diff --git a/extensions/coven/src/runtime.test.ts b/extensions/coven/src/runtime.test.ts
index 98ef3832169..6f457e13f8d 100644
--- a/extensions/coven/src/runtime.test.ts
+++ b/extensions/coven/src/runtime.test.ts
@@ -347,11 +347,14 @@ describe("CovenAcpRuntime", () => {
       mode: "oneshot",
       cwd: workspaceDir,
     });
-    handle.runtimeSessionName = __testing.encodeRuntimeSessionName({
-      agent: "codex",
-      mode: "prompt",
-      cwd: "/tmp/attacker",
-    });
+    handle.runtimeSessionName = `coven:${Buffer.from(
+      JSON.stringify({
+        agent: "codex",
+        mode: "prompt",
+        cwd: "/tmp/attacker",
+      }),
+      "utf8",
+    ).toString("base64url")}`;
 
     await collect(
       runtime.runTurn({
@@ -611,7 +614,6 @@ describe("CovenAcpRuntime", () => {
       agent: "A".repeat(5_000),
       mode: "prompt".repeat(1_000),
       sessionMode: "persistent".repeat(1_000),
-      cwd: "/workspace/".repeat(1_000),
     });
 
     expect(Buffer.byteLength(encoded, "utf8")).toBeLessThanOrEqual("coven:".length + 2_048);
diff --git a/extensions/coven/src/runtime.ts b/extensions/coven/src/runtime.ts
index d019bef8912..e3eec76fc04 100644
--- a/extensions/coven/src/runtime.ts
+++ b/extensions/coven/src/runtime.ts
@@ -51,7 +51,6 @@ type CovenRuntimeSessionState = {
   agent: string;
   mode: string;
   sessionMode?: string;
-  cwd?: string;
 };
 
 type CovenAcpRuntimeParams = {
@@ -109,7 +108,6 @@ function decodeRuntimeSessionName(value: string): CovenRuntimeSessionState | nul
       agent,
       mode: typeof parsed.mode === "string" ? parsed.mode : "prompt",
       ...(typeof parsed.sessionMode === "string" ? { sessionMode: parsed.sessionMode } : {}),
-      ...(typeof parsed.cwd === "string" && parsed.cwd.trim() ? { cwd: parsed.cwd.trim() } : {}),
     };
   } catch {
     return null;