`CLIJSONDecodeError` from receive_messages: JSONDecodeError "Extra data" due to multiple JSON objects in one line

[ujitkumar1]

I'm encountering a recurring issue when using the claude_code_sdk. The following exception is thrown most of the time during execution:

  + Exception Group Traceback (most recent call last):
  |   File "/claude-testing/workflow.py", line 25, in <module>
  |     anyio.run(query_with_options)
  |   File "/.venv/lib/python3.11/site-packages/anyio/_core/_eventloop.py", line 74, in run
  |     return async_backend.run(func, args, {}, backend_options)
  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |   File "/.venv/lib/python3.11/site-packages/anyio/_backends/_asyncio.py", line 2310, in run
  |     return runner.run(wrapper())
  |            ^^^^^^^^^^^^^^^^^^^^^
  |   File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/runners.py", line 118, in run
  |     return self._loop.run_until_complete(task)
  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |   File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 653, in run_until_complete
  |     return future.result()
  |            ^^^^^^^^^^^^^^^
  |   File "/.venv/lib/python3.11/site-packages/anyio/_backends/_asyncio.py", line 2298, in wrapper
  |     return await func(*args)
  |            ^^^^^^^^^^^^^^^^^
  |   File "/workflow.py", line 15, in query_with_options
  |     async for message in query(
  |   File "/.venv/lib/python3.11/site-packages/claude_code_sdk/__init__.py", line 101, in query
  |     async for message in client.process_query(prompt=prompt, options=options):
  |   File "/.venv/lib/python3.11/site-packages/claude_code_sdk/_internal/client.py", line 37, in process_query
  |     async for data in transport.receive_messages():
  |   File "/.venv/lib/python3.11/site-packages/claude_code_sdk/_internal/transport/subprocess_cli.py", line 182, in receive_messages
  |     async with anyio.create_task_group() as tg:
  |   File "/.venv/lib/python3.11/site-packages/anyio/_backends/_asyncio.py", line 772, in __aexit__
  |     raise BaseExceptionGroup(
  | ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception)
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "/.venv/lib/python3.11/site-packages/claude_code_sdk/_internal/transport/subprocess_cli.py", line 192, in receive_messages
    |     data = json.loads(line_str)
    |            ^^^^^^^^^^^^^^^^^^^^
    |   File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/json/__init__.py", line 346, in loads
    |     return _default_decoder.decode(s)
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |   File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/json/decoder.py", line 340, in decode
    |     raise JSONDecodeError("Extra data", s, end)
    | json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 546)
    | 
    | The above exception was the direct cause of the following exception:
    | 
    | Traceback (most recent call last):
    |   File "/.venv/lib/python3.11/site-packages/claude_code_sdk/_internal/transport/subprocess_cli.py", line 196, in receive_messages
    |     raise SDKJSONDecodeError(line_str, e) from e
    | claude_code_sdk._errors.CLIJSONDecodeError: Failed to decode JSON: {"type":"assistant","message":{"id":"msg_016WUwP1zUZvB8wcgSguHGBi","type":"message","role":"assistan...
    +------------------------------------

It appears that the issue is caused by multiple JSON objects being emitted in a single line or without proper separation, leading to a json.decoder.JSONDecodeError: Extra data.

ENV:
claude_code_sdk version: 0.0.10
Python version: 3.11
OS: macOS

[studio-dieulamour]

exact same issue.

[geojakes]

Same

[sharon8811]

me too getting the same

[DavideFerri]

same

[fukubaka0825]

same

[ali-coplanet]

same

[Phantom168]

The issue is due to large JSON messages being split over multiple chunks, and attempting to decode each partial chunk leads to error.

Anyone facing this issue can use the changes here and test if it works for them.

Please let me know if it solved your issue.

[ltawfik]

Hi, thanks for reporting, this should be fixed in latest version 0.0.14