[Feature] Add Command Tool Parser

Signed-off-by:  <>
Signed-off-by: Ubuntu <[email protected]>
Signed-off-by: Doil Kim <[email protected]>

Author: Ubuntu

vllm/entrypoints/openai/tool_parsers/__init__.py

@@ -2,6 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from .abstract_tool_parser import ToolParser, ToolParserManager
+from .command_tool_parser import CommandJsonToolParser
 from .deepseekv3_tool_parser import DeepSeekV3ToolParser
 from .granite_20b_fc_tool_parser import Granite20bFCToolParser
 from .granite_tool_parser import GraniteToolParser
@@ -21,5 +22,6 @@
     "GraniteToolParser", "Hermes2ProToolParser", "MistralToolParser",
     "Internlm2ToolParser", "Llama3JsonToolParser", "JambaToolParser",
     "Llama4PythonicToolParser", "PythonicToolParser", "Phi4MiniJsonToolParser",
-    "DeepSeekV3ToolParser", "xLAMToolParser", "MinimaxToolParser"
+    "DeepSeekV3ToolParser", "xLAMToolParser", "MinimaxToolParser",
+    "CommandJsonToolParser"
 ]

vllm/entrypoints/openai/tool_parsers/command_tool_parser.py

@@ -0,0 +1,151 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import json
+from collections.abc import Sequence
+from typing import Union
+
+import partial_json_parser
+import regex as re
+from partial_json_parser.core.options import Allow
+from transformers import PreTrainedTokenizerBase
+
+from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
+                                              DeltaFunctionCall, DeltaMessage,
+                                              DeltaToolCall,
+                                              ExtractedToolCallInformation,
+                                              FunctionCall, ToolCall)
+from vllm.entrypoints.openai.tool_parsers.abstract_tool_parser import (
+    ToolParser, ToolParserManager)
+from vllm.logger import init_logger
+from vllm.utils import random_uuid
+
+logger = init_logger(__name__)
+
+
+@ToolParserManager.register_module("command_json")
+class CommandJsonToolParser(ToolParser):
+
+    def __init__(self, tokenizer: PreTrainedTokenizerBase):
+        super().__init__(tokenizer)
+        # Streaming state
+        self.prev_tool_call_arr: list[dict] = []
+        self.streamed_args_for_tool: list[str] = []
+        self.current_tool_id: int = -1
+        self.current_tool_name_sent: bool = False
+
+        # Action delimiters
+        self.tool_call_start_token = "<|START_ACTION|>"
+        self.tool_call_end_token = "<|END_ACTION|>"
+        self.tool_call_regex = re.compile(
+            r"<\|START_ACTION\|>(.*?)<\|END_ACTION\|>", re.DOTALL)
+
+        # Precompute token ids
+        self.tool_call_start_token_id = self.vocab.get(
+            self.tool_call_start_token)
+        self.tool_call_end_token_id = self.vocab.get(self.tool_call_end_token)
+        if (self.tool_call_start_token_id is None
+                or self.tool_call_end_token_id is None):
+            raise RuntimeError(
+                "CommandJsonToolParser cannot find start/end tokens in vocab")
+
+    def extract_tool_calls(
+            self, model_output: str,
+            request: ChatCompletionRequest) -> ExtractedToolCallInformation:
+        # Synchronous parsing: look for full action block
+        if self.tool_call_start_token not in model_output:
+            return ExtractedToolCallInformation(tools_called=False,
+                                                tool_calls=[],
+                                                content=model_output)
+        try:
+            match = self.tool_call_regex.search(model_output)
+            if not match:
+                raise ValueError("No action block found")
+            payload = match.group(1)
+            raw_calls = json.loads(payload)
+            tool_calls = []
+            for entry in raw_calls:
+                name = entry.get("tool_name")
+                params = entry.get("parameters", {})
+                tool_calls.append(
+                    ToolCall(type="function",
+                             function=FunctionCall(name=name,
+                                                   arguments=json.dumps(
+                                                       params,
+                                                       ensure_ascii=False))))
+            # content before action
+            prefix = model_output.split(self.tool_call_start_token, 1)[0]
+            return ExtractedToolCallInformation(tools_called=True,
+                                                tool_calls=tool_calls,
+                                                content=prefix or None)
+        except Exception:
+            logger.exception("Error extracting sync tool calls")
+            return ExtractedToolCallInformation(tools_called=False,
+                                                tool_calls=[],
+                                                content=model_output)
+
+    def extract_tool_calls_streaming(
+        self,
+        previous_text: str,
+        current_text: str,
+        delta_text: str,
+        previous_token_ids: Sequence[int],
+        current_token_ids: Sequence[int],
+        delta_token_ids: Sequence[int],
+        request: ChatCompletionRequest,
+    ) -> Union[DeltaMessage, None]:
+
+        prev_start = previous_token_ids.count(self.tool_call_start_token_id)
+        cur_start = current_token_ids.count(self.tool_call_start_token_id)
+        cur_end = current_token_ids.count(self.tool_call_end_token_id)
+
+        # Case 1: Block not started → Text as is
+        if cur_start == 0:
+            return DeltaMessage(content=delta_text)
+
+        # Case 2: Starting a new block
+        if cur_start > prev_start:
+            self.current_tool_id += 1
+            return None
+
+        # Case 3: Inside block, not closed → ignored
+        if cur_start > cur_end:
+            return None
+
+        # Case 4: Block End Point
+        if cur_start == cur_end and self.tool_call_end_token in delta_text:
+            full = current_text + delta_text
+
+            payload = full.split(self.tool_call_start_token, 1)[1] \
+                          .split(self.tool_call_end_token, 1)[0].strip()
+            try:
+                calls = partial_json_parser.loads(payload or "[]", Allow.ALL)
+            except partial_json_parser.core.exceptions.MalformedJSON:
+                logger.debug("Waiting for complete JSON")
+                return None
+            except json.JSONDecodeError:
+                logger.debug("Malformed JSON payload: %s", payload)
+                return None
+
+            calls_list = calls if isinstance(calls, list) else [calls]
+            deltas = []
+            for entry in calls_list:
+                name = entry.get("tool_name")
+                params = entry.get("parameters", {})
+                args = json.dumps(params, ensure_ascii=False)
+                deltas.append(
+                    DeltaToolCall(
+                        index=self.current_tool_id,
+                        type="function",
+                        id=f"chatcmpl-tool-{random_uuid()}",
+                        function=DeltaFunctionCall(
+                            name=name,
+                            arguments=args,
+                        ).model_dump(exclude_none=True),
+                    ))
+
+                self.current_tool_id += 1
+
+            return DeltaMessage(tool_calls=deltas)
+
+        return DeltaMessage(content=delta_text)