* fix(core): raise LLMEmptyResponseError for empty Anthropic responses
Fixes LET-7679: Opus 4.6 occasionally returns empty responses (no content
and no tool calls), causing silent failures with stop_reason=end_turn.
Changes:
- Add LLMEmptyResponseError class (subclass of LLMServerError)
- Raise error in anthropic_client for empty non-streaming responses
- Raise error in anthropic_streaming_interface for empty streaming responses
- Pass through LLMError instances in handle_llm_error to preserve specific types
- Add test for empty streaming response detection
This allows clients (letta-code) to catch this specific error and implement
retry logic with cache-busting modifications.
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* fix(core): set invalid_llm_response stop reason for empty responses
Catch LLMEmptyResponseError specifically and set stop_reason to
invalid_llm_response instead of llm_api_error. This allows clients
to distinguish empty responses from transient API errors.
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fix(core): ensure otid exists when flushing buffered anthropic tool chunks
Anthropic TOOL_USE buffering can emit buffered tool_call/approval chunks on content block stop before otid is assigned in the normal inner_thoughts_complete path. Ensure flush-time chunks get a deterministic otid so streaming clients can reliably correlate deltas.
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* fix(core): handle ResponseIncompleteEvent in OpenAI Responses API streaming
When reasoning models (gpt-5.x) exhaust their max_output_tokens budget
on chain-of-thought reasoning, OpenAI emits a ResponseIncompleteEvent
instead of ResponseCompletedEvent. This was previously unhandled, causing
final_response to remain None — which meant get_content() and
get_tool_call_objects() returned empty results, silently dropping the
partial response.
Now ResponseIncompleteEvent is handled identically to
ResponseCompletedEvent (extracting partial content, usage stats, and
token details), with an additional warning log indicating the incomplete
reason.
* fix(core): propagate finish_reason for Responses API incomplete events
- Guard usage extraction against None usage payload in
ResponseIncompleteEvent handler
- Add _finish_reason override to LettaLLMAdapter so streaming adapters
can explicitly set finish_reason without a chat_completions_response
- Map incomplete_details.reason="max_output_tokens" to
finish_reason="length" in SimpleLLMStreamAdapter, matching the Chat
Completions API convention
- This allows the agent loop's _decide_continuation to correctly return
stop_reason="max_tokens_exceeded" instead of "end_turn" when the model
exhausts its output token budget on reasoning
* fix(core): handle empty content parts in incomplete ResponseOutputMessage
When a model hits max_output_tokens after starting a ResponseOutputMessage
but before producing any content parts, the message has content=[]. This
previously raised ValueError("Got 0 content parts, expected 1"). Now it
logs a warning and skips the empty message, allowing reasoning-only
incomplete responses to be processed cleanly.
* fix(core): map all incomplete reasons to finish_reason, not just max_output_tokens
Handle content_filter and any future unknown incomplete reasons from the
Responses API instead of silently leaving finish_reason as None.
* auto fixes
* auto fix pt2 and transitive deps and undefined var checking locals()
* manual fixes (ignored or letta-code fixed)
* fix circular import
* remove all ignores, add FastAPI rules and Ruff rules
* add ty and precommit
* ruff stuff
* ty check fixes
* ty check fixes pt 2
* error on invalid
get_content() was only setting signature on ReasoningContent items.
When Gemini returns a function call with thought_signature but no
ReasoningContent (e.g. include_thoughts=False), the signature was
stored on self.thinking_signature but never attached to TextContent.
This caused "missing thought_signature in functionCall parts" errors
when the message was echoed back to Gemini on the next turn.
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* fix: handle Anthropic overloaded_error in streaming interfaces
* fix: handle Unicode surrogates in OpenAI requests
Sanitize Unicode surrogate pairs before sending requests to OpenAI API.
Surrogate pairs (U+D800-U+DFFF) are UTF-16 encoding artifacts that cause
UnicodeEncodeError when encoding to UTF-8.
Fixes Datadog error: 'utf-8' codec can't encode character '\ud83c' in
position 326605: surrogates not allowed
* fix: handle UnicodeEncodeError from lone Unicode surrogates in OpenAI requests
Improved sanitize_unicode_surrogates() to explicitly filter out lone
surrogate characters (U+D800 to U+DFFF) which are invalid in UTF-8.
Previous implementation used errors='ignore' which could still fail in
edge cases. New approach directly checks Unicode code points and removes
any surrogates before data reaches httpx encoding.
Also added sanitization to stream_async_responses() method which was
missing it.
Fixes: 'utf-8' codec can't encode character '\ud83c' in position X:
surrogates not allowed
fix: use shared event + .athrow() to properly set stream_was_cancelled flag
**Problem:**
When a run is cancelled via /cancel endpoint, `stream_was_cancelled` remained
False because `RunCancelledException` was raised in the consumer code (wrapper),
which closes the generator from outside. This causes Python to skip the
generator's except blocks and jump directly to finally with the wrong flag value.
**Solution:**
1. Shared `asyncio.Event` registry for cross-layer cancellation signaling
2. `cancellation_aware_stream_wrapper` sets the event when cancellation detected
3. Wrapper uses `.athrow()` to inject exception INTO generator (not consumer-side raise)
4. All streaming interfaces check event in `finally` block to set flag correctly
5. `streaming_service.py` handles `RunCancelledException` gracefully, yields [DONE]
**Changes:**
- streaming_response.py: Event registry + .athrow() injection + graceful handling
- openai_streaming_interface.py: 3 classes check event in finally
- gemini_streaming_interface.py: Check event in finally
- anthropic_*.py: Catch RunCancelledException
- simple_llm_stream_adapter.py: Create & pass event to interfaces
- streaming_service.py: Handle RunCancelledException, yield [DONE], skip double-update
- routers/v1/{conversations,runs}.py: Pass event to wrapper
- integration_test_human_in_the_loop.py: New test for approval + cancellation
**Tests:**
- test_tool_call with cancellation (OpenAI models) ✅
- test_approve_with_cancellation (approval flow + concurrent cancel) ✅
**Known cosmetic warnings (pre-existing):**
- "Run already in terminal state" - agent loop tries to update after /cancel
- "Stream ended without terminal event" - background streaming timing race
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* fix: prevent empty reasoning messages in streaming interfaces
Prevents empty "Thinking..." indicators from appearing in clients by
filtering out reasoning messages with no content at the source.
Changes:
- Gemini: Don't emit ReasoningMessage when only thought_signature exists
- Gemini: Only emit reasoning content if text is non-empty
- Anthropic: Don't emit ReasoningMessage for BetaSignatureDelta
- Anthropic: Only emit reasoning content if thinking text is non-empty
This fixes the issue where providers send signature metadata before
actual thinking content, causing empty reasoning blocks to appear
in the UI after responses complete.
Affects: Gemini reasoning, Anthropic extended thinking
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* fix: handle Anthropic thinking signature correctly
- Only include 'signature' in Anthropic message payload if it is not None (fixes BadRequestError).
- Capture and attach 'signature' to ReasoningMessage in streaming interface.
* fix(anthropic): attach signature to last reasoning message in stream
---------
Co-authored-by: Letta <noreply@letta.com>
* trying tout gpt-5.1-codex
* add unit test for message content
* try to support multimodal
* remove ValueError and add logging on stream error
* prevent stream termination from api spec implementation errors
* fix: remove final_response references from non-Responses API interfaces
* fix: add diagnostic attributes to SimpleOpenAIResponsesStreamingInterface
* fix: remove final_response from SimpleOpenAIStreamingInterface (Chat Completions API)
* fix(core): patch responses api parallel tool calling not returning tool call ids
* fix(core): patch chatcompletions as well
* fix: patch problem with gpt-4.1
* feat: add gemini streaming to new agent loop
* add google as required dependency
* support storing all content parts
* remove extra google references
* feat: add full responses api support in new agent loop
* update matrix in workflow
* relax check for reasoning messages for high effort gpt 5
* fix indent
* one more relax
