run-llama/llama_index · error · ValueError

Initial token count exceeds token limit

Error message

Initial token count exceeds token limit

What it means

Error "Initial token count exceeds token limit" thrown in run-llama/llama_index.

Source

Thrown at llama-index-core/llama_index/core/memory/chat_summary_memory_buffer.py:178

        # NOTE: The llm will have to be set manually in kwargs
        if "llm" in data:
            data.pop("llm")

        return cls(**data, **kwargs)

    def get(
        self, input: Optional[str] = None, initial_token_count: int = 0, **kwargs: Any
    ) -> List[ChatMessage]:
        """Get chat history."""
        chat_history = self.get_all()
        if len(chat_history) == 0:
            return []

        # Give the user the choice whether to count the system prompt or not
        if self.count_initial_tokens:
            if initial_token_count > self.token_limit:
                raise ValueError("Initial token count exceeds token limit")
            self._token_count = initial_token_count

        (
            chat_history_full_text,
            chat_history_to_be_summarized,
        ) = self._split_messages_summary_or_full_text(chat_history)

        if self.llm is None or len(chat_history_to_be_summarized) == 0:
            # Simply remove the message that don't fit the buffer anymore
            updated_history = chat_history_full_text
        else:
            updated_history = [
                self._summarize_oldest_chat_history(chat_history_to_be_summarized),
                *chat_history_full_text,
            ]

        self.reset()
        self._token_count = 0

View on GitHub (pinned to afd0fef371)

Solutions

  1. Increase token_limit_full_text so it exceeds the token count of the initial messages.
  2. Shorten or truncate the initial chat history before constructing the ChatSummaryMemoryBuffer.
  3. Move older messages into a memory block instead of passing them as initial_chat_history.

When it happens

Trigger: Thrown at llama-index-core/llama_index/core/memory/chat_summary_memory_buffer.py:178 when the library encounters an invalid state.

Common situations: See trigger scenarios.


AI-assisted analysis of run-llama/llama_index@afd0fef371 (2026-08-15). Data as JSON: /api/errors/ee4e36c78f88fffe. Report an issue: GitHub.