diff --git a/examples/wave/wave-op-mpi.py b/examples/wave/wave-op-mpi.py
index 7f9059515..ab6c41e5e 100644
--- a/examples/wave/wave-op-mpi.py
+++ b/examples/wave/wave-op-mpi.py
@@ -192,10 +192,7 @@ def main(ctx_factory, dim=2, order=3,
     else:
         actx = actx_class(comm, queue,
                 allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
-                force_device_scalars=True,
-                comm_tag_to_mpi_tag={
-                    _WaveStateTag: 1234,
-                    })
+                force_device_scalars=True)
 
     from meshmode.distributed import MPIMeshDistributor, get_partition_by_pymetis
     mesh_dist = MPIMeshDistributor(comm)
diff --git a/grudge/array_context.py b/grudge/array_context.py
index 7be890e67..675e47a29 100644
--- a/grudge/array_context.py
+++ b/grudge/array_context.py
@@ -32,8 +32,7 @@
 # {{{ imports
 
 from typing import (
-        TYPE_CHECKING, Mapping, Tuple, Any, Callable, Optional,
-        Hashable, Type)
+        TYPE_CHECKING, Mapping, Tuple, Any, Callable, Optional, Type)
 from dataclasses import dataclass
 
 from meshmode.array_context import (
@@ -240,16 +239,10 @@ def __init__(self,
             queue: "pyopencl.CommandQueue",
             *, allocator: Optional["pyopencl.tools.AllocatorInterface"] = None,
             wait_event_queue_length: Optional[int] = None,
-            force_device_scalars: bool = False,
-            comm_tag_to_mpi_tag: Optional[Mapping[Hashable, int]] = None) -> None:
+            force_device_scalars: bool = False) -> None:
         """
         See :class:`arraycontext.impl.pyopencl.PyOpenCLArrayContext` for most
         arguments.
-
-        :arg comm_tag_to_mpi_tag: A mapping from symbolic tags used
-            in the *comm_tag* argument of
-            :func:`grudge.trace_pair.cross_rank_trace_pairs` to numeric values
-            to be used with MPI.
         """
         super().__init__(queue, allocator=allocator,
                 wait_event_queue_length=wait_event_queue_length,
@@ -257,19 +250,13 @@ def __init__(self,
 
         self.mpi_communicator = mpi_communicator
 
-        if comm_tag_to_mpi_tag is None:
-            comm_tag_to_mpi_tag = {}
-
-        self.comm_tag_to_mpi_tag = comm_tag_to_mpi_tag
-
     def clone(self):
         # type-ignore-reason: 'DistributedLazyArrayContext' has no 'queue' member
         # pylint: disable=no-member
         return type(self)(self.mpi_communicator, self.queue,
                 allocator=self.allocator,
                 wait_event_queue_length=self._wait_event_queue_length,
-                force_device_scalars=self._force_device_scalars,
-                comm_tag_to_mpi_tag=self.comm_tag_to_mpi_tag)
+                force_device_scalars=self._force_device_scalars)
 
 # }}}
 
diff --git a/grudge/trace_pair.py b/grudge/trace_pair.py
index 2b9cf14f7..3e6278492 100644
--- a/grudge/trace_pair.py
+++ b/grudge/trace_pair.py
@@ -46,7 +46,9 @@
 """
 
 
-from typing import List, Hashable, Optional
+from typing import List, Hashable, Optional, Type, Any
+
+from pytools.persistent_dict import KeyBuilder
 
 from arraycontext import (
     ArrayContainer,
@@ -432,6 +434,11 @@ def finish(self):
                          exterior=bdry_conn(self.remote_data))
 
 
+class _TagKeyBuilder(KeyBuilder):
+    def update_for_type(self, key_hash, key: Type[Any]):
+        self.rec(key_hash, (key.__module__, key.__name__, key.__name__,))
+
+
 def cross_rank_trace_pairs(
         dcoll: DiscretizationCollection, ary,
         comm_tag: Hashable = None,
@@ -492,16 +499,22 @@ def cross_rank_trace_pairs(
             if isinstance(comm_tag, int):
                 num_tag = comm_tag
 
-            from grudge.array_context import MPIPyOpenCLArrayContext
-            if isinstance(actx, MPIPyOpenCLArrayContext):
-                num_tag = actx.comm_tag_to_mpi_tag.get(comm_tag)
-
             if num_tag is None:
-                raise ValueError("Encountered unknown symbolic tag "
-                        f"'{comm_tag}'. To make this symbolic tag work, "
-                        f"use 'grudge.array_context.MPIPyOpenCLArrayContext' and "
-                        "assign this tag a numerical value via its "
-                        "comm_tag_to_mpi_tag attribute.")
+                # FIXME: This isn't guaranteed to be correct.
+                # See here for discussion:
+                # - https://github.com/illinois-ceesd/mirgecom/issues/617#issuecomment-1057082716  # noqa
+                # - https://github.com/inducer/grudge/pull/222
+                from mpi4py import MPI
+                tag_ub = actx.mpi_communicator.Get_attr(MPI.TAG_UB)
+                key_builder = _TagKeyBuilder()
+                digest = key_builder(comm_tag)
+                num_tag = sum(ord(ch) << i for i, ch in enumerate(digest)) % tag_ub
+
+                from warnings import warn
+                warn("Encountered unknown symbolic tag "
+                        f"'{comm_tag}', assigning a value of '{num_tag}'. "
+                        "This is a temporary workaround, please ensure that "
+                        "tags are sufficiently distinct for your use case.")
 
             comm_tag = num_tag
 
diff --git a/test/test_mpi_communication.py b/test/test_mpi_communication.py
index 2dcf73339..82a6cc234 100644
--- a/test/test_mpi_communication.py
+++ b/test/test_mpi_communication.py
@@ -46,7 +46,10 @@
 from pytools.obj_array import flat_obj_array
 
 import grudge.op as op
-from testlib import SimpleTag
+
+
+class SimpleTag:
+    pass
 
 
 # {{{ mpi test infrastructure
@@ -86,8 +89,7 @@ def run_test_with_mpi_inner():
     if actx_class is MPIPytatoArrayContext:
         actx = actx_class(comm, queue, mpi_base_tag=15000)
     elif actx_class is MPIPyOpenCLArrayContext:
-        actx = actx_class(comm, queue, force_device_scalars=True,
-                comm_tag_to_mpi_tag={SimpleTag: 15000})
+        actx = actx_class(comm, queue, force_device_scalars=True)
     else:
         raise ValueError("unknown actx_class")
 
diff --git a/test/testlib.py b/test/testlib.py
deleted file mode 100644
index 85d8bb395..000000000
--- a/test/testlib.py
+++ /dev/null
@@ -1,5 +0,0 @@
-# Needed here because MPI test orchestration imports the test module twice,
-# leading to two nominally different tag types. Grrr.
-
-class SimpleTag:
-    pass