fix(agent): stop reporting broken streams as output-length truncation (#36705)

A stream that drops mid-response after tokens are delivered (peer-closed
connection, stale-stream reconnect) is converted into a synthetic
finish_reason="length" stub. The conversation loop treated that network
stall as a max-output-tokens truncation: when the dropped content was a
tool call it retried exactly once, then hard-failed with "Response
truncated due to output length limit" — even on large-output models that
never hit any cap (e.g. Opus).

- Tool-call truncation now retries up to 3 times (was 1) with a
  progressive max_tokens boost, and is stub-aware: a PARTIAL_STREAM_STUB_ID
  stall prints "Stream interrupted mid tool-call — retrying (n/3)" instead
  of the false "model hit max output tokens", and the give-up message
  distinguishes a network drop from a real truncation.
- Length-continuation retries preserve the original request's output cap
  as a floor, so a high provider/model default isn't silently downshifted
  to 8K/12K on retry.
- Added _requested_output_cap_from_api_kwargs() helper.

Tests: stub-stall mid-tool-call recovery within 3 retries; continuation
preserves a large provider-default output cap.

Fixes #26425. Salvages the substance of #26427 (cap floor) and #9525
(retry bump), adapted to the post-refactor conversation_loop.py which
handles all three api_modes uniformly.

Co-authored-by: LeonSGP43 <cine.dreamer.one@gmail.com>
Co-authored-by: ygd58 <ygd58@users.noreply.github.com>
This commit is contained in:
Teknium
2026-06-01 03:01:20 -07:00
committed by GitHub
co-authored by LeonSGP43 ygd58
parent b571ec298d
commit 023149f665
3 changed files with 143 additions and 11 deletions
+54 -10
View File
@@ -1739,20 +1739,52 @@ def run_conversation(
if agent.api_mode in {"chat_completions", "bedrock_converse", "anthropic_messages"}:
assistant_message = _trunc_msg
if assistant_message is not None and _trunc_has_tool_calls:
if truncated_tool_call_retries < 1:
_is_stub_stall = (
getattr(response, "id", "") == PARTIAL_STREAM_STUB_ID
)
if truncated_tool_call_retries < 3:
truncated_tool_call_retries += 1
agent._buffer_vprint(
f"⚠️ Truncated tool call detected — retrying API call..."
)
if _is_stub_stall:
# The stream broke mid tool-call (network /
# peer-closed connection), not a real output
# cap — say so instead of "max output tokens".
agent._buffer_vprint(
f"⚠️ Stream interrupted mid tool-call — "
f"retrying ({truncated_tool_call_retries}/3)..."
)
else:
agent._buffer_vprint(
f"⚠️ Truncated tool call detected — "
f"retrying API call "
f"({truncated_tool_call_retries}/3)..."
)
# Boost max_tokens on each retry so the model has
# more room to complete the tool-call JSON. A
# network stall doesn't need a bigger budget, but
# a genuine output-cap truncation does, and the
# boost is harmless for the stall case.
_tc_boost_base = agent.max_tokens if agent.max_tokens else 4096
_tc_boost = _tc_boost_base * (truncated_tool_call_retries + 1)
_tc_requested_cap = agent._requested_output_cap_from_api_kwargs(api_kwargs)
if _tc_requested_cap is not None:
_tc_boost = max(_tc_boost, _tc_requested_cap)
_tc_boost_cap = max(32768, _tc_requested_cap or 0)
agent._ephemeral_max_output_tokens = min(_tc_boost, _tc_boost_cap)
# Don't append the broken response to messages;
# just re-run the same API call from the current
# message state, giving the model another chance.
continue
agent._flush_status_buffer()
agent._vprint(
f"{agent.log_prefix}⚠️ Truncated tool call response detected again — refusing to execute incomplete tool arguments.",
force=True,
)
if _is_stub_stall:
agent._vprint(
f"{agent.log_prefix}⚠️ Stream kept dropping mid tool-call after 3 retries — the action was not executed.",
force=True,
)
else:
agent._vprint(
f"{agent.log_prefix}⚠️ Truncated tool call response detected again — refusing to execute incomplete tool arguments.",
force=True,
)
agent._cleanup_task_resources(effective_task_id)
agent._persist_session(messages, conversation_history)
return {
@@ -1761,7 +1793,12 @@ def run_conversation(
"api_calls": api_call_count,
"completed": False,
"partial": True,
"error": "Response truncated due to output length limit",
"error": (
"Stream repeatedly dropped mid tool-call (network); "
"the tool was not executed"
if _is_stub_stall
else "Response truncated due to output length limit"
),
}
# If we have prior messages, roll back to last complete state
@@ -3412,9 +3449,16 @@ def run_conversation(
# Progressively boost the output token budget on each retry.
# Retry 1 → 2× base, retry 2 → 3× base, capped at 32 768.
# Applies to all providers via _ephemeral_max_output_tokens.
# If the original request already used a larger provider/model
# default budget, keep that floor so continuation retries do
# not accidentally downshift to a much smaller cap.
_boost_base = agent.max_tokens if agent.max_tokens else 4096
_boost = _boost_base * (length_continue_retries + 1)
agent._ephemeral_max_output_tokens = min(_boost, 32768)
_requested_cap = agent._requested_output_cap_from_api_kwargs(api_kwargs)
if _requested_cap is not None:
_boost = max(_boost, _requested_cap)
_boost_cap = max(32768, _requested_cap or 0)
agent._ephemeral_max_output_tokens = min(_boost, _boost_cap)
continue
# Guard: if all retries exhausted without a successful response