diff --git a/e2e/browser-v3/arena/compwob.py b/e2e/browser-v3/arena/compwob.py
new file mode 100644
index 00000000..951a31a1
--- /dev/null
+++ b/e2e/browser-v3/arena/compwob.py
@@ -0,0 +1,45 @@
+"""Register CompWoB (compositional MiniWoB, Furuta et al.) as BrowserGym tasks.
+
+CompWoB exists to test exactly one thing: whether high MiniWoB scores are memorization or ability
+-- specialist systems fell 95%->61% on it. We reuse BrowserGym's own MiniWoB task class untouched,
+pointed at the composed pages, so there is ZERO new scoring code here to be wrong: the reward is
+the same page-owned WOB_REWARD_GLOBAL machinery MiniWoB itself uses, already canary-validated.
+
+Task ids: `compwob.<page-name>` -- the runner's existing dotted-id path handles them unchanged.
+Serving: the composed pages live at MINIWOB_URL/../compwob/<name>.html next to the shared assets.
+"""
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+from browsergym.core.registration import register_task
+from browsergym.miniwob.base import AbstractMiniwobTask
+
+COMPWOB_DIR = Path(os.environ.get(
+    "COMPWOB_HTML_DIR",
+    Path(os.environ.get("MINIWOB_SCRATCH",
+                        "/private/tmp/claude-501/-Users-eric/33681c21-c82a-490e-a036-c4c0ec1414bd/scratchpad"))
+    / "miniwob-plusplus" / "miniwob" / "html" / "compwob"))
+
+
+def compwob_page_names() -> list[str]:
+    """Discovered from the served directory, so the registry can never drift from reality."""
+    if not COMPWOB_DIR.is_dir():
+        return []
+    return sorted(p.stem for p in COMPWOB_DIR.glob("*.html"))
+
+
+ALL_COMPWOB_TASKS: list[type] = []
+
+for _name in compwob_page_names():
+    # '../compwob/<name>' rides the miniwob base_url; the browser normalizes the parent hop.
+    _cls = type(
+        f"Compwob_{_name.replace('-', '_').replace('.', '_')}",
+        (AbstractMiniwobTask,),
+        {"subdomain": f"../compwob/{_name}", "desc": f"CompWoB composed task {_name}"},
+    )
+    # Stable public id: compwob.<name> (the subdomain's ../ prefix stays an URL detail).
+    _cls.get_task_id = classmethod(lambda cls, n=_name: f"compwob.{n}")
+    ALL_COMPWOB_TASKS.append(_cls)
+    register_task(_cls.get_task_id(), _cls, nondeterministic=_cls.nondeterministic)
diff --git a/e2e/browser-v3/arena/run.py b/e2e/browser-v3/arena/run.py
index df113efa..68a1699d 100644
--- a/e2e/browser-v3/arena/run.py
+++ b/e2e/browser-v3/arena/run.py
@@ -92,7 +92,9 @@ def run_episode(arm: str, task: str, seed: int, rec: Recorder, args: argparse.Na
                                       strict=False, multiaction=True)
             # A task name containing '.' is a full BrowserGym suffix (assistantbench.validation.3);
             # bare names stay MiniWoB. One grader per suite, none of them ours.
-            if "." in task:
+            if task.startswith("compwob."):
+                import compwob  # noqa: F401  registers the 101 composed tasks
+            elif "." in task:
                 # Lazy: importing assistantbench pulls HF datasets' multiprocessing machinery in,
                 # which corrupts sync-playwright's event loop for the WHOLE process -- 248 of 252
                 # v16 MiniWoB episodes died to it before this moved out of module scope.
diff --git a/e2e/browser-v3/arena/tasks.py b/e2e/browser-v3/arena/tasks.py
index 80531db6..e3309d9c 100644
--- a/e2e/browser-v3/arena/tasks.py
+++ b/e2e/browser-v3/arena/tasks.py
@@ -83,6 +83,10 @@ def resolve_tasks(spec: str) -> list[str]:
     # AssistantBench validation split: live-web research questions, scored by their question_scorer.
     if spec == "abench":
         return [f"assistantbench.validation.{i}" for i in range(33)]
+    # CompWoB: the 101 composed pages, discovered from the served directory.
+    if spec == "compwob":
+        import compwob
+        return [f"compwob.{n}" for n in compwob.compwob_page_names()]
     if spec in CATEGORIES:
         return sorted(CATEGORIES[spec])
     names = [s.strip() for s in spec.split(",") if s.strip()]