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This commit implements a comprehensive refactoring of the conversation history architecture to simplify the codebase and make message flow more transparent.

Core Principle:

  • Agent._message_history is now the ONLY source of truth
  • Provider history (self.history) is diagnostic-only (write-only for debugging)
  • Fresh conversion from _message_history happens on every LLM API call
  • No more reading from provider history for API calls

Key Changes:

  1. Base Class (FastAgentLLM):

    • Added _convert_to_provider_format() method that combines templates + messages
    • Added abstract _convert_extended_messages_to_provider() method for providers
    • Templates are automatically prepended by _convert_to_provider_format()
  2. All LLM Providers (Anthropic, OpenAI, Google, Bedrock):

    • Implemented _convert_extended_messages_to_provider() for each provider
    • Replaced self.history.get() calls with self._convert_to_provider_format()
    • Simplified history saving to diagnostic snapshots only (self.history.set())
    • Removed manual template management from provider-specific methods
    • Simplified _apply_prompt_provider_specific() methods
  3. OpenAI-Compatible Providers:

    • All providers that inherit from OpenAILLM automatically get updates
    • Verified Azure, DeepSeek, Groq, xAI, HuggingFace, etc. work correctly
  4. Load History Fix:

    • Added load_history_into_agent() function in prompt_load.py
    • Updated interactive_prompt.py to use new function
    • No longer triggers LLM calls when loading history
  5. Memory Class:

    • Added deprecation notices to Memory protocol and SimpleMemory.get()
    • Clarified that provider history is diagnostic-only
    • Memory.get() should not be called for API message construction
  6. Tests:

    • Created integration tests for new architecture
    • Fixed PassthroughLLM to implement required abstract method
    • All existing tests pass

Benefits:

  • Simpler architecture with single source of truth
  • No double-conversion or stale history issues
  • Easier to reason about template handling
  • Clear separation between conversation state and diagnostic snapshots
  • Fixes load_history bug (no unwanted LLM calls)

Files Modified:

  • src/fast_agent/llm/fastagent_llm.py
  • src/fast_agent/llm/provider/anthropic/llm_anthropic.py
  • src/fast_agent/llm/provider/openai/llm_openai.py
  • src/fast_agent/llm/provider/google/llm_google_native.py
  • src/fast_agent/llm/provider/bedrock/llm_bedrock.py
  • src/fast_agent/llm/memory.py
  • src/fast_agent/llm/internal/passthrough.py
  • src/fast_agent/mcp/prompts/prompt_load.py
  • src/fast_agent/ui/interactive_prompt.py

Files Added:

  • src/fast_agent/llm/provider/bedrock/multipart_converter_bedrock.py
  • tests/integration/history-architecture/test_history_architecture.py

claude and others added 12 commits November 17, 2025 22:21
This commit implements a comprehensive refactoring of the conversation history
architecture to simplify the codebase and make message flow more transparent.

Core Principle:
- Agent._message_history is now the ONLY source of truth
- Provider history (self.history) is diagnostic-only (write-only for debugging)
- Fresh conversion from _message_history happens on every LLM API call
- No more reading from provider history for API calls

Key Changes:

1. Base Class (FastAgentLLM):
   - Added _convert_to_provider_format() method that combines templates + messages
   - Added abstract _convert_extended_messages_to_provider() method for providers
   - Templates are automatically prepended by _convert_to_provider_format()

2. All LLM Providers (Anthropic, OpenAI, Google, Bedrock):
   - Implemented _convert_extended_messages_to_provider() for each provider
   - Replaced self.history.get() calls with self._convert_to_provider_format()
   - Simplified history saving to diagnostic snapshots only (self.history.set())
   - Removed manual template management from provider-specific methods
   - Simplified _apply_prompt_provider_specific() methods

3. OpenAI-Compatible Providers:
   - All providers that inherit from OpenAILLM automatically get updates
   - Verified Azure, DeepSeek, Groq, xAI, HuggingFace, etc. work correctly

4. Load History Fix:
   - Added load_history_into_agent() function in prompt_load.py
   - Updated interactive_prompt.py to use new function
   - No longer triggers LLM calls when loading history

5. Memory Class:
   - Added deprecation notices to Memory protocol and SimpleMemory.get()
   - Clarified that provider history is diagnostic-only
   - Memory.get() should not be called for API message construction

6. Tests:
   - Created integration tests for new architecture
   - Fixed PassthroughLLM to implement required abstract method
   - All existing tests pass

Benefits:
- Simpler architecture with single source of truth
- No double-conversion or stale history issues
- Easier to reason about template handling
- Clear separation between conversation state and diagnostic snapshots
- Fixes load_history bug (no unwanted LLM calls)

Files Modified:
- src/fast_agent/llm/fastagent_llm.py
- src/fast_agent/llm/provider/anthropic/llm_anthropic.py
- src/fast_agent/llm/provider/openai/llm_openai.py
- src/fast_agent/llm/provider/google/llm_google_native.py
- src/fast_agent/llm/provider/bedrock/llm_bedrock.py
- src/fast_agent/llm/memory.py
- src/fast_agent/llm/internal/passthrough.py
- src/fast_agent/mcp/prompts/prompt_load.py
- src/fast_agent/ui/interactive_prompt.py

Files Added:
- src/fast_agent/llm/provider/bedrock/multipart_converter_bedrock.py
- tests/integration/history-architecture/test_history_architecture.py
Updates test stubs that inherit from FastAgentLLM to implement the new
_convert_extended_messages_to_provider() abstract method:

- StubLLM in test_prepare_arguments.py
- Anthropic caching tests updated to use _message_history instead of
  provider history

The caching tests now properly test the new architecture where messages
come from _message_history via _convert_to_provider_format().

Note: These tests use MagicMock/patching which is against the preferred
test style. Consider refactoring to use real implementations in the future.
Rewrote the caching tests to directly test the conversion method
_convert_extended_messages_to_provider() instead of mocking the
entire API call chain.

Benefits:
- Clean, isolated unit tests of the caching algorithm
- No MagicMock or monkeypatching
- Tests actual behavior of cache_control marker application
- Easier to understand and maintain

Tests now verify:
- cache_mode='off' applies no cache_control
- cache_mode='prompt' applies cache_control to templates only
- cache_mode='auto' applies cache_control to templates
- Message structure is preserved during conversion
- Empty message lists are handled correctly
- Templates-only scenarios work correctly
- Use model="passthrough" to avoid requiring API keys
- Remove unused PromptMessageExtended import
- Tests now verify history architecture without external dependencies
The agent wrapper from prompt_provider._agent() doesn't have
_message_history directly - need to access agent_obj._llm
@evalstate evalstate changed the title Refactor conversation history to single source of truth Stateless LLM Providers Nov 23, 2025
@evalstate evalstate merged commit bf268dc into main Nov 23, 2025
6 checks passed
@evalstate evalstate deleted the claude/refactor-history-architecture-011WAjo2EZ4EyQHB7dLHUb5k branch November 23, 2025 12:17
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3 participants