Fix json reading and anyio error

src/claude_code_sdk/_internal/query.py

@@ -15,7 +15,6 @@ from mcp.types import (
 )
 
 from ..types import (
-    PermissionResult,
     PermissionResultAllow,
     PermissionResultDeny,
     SDKControlPermissionRequest,
@@ -444,15 +443,14 @@ class Query:
 
     async def receive_messages(self) -> AsyncIterator[dict[str, Any]]:
         """Receive SDK messages (not control messages)."""
-        async with self._message_receive:
-            async for message in self._message_receive:
-                # Check for special messages
-                if message.get("type") == "end":
-                    break
-                elif message.get("type") == "error":
-                    raise Exception(message.get("error", "Unknown error"))
+        async for message in self._message_receive:
+            # Check for special messages
+            if message.get("type") == "end":
+                break
+            elif message.get("type") == "error":
+                raise Exception(message.get("error", "Unknown error"))
 
-                yield message
+            yield message
 
     async def close(self) -> None:
         """Close the query and transport."""

src/claude_code_sdk/_internal/transport/subprocess_cli.py

@@ -301,20 +301,39 @@ class SubprocessCLITransport(Transport):
         if not self._process or not self._stdout_stream:
             raise CLIConnectionError("Not connected")
 
+        json_buffer = ""
+        _MAX_BUFFER_SIZE = 1024 * 1024  # 1MB buffer limit
+
         # Process stdout messages
         try:
             async for line in self._stdout_stream:
-                line = line.strip()
-                if not line:
+                line_str = line.strip()
+                if not line_str:
                     continue
 
-                try:
-                    yield json.loads(line)
-                except json.JSONDecodeError as e:
+                # Accumulate partial JSON until we can parse it
+                # Note: TextReceiveStream can truncate long lines, so we need to buffer
+                # and speculatively parse until we get a complete JSON object
+                json_buffer += line_str
+
+                if len(json_buffer) > _MAX_BUFFER_SIZE:
+                    json_buffer = ""
                     raise SDKJSONDecodeError(
-                        f"Invalid JSON from CLI: {line[:100]}",
-                        e,
-                    ) from e
+                        f"JSON message exceeded maximum buffer size of {_MAX_BUFFER_SIZE} bytes",
+                        ValueError(
+                            f"Buffer size {len(json_buffer)} exceeds limit {_MAX_BUFFER_SIZE}"
+                        ),
+                    )
+
+                try:
+                    data = json.loads(json_buffer)
+                    json_buffer = ""
+                    yield data
+                except json.JSONDecodeError:
+                    # We are speculatively decoding the buffer until we get
+                    # a full JSON object. If there is an actual issue, we
+                    # raise an error after _MAX_BUFFER_SIZE.
+                    continue
 
         except anyio.ClosedResourceError:
             pass