diff --git a/replit_river/codegen/client.py b/replit_river/codegen/client.py
index cac352c0..ee60c517 100644
--- a/replit_river/codegen/client.py
+++ b/replit_river/codegen/client.py
@@ -420,6 +420,12 @@ def extract_props(tpe: RiverType) -> list[dict[str, RiverType]]:
                         current_chunks.append(f"  {name}: {type_name}")
                 typeddict_encoder.append(",")
             typeddict_encoder.append("}")
+            # exclude_none
+            typeddict_encoder = (
+                ["{k: v for (k, v) in ("]
+                + typeddict_encoder
+                + [").items() if v is not None}"]
+            )
         else:
             typeddict_encoder.append("{}")
             current_chunks.append("  pass")
diff --git a/scripts/parity/check_parity.py b/scripts/parity/check_parity.py
index 4ecc3626..8e75532c 100644
--- a/scripts/parity/check_parity.py
+++ b/scripts/parity/check_parity.py
@@ -1,4 +1,4 @@
-from typing import Any, Callable, Literal, TypedDict, TypeVar, Union, cast
+from typing import Any, Callable, Literal, TypedDict, TypeVar, Union
 
 import pyd
 import tyd
@@ -16,15 +16,45 @@
 
 A = TypeVar("A")
 
+PrimitiveType = (
+    bool | str | int | float | dict[str, "PrimitiveType"] | list["PrimitiveType"]
+)
+
+
+def deep_equal(a: PrimitiveType, b: PrimitiveType) -> Literal[True]:
+    if a == b:
+        return True
+    elif isinstance(a, dict) and isinstance(b, dict):
+        a_keys: PrimitiveType = list(a.keys())
+        b_keys: PrimitiveType = list(b.keys())
+        assert deep_equal(a_keys, b_keys)
+
+        # We do this dance again because Python variance is hard. Feel free to fix it.
+        keys = set(a.keys())
+        keys.update(b.keys())
+        for k in keys:
+            aa: PrimitiveType = a[k]
+            bb: PrimitiveType = b[k]
+            assert deep_equal(aa, bb)
+        return True
+    elif isinstance(a, list) and isinstance(b, list):
+        assert len(a) == len(b)
+        for i in range(len(a)):
+            assert deep_equal(a[i], b[i])
+        return True
+    else:
+        assert a == b, f"{a} != {b}"
+        return True
+
 
 def baseTestPattern(
     x: A, encode: Callable[[A], Any], adapter: TypeAdapter[Any]
 ) -> None:
     a = encode(x)
     m = adapter.validate_python(a)
-    z = adapter.dump_python(m)
+    z = adapter.dump_python(m, by_alias=True, exclude_none=True)
 
-    assert a == z
+    assert deep_equal(a, z)
 
 
 def testAiexecExecInit() -> None:
@@ -93,7 +123,39 @@ def testAgenttoollanguageserverGetcodesymbolInput() -> None:
             "line": gen_float(),
             "character": gen_float(),
         },
-        "kind": cast(kind_type, gen_opt(gen_choice(list(range(1, 27))))()),
+        "kind": gen_choice(
+            list[kind_type](
+                [
+                    1,
+                    2,
+                    3,
+                    4,
+                    5,
+                    6,
+                    7,
+                    8,
+                    9,
+                    10,
+                    11,
+                    12,
+                    13,
+                    14,
+                    15,
+                    16,
+                    17,
+                    18,
+                    19,
+                    20,
+                    21,
+                    22,
+                    23,
+                    24,
+                    25,
+                    26,
+                    None,
+                ]
+            )
+        )(),
     }
 
     baseTestPattern(
@@ -116,17 +178,17 @@ def testShellexecSpawnInput() -> None:
         "env": gen_opt(gen_dict(gen_str))(),
         "cwd": gen_opt(gen_str)(),
         "size": gen_opt(
-            lambda: cast(
-                size_type,
+            lambda: size_type(
                 {
                     "rows": gen_int(),
                     "cols": gen_int(),
-                },
-            )
+                }
+            ),
         )(),
         "useReplitRunEnv": gen_opt(gen_bool)(),
         "useCgroupMagic": gen_opt(gen_bool)(),
         "interactive": gen_opt(gen_bool)(),
+        "onlySpawnIfNoProcesses": gen_opt(gen_bool)(),
     }
 
     baseTestPattern(
@@ -146,12 +208,82 @@ def testConmanfilesystemPersistInput() -> None:
     )
 
 
+closeFile = tyd.ReplspaceapiInitInputOneOf_closeFile
+githubToken = tyd.ReplspaceapiInitInputOneOf_githubToken
+sshToken0 = tyd.ReplspaceapiInitInputOneOf_sshToken0
+sshToken1 = tyd.ReplspaceapiInitInputOneOf_sshToken1
+allowDefaultBucketAccess = tyd.ReplspaceapiInitInputOneOf_allowDefaultBucketAccess
+
+allowDefaultBucketAccessResultOk = (
+    tyd.ReplspaceapiInitInputOneOf_allowDefaultBucketAccessResultOneOf_ok
+)
+allowDefaultBucketAccessResultError = (
+    tyd.ReplspaceapiInitInputOneOf_allowDefaultBucketAccessResultOneOf_error
+)
+
+
+def testReplspaceapiInitInput() -> None:
+    x: tyd.ReplspaceapiInitInput = gen_choice(
+        list[tyd.ReplspaceapiInitInput](
+            [
+                closeFile(
+                    {"kind": "closeFile", "filename": gen_str(), "nonce": gen_str()}
+                ),
+                githubToken(
+                    {"kind": "githubToken", "token": gen_str(), "nonce": gen_str()}
+                ),
+                sshToken0(
+                    {
+                        "kind": "sshToken",
+                        "nonce": gen_str(),
+                        "SSHHostname": gen_str(),
+                        "token": gen_str(),
+                    }
+                ),
+                sshToken1({"kind": "sshToken", "nonce": gen_str(), "error": gen_str()}),
+                allowDefaultBucketAccess(
+                    {
+                        "kind": "allowDefaultBucketAccess",
+                        "nonce": gen_str(),
+                        "result": gen_choice(
+                            list[
+                                tyd.ReplspaceapiInitInputOneOf_allowDefaultBucketAccessResult
+                            ](
+                                [
+                                    allowDefaultBucketAccessResultOk(
+                                        {
+                                            "bucketId": gen_str(),
+                                            "sourceReplId": gen_str(),
+                                            "status": "ok",
+                                            "targetReplId": gen_str(),
+                                        }
+                                    ),
+                                    allowDefaultBucketAccessResultError(
+                                        {"message": gen_str(), "status": "error"}
+                                    ),
+                                ]
+                            )
+                        )(),
+                    }
+                ),
+            ]
+        )
+    )()
+
+    baseTestPattern(
+        x,
+        tyd.encode_ReplspaceapiInitInput,
+        TypeAdapter(pyd.ReplspaceapiInitInput),
+    )
+
+
 def main() -> None:
     testAiexecExecInit()
     testAgenttoollanguageserverOpendocumentInput()
     testAgenttoollanguageserverGetcodesymbolInput()
     testShellexecSpawnInput()
     testConmanfilesystemPersistInput()
+    testReplspaceapiInitInput()
 
 
 if __name__ == "__main__":
diff --git a/scripts/parity/gen.py b/scripts/parity/gen.py
index ae777183..92bae50b 100644
--- a/scripts/parity/gen.py
+++ b/scripts/parity/gen.py
@@ -1,15 +1,15 @@
 import random
+import string
 from typing import Callable, Optional, TypeVar
 
 A = TypeVar("A")
 
 
+printable_chars = string.ascii_letters + string.digits
+
+
 def gen_char() -> str:
-    pos = random.randint(0, 26 * 2)
-    if pos < 26:
-        return chr(ord("A") + pos)
-    else:
-        return chr(ord("a") + pos - 26)
+    return random.choice(printable_chars)
 
 
 def gen_str() -> str: