diff --git a/pyro/params/param_store.py b/pyro/params/param_store.py
index c191227f67..4e2ba9e74d 100644
--- a/pyro/params/param_store.py
+++ b/pyro/params/param_store.py
@@ -19,8 +19,12 @@
 import torch
 from torch.distributions import constraints, transform_to
 from torch.serialization import MAP_LOCATION
+from typing_extensions import TypedDict
 
-from pyro.types import StateDict
+
+class StateDict(TypedDict):
+    params: Dict[str, torch.Tensor]
+    constraints: Dict[str, constraints.Constraint]
 
 
 class ParamStoreDict:
diff --git a/pyro/poutine/runtime.py b/pyro/poutine/runtime.py
index 64640f106a..2c51f8189f 100644
--- a/pyro/poutine/runtime.py
+++ b/pyro/poutine/runtime.py
@@ -14,9 +14,10 @@
 )
 
 if TYPE_CHECKING:
+    from typing_extensions import TypedDict
+
     from pyro.poutine.indep_messenger import CondIndepStackFrame
     from pyro.poutine.messenger import Messenger
-    from pyro.types import Message
 
 # the global pyro stack
 _PYRO_STACK: List[Messenger] = []
@@ -25,6 +26,24 @@
 _PYRO_PARAM_STORE = ParamStoreDict()
 
 
+class Message(TypedDict, total=False):
+    type: Optional[str]
+    name: str
+    fn: Callable
+    is_observed: bool
+    args: Tuple
+    kwargs: Dict
+    value: Optional[torch.Tensor]
+    scale: float
+    mask: Union[bool, torch.Tensor, None]
+    cond_indep_stack: Tuple[CondIndepStackFrame, ...]
+    done: bool
+    stop: bool
+    continuation: Optional[Callable[[Message], None]]
+    infer: Optional[Dict[str, Union[str, bool]]]
+    obs: Optional[torch.Tensor]
+
+
 class _DimAllocator:
     """
     Dimension allocator for internal use by :class:`plate`.
diff --git a/pyro/types.py b/pyro/types.py
index 3a62caf8e3..2ca6791f10 100644
--- a/pyro/types.py
+++ b/pyro/types.py
@@ -3,13 +3,14 @@
 
 from __future__ import annotations
 
-from typing import Callable, Dict, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Callable, Dict, Optional, Tuple, Union
 
-import torch
-from torch.distributions import constraints
-from typing_extensions import TypedDict
+if TYPE_CHECKING:
+    import torch
+    from torch.distributions import constraints
+    from typing_extensions import TypedDict
 
-from pyro.poutine.indep_messenger import CondIndepStackFrame
+    from pyro.poutine.indep_messenger import CondIndepStackFrame
 
 
 class Message(TypedDict, total=False):