Method append

src/agent/transcript.py:193–217

Append one message as a UTF-8 JSON line, terminated with ``\\n``. Crash-safety: a single ``os.write`` of the line ensures the writer either appends the whole line or nothing. POSIX guarantees this for sizes ≤ ``PIPE_BUF`` (≥4096 bytes on every modern Unix); for large

(self, message: Any)

        return self._path

    def append(self, message: Any) -> None:
        """Append one message as a UTF-8 JSON line, terminated with ``\\n``.

        Crash-safety: a single ``os.write`` of the line ensures the
        writer either appends the whole line or nothing. POSIX
        guarantees this for sizes ≤ ``PIPE_BUF`` (≥4096 bytes on every
        modern Unix); for larger lines the reader is tolerant of
        partial trailing content per the JSONL format design.
        """
        if self._closed or self._fd is None:
            raise RuntimeError("TranscriptWriter is closed")
        line = _serialize_message(message) + "\n"
        encoded = line.encode("utf-8")
        # ``os.write`` may short-write under specific OS conditions;
        # loop until the whole buffer is on disk. For O_APPEND files
        # the returned ``n`` is byte count of THIS write, so the loop
        # is straightforward.
        view = memoryview(encoded)
        while view:
            written = os.write(self._fd, view)
            if written <= 0:
                # Defensive: 0-byte returns shouldn't happen on regular
                # files but the loop would spin forever otherwise.
                raise OSError(f"transcript write returned {written}")
            view = view[written:]

    def close(self) -> None:
        if self._closed: