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_TokenCountingChatModel Class — langchain Architecture

Architecture documentation for the _TokenCountingChatModel class in test_context_editing.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  e4abac34_2d3d_5daa_0083_f37eeae00aa4["_TokenCountingChatModel"]
  08f149d6_0ef5_52a4_96df_fceeb68e4ea8["FakeChatModel"]
  e4abac34_2d3d_5daa_0083_f37eeae00aa4 -->|extends| 08f149d6_0ef5_52a4_96df_fceeb68e4ea8
  95bc2c91_0832_8fb7_f8e0_c4d613e022d3["test_context_editing.py"]
  e4abac34_2d3d_5daa_0083_f37eeae00aa4 -->|defined in| 95bc2c91_0832_8fb7_f8e0_c4d613e022d3
  fa2312c7_2802_6fd6_1396_bf6702991289["get_num_tokens_from_messages()"]
  e4abac34_2d3d_5daa_0083_f37eeae00aa4 -->|method| fa2312c7_2802_6fd6_1396_bf6702991289

Relationship Graph

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py lines 33–42

class _TokenCountingChatModel(FakeChatModel):
    """Fake chat model that counts tokens deterministically for tests."""

    @override
    def get_num_tokens_from_messages(
        self,
        messages: list[BaseMessage],
        tools: Sequence | None = None,
    ) -> int:
        return sum(_count_message_tokens(message) for message in messages)

Defined In

Extends

Source

Frequently Asked Questions

What is the _TokenCountingChatModel class?
_TokenCountingChatModel is a class in the langchain codebase, defined in libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py.
Where is _TokenCountingChatModel defined?
_TokenCountingChatModel is defined in libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py at line 33.
What does _TokenCountingChatModel extend?
_TokenCountingChatModel extends FakeChatModel.

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