323 lines
12 KiB
Python
323 lines
12 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
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import importlib
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from collections.abc import Sequence
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from typing import Any
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from openai.types.responses.function_tool import FunctionTool
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from vllm.entrypoints.chat_utils import make_tool_call_id
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from vllm.entrypoints.openai.chat_completion.protocol import (
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ChatCompletionRequest,
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ChatCompletionToolsParam,
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)
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from vllm.entrypoints.openai.engine.protocol import (
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DeltaFunctionCall,
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DeltaMessage,
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DeltaToolCall,
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ExtractedToolCallInformation,
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FunctionCall,
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ToolCall,
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)
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from vllm.entrypoints.openai.responses.protocol import ResponsesRequest
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from vllm.logger import init_logger
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from vllm.tokenizers import TokenizerLike
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from vllm.tool_parsers.abstract_tool_parser import Tool, ToolParser
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logger = init_logger(__name__)
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def _rust_tool_parser_module() -> Any:
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try:
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return importlib.import_module("vllm._rust_tool_parser")
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except ImportError as exc:
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raise RuntimeError(
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"Rust tool parsing requires the vllm._rust_tool_parser PyO3 "
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"extension. Rebuild vLLM with Rust frontend/extensions enabled."
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) from exc
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class RustToolParser(ToolParser):
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"""Adapter from an opaque Rust parser to the vLLM ToolParser API.
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Subclasses provide only model-specific configuration: the exact Rust parser
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name and an optional tool-call start marker for fast complete-output
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rejection.
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This class keeps the vLLM-specific bridge work:
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- convert vLLM tool definitions into the Rust ``Tool`` shape;
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- translate typed Rust parser outputs into vLLM protocol objects; and
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- maintain vLLM streaming bookkeeping used by finish-reason handling.
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The parser grammar and incremental parser state stay in Rust.
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"""
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# Rust-backed parsers are opaque to Python by default. Do not use vLLM's
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# standard JSON required/named handling; let the Rust parser consume the
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# model's native tool-call syntax.
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supports_required_and_named = False
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rust_parser_name: str
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tool_call_start_token: str | None = None
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def __init__(self, tokenizer: TokenizerLike, tools: list[Tool] | None = None):
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super().__init__(tokenizer, tools)
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self._parser: Any | None = None
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self._error: Exception | None = None
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if not self.model_tokenizer:
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raise ValueError(
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"The model tokenizer must be passed to the ToolParser "
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"constructor during construction."
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)
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logger.debug(
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"vLLM successfully imported tool parser %s", self.__class__.__name__
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)
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def adjust_request(
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self, request: ChatCompletionRequest | ResponsesRequest
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) -> ChatCompletionRequest | ResponsesRequest:
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"""Adjust request options without installing Python-side constraints.
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Rust-backed parsers are treated as source-of-truth opaque parsers. The
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bridge intentionally avoids ``super().adjust_request()`` so Python does
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not install JSON schema guidance or structural-tag constraints that may
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conflict with the Rust parser's native grammar.
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"""
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if self._get_parser().preserve_special_tokens():
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request.skip_special_tokens = False
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return request
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def _rust_tools(self) -> list[Any]:
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"""Build Rust ``Tool`` objects from vLLM tool definitions."""
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if not self.tools:
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return []
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tools: list[Any] = []
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for tool in self.tools:
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if isinstance(tool, FunctionTool):
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name = tool.name
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description = tool.description
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parameters = tool.parameters or {}
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strict = getattr(tool, "strict", None)
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elif isinstance(tool, ChatCompletionToolsParam):
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name = tool.function.name
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description = tool.function.description
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parameters = tool.function.parameters or {}
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strict = getattr(tool.function, "strict", None)
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else:
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continue
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tools.append(
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_rust_tool_parser_module().Tool(name, description, parameters, strict)
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)
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return tools
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def _new_parser(self) -> Any:
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"""Create a fresh Rust parser with the current tool schemas."""
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return _rust_tool_parser_module().ToolParser(
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self.rust_parser_name, self._rust_tools()
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)
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def _get_parser(self) -> Any:
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if self._parser is None:
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self._parser = self._new_parser()
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return self._parser
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def _reset_streaming_state(self) -> None:
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"""Reset parser state for a new request on a reused parser instance."""
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self._parser = self._new_parser()
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self._error = None
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self.prev_tool_call_arr.clear()
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self.streamed_args_for_tool.clear()
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self.current_tool_id = -1
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self.current_tool_name_sent = False
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def _ensure_tool_state(self, index: int) -> None:
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"""Grow vLLM streaming state arrays to contain ``index``."""
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while len(self.prev_tool_call_arr) <= index:
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self.prev_tool_call_arr.append({})
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while len(self.streamed_args_for_tool) <= index:
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self.streamed_args_for_tool.append("")
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def _record_delta(
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self, index: int, name: str | None, arguments: str | None
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) -> str | None:
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"""Mirror a Rust parser delta into vLLM streaming bookkeeping.
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``prev_tool_call_arr`` and ``streamed_args_for_tool`` are read later by
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the chat serving layer to decide the final ``tool_calls`` finish reason
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and to flush any remaining argument bytes.
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"""
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tool_call_id = None
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self._ensure_tool_state(index)
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if name is not None:
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# Prefer the model-emitted ID surfaced by the Rust parser (e.g.
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# Kimi K2) over a randomly generated one.
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tool_call_id = self._get_parser().tool_call_id(index) or make_tool_call_id()
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self.prev_tool_call_arr[index] = {"name": name, "arguments": {}}
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self.current_tool_name_sent = True
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if arguments is not None:
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self.streamed_args_for_tool[index] += arguments
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self.prev_tool_call_arr[index]["arguments"] = self.streamed_args_for_tool[
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index
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]
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self.current_tool_id = index
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return tool_call_id
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def _delta_message_from_parser_output(
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self, parser_output: Any | None
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) -> DeltaMessage | None:
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"""Translate one Rust parser output into a vLLM ``DeltaMessage``."""
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if parser_output is None:
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return None
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normal_text = parser_output.normal_text or None
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tool_calls: list[DeltaToolCall] = []
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for tool_call in parser_output.calls:
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index = tool_call.tool_index
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name = tool_call.name
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arguments: str | None = tool_call.arguments
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if name is None and arguments is None:
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continue
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tool_call_id = self._record_delta(index, name, arguments)
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tool_calls.append(
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DeltaToolCall(
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index=index,
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id=tool_call_id,
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type="function" if name is not None else None,
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function=DeltaFunctionCall(
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name=name,
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arguments=arguments,
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),
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)
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)
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if normal_text is None and not tool_calls:
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return None
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return DeltaMessage(content=normal_text, tool_calls=tool_calls)
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def _parse_complete(self, model_output: str) -> tuple[Any, dict[int, str]] | None:
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"""Parse complete model output with a throwaway Rust parser instance.
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Returns the coalesced parser output along with any model-emitted tool
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call IDs keyed by tool index.
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"""
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parser = self._new_parser()
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output = _rust_tool_parser_module().ToolParserOutput()
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try:
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parser.parse_into(model_output, output)
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# finish() clears parser state, so snapshot model-emitted IDs first.
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tool_call_ids = {
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call.tool_index: tool_call_id
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for call in output.calls
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if (tool_call_id := parser.tool_call_id(call.tool_index)) is not None
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}
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output.append(parser.finish())
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except Exception:
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logger.exception(
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"Error parsing %s tool call output.", self.rust_parser_name
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)
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return None
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return output.coalesce(), tool_call_ids
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def extract_tool_calls(
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self,
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model_output: str,
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request: ChatCompletionRequest,
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) -> ExtractedToolCallInformation:
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"""Extract tool calls from complete model output (non-streaming)."""
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if (
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self.tool_call_start_token is not None
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and self.tool_call_start_token not in model_output
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):
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return ExtractedToolCallInformation(
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tools_called=False,
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tool_calls=[],
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content=model_output,
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)
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parse_result = self._parse_complete(model_output)
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if parse_result is None:
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return ExtractedToolCallInformation(
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tools_called=False,
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tool_calls=[],
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content=model_output,
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)
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parsed, tool_call_ids = parse_result
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tool_calls: list[ToolCall] = []
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self.prev_tool_call_arr.clear()
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for parsed_tool_call in parsed.calls:
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name = parsed_tool_call.name
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arguments = parsed_tool_call.arguments or "{}"
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if name is None:
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continue
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tool_calls.append(
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ToolCall(
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id=tool_call_ids.get(parsed_tool_call.tool_index)
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or make_tool_call_id(),
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type="function",
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function=FunctionCall(name=name, arguments=arguments),
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)
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)
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self.prev_tool_call_arr.append({"name": name, "arguments": arguments})
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if not tool_calls:
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return ExtractedToolCallInformation(
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tools_called=False,
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tool_calls=[],
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content=model_output,
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)
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content = parsed.normal_text or None
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return ExtractedToolCallInformation(
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tools_called=True,
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tool_calls=tool_calls,
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content=content,
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)
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def extract_tool_calls_streaming(
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self,
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previous_text: str,
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current_text: str,
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delta_text: str,
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previous_token_ids: Sequence[int], # pylint: disable=unused-argument
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current_token_ids: Sequence[int], # pylint: disable=unused-argument
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delta_token_ids: Sequence[int], # pylint: disable=unused-argument
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request: ChatCompletionRequest, # pylint: disable=unused-argument
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) -> DeltaMessage | None:
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"""Extract tool calls from streaming model output.
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The Rust parser owns the incremental buffer, so this adapter feeds only
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the newest text delta and lets the serving layer handle final empty
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chunks.
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"""
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# TODO: Add a final-chunk hook if streaming needs to call Rust finish().
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if not previous_text:
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self._reset_streaming_state()
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if self._error is not None:
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return None
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parser_output = _rust_tool_parser_module().ToolParserOutput()
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try:
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self._get_parser().parse_into(delta_text, parser_output)
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except Exception as error:
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self._error = error
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logger.exception(
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"Error parsing %s streaming tool call output.",
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self.rust_parser_name,
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)
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delta_message = self._delta_message_from_parser_output(parser_output)
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if delta_message is not None:
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return delta_message
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return None
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