers: [TerminalGateway, TerminalService],
+  providers: [TerminalGateway, TerminalService, TerminalSessionService],
+  exports: [TerminalSessionService],
 })
 export class TerminalModule {}

apps/web/src/hooks/useChat.ts

@@ -294,7 +294,7 @@ export function useChat(options: UseChatOptions = {}): UseChatReturn {
           const response = await sendChatMessage(request);
 
           const assistantMessage: Message = {
-            id: `assistant-${Date.now().toString()}`,
+            id: `assistant-${Date.now().toString()}-${Math.random().toString(36).slice(2, 8)}`,
             role: "assistant",
             content: response.message.content,
             createdAt: new Date().toISOString(),
@@ -328,7 +328,7 @@ export function useChat(options: UseChatOptions = {}): UseChatReturn {
           });
 
           const errorMessage: Message = {
-            id: `error-${String(Date.now())}`,
+            id: `error-${String(Date.now())}-${Math.random().toString(36).slice(2, 8)}`,
             role: "assistant",
             content: "Something went wrong. Please try again.",
             createdAt: new Date().toISOString(),