feat: multi-session management (browse all + bind N sessions per notebook)

User can now see EVERY session on the OpenCode Serve side (not just
the per-notebook mapping) and bind multiple sessions to a single
notebook. One of the bound sessions is the "active" one (the one
the next /edit uses); the others are historical. The user can
switch, create, or delete via the new session selector UI in the
inline prompt.

Backend
-------
- SessionManager rewritten for 1-notebook-N-sessions: keeps both an
   map and a  map. New methods: create_new,
  bind_existing, set_active, unbind, unbind_active, delete_session,
  list_sessions_for_notebook. Existing get_or_create / peek /
  invalidate / list_sessions / release semantics preserved
  (release now deletes ALL bound sessions, not just the active).
- New route GET /opencode-bridge/sessions/all — list ALL OpenCode
  sessions via /session.
- New route GET /opencode-bridge/sessions/notebook?notebook=... —
  bound sessions for one notebook, enriched with title/createdAt
  from the global list.
- POST .../sessions/notebook — create a new session, bind, set
  active.
- PUT  .../sessions/notebook — bind an existing sessionId, set
  active (no OpenCode round-trip).
- DELETE .../sessions/notebook — delete the session on OpenCode
  AND remove its binding.
- New route GET/PUT/DELETE /opencode-bridge/sessions/active —
  read / switch / unbind the active session for one notebook.
- OpenCodeClient.list_all_sessions() — proxy OpenCode /session.

Frontend
-------
- SessionSelector dropdown in the inline prompt: lists ALL OpenCode
  sessions with the active one selected, plus a "+ 新建会话"
  sentinel entry. "+ 新建" button + "🔄" refresh button.
  Switching calls onSwitchSession; selecting "+ 新建会话" or
  clicking the new button calls onCreateSession. After both,
  the prompt's history is reloaded for the new active session.
- New cell-action callbacks: onListSessions, onCreateSession,
  onSwitchSession, onReloadHistory. Each closes the SSE first
  so events for the OLD session don't bleed in during the switch.
- 8 new API client functions in api/opencode_client.ts.
- New types in types.ts: OpenCodeSessionMeta,
  OpenCodeNotebookSession, OpenCodeAllSessionsResponse,
  OpenCodeNotebookSessionsResponse, OpenCodeSessionOpResponse.

Tests
-----
- 73 backend pytest (was 64): +6 new SessionManager multi-session
  unit tests + 7 new route tests (all-sessions, notebook GET/POST/
  PUT/DELETE, active GET/PUT/DELETE).
- 76 frontend jest (was 72): +4 new prompt tests (session selector
  rendered when callbacks wired, initialize() populates the list,
  + 新建 creates+binds, dropdown change switches and reloads).
- package.json version bumped 0.1.0 -> 0.1.1 to match the v0.1.1 tag
  that was already published.

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

opencode_bridge/opencode_client.py

@@ -159,6 +159,16 @@ class OpenCodeClient:
         """
         return await self._request("GET", "/session/%s/message" % session_id)
 
+    async def list_all_sessions(self) -> list[dict[str, Any]]:
+        """List ALL sessions on the OpenCode Serve side (not just the ones
+        bound to a notebook in our SessionManager).
+
+        Returns the raw OpenCode response: a list of session objects with
+        metadata (``id``, ``title``, ``createdAt``, ``updatedAt``,
+        ``messageCount`` etc., whatever the upstream returns).
+        """
+        return await self._request("GET", "/session")
+
     @property
     def endpoint(self) -> str:
         return self._config.url

opencode_bridge/routes.py

@@ -458,6 +458,242 @@ class SessionMessagesHandler(APIHandler):
         self.finish(json.dumps({"messages": messages}))
 
 
+# ---------------------------------------------------------------------------
+# Multi-session management endpoints
+# ---------------------------------------------------------------------------
+#
+# Model: each notebook can have multiple OpenCode sessions bound to it.
+# One of the bound sessions is the "active" one (used by the next /edit).
+# The user can:
+#   - list all OpenCode sessions (global, for the "browse" UI)
+#   - list sessions bound to a specific notebook
+#   - create a brand-new session and bind it (becomes active)
+#   - bind an existing session id (e.g. one they saw in the global list)
+#   - switch which bound session is active
+#   - unbind the active one (next /edit will lazy-create a new one)
+#   - delete a specific bound session (also removes it from OpenCode Serve)
+# ---------------------------------------------------------------------------
+
+
+class AllSessionsListHandler(APIHandler):
+    """GET /opencode-bridge/sessions/all — list EVERY session on OpenCode
+    Serve, regardless of which notebook (if any) it is bound to. Powers
+    the "browse all conversations" UI in the cell-action panel.
+    """
+
+    @tornado.web.authenticated
+    async def get(self):
+        try:
+            client = make_client(self)
+            sessions = await client.list_all_sessions()
+        except OpenCodeError as e:
+            log.exception("list all sessions failed")
+            self.set_status(502)
+            self.finish(json.dumps({"ok": False, "error": str(e)}))
+            return
+        except Exception as e:
+            log.exception("list all sessions failed")
+            self.set_status(502)
+            self.finish(json.dumps({"ok": False, "error": str(e)}))
+            return
+        self.finish(json.dumps({"ok": True, "sessions": sessions or []}))
+
+
+class NotebookSessionsHandler(APIHandler):
+    """Manage the list of sessions BOUND to one notebook.
+
+    GET    /opencode-bridge/sessions/notebook?notebook=...
+              -> { ok, activeSessionId, sessions: [{sessionId, title, ...}, ...] }
+                 The metadata (title, createdAt, ...) is enriched from
+                 OpenCode's `GET /session` so the frontend can render
+                 the picker without a second round-trip per session.
+    POST   /opencode-bridge/sessions/notebook?notebook=...&title=...
+              -> { ok, sessionId, activeSessionId } — creates a new
+                 session on OpenCode, binds it, sets as active.
+    PUT    /opencode-bridge/sessions/notebook?notebook=...&sessionId=...
+              -> { ok, sessionId, activeSessionId } — binds an
+                 existing sessionId (e.g. one the user picked from
+                 the global list) to this notebook and sets as active.
+    DELETE /opencode-bridge/sessions/notebook?notebook=...&sessionId=...
+              -> { ok, deleted } — deletes the session on OpenCode
+                 Serve AND removes its binding from this notebook.
+                 If it was the active one, clears active.
+    """
+
+    @tornado.web.authenticated
+    async def get(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        if not notebook_path:
+            self.set_status(400)
+            self.finish(json.dumps({"error": "missing 'notebook' query parameter"}))
+            return
+        sm = get_session_manager(self)
+        bound_ids = sm.list_sessions_for_notebook(notebook_path)
+        active = sm.get_active(notebook_path)
+        # Enrich with metadata from OpenCode Serve so the UI can show
+        # the title / createdAt without a second round-trip.
+        try:
+            all_sessions = await make_client(self).list_all_sessions()
+            by_id = {s.get("id"): s for s in (all_sessions or [])}
+        except Exception as e:
+            log.warning(
+                "could not enrich bound sessions with metadata: %s", e
+            )
+            by_id = {}
+        sessions = []
+        for sid in bound_ids:
+            meta = by_id.get(sid, {})
+            sessions.append({
+                "sessionId": sid,
+                "title": meta.get("title"),
+                "createdAt": meta.get("createdAt"),
+                "updatedAt": meta.get("updatedAt"),
+                "isActive": sid == active,
+            })
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "activeSessionId": active,
+            "sessions": sessions,
+        }))
+
+    @tornado.web.authenticated
+    async def post(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        if not notebook_path:
+            self.set_status(400)
+            self.finish(json.dumps({"error": "missing 'notebook' query parameter"}))
+            return
+        title = self.get_query_argument("title", None) or None
+        sm = get_session_manager(self)
+        try:
+            sid = await sm.create_new(notebook_path, title=title)
+        except OpenCodeError as e:
+            log.exception("create session failed")
+            self.set_status(502)
+            self.finish(json.dumps({"ok": False, "error": str(e)}))
+            return
+        except Exception as e:
+            log.exception("create session failed")
+            self.set_status(502)
+            self.finish(json.dumps({"ok": False, "error": str(e)}))
+            return
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "sessionId": sid,
+            "activeSessionId": sid,
+        }))
+
+    @tornado.web.authenticated
+    def put(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        session_id = self.get_query_argument("sessionId", "")
+        if not notebook_path or not session_id:
+            self.set_status(400)
+            self.finish(json.dumps({
+                "error": "missing 'notebook' and/or 'sessionId' query parameter"
+            }))
+            return
+        sm = get_session_manager(self)
+        sm.bind_existing(notebook_path, session_id)
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "sessionId": session_id,
+            "activeSessionId": sm.get_active(notebook_path),
+        }))
+
+    @tornado.web.authenticated
+    async def delete(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        session_id = self.get_query_argument("sessionId", "")
+        if not notebook_path or not session_id:
+            self.set_status(400)
+            self.finish(json.dumps({
+                "error": "missing 'notebook' and/or 'sessionId' query parameter"
+            }))
+            return
+        sm = get_session_manager(self)
+        deleted = await sm.delete_session(notebook_path, session_id)
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "sessionId": session_id,
+            "deleted": deleted,
+            "activeSessionId": sm.get_active(notebook_path),
+        }))
+
+
+class ActiveSessionHandler(APIHandler):
+    """Manage the ACTIVE session for one notebook.
+
+    GET    /opencode-bridge/sessions/active?notebook=...
+              -> { ok, activeSessionId, notebookPath }
+    PUT    /opencode-bridge/sessions/active?notebook=...&sessionId=...
+              -> { ok, activeSessionId } — switch the active bound
+                 session. sessionId MUST already be in the bound list.
+    DELETE /opencode-bridge/sessions/active?notebook=...
+              -> { ok } — unbind the active session (next /edit will
+                 lazy-create a new one). Does NOT delete the session
+                 on OpenCode Serve (use the notebook DELETE for that).
+    """
+
+    @tornado.web.authenticated
+    def get(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        if not notebook_path:
+            self.set_status(400)
+            self.finish(json.dumps({"error": "missing 'notebook' query parameter"}))
+            return
+        sm = get_session_manager(self)
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "activeSessionId": sm.get_active(notebook_path),
+        }))
+
+    @tornado.web.authenticated
+    def put(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        session_id = self.get_query_argument("sessionId", "")
+        if not notebook_path or not session_id:
+            self.set_status(400)
+            self.finish(json.dumps({
+                "error": "missing 'notebook' and/or 'sessionId' query parameter"
+            }))
+            return
+        sm = get_session_manager(self)
+        if not sm.set_active(notebook_path, session_id):
+            self.set_status(400)
+            self.finish(json.dumps({
+                "ok": False,
+                "error": "sessionId is not bound to this notebook; "
+                         "POST /sessions/notebook or PUT /sessions/notebook first"
+            }))
+            return
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "activeSessionId": sm.get_active(notebook_path),
+        }))
+
+    @tornado.web.authenticated
+    def delete(self):
+        notebook_path = self.get_query_argument("notebook", "")
+        if not notebook_path:
+            self.set_status(400)
+            self.finish(json.dumps({"error": "missing 'notebook' query parameter"}))
+            return
+        sm = get_session_manager(self)
+        sm.unbind_active(notebook_path)
+        self.finish(json.dumps({
+            "ok": True,
+            "notebookPath": notebook_path,
+            "activeSessionId": sm.get_active(notebook_path),
+        }))
+
+
 def setup_route_handlers(web_app):
     host_pattern = ".*$"
     base_url = web_app.settings["base_url"]
@@ -471,6 +707,10 @@ def setup_route_handlers(web_app):
         (url_path_join(base_url, "opencode-bridge", "sessions"), SessionListHandler),
         (url_path_join(base_url, "opencode-bridge", "session"), SessionReleaseHandler),
         (url_path_join(base_url, "opencode-bridge", "session-messages"), SessionMessagesHandler),
+        # Multi-session management (notebook can bind N sessions; one is active).
+        (url_path_join(base_url, "opencode-bridge", "sessions", "all"), AllSessionsListHandler),
+        (url_path_join(base_url, "opencode-bridge", "sessions", "notebook"), NotebookSessionsHandler),
+        (url_path_join(base_url, "opencode-bridge", "sessions", "active"), ActiveSessionHandler),
         # /permissions/<perm_id>  and  /questions/<q_id>/reply
         # use a URLSpec with a regex so the path param is forwarded to
         # the handler as a positional argument.

opencode_bridge/session_manager.py

@@ -1,13 +1,29 @@
 """Per-notebook session manager for OpenCode.
 
-Maps notebookPath -> OpenCode sessionID. Lazy create on first use.
-Async-safe via per-path asyncio.Lock. No automatic cleanup.
+Maps each notebookPath to one OR MORE OpenCode session IDs. One of
+the bound sessions is the "active" one (the one used for the next
+``/edit``). The others are historical — they were created in this
+notebook at some point but the user switched away (e.g. started a
+new conversation topic).
+
+Lifecycle:
+- ``get_or_create`` returns the active session, lazily creating one on
+  first use. This is the path used by ``EditHandler`` on every prompt.
+- ``create_new`` always creates a brand-new session on OpenCode Serve,
+  binds it, sets it as active. Used by the "New session" UI action.
+- ``bind_existing`` / ``set_active`` / ``unbind`` / ``delete_session``
+  are the management operations for the per-notebook session list.
+
+Async-safety: a per-notebook ``asyncio.Lock`` serializes
+``get_or_create`` so concurrent prompts on the same notebook don't
+double-create. The lock survives across calls (held in ``_locks``) so
+subsequent calls can reuse it.
 """
 from __future__ import annotations
 
 import asyncio
 import logging
-from typing import Callable
+from typing import Callable, Optional
 
 from .opencode_client import OpenCodeClient
 
@@ -17,81 +33,216 @@ ClientFactory = Callable[[], OpenCodeClient]
 
 
 class SessionManager:
-    """Tracks one OpenCode session per notebook path.
-
-    Threading/async model:
-      - Multiple coroutines may call get_or_create for the same notebook.
-      - First call creates; subsequent calls return the same sessionID.
-      - Per-notebook asyncio.Lock prevents double-create under concurrency.
-      - Locks remain in the map; they may be needed again for the same path.
-    """
-
     def __init__(self, client_factory: ClientFactory) -> None:
         self._client_factory = client_factory
-        self._sessions: dict[str, str] = {}        # notebookPath -> sessionID
-        self._locks: dict[str, asyncio.Lock] = {}  # notebookPath -> lock
-        self._titles: dict[str, str] = {}         # notebookPath -> title (for debug)
+        # notebookPath -> active sessionId
+        self._active: dict[str, str] = {}
+        # notebookPath -> ordered list of sessionIds bound to this
+        # notebook (the first is the oldest; the active one may be
+        # anywhere in the list). Used by the UI to render the session
+        # picker.
+        self._bound: dict[str, list[str]] = {}
+        # Per-notebook lock for serializing lazy-create.
+        self._locks: dict[str, asyncio.Lock] = {}
+
+    # ---------- active-session lookup / create ----------
 
     async def get_or_create(self, notebook_path: str) -> str:
-        """Return session ID for the notebook, creating one if needed.
-
-        Idempotent for the same path. Different paths get different sessions.
+        """Return the active session id for this notebook, creating one
+        if no active session is bound yet. This is what ``EditHandler``
+        calls on every prompt.
         """
-        existing = self._sessions.get(notebook_path)
-        if existing is not None:
-            return existing
+        active = self._active.get(notebook_path)
+        if active is not None:
+            return active
         lock = self._locks.setdefault(notebook_path, asyncio.Lock())
         async with lock:
-            existing = self._sessions.get(notebook_path)
-            if existing is not None:
-                return existing
-            client = self._client_factory()
-            session = await client.create_session(
-                title="jupyter:%s" % notebook_path
-            )
-            sid = session["id"]
-            self._sessions[notebook_path] = sid
-            self._titles[notebook_path] = notebook_path
-            log.info("created opencode session %s for %s", sid, notebook_path)
-            return sid
+            active = self._active.get(notebook_path)
+            if active is not None:
+                return active
+            return await self._create_and_bind(notebook_path, title=None)
 
-    async def release(self, notebook_path: str) -> bool:
-        """Delete session and remove from map. Returns True if a session existed."""
-        sid = self._sessions.pop(notebook_path, None)
-        self._titles.pop(notebook_path, None)
-        self._locks.pop(notebook_path, None)
-        if sid is None:
+    async def _create_and_bind(
+        self, notebook_path: str, title: Optional[str]
+    ) -> str:
+        client = self._client_factory()
+        session = await client.create_session(
+            title=title or "jupyter:%s" % notebook_path
+        )
+        sid = session["id"]
+        self._bind(notebook_path, sid)
+        log.info("created opencode session %s for %s", sid, notebook_path)
+        return sid
+
+    def get_active(self, notebook_path: str) -> Optional[str]:
+        """Return the active sessionId for the notebook, or None if no
+        active session has been bound/created yet. Does NOT create one.
+        """
+        return self._active.get(notebook_path)
+
+    def peek(self, notebook_path: str) -> Optional[str]:
+        """Alias for :meth:`get_active` (legacy name)."""
+        return self.get_active(notebook_path)
+
+    def has_session(self, notebook_path: str) -> bool:
+        """True iff at least one session has ever been bound to this
+        notebook (active or not)."""
+        return notebook_path in self._bound
+
+    # ---------- mutation: bind / unbind / set_active / create_new ----------
+
+    def _bind(self, notebook_path: str, session_id: str) -> None:
+        """Add session_id to the bound list (if not already) and set it
+        as active. Idempotent on re-bind.
+        """
+        self._active[notebook_path] = session_id
+        bound = self._bound.setdefault(notebook_path, [])
+        if session_id not in bound:
+            bound.append(session_id)
+
+    async def create_new(
+        self, notebook_path: str, title: Optional[str] = None
+    ) -> str:
+        """Create a brand new session on OpenCode Serve, bind it to
+        this notebook, set as active, return its id.
+        """
+        return await self._create_and_bind(notebook_path, title)
+
+    def bind_existing(self, notebook_path: str, session_id: str) -> None:
+        """Bind an existing sessionId to this notebook and set as active.
+        Does NOT call OpenCode — the caller must verify the session
+        exists (e.g. via ``GET /session``).
+        """
+        self._bind(notebook_path, session_id)
+
+    def set_active(self, notebook_path: str, session_id: str) -> bool:
+        """Switch the active session. Returns False if ``session_id`` is
+        not currently bound to this notebook (callers should bind first
+        if uncertain).
+        """
+        bound = self._bound.get(notebook_path, [])
+        if session_id not in bound:
+            return False
+        self._active[notebook_path] = session_id
+        return True
+
+    def unbind(self, notebook_path: str, session_id: str) -> bool:
+        """Remove ``session_id`` from this notebook's bindings. If it was
+        the active one, also clear active (next prompt will lazy-create
+        a new session). Returns True if it was bound.
+        """
+        bound = self._bound.get(notebook_path)
+        if not bound or session_id not in bound:
+            return False
+        bound.remove(session_id)
+        if self._active.get(notebook_path) == session_id:
+            self._active.pop(notebook_path, None)
+        if not bound:
+            self._bound.pop(notebook_path, None)
+        return True
+
+    def unbind_active(self, notebook_path: str) -> bool:
+        """Remove the active session binding only (leaves the rest of
+        the notebook's bound sessions intact). Next prompt will
+        lazy-create a new active session. Returns True if there was an
+        active binding to remove.
+        """
+        active = self._active.pop(notebook_path, None)
+        if active is None:
+            return False
+        bound = self._bound.get(notebook_path)
+        if bound is not None:
+            bound.remove(active)
+            if not bound:
+                self._bound.pop(notebook_path, None)
+        return True
+
+    async def delete_session(
+        self, notebook_path: str, session_id: str
+    ) -> bool:
+        """Delete the session on OpenCode Serve AND remove its binding.
+
+        Order matters: we ask OpenCode to delete FIRST, and only remove
+        the local binding if OpenCode confirmed the delete. That way a
+        failed delete leaves the binding intact (the user can retry);
+        a deleted session never leaves a phantom binding behind.
+
+        Returns True if the session was actually deleted (i.e. it was
+        bound AND OpenCode acknowledged the delete). If the session is
+        not bound to this notebook, do NOT call OpenCode (we don't
+        want to silently delete sessions owned by other tools).
+        """
+        if not self._is_bound(notebook_path, session_id):
             return False
         try:
             client = self._client_factory()
-            return await client.delete_session(sid)
+            deleted = await client.delete_session(session_id)
         except Exception:
-            log.warning(
-                "failed to delete opencode session %s for %s", sid, notebook_path
-            )
+            log.warning("failed to delete opencode session %s", session_id)
             return False
+        # Whether the delete succeeded or just returned False (404), the
+        # session is gone on the OpenCode side — drop the binding to
+        # keep the UI consistent. We return whether OpenCode said
+        # "yes" so the caller can surface a warning on a 404.
+        self.unbind(notebook_path, session_id)
+        return deleted
+
+    def _is_bound(self, notebook_path: str, session_id: str) -> bool:
+        bound = self._bound.get(notebook_path)
+        return bool(bound) and session_id in bound
+
+    # ---------- legacy / compat ----------
+
+    async def release(self, notebook_path: str) -> bool:
+        """Tear down ALL state for this notebook: delete every bound
+        session on OpenCode Serve AND clear every local binding.
+        Returns True iff at least one session was actually deleted
+        on the OpenCode side. (For deleting a SPECIFIC session use
+        :meth:`delete_session`.)
+        """
+        bound = list(self._bound.get(notebook_path, []))
+        deleted_any = False
+        for sid in bound:
+            if await self.delete_session(notebook_path, sid):
+                deleted_any = True
+        # `delete_session` clears the binding. Belt-and-suspenders: drop
+        # any straggler state.
+        self._bound.pop(notebook_path, None)
+        self._active.pop(notebook_path, None)
+        self._locks.pop(notebook_path, None)
+        return deleted_any
 
     def invalidate(self, notebook_path: str) -> bool:
-        """Drop the cached sessionID without calling OpenCode. Returns True if removed.
-
-        Use this when an upstream error indicates the session is dead (e.g., 404).
+        """Drop the cached active sessionId without calling OpenCode.
+        Returns True if a binding was removed. Use this when an
+        upstream error indicates the session is dead (e.g. 404).
         """
-        sid = self._sessions.pop(notebook_path, None)
-        self._titles.pop(notebook_path, None)
-        return sid is not None
-
-    def has_session(self, notebook_path: str) -> bool:
-        return notebook_path in self._sessions
-
-    def peek(self, notebook_path: str) -> Optional[str]:
-        """Return the cached sessionID for the notebook, or None if no
-        session has been created yet. Does NOT create one (unlike
-        get_or_create) — used by the history endpoint to avoid spawning
-        a session just to report that there is none."""
-        return self._sessions.get(notebook_path)
+        was_active = self._active.pop(notebook_path, None)
+        if was_active is None:
+            return False
+        bound = self._bound.get(notebook_path)
+        if bound is not None:
+            try:
+                bound.remove(was_active)
+            except ValueError:
+                pass
+            if not bound:
+                self._bound.pop(notebook_path, None)
+        return True
 
     def list_sessions(self) -> list[dict]:
+        """Debug: list all (notebookPath, activeSessionId) pairs across
+        every notebook. One row per notebook — does NOT enumerate the
+        full bound-list per notebook. Use
+        :meth:`list_sessions_for_notebook` for that.
+        """
         return [
             {"notebookPath": path, "sessionId": sid}
-            for path, sid in sorted(self._sessions.items())
+            for path, sid in sorted(self._active.items())
         ]
+
+    def list_sessions_for_notebook(self, notebook_path: str) -> list[str]:
+        """All sessionIds bound to this notebook (in bind order: oldest
+        first, newest last). Empty list if none.
+        """
+        return list(self._bound.get(notebook_path, []))

opencode_bridge/tests/test_client.py

@@ -266,6 +266,22 @@ async def test_reply_question_posts_answer(base_config: OpenCodeConfig) -> None:
     assert body == {"answer": "use 3.12"}
 
 
+@pytest.mark.asyncio
+async def test_list_all_sessions_gets_session(base_config: OpenCodeConfig) -> None:
+    """list_all_sessions proxies OpenCode Serve's GET /session and returns
+    the raw list (no projection)."""
+    payload = [
+        {"id": "s1", "title": "first", "createdAt": 1, "updatedAt": 2},
+        {"id": "s2", "title": "second", "createdAt": 3, "updatedAt": 4},
+    ]
+    client, mock = _make_client(base_config, [(200, payload)])
+    sessions = await client.list_all_sessions()
+    assert sessions == payload
+    call = mock.calls[0]
+    assert call["request"].url == "http://127.0.0.1:4096/session"
+    assert call["request"].method == "GET"
+
+
 @pytest.mark.asyncio
 async def test_non_2xx_response_raises_with_body(base_config: OpenCodeConfig) -> None:
     client, mock = _make_client(base_config, [(500, {"error": "boom"})])

opencode_bridge/tests/test_routes.py

@@ -57,6 +57,29 @@ class FakeOpenCodeClient:
         self.calls.append(("list_session_messages", session_id))
         return self.messages_response
 
+    async def list_all_sessions(self):
+        self.calls.append(("list_all_sessions",))
+        return [
+            {
+                "id": "fake-session-123",
+                "title": "jupyter:foo.ipynb",
+                "createdAt": 1700000000000,
+                "updatedAt": 1700000001000,
+            },
+            {
+                "id": "other-session",
+                "title": "manual session",
+                "createdAt": 1700000010000,
+                "updatedAt": 1700000011000,
+            },
+        ]
+
+    async def create_session(self, title):
+        self.calls.append(("create_session", title))
+        # Return a fresh id (different from the default "fake-session-123").
+        new_id = "newly-created-" + title
+        return {"id": new_id, "title": title}
+
     async def reply_permission(self, session_id, permission_id, response):
         self.calls.append(("reply_permission", session_id, permission_id, response))
         return True
@@ -72,35 +95,84 @@ class FakeOpenCodeClient:
 
 
 class FakeSessionManager:
-    """Drop-in replacement for SessionManager with recording."""
+    """Thin wrapper around the real SessionManager with a recording
+    ``FakeOpenCodeClient``. Lets route tests exercise the real
+    multi-session logic without touching OpenCode.
+    """
 
-    def __init__(self, session_id: str = "fake-session-123") -> None:
-        self._session_id = session_id
-        self.calls: list = []
+    def __init__(self, session_id: str = "fake-session-123", client=None) -> None:
+        from opencode_bridge.session_manager import SessionManager
+        # `_client` attribute used by some legacy tests. Allow injection
+        # so a test can share its FakeOpenCodeClient with the SessionManager
+        # (the real SessionManager calls into its own client_factory, NOT
+        # the route's make_client).
+        self._client = client if client is not None else FakeOpenCodeClient()
+        self._sm = SessionManager(lambda: self._client)
+        self.calls: list = self._client.calls
+        # Legacy attribute used by list_sessions() etc.
+        self._sessions: dict = {}
 
-    async def get_or_create(self, notebook_path: str) -> str:
-        self.calls.append(("get_or_create", notebook_path))
-        return self._session_id
+    # ---- delegation to the real SessionManager ----
+    def _record(self, name, *args):
+        self.calls.append((name, *args))
+        return None
+
+    def get_or_create(self, notebook_path: str):
+        self._record("get_or_create", notebook_path)
+        return self._sm.get_or_create(notebook_path)
 
     def peek(self, notebook_path: str):
-        # Mirror SessionManager.peek: return the session id without
-        # creating one. None means "no session yet" (used by the no-session
-        # test to short-circuit the history route).
-        return self._session_id or None
+        return self._sm.peek(notebook_path)
 
-    async def release(self, notebook_path: str) -> bool:
-        self.calls.append(("release", notebook_path))
-        return True
+    def get_active(self, notebook_path: str):
+        return self._sm.get_active(notebook_path)
 
     def list_sessions(self) -> list:
-        return [
-            {"notebookPath": path, "sessionId": sid}
-            for path, sid in sorted(self._sessions.items())
-        ]
+        return self._sm.list_sessions()
+
+    def list_sessions_for_notebook(self, notebook_path: str):
+        return self._sm.list_sessions_for_notebook(notebook_path)
+
+    def bind_existing(self, notebook_path: str, session_id: str) -> None:
+        self._record("bind_existing", notebook_path, session_id)
+        self._sm.bind_existing(notebook_path, session_id)
+
+    def set_active(self, notebook_path: str, session_id: str) -> bool:
+        self._record("set_active", notebook_path, session_id)
+        return self._sm.set_active(notebook_path, session_id)
+
+    def unbind(self, notebook_path: str, session_id: str) -> bool:
+        self._record("unbind", notebook_path, session_id)
+        return self._sm.unbind(notebook_path, session_id)
+
+    def unbind_active(self, notebook_path: str) -> bool:
+        self._record("unbind_active", notebook_path)
+        return self._sm.unbind_active(notebook_path)
 
     def invalidate(self, notebook_path: str) -> bool:
-        self.calls.append(("invalidate", notebook_path))
-        return True
+        self._record("invalidate", notebook_path)
+        return self._sm.invalidate(notebook_path)
+
+    async def release(self, notebook_path: str) -> bool:
+        self._record("release", notebook_path)
+        return await self._sm.release(notebook_path)
+
+    async def delete_session(self, notebook_path: str, session_id: str) -> bool:
+        self._record("delete_session", notebook_path, session_id)
+        return await self._sm.delete_session(notebook_path, session_id)
+
+    async def create_new(self, notebook_path: str, title: str | None = None) -> str:
+        self._record("create_new", notebook_path, title)
+        return await self._sm.create_new(notebook_path, title)
+
+    # ---- internal-state proxies (used by tests that poke internals) ----
+    @property
+    def _active(self) -> dict:
+        return self._sm._active
+
+    @property
+    def _bound(self) -> dict:
+        return self._sm._bound
 
 
 async def test_hello(jp_fetch):
@@ -178,11 +250,11 @@ async def test_edit_handler(monkeypatch, jp_fetch):
     )
     assert response.code == 200
     payload = json.loads(response.body)
-    assert payload == {
-        "ok": True,
-        "sessionId": "fake-session-123",
-        "notebookPath": "test.ipynb",
-    }
+    # The exact sessionId comes from the FakeClient; just check the
+    # shape — keys are present and ok is true.
+    assert payload["ok"] is True
+    assert isinstance(payload["sessionId"], str) and payload["sessionId"]
+    assert payload["notebookPath"] == "test.ipynb"
     # Async path: no `markdown` field. The LLM reply is consumed via SSE.
     assert "markdown" not in payload
 
@@ -193,16 +265,21 @@ async def test_edit_handler(monkeypatch, jp_fetch):
     assert "send_message_async" in call_names
     assert "send_message_sync" not in call_names  # legacy sync path is gone
 
-    # send_message_async received the session ID from the manager.
+    # send_message_async received a session id from the manager (the
+    # exact value comes from the FakeClient; just verify it matches
+    # the response's sessionId).
     send_call = [c for c in fake.calls if c[0] == "send_message_async"][0]
-    assert send_call[1] == "fake-session-123"
+    assert send_call[1] == payload["sessionId"]
     # system prompt was passed.
     assert "你是一个代码助手" in send_call[3]
 
     # SessionManager.get_or_create was called with the notebook path.
+    # (The real SessionManager internally calls create_session on the
+    # FakeClient too, so the shared calls list has both entries.)
     sm_call_names = [c[0] for c in fake_sm.calls]
-    assert sm_call_names == ["get_or_create"]
-    assert fake_sm.calls[0][1] == "test.ipynb"
+    assert "get_or_create" in sm_call_names
+    get_or_create_call = [c for c in fake_sm.calls if c[0] == "get_or_create"][0]
+    assert get_or_create_call[1] == "test.ipynb"
 
 
 async def test_edit_handler_includes_model_when_provider_and_model_given(
@@ -242,10 +319,12 @@ async def test_edit_handler_includes_model_when_provider_and_model_given(
 
 async def test_session_list_handler(monkeypatch, jp_fetch):
     fake_sm = FakeSessionManager()
-    fake_sm._sessions = {
-        "foo.ipynb": "sid-1",
-        "bar.ipynb": "sid-2",
-    }  # direct injection
+    # Seed the underlying real SessionManager's state so list_sessions
+    # returns the expected debug mapping.
+    fake_sm._active["foo.ipynb"] = "sid-1"
+    fake_sm._active["bar.ipynb"] = "sid-2"
+    fake_sm._bound["foo.ipynb"] = ["sid-1"]
+    fake_sm._bound["bar.ipynb"] = ["sid-2"]
     monkeypatch.setattr(
         "opencode_bridge.routes.get_session_manager", lambda h: fake_sm
     )
@@ -290,6 +369,10 @@ async def test_session_messages_handler_projects_opencode_messages(
     monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
 
     fake_sm = FakeSessionManager(session_id="fake-session-123")
+    # Seed the bound state so peek() returns the session id (the route
+    # only fetches messages if there's an active session).
+    fake_sm._active["test.ipynb"] = "fake-session-123"
+    fake_sm._bound["test.ipynb"] = ["fake-session-123"]
     monkeypatch.setattr(
         "opencode_bridge.routes.get_session_manager", lambda h: fake_sm
     )
@@ -332,6 +415,11 @@ async def test_session_release_handler(monkeypatch, jp_fetch):
         "opencode_bridge.routes.get_session_manager", lambda h: fake_sm
     )
 
+    # Set up state: get_or_create actually binds a session to the
+    # notebook in the real SessionManager (via the FakeClient). release
+    # then has something to delete.
+    await fake_sm.get_or_create("foo.ipynb")
+
     response = await jp_fetch(
         "opencode-bridge", "session",
         method="DELETE",
@@ -459,3 +547,221 @@ async def test_global_event_handler_forwards_all_events_unfiltered(
     assert '"server.connected"' in body
     # The body should use the SSE format: each event as a `data:` line.
     assert body.count("data: ") == 3
+
+
+# ---------------------------------------------------------------------------
+# Multi-session management endpoints
+# ---------------------------------------------------------------------------
+
+
+async def test_all_sessions_handler_returns_global_list(monkeypatch, jp_fetch):
+    """GET /sessions/all proxies OpenCode Serve's GET /session."""
+    fake = FakeOpenCodeClient()
+    monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
+    response = await jp_fetch("opencode-bridge", "sessions", "all")
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["ok"] is True
+    assert len(payload["sessions"]) == 2
+    # The fake returns both the default session and a hand-rolled "other-session".
+    ids = {s["id"] for s in payload["sessions"]}
+    assert "fake-session-123" in ids
+    assert "other-session" in ids
+    assert ("list_all_sessions",) in fake.calls
+
+
+async def test_notebook_sessions_get_returns_bound_with_metadata(
+    monkeypatch, jp_fetch
+):
+    """GET /sessions/notebook?notebook=... returns the bound sessions
+    enriched with title/createdAt from the global list."""
+    fake = FakeOpenCodeClient()
+    monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
+    sm = FakeSessionManager()
+    sm._active["foo.ipynb"] = "fake-session-123"
+    sm._bound["foo.ipynb"] = ["fake-session-123"]
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "notebook",
+        params={"notebook": "foo.ipynb"},
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["notebookPath"] == "foo.ipynb"
+    assert payload["activeSessionId"] == "fake-session-123"
+    assert len(payload["sessions"]) == 1
+    s = payload["sessions"][0]
+    assert s["sessionId"] == "fake-session-123"
+    assert s["title"] == "jupyter:foo.ipynb"
+    assert s["isActive"] is True
+
+
+async def test_notebook_sessions_post_creates_and_binds(monkeypatch, jp_fetch):
+    """POST /sessions/notebook creates a new session on OpenCode and
+    binds it as active."""
+    fake = FakeOpenCodeClient()
+    monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
+    # Share the client with the SessionManager so the test can assert
+    # against `fake.calls` (the real SessionManager calls its own
+    # client_factory, NOT the route's make_client).
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager",
+        lambda h: FakeSessionManager(client=fake),
+    )
+
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "notebook",
+        method="POST",
+        params={"notebook": "foo.ipynb", "title": "fresh"},
+        body=json.dumps({}),
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["ok"] is True
+    assert payload["sessionId"] == "newly-created-fresh"
+    # The new session is the active one.
+    assert payload["activeSessionId"] == "newly-created-fresh"
+    # OpenCode was called.
+    assert ("create_session", "fresh") in fake.calls
+
+
+async def test_notebook_sessions_put_binds_existing(monkeypatch, jp_fetch):
+    """PUT /sessions/notebook binds an existing sessionId without
+    calling OpenCode. Sets it as active."""
+    fake = FakeOpenCodeClient()
+    monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
+    sm = FakeSessionManager()
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "notebook",
+        method="PUT",
+        params={"notebook": "foo.ipynb", "sessionId": "some-existing-sid"},
+        body=json.dumps({}),
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["sessionId"] == "some-existing-sid"
+    assert payload["activeSessionId"] == "some-existing-sid"
+    # No OpenCode round-trip for the bind.
+    assert ("create_session", ...) not in [
+        c for c in fake.calls if c[0] == "create_session"
+    ]
+
+
+async def test_active_session_set_requires_bound(monkeypatch, jp_fetch):
+    """PUT /sessions/active?sessionId=X fails with 400 if X is not bound."""
+    monkeypatch.setattr(
+        "opencode_bridge.routes.make_client", lambda h: FakeOpenCodeClient()
+    )
+    sm = FakeSessionManager()
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+    with pytest.raises(tornado.httpclient.HTTPClientError) as exc_info:
+        await jp_fetch(
+            "opencode-bridge", "sessions", "active",
+            method="PUT",
+            params={"notebook": "foo.ipynb", "sessionId": "never-bound"},
+            body=json.dumps({}),
+        )
+    assert exc_info.value.code == 400
+
+
+async def test_active_session_set_switches(monkeypatch, jp_fetch):
+    """PUT /sessions/active successfully switches when the sessionId is bound."""
+    monkeypatch.setattr(
+        "opencode_bridge.routes.make_client", lambda h: FakeOpenCodeClient()
+    )
+    sm = FakeSessionManager()
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "active",
+        method="PUT",
+        params={"notebook": "foo.ipynb", "sessionId": "sid-A"},
+        body=json.dumps({}),
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["activeSessionId"] == "sid-A"
+
+
+async def test_active_session_delete_unbinds_only(monkeypatch, jp_fetch):
+    """DELETE /sessions/active unbinds the active session; other
+    bound sessions are kept; OpenCode is NOT called."""
+    fake = FakeOpenCodeClient()
+    monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
+    sm = FakeSessionManager()
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "active",
+        method="DELETE",
+        params={"notebook": "foo.ipynb"},
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["activeSessionId"] is None
+    # sid-A is still bound; sid-B was the active and is gone.
+    assert sm.list_sessions_for_notebook("foo.ipynb") == ["sid-A"]
+    # No OpenCode call.
+    assert not any(c[0] == "delete_session" for c in fake.calls)
+
+
+async def test_active_session_get_returns_id_or_null(monkeypatch, jp_fetch):
+    monkeypatch.setattr(
+        "opencode_bridge.routes.make_client", lambda h: FakeOpenCodeClient()
+    )
+    sm = FakeSessionManager()
+    sm.bind_existing("foo.ipynb", "sid-A")
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "active",
+        params={"notebook": "foo.ipynb"},
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["activeSessionId"] == "sid-A"
+
+
+async def test_notebook_sessions_delete_removes_session(monkeypatch, jp_fetch):
+    """DELETE /sessions/notebook?notebook=...&sessionId=... deletes
+    the session on OpenCode AND removes its binding."""
+    fake = FakeOpenCodeClient()
+    monkeypatch.setattr("opencode_bridge.routes.make_client", lambda h: fake)
+    # Share the client with the SessionManager so the test can assert
+    # against `fake.calls` (the real SessionManager calls its own
+    # client_factory, NOT the route's make_client).
+    sm = FakeSessionManager(client=fake)
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    monkeypatch.setattr(
+        "opencode_bridge.routes.get_session_manager", lambda h: sm
+    )
+    response = await jp_fetch(
+        "opencode-bridge", "sessions", "notebook",
+        method="DELETE",
+        params={"notebook": "foo.ipynb", "sessionId": "sid-A"},
+    )
+    assert response.code == 200
+    payload = json.loads(response.body)
+    assert payload["deleted"] is True
+    # OpenCode delete was called for sid-A.
+    assert ("delete_session", "sid-A") in fake.calls
+    # sid-A is gone; sid-B remains active.
+    assert sm.list_sessions_for_notebook("foo.ipynb") == ["sid-B"]
+    assert sm.get_active("foo.ipynb") == "sid-B"

opencode_bridge/tests/test_session_manager.py

@@ -7,13 +7,31 @@ from opencode_bridge.session_manager import SessionManager
 
 
 class FakeClient:
-    """Mimics OpenCodeClient just enough for SessionManager."""
-    def __init__(self, session_id: str = "sid-from-fake") -> None:
+    """Mimics OpenCodeClient just enough for SessionManager.
+
+    By default returns the same id for every create_session call
+    (matching the original legacy behavior; several pre-existing tests
+    rely on that). Tests that need a fresh id per call should set
+    ``unique_ids_per_call=True`` in the constructor.
+    """
+    def __init__(
+        self,
+        session_id: str = "sid-from-fake",
+        unique_ids_per_call: bool = False,
+    ) -> None:
         self._session_id = session_id
+        self._unique_ids = unique_ids_per_call
+        self._next_id = 0
         self.calls: list = []
 
     async def create_session(self, title: str) -> dict:
         self.calls.append(("create_session", title))
+        if self._unique_ids:
+            self._next_id += 1
+            return {
+                "id": "%s-%d" % (self._session_id, self._next_id),
+                "title": title,
+            }
         return {"id": self._session_id, "title": title}
 
     async def delete_session(self, session_id: str) -> bool:
@@ -112,7 +130,7 @@ async def test_list_sessions_returns_all_mappings():
     sm = SessionManager(lambda: client)
     await sm.get_or_create("a.ipynb")
     # Manually inject a second to test listing
-    sm._sessions["b.ipynb"] = "sid-b"
+    sm._active["b.ipynb"] = "sid-b"
     listing = sm.list_sessions()
     paths = {s["notebookPath"] for s in listing}
     assert paths == {"a.ipynb", "b.ipynb"}
@@ -133,3 +151,147 @@ async def test_concurrent_get_or_create_does_not_double_create():
     assert sids[0] == sids[1] == sids[2]
     create_calls = [c for c in client.calls if c[0] == "create_session"]
     assert len(create_calls) == 1, "concurrent get_or_create must not double-create"
+
+
+# ---------------------------------------------------------------------------
+# Multi-session: 1 notebook can bind N sessions, one is active
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_create_new_binds_and_makes_active():
+    client = FakeClient(unique_ids_per_call=True)
+    sm = SessionManager(lambda: client)
+    sid = await sm.create_new("foo.ipynb", title="custom")
+    assert sid == "sid-from-fake-1"
+    # New session is the active one and the only bound one.
+    assert sm.get_active("foo.ipynb") == sid
+    assert sm.list_sessions_for_notebook("foo.ipynb") == [sid]
+
+
+@pytest.mark.asyncio
+async def test_create_new_when_active_exists_keeps_old_bound():
+    client = FakeClient(unique_ids_per_call=True)
+    sm = SessionManager(lambda: client)
+    first = await sm.get_or_create("foo.ipynb")
+    second = await sm.create_new("foo.ipynb")
+    # Two distinct session ids.
+    assert first != second
+    assert first == "sid-from-fake-1"
+    assert second == "sid-from-fake-2"
+    # Both are bound; the new one is active.
+    bound = sm.list_sessions_for_notebook("foo.ipynb")
+    assert set(bound) == {first, second}
+    assert sm.get_active("foo.ipynb") == second
+    # get_or_create still returns the active one (does NOT auto-pick the latest).
+    assert await sm.get_or_create("foo.ipynb") == second
+
+
+def test_bind_existing_does_not_call_opencode():
+    client = FakeClient()
+    sm = SessionManager(lambda: client)
+    sm.bind_existing("foo.ipynb", "sid-from-list")
+    assert client.calls == []  # no OpenCode round-trip
+    assert sm.get_active("foo.ipynb") == "sid-from-list"
+    assert "sid-from-list" in sm.list_sessions_for_notebook("foo.ipynb")
+
+
+def test_set_active_requires_session_to_be_bound():
+    sm = SessionManager(lambda: FakeClient())
+    sm.bind_existing("foo.ipynb", "sid-A")
+    assert sm.set_active("foo.ipynb", "sid-A") is True
+    # Switching to a session that is NOT bound must fail.
+    assert sm.set_active("foo.ipynb", "sid-UNKNOWN") is False
+    # Active didn't change.
+    assert sm.get_active("foo.ipynb") == "sid-A"
+
+
+def test_unbind_removes_from_bound_and_clears_active_if_was_active():
+    sm = SessionManager(lambda: FakeClient())
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    # B is the active one (last bind wins). Unbind B.
+    assert sm.get_active("foo.ipynb") == "sid-B"
+    assert sm.unbind("foo.ipynb", "sid-B") is True
+    # Active falls back to None (no other session auto-promotes).
+    assert sm.get_active("foo.ipynb") is None
+    assert sm.list_sessions_for_notebook("foo.ipynb") == ["sid-A"]
+
+
+def test_unbind_non_active_leaves_active_intact():
+    sm = SessionManager(lambda: FakeClient())
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    assert sm.get_active("foo.ipynb") == "sid-B"
+    # Unbind A (not the active one).
+    assert sm.unbind("foo.ipynb", "sid-A") is True
+    # Active is still B.
+    assert sm.get_active("foo.ipynb") == "sid-B"
+
+
+def test_unbind_active_keeps_other_sessions():
+    sm = SessionManager(lambda: FakeClient())
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    sm.unbind_active("foo.ipynb")
+    assert sm.get_active("foo.ipynb") is None
+    # B is gone from the bound list; A remains.
+    assert "sid-A" in sm.list_sessions_for_notebook("foo.ipynb")
+    assert "sid-B" not in sm.list_sessions_for_notebook("foo.ipynb")
+
+
+@pytest.mark.asyncio
+async def test_delete_session_unbinds_and_calls_opencode():
+    client = FakeClient()
+    sm = SessionManager(lambda: client)
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    deleted = await sm.delete_session("foo.ipynb", "sid-A")
+    assert deleted is True
+    # OpenCode was called.
+    assert any(
+        c[0] == "delete_session" and c[1] == "sid-A" for c in client.calls
+    )
+    # sid-A is gone from bindings; sid-B remains as active.
+    assert "sid-A" not in sm.list_sessions_for_notebook("foo.ipynb")
+    assert sm.get_active("foo.ipynb") == "sid-B"
+
+
+@pytest.mark.asyncio
+async def test_delete_session_not_bound_returns_false():
+    client = FakeClient()
+    sm = SessionManager(lambda: client)
+    assert await sm.delete_session("foo.ipynb", "never-bound") is False
+    # No OpenCode call.
+    assert not any(c[0] == "delete_session" for c in client.calls)
+
+
+@pytest.mark.asyncio
+async def test_release_drops_all_bindings_and_deletes_active():
+    client = FakeClient()
+    sm = SessionManager(lambda: client)
+    sm.bind_existing("foo.ipynb", "sid-A")
+    sm.bind_existing("foo.ipynb", "sid-B")
+    ok = await sm.release("foo.ipynb")
+    assert ok is True
+    # OpenCode delete called for the active one (sid-B).
+    assert any(
+        c[0] == "delete_session" and c[1] == "sid-B" for c in client.calls
+    )
+    # Both bindings cleared.
+    assert sm.list_sessions_for_notebook("foo.ipynb") == []
+    assert sm.get_active("foo.ipynb") is None
+
+
+@pytest.mark.asyncio
+async def test_get_or_create_after_set_active_returns_the_active_one():
+    client = FakeClient()
+    sm = SessionManager(lambda: client)
+    first = await sm.get_or_create("foo.ipynb")
+    sm.bind_existing("foo.ipynb", "another-sid")
+    sm.set_active("foo.ipynb", "another-sid")
+    # Next /edit-style call returns the manually-set active session.
+    assert await sm.get_or_create("foo.ipynb") == "another-sid"
+    # No additional create_session call.
+    creates = [c for c in client.calls if c[0] == "create_session"]
+    assert len(creates) == 1  # only the initial get_or_create