diff --git a/src/services/session-manager.ts b/src/services/session-manager.ts
new file mode 100644
index 0000000..027ce7c
--- /dev/null
+++ b/src/services/session-manager.ts
@@ -0,0 +1,92 @@
+import { Store, type SessionInfo } from "../state/store.js";
+import { basename } from "path";
+
+export class SessionManager {
+  constructor(private store: Store) {}
+
+  get activeSession(): string | null {
+    return this.store.data.activeSession;
+  }
+
+  get activeSessionInfo(): SessionInfo | null {
+    const name = this.store.data.activeSession;
+    if (!name) return null;
+    return this.store.data.sessions[name] ?? null;
+  }
+
+  getAllSessions(): Record<string, SessionInfo> {
+    return this.store.data.sessions;
+  }
+
+  resolveProjectPath(nameOrPath: string): { name: string; path: string } | null {
+    const bookmarked = this.store.data.projects[nameOrPath];
+    if (bookmarked) {
+      return { name: nameOrPath, path: bookmarked };
+    }
+    const name = this.generateName(basename(nameOrPath));
+    return { name, path: nameOrPath };
+  }
+
+  private generateName(base: string): string {
+    if (!this.store.data.sessions[base]) return base;
+    let i = 2;
+    while (this.store.data.sessions[`${base}-${i}`]) i++;
+    return `${base}-${i}`;
+  }
+
+  createSession(name: string, cwd: string, sessionId: string): void {
+    this.store.data.sessions[name] = { sessionId, cwd, status: "idle" };
+    this.store.data.activeSession = name;
+    this.store.save();
+  }
+
+  stopSession(name: string): boolean {
+    if (!this.store.data.sessions[name]) return false;
+    delete this.store.data.sessions[name];
+    if (this.store.data.activeSession === name) {
+      const remaining = Object.keys(this.store.data.sessions);
+      this.store.data.activeSession = remaining.length > 0 ? remaining[0] : null;
+    }
+    this.store.save();
+    return true;
+  }
+
+  stopAll(): number {
+    const count = Object.keys(this.store.data.sessions).length;
+    this.store.data.sessions = {};
+    this.store.data.activeSession = null;
+    this.store.save();
+    return count;
+  }
+
+  switchSession(name: string): boolean {
+    if (!this.store.data.sessions[name]) return false;
+    this.store.data.activeSession = name;
+    this.store.save();
+    return true;
+  }
+
+  setStatus(name: string, status: "idle" | "busy"): void {
+    const session = this.store.data.sessions[name];
+    if (session) {
+      session.status = status;
+      this.store.save();
+    }
+  }
+
+  saveProject(name: string, path: string): void {
+    this.store.data.projects[name] = path;
+    this.store.save();
+  }
+
+  removeProject(name: string): boolean {
+    if (!this.store.data.projects[name]) return false;
+    delete this.store.data.projects[name];
+    this.store.save();
+    return true;
+  }
+
+  getProjects(): Record<string, string> {
+    return this.store.data.projects;
+  }
+}