SYSTEM PROMPT ISSUES

[mbt1909432]

when add '\n' to the system prompt ，the program cannot run

[arindam-giri]

\n is allowed in system_prompt, I just checked. Avoid having any commented lines between agent options arguments.

[QudaRulo]

same issue Maybe you can use the monkey patch by claude to reslove the problem temporarily. Indeed, prompt.replace("\n", "") can also solve the problem. Apart from line breaks, I haven’t encountered other cases so far.

from claude_agent_sdk._internal.transport.subprocess_cli import SubprocessCLITransport

_original_build_command = SubprocessCLITransport._build_command


def _patched_build_command(self):
    cmd = _original_build_command(self)

    # find and replace --system-prompt
    if "--system-prompt" in cmd:
        idx = cmd.index("--system-prompt")
        if idx + 1 < len(cmd):
            system_prompt = cmd[idx + 1]
            # tempfile
            if "\n" in system_prompt:
                temp_file = tempfile.NamedTemporaryFile(mode="w", suffix=".txt", delete=False, encoding="utf-8")
                temp_file.write(system_prompt)
                temp_file.close()

                cmd[idx + 1] = f"@{temp_file.name}"

    if "--append-system-prompt" in cmd:
        idx = cmd.index("--append-system-prompt")
        if idx + 1 < len(cmd):
            append_prompt = cmd[idx + 1]
            if "\n" in append_prompt:
                temp_file = tempfile.NamedTemporaryFile(mode="w", suffix=".txt", delete=False, encoding="utf-8")
                temp_file.write(append_prompt)
                temp_file.close()

                cmd[idx + 1] = f"@{temp_file.name}"

    return cmd
SubprocessCLITransport._build_command = _patched_build_command
print("[Workaround] Applied monkey patch to fix multi-line system_prompt issue")