kovidgoyal/kitty · warning

Clipboard write request has more data than allowed by clipbo

Error message

Clipboard write request has more data than allowed by clipboard_max_size ({self.max_size} bytes), ignoring further data

What it means

A clipboard write request exceeded clipboard_max_size; kitty discards the excess data and marks the request as size-exceeded. The remainder of the transfer is ignored.

Source

Thrown at kitty/clipboard.py:356

            self.currently_writing_mime = ''
            if incomplete:
                # the data is not padded to a multiple of four bytes. This is
                # tolerated for the legacy OSC 52 protocol as it has no way to
                # report errors to the client.
                if self.protocol_type is ProtocolType.osc_5522:
                    raise self.abort('Incomplete base64 data, missing padding bytes')
                log_error('Received incomplete data for clipboard')

    def write_base64_data(self, b: bytes | memoryview) -> None:
        if not self.max_size_exceeded:
            try:
                decoded = self.decoder.decode(b)
            except ValueError as e:
                raise self.abort(f'Invalid base64 data: {e}') from e
            if decoded:
                self.tempfile.write(decoded)
                if self.max_size > 0 and self.tempfile.tell() > self.max_size:
                    log_error(f'Clipboard write request has more data than allowed by clipboard_max_size ({self.max_size} bytes), ignoring further data')
                    self.max_size_exceeded = True

    def data_for(self, mime: str = 'text/plain', offset: int = 0, size: int = -1) -> bytes:
        start, full_size = self.mime_map[mime]
        if size == -1:
            size = full_size
        return self.tempfile.read(start + offset, size)


class GrantedPermission:
    one_time: bool = False
    write_ban: bool = False
    read_ban: bool = False

    def __init__(self, read: bool = False, write: bool = False, one_time: bool = False):
        self.read, self.write = read, write
        self.one_time = one_time

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Raise `clipboard_max_size` in kitty.conf if the large copies are intended
2. Fix the sender to not push oversized payloads
3. Keep it as is if the cap is a deliberate security measure

Example fix

# before
clipboard_max_size 10000000
# after
clipboard_max_size 512000000

size = len(payload)
from kitty.config import defaults  # pseudo
if size > CLIPBOARD_MAX_SIZE: skip_or_split()

When it happens

Trigger: An app (OSC 52/5522) writes clipboard data larger than the configured `clipboard_max_size` (default 512MB, often lowered). tempfile.tell() exceeds max_size during write_base64_data.

Common situations: Users lowering clipboard_max_size to harden kitty, then copying huge images/files; remote sessions tunneling binary clipboard payloads.

Related errors

• Too much piped data
• This should be run as kitten broadcast
• No option named: {k}
• No custom kitten named {kitten} found
• Not a number: {x} with error: {e}

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/a0a52d130a57adbb. Report an issue: GitHub.