fix(bedrock): filter internal json_tool_call when mixed with real tools

Fixes #18381: When using both tools and response_format with Bedrock
Converse API, LiteLLM internally adds json_tool_call to handle structured
output. Bedrock may return both this internal tool AND real user-defined
tools, breaking consumers like OpenAI Agents SDK.

Changes:
- Non-streaming: Added _filter_json_mode_tools() to handle 3 scenarios:
  only json_tool_call (convert to content), mixed (filter it out), or
  no json_tool_call (pass through)
- Streaming: Added json_mode tracking to AWSEventStreamDecoder to suppress
  json_tool_call chunks and convert to text content
- Fixed optional_params.pop() mutation issue

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
This commit is contained in:
Julio Quinteros Pro
2026-02-28 00:18:56 -03:00
co-authored by Claude Sonnet 4.5
parent d49abf8577
commit fcabf9b602
4 changed files with 391 additions and 49 deletions
@@ -68,7 +68,7 @@ def make_sync_call(
model_response=model_response, json_mode=json_mode
)
else:
decoder = AWSEventStreamDecoder(model=model)
decoder = AWSEventStreamDecoder(model=model, json_mode=json_mode)
completion_stream = decoder.iter_bytes(response.iter_bytes(chunk_size=stream_chunk_size))
# LOGGING
@@ -1779,6 +1779,81 @@ class AmazonConverseConfig(BaseConfig):
return content_str, tools, reasoningContentBlocks, citationsContentBlocks
@staticmethod
def _filter_json_mode_tools(
json_mode: Optional[bool],
tools: List[ChatCompletionToolCallChunk],
chat_completion_message: ChatCompletionResponseMessage,
) -> Optional[List[ChatCompletionToolCallChunk]]:
"""
When json_mode is True, Bedrock may return the internal `json_tool_call`
tool alongside real user-defined tools. This method handles 3 scenarios:
1. Only json_tool_call present -> convert to text content, return None
2. Mixed json_tool_call + real -> filter out json_tool_call, return real tools
3. No json_tool_call / no json_mode -> return tools as-is
"""
if not json_mode or not tools:
return tools if tools else None
json_tool_indices = [
i
for i, t in enumerate(tools)
if t["function"].get("name") == RESPONSE_FORMAT_TOOL_NAME
]
if not json_tool_indices:
# No json_tool_call found, return tools unchanged
return tools
if len(json_tool_indices) == len(tools):
# All tools are json_tool_call — convert first one to content
verbose_logger.debug(
"Processing JSON tool call response for response_format"
)
json_mode_content_str: Optional[str] = tools[0]["function"].get(
"arguments"
)
if json_mode_content_str is not None:
try:
response_data = json.loads(json_mode_content_str)
if (
isinstance(response_data, dict)
and "properties" in response_data
and len(response_data) == 1
):
response_data = response_data["properties"]
json_mode_content_str = json.dumps(response_data)
except json.JSONDecodeError:
pass
chat_completion_message["content"] = json_mode_content_str
return None
# Mixed: filter out json_tool_call, keep real tools.
# Preserve the json_tool_call content as message text so the structured
# output from response_format is not silently lost.
first_idx = json_tool_indices[0]
json_mode_args = tools[first_idx]["function"].get("arguments")
if json_mode_args is not None:
try:
response_data = json.loads(json_mode_args)
if (
isinstance(response_data, dict)
and "properties" in response_data
and len(response_data) == 1
):
response_data = response_data["properties"]
json_mode_args = json.dumps(response_data)
except json.JSONDecodeError:
pass
existing = chat_completion_message.get("content") or ""
chat_completion_message["content"] = (
existing + json_mode_args if existing else json_mode_args
)
real_tools = [t for i, t in enumerate(tools) if i not in json_tool_indices]
return real_tools if real_tools else None
def _transform_response( # noqa: PLR0915
self,
model: str,
@@ -1801,7 +1876,7 @@ class AmazonConverseConfig(BaseConfig):
additional_args={"complete_input_dict": data},
)
json_mode: Optional[bool] = optional_params.pop("json_mode", None)
json_mode: Optional[bool] = optional_params.get("json_mode", None)
## RESPONSE OBJECT
try:
completion_response = ConverseResponseBlock(**response.json()) # type: ignore
@@ -1885,37 +1960,13 @@ class AmazonConverseConfig(BaseConfig):
self._transform_thinking_blocks(reasoningContentBlocks)
)
chat_completion_message["content"] = content_str
if (
json_mode is True
and tools is not None
and len(tools) == 1
and tools[0]["function"].get("name") == RESPONSE_FORMAT_TOOL_NAME
):
verbose_logger.debug(
"Processing JSON tool call response for response_format"
)
json_mode_content_str: Optional[str] = tools[0]["function"].get("arguments")
if json_mode_content_str is not None:
# Bedrock returns the response wrapped in a "properties" object
# We need to extract the actual content from this wrapper
try:
response_data = json.loads(json_mode_content_str)
# If Bedrock wrapped the response in "properties", extract the content
if (
isinstance(response_data, dict)
and "properties" in response_data
and len(response_data) == 1
):
response_data = response_data["properties"]
json_mode_content_str = json.dumps(response_data)
except json.JSONDecodeError:
# If parsing fails, use the original response
pass
chat_completion_message["content"] = json_mode_content_str
elif tools:
chat_completion_message["tool_calls"] = tools
filtered_tools = self._filter_json_mode_tools(
json_mode=json_mode,
tools=tools,
chat_completion_message=chat_completion_message,
)
if filtered_tools:
chat_completion_message["tool_calls"] = filtered_tools
## CALCULATING USAGE - bedrock returns usage in the headers
usage = self._transform_usage(completion_response["usage"])
+48 -16
View File
@@ -22,6 +22,7 @@ import litellm
from litellm import verbose_logger
from litellm._uuid import uuid
from litellm.caching.caching import InMemoryCache
from litellm.constants import RESPONSE_FORMAT_TOOL_NAME
from litellm.litellm_core_utils.core_helpers import map_finish_reason
from litellm.litellm_core_utils.litellm_logging import Logging
from litellm.litellm_core_utils.logging_utils import track_llm_api_timing
@@ -252,7 +253,7 @@ async def make_call(
response.aiter_bytes(chunk_size=stream_chunk_size)
)
else:
decoder = AWSEventStreamDecoder(model=model)
decoder = AWSEventStreamDecoder(model=model, json_mode=json_mode)
completion_stream = decoder.aiter_bytes(
response.aiter_bytes(chunk_size=stream_chunk_size)
)
@@ -346,7 +347,7 @@ def make_sync_call(
response.iter_bytes(chunk_size=stream_chunk_size)
)
else:
decoder = AWSEventStreamDecoder(model=model)
decoder = AWSEventStreamDecoder(model=model, json_mode=json_mode)
completion_stream = decoder.iter_bytes(
response.iter_bytes(chunk_size=stream_chunk_size)
)
@@ -1282,7 +1283,7 @@ def get_response_stream_shape():
class AWSEventStreamDecoder:
def __init__(self, model: str) -> None:
def __init__(self, model: str, json_mode: Optional[bool] = False) -> None:
from botocore.parsers import EventStreamJSONParser
self.model = model
@@ -1290,6 +1291,8 @@ class AWSEventStreamDecoder:
self.content_blocks: List[ContentBlockDeltaEvent] = []
self.tool_calls_index: Optional[int] = None
self.response_id: Optional[str] = None
self.json_mode = json_mode
self._current_tool_name: Optional[str] = None
def check_empty_tool_call_args(self) -> bool:
"""
@@ -1391,6 +1394,16 @@ class AWSEventStreamDecoder:
response_tool_name = get_bedrock_tool_name(
response_tool_name=_response_tool_name
)
self._current_tool_name = response_tool_name
# When json_mode is True, suppress the internal json_tool_call
# and convert its content to text in delta events instead
if (
self.json_mode is True
and response_tool_name == RESPONSE_FORMAT_TOOL_NAME
):
return tool_use, provider_specific_fields, thinking_blocks
self.tool_calls_index = (
0 if self.tool_calls_index is None else self.tool_calls_index + 1
)
@@ -1445,19 +1458,27 @@ class AWSEventStreamDecoder:
if "text" in delta_obj:
text = delta_obj["text"]
elif "toolUse" in delta_obj:
tool_use = {
"id": None,
"type": "function",
"function": {
"name": None,
"arguments": delta_obj["toolUse"]["input"],
},
"index": (
self.tool_calls_index
if self.tool_calls_index is not None
else index
),
}
# When json_mode is True and this is the internal json_tool_call,
# convert tool input to text content instead of tool call arguments
if (
self.json_mode is True
and self._current_tool_name == RESPONSE_FORMAT_TOOL_NAME
):
text = delta_obj["toolUse"]["input"]
else:
tool_use = {
"id": None,
"type": "function",
"function": {
"name": None,
"arguments": delta_obj["toolUse"]["input"],
},
"index": (
self.tool_calls_index
if self.tool_calls_index is not None
else index
),
}
elif "reasoningContent" in delta_obj:
provider_specific_fields = {
"reasoningContent": delta_obj["reasoningContent"],
@@ -1494,6 +1515,17 @@ class AWSEventStreamDecoder:
) -> Optional[ChatCompletionToolCallChunk]:
"""Handle stop/contentBlockIndex event in converse chunk parsing."""
tool_use: Optional[ChatCompletionToolCallChunk] = None
# If the ending block was the internal json_tool_call, skip emitting
# the empty-args tool chunk and reset tracking state
if (
self.json_mode is True
and self._current_tool_name == RESPONSE_FORMAT_TOOL_NAME
):
self._current_tool_name = None
return tool_use
self._current_tool_name = None
is_empty = self.check_empty_tool_call_args()
if is_empty:
tool_use = {
@@ -3493,3 +3493,262 @@ class TestBedrockMinThinkingBudgetTokens:
drop_params=False,
)
assert "thinking" not in result or result.get("thinking") is None
def test_transform_response_with_both_json_tool_call_and_real_tool():
"""
When Bedrock returns BOTH json_tool_call AND a real tool (get_weather),
only the real tool should remain in tool_calls. The json_tool_call should be filtered out.
Fixes https://github.com/BerriAI/litellm/issues/18381
"""
from litellm.llms.bedrock.chat.converse_transformation import AmazonConverseConfig
from litellm.types.utils import ModelResponse
response_json = {
"metrics": {"latencyMs": 200},
"output": {
"message": {
"role": "assistant",
"content": [
{
"toolUse": {
"toolUseId": "tooluse_json_001",
"name": "json_tool_call",
"input": {
"Current_Temperature": 62,
"Weather_Explanation": "Mild and cool.",
},
}
},
{
"toolUse": {
"toolUseId": "tooluse_weather_001",
"name": "get_weather",
"input": {
"location": "San Francisco, CA",
"unit": "fahrenheit",
},
}
},
],
}
},
"stopReason": "tool_use",
"usage": {
"inputTokens": 100,
"outputTokens": 50,
"totalTokens": 150,
"cacheReadInputTokenCount": 0,
"cacheReadInputTokens": 0,
"cacheWriteInputTokenCount": 0,
"cacheWriteInputTokens": 0,
},
}
class MockResponse:
def json(self):
return response_json
@property
def text(self):
return json.dumps(response_json)
config = AmazonConverseConfig()
model_response = ModelResponse()
optional_params = {"json_mode": True}
result = config._transform_response(
model="bedrock/anthropic.claude-3-5-sonnet-20240620-v1:0",
response=MockResponse(),
model_response=model_response,
stream=False,
logging_obj=None,
optional_params=optional_params,
api_key=None,
data=None,
messages=[],
encoding=None,
)
# Only real tool should remain
assert result.choices[0].message.tool_calls is not None
assert len(result.choices[0].message.tool_calls) == 1
assert result.choices[0].message.tool_calls[0].function.name == "get_weather"
assert (
result.choices[0].message.tool_calls[0].function.arguments
== '{"location": "San Francisco, CA", "unit": "fahrenheit"}'
)
# json_tool_call content should be preserved as message text
content = result.choices[0].message.content
assert content is not None
parsed = json.loads(content)
assert parsed["Current_Temperature"] == 62
assert parsed["Weather_Explanation"] == "Mild and cool."
def test_transform_response_does_not_mutate_optional_params():
"""
Verify that optional_params still contains json_mode after _transform_response.
Previously, .pop() was used which mutated the caller's dict.
"""
from litellm.llms.bedrock.chat.converse_transformation import AmazonConverseConfig
from litellm.types.utils import ModelResponse
response_json = {
"metrics": {"latencyMs": 50},
"output": {
"message": {
"role": "assistant",
"content": [
{
"toolUse": {
"toolUseId": "tooluse_001",
"name": "json_tool_call",
"input": {"result": "ok"},
}
}
],
}
},
"stopReason": "tool_use",
"usage": {
"inputTokens": 10,
"outputTokens": 5,
"totalTokens": 15,
"cacheReadInputTokenCount": 0,
"cacheReadInputTokens": 0,
"cacheWriteInputTokenCount": 0,
"cacheWriteInputTokens": 0,
},
}
class MockResponse:
def json(self):
return response_json
@property
def text(self):
return json.dumps(response_json)
config = AmazonConverseConfig()
model_response = ModelResponse()
optional_params = {"json_mode": True, "other_key": "value"}
config._transform_response(
model="bedrock/anthropic.claude-3-5-sonnet-20240620-v1:0",
response=MockResponse(),
model_response=model_response,
stream=False,
logging_obj=None,
optional_params=optional_params,
api_key=None,
data=None,
messages=[],
encoding=None,
)
# json_mode should still be in optional_params (not popped)
assert "json_mode" in optional_params
assert optional_params["json_mode"] is True
assert optional_params["other_key"] == "value"
def test_streaming_filters_json_tool_call_with_real_tools():
"""
Simulate streaming chunks where both json_tool_call and a real tool arrive.
Verify json_tool_call chunks are converted to text content while real tool
chunks pass through normally.
"""
from litellm.llms.bedrock.chat.invoke_handler import AWSEventStreamDecoder
from litellm.types.llms.bedrock import (
ContentBlockDeltaEvent,
ContentBlockStartEvent,
)
decoder = AWSEventStreamDecoder(model="test-model", json_mode=True)
# Chunk 1: json_tool_call start
json_start = ContentBlockStartEvent(
toolUse={
"toolUseId": "tooluse_json_001",
"name": "json_tool_call",
}
)
tool_use_1, _, _ = decoder._handle_converse_start_event(json_start)
# json_tool_call start should be suppressed (return None tool_use)
assert tool_use_1 is None
# tool_calls_index should NOT have been incremented
assert decoder.tool_calls_index is None
# Chunk 2: json_tool_call delta — should become text, not tool_use
json_delta = ContentBlockDeltaEvent(toolUse={"input": '{"temp": 62}'})
text_2, tool_use_2, _, _, _ = decoder._handle_converse_delta_event(
json_delta, index=0
)
assert text_2 == '{"temp": 62}'
assert tool_use_2 is None
# Chunk 3: json_tool_call stop
stop_tool = decoder._handle_converse_stop_event(index=0)
assert stop_tool is None
# _current_tool_name should be reset
assert decoder._current_tool_name is None
# Chunk 4: real tool start
real_start = ContentBlockStartEvent(
toolUse={
"toolUseId": "tooluse_weather_001",
"name": "get_weather",
}
)
tool_use_4, _, _ = decoder._handle_converse_start_event(real_start)
assert tool_use_4 is not None
assert tool_use_4["function"]["name"] == "get_weather"
assert decoder.tool_calls_index == 0
# Chunk 5: real tool delta
real_delta = ContentBlockDeltaEvent(
toolUse={"input": '{"location": "SF"}'}
)
text_5, tool_use_5, _, _, _ = decoder._handle_converse_delta_event(
real_delta, index=1
)
assert text_5 == ""
assert tool_use_5 is not None
assert tool_use_5["function"]["arguments"] == '{"location": "SF"}'
def test_streaming_without_json_mode_passes_all_tools():
"""
Verify backward compatibility: when json_mode=False, all tools
(including json_tool_call if present) pass through unchanged.
"""
from litellm.llms.bedrock.chat.invoke_handler import AWSEventStreamDecoder
from litellm.types.llms.bedrock import (
ContentBlockDeltaEvent,
ContentBlockStartEvent,
)
decoder = AWSEventStreamDecoder(model="test-model", json_mode=False)
# json_tool_call start — should pass through when json_mode=False
json_start = ContentBlockStartEvent(
toolUse={
"toolUseId": "tooluse_json_001",
"name": "json_tool_call",
}
)
tool_use, _, _ = decoder._handle_converse_start_event(json_start)
assert tool_use is not None
assert tool_use["function"]["name"] == "json_tool_call"
assert decoder.tool_calls_index == 0
# json_tool_call delta — should be a tool_use, not text
json_delta = ContentBlockDeltaEvent(toolUse={"input": '{"data": 1}'})
text, tool_use_delta, _, _, _ = decoder._handle_converse_delta_event(
json_delta, index=0
)
assert text == ""
assert tool_use_delta is not None
assert tool_use_delta["function"]["arguments"] == '{"data": 1}'