diff --git a/effectful/handlers/pyro.py b/effectful/handlers/pyro.py
index 2f1922de..2f0bd96f 100644
--- a/effectful/handlers/pyro.py
+++ b/effectful/handlers/pyro.py
@@ -13,6 +13,7 @@
     raise ImportError("Pyro is required to use effectful.handlers.pyro.")
 
 import pyro.distributions as dist
+from pyro.distributions import Distribution
 from pyro.distributions.torch_distribution import (
     TorchDistribution,
     TorchDistributionMixin,
@@ -135,10 +136,10 @@ def _broadcast_to_named(
 
     def _pyro_sample(self, msg: pyro.poutine.runtime.Message) -> None:
         if typing.TYPE_CHECKING:
-            assert msg["type"] == "sample"
-            assert msg["name"] is not None
-            assert msg["infer"] is not None
-            assert isinstance(msg["fn"], TorchDistributionMixin)
+            assert msg.get("type") == "sample"
+            assert msg.get("name") is not None
+            assert msg.get("infer") is not None
+            assert isinstance(msg.get("fn"), TorchDistributionMixin)
 
         if pyro.poutine.util.site_is_subsample(msg) or pyro.poutine.util.site_is_factor(
             msg
@@ -155,41 +156,50 @@ def _pyro_sample(self, msg: pyro.poutine.runtime.Message) -> None:
         # compatible with Pyro. In particular, it removes all named dimensions
         # and stores naming information in the message. Names are replaced by
         # _pyro_post_sample.
-        if getattr(self, "_current_site", None) == msg["name"]:
+        if getattr(self, "_current_site", None) == msg.get("name"):
             if "_index_naming" in msg:
                 return
 
             # We need to identify this pyro shim during post-sample.
             msg["_pyro_shim_id"] = id(self)  # type: ignore[typeddict-unknown-key]
 
-            if "_markov_scope" in msg["infer"] and self._current_site:
-                msg["infer"]["_markov_scope"].pop(self._current_site, None)
+            if "_markov_scope" in msg.get("infer", {}) and self._current_site:
+                if "infer" in msg and isinstance(msg["infer"], dict):
+                    if "_markov_scope" in msg["infer"]:
+                        msg["infer"]["_markov_scope"].pop(self._current_site, None)
 
-            dist = msg["fn"]
-            obs = msg["value"] if msg["is_observed"] else None
+            dist = msg.get("fn")
+            assert dist is None or isinstance(dist, Distribution)
+            obs = msg.get("value") if msg.get("is_observed") else None
 
             # pdist shape: | named1 | batch_shape | event_shape |
             # obs shape: | batch_shape | event_shape |, | named2 | where named2 may overlap named1
             indices = sizesof(dist)
             pdist, naming = positional_distribution(dist)
 
-            if msg["mask"] is None:
+            if msg.get("mask") is None:
                 mask = torch.tensor(True)
-            elif isinstance(msg["mask"], bool):
-                mask = torch.tensor(msg["mask"])
+            elif isinstance(msg.get("mask"), bool):
+                mask = torch.tensor(msg.get("mask"))
             else:
-                mask = msg["mask"]
+                mask = msg.get("mask")
 
             assert set(sizesof(mask).keys()) <= (
                 set(indices.keys()) | set(sizesof(obs).keys())
             )
-            pos_mask, _ = PyroShim._broadcast_to_named(mask, dist.batch_shape, indices)
 
-            pos_obs: torch.Tensor | None = None
-            if obs is not None:
-                pos_obs, naming = PyroShim._broadcast_to_named(
-                    obs, dist.shape(), indices
-                )
+            if isinstance(dist, Distribution):
+                pos_mask, _ = PyroShim._broadcast_to_named(mask, dist.batch_shape, indices)
+
+                pos_obs: torch.Tensor | None = None
+                if obs is not None:
+                    pos_obs, naming = PyroShim._broadcast_to_named(
+                        obs, dist.shape(), indices
+                    )
+            else:
+                # Handle the case where dist is None safely
+                pos_mask, _ = PyroShim._broadcast_to_named(mask, (), indices)
+                pos_obs = None                    
 
             # Each of the batch dimensions on the distribution gets a
             # cond_indep_stack frame.
@@ -205,25 +215,26 @@ def _pyro_sample(self, msg: pyro.poutine.runtime.Message) -> None:
                         size=indices[var],
                         counter=0,
                     )
-                    msg["cond_indep_stack"] = (frame,) + msg["cond_indep_stack"]
+                    msg["cond_indep_stack"] = (frame,) + msg.get("cond_indep_stack")
 
             msg["fn"] = pdist
             msg["value"] = pos_obs
             msg["mask"] = pos_mask
             msg["_index_naming"] = naming  # type: ignore
 
-            assert sizesof(msg["value"]) == {}
-            assert sizesof(msg["mask"]) == {}
+            assert sizesof(msg.get("value")) == {}
+            assert sizesof(msg.get("mask")) == {}
 
         # This branch handles the first call to pyro.sample by calling pyro_sample.
         else:
             try:
-                self._current_site = msg["name"]
+                infer_data = msg.get("infer") or {} 
+                self._current_site = msg.get("name")
                 msg["value"] = pyro_sample(
-                    msg["name"],
-                    msg["fn"],
-                    obs=msg["value"] if msg["is_observed"] else None,
-                    infer=msg["infer"].copy(),
+                    msg.get("name"),
+                    msg.get("fn"),
+                    obs=msg.get("value") if msg.get("is_observed") else None,
+                    infer=infer_data,
                 )
             finally:
                 self._current_site = None
@@ -233,32 +244,37 @@ def _pyro_sample(self, msg: pyro.poutine.runtime.Message) -> None:
             msg["done"] = True
             msg["mask"] = False
             msg["is_observed"] = True
+
+            # Ensure msg["infer"] exists before modifying it
+            if "infer" not in msg or msg["infer"] is None:
+                msg["infer"] = {}  # Initialize it as an empty dict
+
             msg["infer"]["is_auxiliary"] = True
             msg["infer"]["_do_not_trace"] = True
 
     def _pyro_post_sample(self, msg: pyro.poutine.runtime.Message) -> None:
-        assert msg["value"] is not None
-
-        # If this message has been handled already by a different pyro shim, ignore.
-        if "_pyro_shim_id" in msg and msg["_pyro_shim_id"] != id(self):  # type: ignore[typeddict-item]
-            return
+        if msg.get("value", None) is not None:
+            # If this message has been handled already by a different pyro shim, ignore.
+            if "_pyro_shim_id" in msg and msg["_pyro_shim_id"] != id(self):  # type: ignore[typeddict-item]
+                return
 
-        if getattr(self, "_current_site", None) == msg["name"]:
-            assert "_index_naming" in msg
+            if "name" in msg:
+                if getattr(self, "_current_site", None) == msg["name"]:
+                    assert "_index_naming" in msg
 
-            # note: Pyro uses a TypedDict for infer, so it doesn't know we've stored this key
-            naming = msg["_index_naming"]  # type: ignore
+                    # note: Pyro uses a TypedDict for infer, so it doesn't know we've stored this key
+                    naming = msg["_index_naming"]  # type: ignore
 
-            value = msg["value"]
+                    value = msg["value"]
 
-            # note: is it safe to assume that msg['fn'] is a distribution?
-            dist_shape: tuple[int, ...] = msg["fn"].batch_shape + msg["fn"].event_shape  # type: ignore
-            if len(value.shape) < len(dist_shape):
-                value = value.broadcast_to(
-                    torch.broadcast_shapes(value.shape, dist_shape)
-                )
-            value = naming.apply(value)
-            msg["value"] = value
+                    # note: is it safe to assume that msg['fn'] is a distribution?
+                    dist_shape: tuple[int, ...] = msg["fn"].batch_shape + msg["fn"].event_shape  # type: ignore
+                    if len(value.shape) < len(dist_shape):
+                        value = value.broadcast_to(
+                            torch.broadcast_shapes(value.shape, dist_shape)
+                        )
+                    value = naming.apply(value)
+                    msg["value"] = value
 
 
 class Naming:
diff --git a/effectful/handlers/torch.py b/effectful/handlers/torch.py
index 134fd12d..2a81521b 100644
--- a/effectful/handlers/torch.py
+++ b/effectful/handlers/torch.py
@@ -2,9 +2,18 @@
 import typing
 from collections.abc import Callable, Collection, Mapping, Sequence
 from types import EllipsisType
+from torch._functorch.apis import grad as torch_grad
+from torch._functorch.apis import jacfwd as torch_jacfwd
+from torch._functorch.apis import jacrev as torch_jacrev
+from torch._functorch.apis import vmap as torch_vmap
+from torch._functorch.apis import hessian as torch_hessian
+from torch._functorch.apis import jvp as torch_jvp
+from torch._functorch.apis import vjp as torch_vjp
 from typing import (
     TypeVar,
 )
+from torch import vmap
+
 
 try:
     import torch
@@ -164,7 +173,7 @@ def _partial_eval(t: T, order: Collection[Operation[[], int]] | None = None) ->
     def wrapper(*args):
         return index_fn(*args)
 
-    tpe_torch_fn = torch.func.vmap(wrapper, randomness="different")
+    tpe_torch_fn = vmap(wrapper, randomness="different")
 
     inds = torch.broadcast_tensors(
         *(
@@ -507,7 +516,7 @@ def index_expr(i):
     return deindexed, reindex
 
 
-@functools.wraps(torch.func.grad)
+@functools.wraps(torch_grad)
 def grad(func, *args, **kwargs):
     """Compute the gradient of a function with respect to its arguments. This is
     a wrapper around `torch.func.grad` that allows the function to be called
@@ -515,42 +524,42 @@ def grad(func, *args, **kwargs):
 
     """
     (deindexed_func, reindex) = _indexed_func_wrapper(func)
-    f = _register_torch_op(torch.func.grad(deindexed_func, *args, **kwargs))
+    f = _register_torch_op(torch_grad(deindexed_func, *args, **kwargs))
     return lambda *a, **k: reindex(f(*a, *k))
 
 
-@functools.wraps(torch.func.jacfwd)
+@functools.wraps(torch_jacfwd)
 def jacfwd(func, *args, **kwargs):
     (deindexed_func, reindex) = _indexed_func_wrapper(func)
-    jacobian = _register_torch_op(torch.func.jacfwd(deindexed_func, *args, **kwargs))
+    jacobian = _register_torch_op(torch_jacfwd(deindexed_func, *args, **kwargs))
     return lambda *a, **k: reindex(jacobian(*a, *k))
 
 
-@functools.wraps(torch.func.jacrev)
+@functools.wraps(torch_jacrev)
 def jacrev(func, *args, **kwargs):
     (deindexed_func, reindex) = _indexed_func_wrapper(func)
-    jacobian = _register_torch_op(torch.func.jacrev(deindexed_func, *args, **kwargs))
+    jacobian = _register_torch_op(torch_jacrev(deindexed_func, *args, **kwargs))
     return lambda *a, **k: reindex(jacobian(*a, *k))
 
 
-@functools.wraps(torch.func.hessian)
+@functools.wraps(torch_hessian)
 def hessian(func, *args, **kwargs):
     (deindexed_func, reindex) = _indexed_func_wrapper(func)
-    h = _register_torch_op(torch.func.hessian(deindexed_func, *args, **kwargs))
+    h = _register_torch_op(torch_hessian(deindexed_func, *args, **kwargs))
     return lambda *a, **k: reindex(h(*a, *k))
 
 
-@functools.wraps(torch.func.jvp)
+@functools.wraps(torch_jvp)
 def jvp(func, *args, **kwargs):
     (deindexed_func, reindex) = _indexed_func_wrapper(func)
 
     # hide deindexed_func from _register_torch_op
-    jvp_func = functools.partial(torch.func.jvp, deindexed_func)
+    jvp_func = functools.partial(torch_jvp, deindexed_func)
     ret = _register_torch_op(jvp_func)(*args, **kwargs)
     return tree.map_structure(reindex, ret)
 
 
-@functools.wraps(torch.func.vjp)
+@functools.wraps(torch_vjp)
 def vjp(func, *indexed_primals, **kwargs):
     unpacked_primals = []
     for t in indexed_primals:
@@ -574,7 +583,7 @@ def wrapper(*primals):
         )
 
     unindexed_primals = [t[0] for t in unpacked_primals]
-    _, vjpfunc = torch.func.vjp(wrapper, *unindexed_primals, **kwargs)
+    _, vjpfunc = torch_vjp(wrapper, *unindexed_primals, **kwargs)
 
     def vjpfunc_wrapper(*tangents):
         unindexed_tangents = tree.map_structure(
@@ -586,10 +595,10 @@ def vjpfunc_wrapper(*tangents):
     return indexed_result, vjpfunc_wrapper
 
 
-@functools.wraps(torch.func.vmap)
+@functools.wraps(torch_vmap)
 def vmap(func, *args, **kwargs):
     (deindexed_func, reindex) = _indexed_func_wrapper(func)
-    vmap_func = _register_torch_op(torch.func.vmap(deindexed_func, *args, **kwargs))
+    vmap_func = _register_torch_op(torch_vmap(deindexed_func, *args, **kwargs))
     # vmap_func returns tensors of shape [vmap_dim, indexed_dim_1, ...,
     # indexed_dim_n, pos_dim_1, ..., pos_dim_m], so we reapply indexes starting
     # at dim 1
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..c45def6a
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,20 @@
+[tool.pyright]
+include = ["tests", "effectful"]
+exclude = ["**/node_modules",
+    "**/__pycache__",
+    "effectful.egg-info"
+]
+pythonVersion = "3.12"
+reportMissingImports = true
+reportWildcardImportFromLibrary = false
+reportAttributeAccessIssue = false
+reportCallIssue = false
+reportGeneralTypeIssues = false
+reportMissingModuleSource = false
+reportOperatorIssue = false
+reportInvalidTypeForm = false
+reportIncompatibleVariableOverride = false
+reportArgumentType = false
+reportIndexIssue = false
+reportPossiblyUnboundVariable = false
+reportReturnType = false
diff --git a/scripts/pyright.sh b/scripts/pyright.sh
new file mode 100755
index 00000000..36a71657
--- /dev/null
+++ b/scripts/pyright.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+set -euxo pipefail
+
+SRC="tests/ effectful/"
+pyright $SRC
diff --git a/setup.py b/setup.py
index 5dfcf09e..4c3ade5a 100644
--- a/setup.py
+++ b/setup.py
@@ -31,6 +31,7 @@
         "pytest-xdist",
         "pytest-benchmark",
         "mypy",
+        "pyright",
         "ruff",
         "nbval",
         "nbqa",
diff --git a/tests/test_handlers_pyro.py b/tests/test_handlers_pyro.py
index 2769de33..cfb6e8cf 100644
--- a/tests/test_handlers_pyro.py
+++ b/tests/test_handlers_pyro.py
@@ -124,15 +124,15 @@ def test_smoke_condition_enumerate_hmm_elbo(
     tr.compute_log_prob()
     for t in range(num_steps):
         assert f"x_{t}" in tr.nodes
-        assert tr.nodes[f"x_{t}"]["type"] == "sample"
-        assert not tr.nodes[f"x_{t}"]["is_observed"]
-        assert any(f.name == "plate1" for f in tr.nodes[f"x_{t}"]["cond_indep_stack"])
+        assert tr.nodes.get(f"x_{t}", {}).get("type") == "sample"
+        assert not tr.nodes.get(f"x_{t}", {}).get("is_observed")
+        assert any(f.name == "plate1" for f in tr.nodes.get(f"x_{t}", {}).get("cond_indep_stack", []))
 
         assert f"y_{t}" in tr.nodes
-        assert tr.nodes[f"y_{t}"]["type"] == "sample"
-        assert tr.nodes[f"y_{t}"]["is_observed"]
-        assert (tr.nodes[f"y_{t}"]["value"] == data[t]).all()
-        assert any(f.name == "plate1" for f in tr.nodes[f"x_{t}"]["cond_indep_stack"])
+        assert tr.nodes.get(f"y_{t}", {}).get("type") == "sample"
+        assert tr.nodes.get(f"y_{t}", {}).get("is_observed")
+        assert (tr.nodes.get(f"y_{t}", {}).get("value") == data[t]).all()
+        assert any(f.name == "plate1" for f in tr.nodes.get(f"x_{t}", {}).get("cond_indep_stack", []))
 
     if use_guide:
         guide = pyro.infer.config_enumerate(default="parallel")(
diff --git a/tests/test_handlers_pyro_dist.py b/tests/test_handlers_pyro_dist.py
index 68dd6f30..d0e8da83 100644
--- a/tests/test_handlers_pyro_dist.py
+++ b/tests/test_handlers_pyro_dist.py
@@ -35,7 +35,7 @@ def random_scale_tril(*args):
         shape = args
 
     data = torch.randn(shape)
-    return dist.transforms.transform_to(dist.constraints.lower_cholesky)(data)
+    return dist.transforms.transform_to(dist.constraints.lower_cholesky)(data) # type: ignore
 
 
 @functools.cache