diff --git a/tests/web/pi-adapter.test.ts b/tests/web/pi-adapter.test.ts
index af2f7476..ea88a01a 100644
--- a/tests/web/pi-adapter.test.ts
+++ b/tests/web/pi-adapter.test.ts
@@ -101,9 +101,33 @@ test("snapshot pins current and selected sessions while bounding the projection"
         (session) => session.id === current.getSessionId(),
       ),
     );
+    const currentSummary = snapshot.sessions.find(
+      (session) => session.id === current.getSessionId(),
+    );
+    assert.deepEqual(
+      {
+        source: currentSummary?.source,
+        origin: currentSummary?.origin,
+        controller: currentSummary?.controller,
+        readOnly: currentSummary?.readOnly,
+      },
+      {
+        source: "web-session",
+        origin: "web",
+        controller: "web",
+        readOnly: false,
+      },
+    );
     assert.ok(
       snapshot.sessions.some((session) => session.path === selectedPath),
     );
+    const selectedSummary = snapshot.sessions.find(
+      (session) => session.path === selectedPath,
+    );
+    assert.equal(selectedSummary?.source, "web-session");
+    assert.equal(selectedSummary?.origin, "web");
+    assert.equal(selectedSummary?.controller, "none");
+    assert.equal(selectedSummary?.readOnly, false);
     assert.equal(snapshot.selectedSession?.path, selectedPath);
     assert.equal(
       (
diff --git a/web/adapter/pi-adapter.ts b/web/adapter/pi-adapter.ts
index fb4c0bc9..fe604a90 100644
--- a/web/adapter/pi-adapter.ts
+++ b/web/adapter/pi-adapter.ts
@@ -341,6 +341,10 @@ export class PiWebAdapter {
         id: session.id,
         path: session.path,
         cwd: resolve(session.cwd),
+        source: "web-session" as const,
+        origin: "web" as const,
+        controller: session.id === currentId ? ("web" as const) : ("none" as const),
+        readOnly: false as const,
         ...(session.name
           ? { name: boundedText(session.name, WEB_MAX_SESSION_PREVIEW) }
           : {}),
@@ -378,6 +382,10 @@ export class PiWebAdapter {
         id: currentId,
         path: currentPath,
         cwd: resolve(this.runtime.cwd),
+        source: "web-session" as const,
+        origin: "web" as const,
+        controller: "web" as const,
+        readOnly: false as const,
         ...(this.runtime.sessionManager.getSessionName()
           ? {
               name: boundedText(
diff --git a/web/protocol/types.ts b/web/protocol/types.ts
index a7429b6e..60addc90 100644
--- a/web/protocol/types.ts
+++ b/web/protocol/types.ts
@@ -27,6 +27,10 @@ export interface WebSessionSummary {
   id: string;
   path: string;
   cwd: string;
+  source: "web-session";
+  origin: "web";
+  controller: "web" | "none";
+  readOnly: false;
   name?: string;
   modified: string;
   created: string;