[New Model] Add Seed-Oss model (#23241)

Signed-off-by: jiabin.00 <jiabin.00@bytedance.com>
Signed-off-by: Jee Jee Li <pandaleefree@gmail.com>
Co-authored-by: Jee Jee Li <pandaleefree@gmail.com>

docs/models/supported_models.md

@@ -401,6 +401,7 @@ th {
 | `Qwen2MoeForCausalLM` | Qwen2MoE | `Qwen/Qwen1.5-MoE-A2.7B`, `Qwen/Qwen1.5-MoE-A2.7B-Chat`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `Qwen3ForCausalLM` | Qwen3 | `Qwen/Qwen3-8B`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `Qwen3MoeForCausalLM` | Qwen3MoE | `Qwen/Qwen3-30B-A3B`, etc. | ✅︎ | ✅︎ | ✅︎ |
+| `SeedOssForCausalLM` | SeedOss | `ByteDance-Seed/Seed-OSS-36B-Instruct`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `StableLmForCausalLM` | StableLM | `stabilityai/stablelm-3b-4e1t`, `stabilityai/stablelm-base-alpha-7b-v2`, etc. | | | ✅︎ |
 | `Starcoder2ForCausalLM` | Starcoder2 | `bigcode/starcoder2-3b`, `bigcode/starcoder2-7b`, `bigcode/starcoder2-15b`, etc. | | ✅︎ | ✅︎ |
 | `SolarForCausalLM` | Solar Pro | `upstage/solar-pro-preview-instruct`, etc. | ✅︎ | ✅︎ | ✅︎ |

tests/models/registry.py

@@ -292,6 +292,9 @@ _TEXT_GENERATION_EXAMPLE_MODELS = {
     "Qwen3ForCausalLM": _HfExamplesInfo("Qwen/Qwen3-8B"),
     "Qwen3MoeForCausalLM": _HfExamplesInfo("Qwen/Qwen3-30B-A3B"),
     "RWForCausalLM": _HfExamplesInfo("tiiuae/falcon-40b"),
+    "SeedOssForCausalLM": _HfExamplesInfo("ByteDance-Seed/Seed-OSS-36B-Instruct", # noqa: E501
+                                          trust_remote_code=True,
+                                          is_available_online=False),
     "SmolLM3ForCausalLM": _HfExamplesInfo("HuggingFaceTB/SmolLM3-3B"),
     "StableLMEpochForCausalLM": _HfExamplesInfo("stabilityai/stablelm-zephyr-3b"),  # noqa: E501
     "StableLmForCausalLM": _HfExamplesInfo("stabilityai/stablelm-3b-4e1t"),

tests/tool_use/test_seed_oss_tool_parser.py

@@ -0,0 +1,459 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# ruff: noqa: E501
+
+import json
+from collections.abc import Generator
+from typing import Optional
+
+import pytest
+
+from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
+                                              ChatCompletionToolsParam,
+                                              DeltaMessage, FunctionCall,
+                                              ToolCall)
+from vllm.entrypoints.openai.tool_parsers import SeedOssToolParser
+from vllm.transformers_utils.detokenizer import detokenize_incrementally
+from vllm.transformers_utils.tokenizer import AnyTokenizer, get_tokenizer
+
+# Use a common model that is likely to be available
+MODEL = "ByteDance-Seed/Seed-OSS-36B-Instruct"
+
+
+@pytest.fixture(scope="module")
+def seed_oss_tokenizer():
+    return get_tokenizer(tokenizer_name=MODEL, trust_remote_code=True)
+
+
+@pytest.fixture
+def seed_oss_tool_parser(seed_oss_tokenizer):
+    return SeedOssToolParser(seed_oss_tokenizer)
+
+
+@pytest.fixture
+def sample_tools():
+    return [
+        ChatCompletionToolsParam(
+            type="function",
+            function={
+                "name": "get_weather",
+                "description": "Get current temperature for a given location.",
+                "parameters": {
+                    "type": "object",
+                    "properties": {
+                        "location": {
+                            "type": "string",
+                            "description":
+                            "City and country e.g. Bogotá, Colombia"
+                        },
+                        "unit": {
+                            "type": "string",
+                            "description": "this is the unit of temperature"
+                        }
+                    },
+                    "required": ["location"],
+                    "additionalProperties": False
+                },
+                "returns": {
+                    "type": "object",
+                    "properties": {
+                        "temperature": {
+                            "type": "number",
+                            "description": "temperature in celsius"
+                        }
+                    },
+                    "required": ["temperature"],
+                    "additionalProperties": False
+                },
+                "strict": True
+            }),
+    ]
+
+
+def assert_tool_calls(actual_tool_calls: list[ToolCall],
+                      expected_tool_calls: list[ToolCall]):
+    assert len(actual_tool_calls) == len(expected_tool_calls)
+
+    for actual_tool_call, expected_tool_call in zip(actual_tool_calls,
+                                                    expected_tool_calls):
+        # Seed-OSS tool call will not generate id
+        assert actual_tool_call.type == "function"
+        assert actual_tool_call.function == expected_tool_call.function
+
+        assert actual_tool_call.function.name == expected_tool_call.function.name
+        assert actual_tool_call.function.arguments == expected_tool_call.function.arguments
+
+
+def test_extract_tool_calls_no_tools(seed_oss_tool_parser):
+    model_output = "This is a test response without any tool calls"
+    extracted_tool_calls = seed_oss_tool_parser.extract_tool_calls(
+        model_output, request=None)  # type: ignore[arg-type]
+
+    assert not extracted_tool_calls.tools_called
+    assert extracted_tool_calls.tool_calls == []
+    assert extracted_tool_calls.content == model_output
+
+
+@pytest.mark.parametrize(
+    ids=[
+        "tool_call_0_thinking_budget",
+        "tool_call_512_thinkg_budget",
+        "tool_call_unlimited_thinking_budget",
+    ],
+    argnames=["model_output", "expected_tool_calls", "expected_content"],
+    argvalues=[
+        ("""<seed:think>\n</seed:cot_budget_reflect>\n</seed:cot_budget_reflect>\n"""
+         """The current thinking budget is 0, so I will directly start answering the question.\n</seed:think>\n"""
+         """<seed:tool_call>\n<function=get_weather>\n"""
+         """<parameter=location>Barcelona, Spain</parameter>\n</function>\n</seed:tool_call>""",
+         [
+             ToolCall(function=FunctionCall(
+                 name="get_weather",
+                 arguments=json.dumps({
+                     "location": "Barcelona, Spain",
+                 }, ),
+             ),
+                      type='function')
+         ],
+         """<seed:think>\n</seed:cot_budget_reflect>\n</seed:cot_budget_reflect>\n"""
+         """The current thinking budget is 0, so I will directly start answering the question.\n</seed:think>\n"""
+         ),
+        (
+            """<seed:think>The user\'s current thinking budget is 512.</seed:cot_budget_reflect>\nLet me analyze the """
+            """question. The user wants to know the weather in Barcelona, Spain. Looking at the functions available, """
+            """there\'s a get_weather function that can retrieve the current temperature for a given location. \n\nFirst, """
+            """check the parameters required by get_weather: location is mandatory (needs city and country), and unit is """
+            """optional. The user provided "Barcelona Spain" as the location, which fits the required format (city, """
+            """country). \n<seed:cot_budget_reflect>I have used 131 tokens, and there are 381 tokens remaining for use."""
+            """</seed:cot_budget_reflect>\n Since the unit isn\'t specified, the function will default to Celsius, which """
+            """is fine. \n\nThere\'s no need to ask for more information because the location is clear. So I should call """
+            """the get_weather function with location set to "Barcelona, Spain" (adding a comma for clarity, though the """
+            """user\'s input has a space, but the function might accept either; to be safe, using the standard format """
+            """with a comma).\n<seed:cot_budget_reflect>I have used 257 tokens, and there are 255 tokens remaining for """
+            """use.</seed:cot_budget_reflect>\n The unit parameter can be omitted since it\'s optional.</seed:think>\n"""
+            """<seed:tool_call>\n<function=get_weather>\n<parameter=location>Barcelona, Spain</parameter>\n</function>"""
+            """\n</seed:tool_call>""",
+            [
+                ToolCall(function=FunctionCall(
+                    name="get_weather",
+                    arguments=json.dumps({
+                        "location": "Barcelona, Spain",
+                    }, ),
+                ),
+                         type='function')
+            ],
+            """<seed:think>The user\'s current thinking budget is 512.</seed:cot_budget_reflect>\nLet me analyze the """
+            """question. The user wants to know the weather in Barcelona, Spain. Looking at the functions available, """
+            """there\'s a get_weather function that can retrieve the current temperature for a given location. \n\nFirst, """
+            """check the parameters required by get_weather: location is mandatory (needs city and country), and unit is """
+            """optional. The user provided "Barcelona Spain" as the location, which fits the required format (city, """
+            """country). \n<seed:cot_budget_reflect>I have used 131 tokens, and there are 381 tokens remaining for use."""
+            """</seed:cot_budget_reflect>\n Since the unit isn\'t specified, the function will default to Celsius, which """
+            """is fine. \n\nThere\'s no need to ask for more information because the location is clear. So I should call """
+            """the get_weather function with location set to "Barcelona, Spain" (adding a comma for clarity, though the """
+            """user\'s input has a space, but the function might accept either; to be safe, using the standard format """
+            """with a comma).\n<seed:cot_budget_reflect>I have used 257 tokens, and there are 255 tokens remaining for """
+            """use.</seed:cot_budget_reflect>\n The unit parameter can be omitted since it\'s optional.</seed:think>\n""",
+        ),
+        (
+            """<seed:think>\nGot it, let\'s see. The user asked for the weather in Barcelona, Spain. """
+            """First, I need to remember the function I can use: get_weather. The function requires a """
+            """location (city and country) which is "Barcelona, Spain" here, and unit is optional. Since """
+            """the user didn\'t specify the unit, the default in the function is Celsius, right? Wait, """
+            """let me check the function docstring again. Oh, the function says unit is optional, and """
+            """returns temperature in Celsius. So I should call get_weather with location "Barcelona, """
+            """Spain" and maybe omit unit or set to Celsius. Let me format the function call correctly. """
+            """The format is <seed:tool_call>\n<function=get_weather>\n<parameter=location>Barcelona, """
+            """Spain</parameter>\n<parameter=unit>celsius</parameter>\n</function>\n</seed:tool_call>. """
+            """Wait, but does the unit parameter accept "celsius"? The docstring says unit is the unit """
+            """of temperature, but the return is in Celsius anyway. Maybe even if I don\'t pass unit, """
+            """it\'s okay, but to be explicit, maybe pass "celsius". Let me go with that. So the function """
+            """call should be as above. Then wait for the result to come back and tell the user the """
+            """temperature in Celsius.</seed:think><seed:tool_call>\n<function=get_weather>\n<parameter=location>"""
+            """Barcelona, Spain</parameter>\n<parameter=unit>celsius</parameter>\n</function>\n</seed:tool_call>""",
+            [
+                ToolCall(function=FunctionCall(
+                    name="get_weather",
+                    arguments=json.dumps(
+                        {
+                            "location": "Barcelona, Spain",
+                            "unit": "celsius",
+                        }, ),
+                ),
+                         type='function')
+            ],
+            """<seed:think>\nGot it, let\'s see. The user asked for the weather in Barcelona, Spain. """
+            """First, I need to remember the function I can use: get_weather. The function requires a """
+            """location (city and country) which is "Barcelona, Spain" here, and unit is optional. Since """
+            """the user didn\'t specify the unit, the default in the function is Celsius, right? Wait, """
+            """let me check the function docstring again. Oh, the function says unit is optional, and """
+            """returns temperature in Celsius. So I should call get_weather with location "Barcelona, """
+            """Spain" and maybe omit unit or set to Celsius. Let me format the function call correctly. """
+            """The format is <seed:tool_call>\n<function=get_weather>\n<parameter=location>Barcelona, """
+            """Spain</parameter>\n<parameter=unit>celsius</parameter>\n</function>\n</seed:tool_call>. """
+            """Wait, but does the unit parameter accept "celsius"? The docstring says unit is the unit """
+            """of temperature, but the return is in Celsius anyway. Maybe even if I don\'t pass unit, """
+            """it\'s okay, but to be explicit, maybe pass "celsius". Let me go with that. So the function """
+            """call should be as above. Then wait for the result to come back and tell the user the """
+            """temperature in Celsius.</seed:think>""",
+        ),
+    ],
+)
+def test_extract_tool_calls(seed_oss_tool_parser, sample_tools, model_output,
+                            expected_tool_calls, expected_content):
+    request = ChatCompletionRequest(model=MODEL,
+                                    messages=[],
+                                    tools=sample_tools)
+    extracted_tool_calls = seed_oss_tool_parser.extract_tool_calls(
+        model_output, request=request)  # type: ignore[arg-type]
+    assert extracted_tool_calls.tools_called
+
+    assert_tool_calls(extracted_tool_calls.tool_calls, expected_tool_calls)
+
+    assert extracted_tool_calls.content == expected_content
+
+
+def test_streaming_tool_calls_no_tools(seed_oss_tool_parser):
+    model_output = "This is a test response without any tool calls"
+
+    result = seed_oss_tool_parser.extract_tool_calls_streaming(
+        previous_text="his is a test response",
+        current_text=model_output,
+        delta_text=" without any tool calls.",
+        previous_token_ids=[],
+        current_token_ids=[],
+        delta_token_ids=[],
+        request=None,
+    )
+
+    # Should return the delta text as content
+    assert result is not None
+    assert hasattr(result, 'content')
+    assert result.content == " without any tool calls."
+
+
+def stream_delta_message_generator(
+    seed_oss_tool_parser: SeedOssToolParser,
+    seed_oss_tokenizer: AnyTokenizer,
+    model_output: str,
+    request: Optional[ChatCompletionRequest] = None
+) -> Generator[DeltaMessage, None, None]:
+    all_token_ids = seed_oss_tokenizer.encode(model_output,
+                                              add_special_tokens=False)
+
+    previous_text = ""
+    previous_tokens = None
+    prefix_offset = 0
+    read_offset = 0
+    for i, delta_token in enumerate(all_token_ids):
+        delta_token_ids = [delta_token]
+        previous_token_ids = all_token_ids[:i]
+        current_token_ids = all_token_ids[:i + 1]
+
+        (new_tokens, delta_text, new_prefix_offset,
+         new_read_offset) = detokenize_incrementally(
+             tokenizer=seed_oss_tokenizer,
+             all_input_ids=current_token_ids,
+             prev_tokens=previous_tokens,
+             prefix_offset=prefix_offset,
+             read_offset=read_offset,
+             skip_special_tokens=False,
+             spaces_between_special_tokens=True,
+         )
+
+        current_text = previous_text + delta_text
+
+        delta_message = seed_oss_tool_parser.extract_tool_calls_streaming(
+            previous_text,
+            current_text,
+            delta_text,
+            previous_token_ids,
+            current_token_ids,
+            delta_token_ids,
+            request=request,
+        )
+        if delta_message:
+            yield delta_message
+
+        previous_text = current_text
+        previous_tokens = (previous_tokens +
+                           new_tokens if previous_tokens else new_tokens)
+        prefix_offset = new_prefix_offset
+        read_offset = new_read_offset
+
+
+@pytest.mark.parametrize(
+    ids=[
+        "tool_call_0_thinking_budget",
+        "tool_call_512_thinkg_budget",
+        "tool_call_unlimited_thinking_budget",
+    ],
+    argnames=["model_output", "expected_tool_calls", "expected_content"],
+    argvalues=[
+        ("""<seed:think>\n</seed:cot_budget_reflect>\n</seed:cot_budget_reflect>\n"""
+         """The current thinking budget is 0, so I will directly start answering the question.\n</seed:think>\n"""
+         """<seed:tool_call>\n<function=get_weather>\n"""
+         """<parameter=location>Barcelona, Spain</parameter>\n</function>\n</seed:tool_call>""",
+         [
+             ToolCall(function=FunctionCall(
+                 name="get_weather",
+                 arguments=json.dumps({
+                     "location": "Barcelona, Spain",
+                 }, ),
+             ),
+                      type='function')
+         ],
+         """<seed:think>\n</seed:cot_budget_reflect>\n</seed:cot_budget_reflect>\n"""
+         """The current thinking budget is 0, so I will directly start answering the question.\n</seed:think>\n"""
+         ),
+        (
+            """<seed:think>The user\'s current thinking budget is 512.</seed:cot_budget_reflect>\nLet me analyze the """
+            """question. The user wants to know the weather in Barcelona, Spain. Looking at the functions available, """
+            """there\'s a get_weather function that can retrieve the current temperature for a given location. \n\nFirst, """
+            """check the parameters required by get_weather: location is mandatory (needs city and country), and unit is """
+            """optional. The user provided "Barcelona Spain" as the location, which fits the required format (city, """
+            """country). \n<seed:cot_budget_reflect>I have used 131 tokens, and there are 381 tokens remaining for use."""
+            """</seed:cot_budget_reflect>\n Since the unit isn\'t specified, the function will default to Celsius, which """
+            """is fine. \n\nThere\'s no need to ask for more information because the location is clear. So I should call """
+            """the get_weather function with location set to "Barcelona, Spain" (adding a comma for clarity, though the """
+            """user\'s input has a space, but the function might accept either; to be safe, using the standard format """
+            """with a comma).\n<seed:cot_budget_reflect>I have used 257 tokens, and there are 255 tokens remaining for """
+            """use.</seed:cot_budget_reflect>\n The unit parameter can be omitted since it\'s optional.</seed:think>\n"""
+            """<seed:tool_call>\n<function=get_weather>\n<parameter=location>Barcelona, Spain</parameter>\n</function>"""
+            """\n</seed:tool_call>""",
+            [
+                ToolCall(function=FunctionCall(
+                    name="get_weather",
+                    arguments=json.dumps({
+                        "location": "Barcelona, Spain",
+                    }, ),
+                ),
+                         type='function')
+            ],
+            """<seed:think>The user\'s current thinking budget is 512.</seed:cot_budget_reflect>\nLet me analyze the """
+            """question. The user wants to know the weather in Barcelona, Spain. Looking at the functions available, """
+            """there\'s a get_weather function that can retrieve the current temperature for a given location. \n\nFirst, """
+            """check the parameters required by get_weather: location is mandatory (needs city and country), and unit is """
+            """optional. The user provided "Barcelona Spain" as the location, which fits the required format (city, """
+            """country). \n<seed:cot_budget_reflect>I have used 131 tokens, and there are 381 tokens remaining for use."""
+            """</seed:cot_budget_reflect>\n Since the unit isn\'t specified, the function will default to Celsius, which """
+            """is fine. \n\nThere\'s no need to ask for more information because the location is clear. So I should call """
+            """the get_weather function with location set to "Barcelona, Spain" (adding a comma for clarity, though the """
+            """user\'s input has a space, but the function might accept either; to be safe, using the standard format """
+            """with a comma).\n<seed:cot_budget_reflect>I have used 257 tokens, and there are 255 tokens remaining for """
+            """use.</seed:cot_budget_reflect>\n The unit parameter can be omitted since it\'s optional.</seed:think>\n""",
+        ),
+        (
+            """<seed:think>\nGot it, let\'s see. The user asked for the weather in Barcelona, Spain. """
+            """First, I need to remember the function I can use: get_weather. The function requires a """
+            """location (city and country) which is "Barcelona, Spain" here, and unit is optional. Since """
+            """the user didn\'t specify the unit, the default in the function is Celsius, right? Wait, """
+            """let me check the function docstring again. Oh, the function says unit is optional, and """
+            """returns temperature in Celsius. So I should call get_weather with location "Barcelona, """
+            """Spain" and maybe omit unit or set to Celsius. Let me format the function call correctly. """
+            """The format is <seed:tool_call>\n<function=get_weather>\n<parameter=location>Barcelona, """
+            """Spain</parameter>\n<parameter=unit>celsius</parameter>\n</function>\n</seed:tool_call>. """
+            """Wait, but does the unit parameter accept "celsius"? The docstring says unit is the unit """
+            """of temperature, but the return is in Celsius anyway. Maybe even if I don\'t pass unit, """
+            """it\'s okay, but to be explicit, maybe pass "celsius". Let me go with that. So the function """
+            """call should be as above. Then wait for the result to come back and tell the user the """
+            """temperature in Celsius.</seed:think><seed:tool_call>\n<function=get_weather>\n<parameter=location>"""
+            """Barcelona, Spain</parameter>\n<parameter=unit>celsius</parameter>\n</function>\n</seed:tool_call>""",
+            [
+                ToolCall(function=FunctionCall(
+                    name="get_weather",
+                    arguments=json.dumps(
+                        {
+                            "location": "Barcelona, Spain",
+                            "unit": "celsius",
+                        }, ),
+                ),
+                         type='function')
+            ],
+            """<seed:think>\nGot it, let\'s see. The user asked for the weather in Barcelona, Spain. """
+            """First, I need to remember the function I can use: get_weather. The function requires a """
+            """location (city and country) which is "Barcelona, Spain" here, and unit is optional. Since """
+            """the user didn\'t specify the unit, the default in the function is Celsius, right? Wait, """
+            """let me check the function docstring again. Oh, the function says unit is optional, and """
+            """returns temperature in Celsius. So I should call get_weather with location "Barcelona, """
+            """Spain" and maybe omit unit or set to Celsius. Let me format the function call correctly. """
+            """The format is <seed:tool_call>\n<function=get_weather>\n<parameter=location>Barcelona, """
+            """Spain</parameter>\n<parameter=unit>celsius</parameter>\n</function>\n</seed:tool_call>. """
+            """Wait, but does the unit parameter accept "celsius"? The docstring says unit is the unit """
+            """of temperature, but the return is in Celsius anyway. Maybe even if I don\'t pass unit, """
+            """it\'s okay, but to be explicit, maybe pass "celsius". Let me go with that. So the function """
+            """call should be as above. Then wait for the result to come back and tell the user the """
+            """temperature in Celsius.</seed:think>""",
+        ),
+    ],
+)
+def test_streaming_tool_calls(seed_oss_tool_parser, seed_oss_tokenizer,
+                              sample_tools, model_output, expected_tool_calls,
+                              expected_content):
+    """Test incremental streaming behavior"""
+    request = ChatCompletionRequest(model=MODEL,
+                                    messages=[],
+                                    tools=sample_tools)
+
+    other_content = ''
+    tool_states = {}  # Track state per tool index
+
+    for delta_message in stream_delta_message_generator(
+            seed_oss_tool_parser, seed_oss_tokenizer, model_output, request):
+        # role should never be streamed from tool parser
+        assert not delta_message.role
+
+        if delta_message.content:
+            other_content += delta_message.content
+
+        if delta_message.tool_calls:
+            for tool_call in delta_message.tool_calls:
+                idx = tool_call.index
+
+                # Initialize state for new tool
+                if idx not in tool_states:
+                    tool_states[idx] = {
+                        "id": None,
+                        "name": None,
+                        "arguments": "",
+                        "type": None
+                    }
+
+                # First chunk should have id, name, and type
+                if tool_call.id:
+                    tool_states[idx]["id"] = tool_call.id
+
+                if tool_call.type:
+                    assert tool_call.type == "function"
+                    tool_states[idx]["type"] = tool_call.type
+
+                if tool_call.function:
+                    if tool_call.function.name:
+                        # Should only be set once
+                        assert tool_states[idx]["name"] is None
+                        tool_states[idx]["name"] = tool_call.function.name
+
+                    if tool_call.function.arguments is not None:
+                        # Accumulate arguments incrementally
+                        tool_states[idx][
+                            "arguments"] += tool_call.function.arguments
+
+    # Verify final content
+    assert other_content == expected_content
+
+    # Verify we got all expected tool calls
+    assert len(tool_states) == len(expected_tool_calls)
+
+    # Verify each tool call
+    for idx, expected_tool in enumerate(expected_tool_calls):
+        state = tool_states[idx]
+        assert state["id"] is not None
+        assert state["type"] == "function"
+        assert state["name"] == expected_tool.function.name
+
+        # Parse accumulated arguments
+        arguments_str = state["arguments"]
+        assert arguments_str is not None
+        actual_args = json.loads(arguments_str)
+        expected_args = json.loads(expected_tool.function.arguments)
+        assert actual_args == expected_args

vllm/entrypoints/openai/tool_parsers/__init__.py

@@ -18,6 +18,7 @@ from .mistral_tool_parser import MistralToolParser
 from .phi4mini_tool_parser import Phi4MiniJsonToolParser
 from .pythonic_tool_parser import PythonicToolParser
 from .qwen3coder_tool_parser import Qwen3CoderToolParser
+from .seed_oss_tool_parser import SeedOssToolParser
 from .step3_tool_parser import Step3ToolParser
 from .xlam_tool_parser import xLAMToolParser
 
@@ -41,5 +42,6 @@ __all__ = [
     "HunyuanA13BToolParser",
     "Glm4MoeModelToolParser",
     "Qwen3CoderToolParser",
+    "SeedOssToolParser",
     "Step3ToolParser",
 ]

vllm/entrypoints/openai/tool_parsers/seed_oss_tool_parser.py

@@ -0,0 +1,676 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# Adapted from qwen3coder xml parser, All rights reserved.
+# ruff: noqa: E501
+
+import ast
+import json
+import uuid
+from collections.abc import Sequence
+from typing import Any, Optional, Union
+
+import regex as re
+
+from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
+                                              ChatCompletionToolsParam,
+                                              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.transformers_utils.tokenizer import AnyTokenizer
+
+logger = init_logger(__name__)
+
+
+@ToolParserManager.register_module("seed_oss")
+class SeedOssToolParser(ToolParser):
+    TOOL_CALL_START = "<seed:tool_call>"
+    TOOL_CALL_END = "</seed:tool_call>"
+
+    def __init__(self, tokenizer: AnyTokenizer):
+        super().__init__(tokenizer)
+
+        # --- streaming state ---
+        self._reset_streaming_state()
+        self.prev_tool_call_arr: list[dict] = []
+
+        self.tool_call_start_token: str = self.TOOL_CALL_START
+        self.tool_call_end_token: str = self.TOOL_CALL_END
+        # Sentinel tokens for streaming mode
+        self.tool_call_prefix: str = "<function="
+        self.function_end_token: str = "</function>"
+        self.parameter_prefix: str = "<parameter="
+        self.parameter_end_token: str = "</parameter>"
+        self.think_start_token: str = "<seed:think>"
+        self.think_end_token: str = "</seed:think>"
+        self.is_tool_call_started: bool = False
+        self.is_thinking_end: bool = False
+        self.failed_count: int = 0
+        self._reset_streaming_state()
+
+        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)
+        self.think_end_token_id = self.vocab.get(self.think_end_token)
+
+        if (self.tool_call_start_token_id is None
+                or self.tool_call_end_token_id is None):
+            raise RuntimeError(
+                "Seed_Oss XML parser: tokenizer did not include "
+                "<seed:tool_call> or its closing tag.")
+
+        tool_start_re = re.escape(self.tool_call_start_token)
+        tool_end_re = re.escape(self.tool_call_end_token)
+
+        self.tool_call_complete_regex = re.compile(
+            rf"{tool_start_re}(.*?){tool_end_re}", re.DOTALL)
+        self.tool_call_regex = re.compile(
+            rf"{tool_start_re}(.*?){tool_end_re}|{tool_start_re}(.*?)$",
+            re.DOTALL)
+
+        self.tool_call_function_regex = re.compile(
+            r"<function=(.*?)</function>|<function=(.*)$", re.DOTALL)
+        self.tool_call_parameter_regex = re.compile(
+            r"<parameter=(.*?)</parameter>|<parameter=(.*?)$", re.DOTALL)
+
+        logger.info("vLLM Seed-Oss XML tool parser loaded (%s).",
+                    self.__class__.__name__)
+
+    def _generate_tool_call_id(self) -> str:
+        """Generate a unique tool call ID."""
+        return f"call_{uuid.uuid4().hex[:24]}"
+
+    def _reset_streaming_state(self):
+        """Reset all streaming state."""
+        self.current_tool_index = 0
+        self.is_tool_call_started = False
+        self.header_sent = False
+        self.current_tool_id = -1
+        self.current_function_name = None
+        self.current_param_name = None
+        self.current_param_value = ""
+        self.param_count = 0
+        self.in_param = False
+        self.in_function = False
+        self.accumulated_text = ""
+        self.json_started = False
+        self.json_closed = False
+
+    def _parse_xml_function_call(
+            self, function_call_str: str,
+            tools: Optional[list[ChatCompletionToolsParam]]
+    ) -> Optional[ToolCall]:
+
+        def get_arguments_config(func_name: str) -> dict:
+            if tools is None:
+                return {}
+            for config in tools:
+                if not hasattr(config, "type") or not (
+                        hasattr(config, "function")
+                        and hasattr(config.function, "name")):
+                    continue
+                if (config.type == "function"
+                        and config.function.name == func_name):
+                    if not hasattr(config.function, "parameters"):
+                        return {}
+                    params = config.function.parameters
+                    if isinstance(params, dict) and "properties" in params:
+                        return params["properties"]
+                    elif isinstance(params, dict):
+                        return params
+                    else:
+                        return {}
+            logger.warning("Tool '%s' is not defined in the tools list.",
+                           func_name)
+            return {}
+
+        def convert_param_value(param_value: str, param_name: str,
+                                param_config: dict, func_name: str) -> Any:
+            # Handle null value for any type
+            if param_value.lower() == "null":
+                return None
+
+            if param_name not in param_config:
+                if param_config != {}:
+                    logger.warning(
+                        "Parsed parameter '%s' is not defined in "
+                        "the tool parameters for tool '%s', "
+                        "directly returning the string value.", param_name,
+                        func_name)
+                return param_value
+
+            if (isinstance(param_config[param_name], dict)
+                    and "type" in param_config[param_name]):
+                param_type = str(
+                    param_config[param_name]["type"]).strip().lower()
+            else:
+                param_type = "string"
+            if param_type in [
+                    "string", "str", "text", "varchar", "char", "enum"
+            ]:
+                return param_value
+            elif (param_type.startswith("int") or param_type.startswith("uint")
+                  or param_type.startswith("long")
+                  or param_type.startswith("short")
+                  or param_type.startswith("unsigned")):
+                try:
+                    param_value = int(param_value)  # type: ignore
+                except (ValueError, TypeError):
+                    logger.warning(
+                        "Parsed value '%s' of parameter '%s' is not an integer in tool "
+                        "'%s', degenerating to string.", param_value,
+                        param_name, func_name)
+                return param_value
+            elif param_type.startswith("num") or param_type.startswith(
+                    "float"):
+                try:
+                    float_param_value = float(param_value)
+                    param_value = float_param_value if float_param_value - int(
+                        float_param_value) != 0 else int(
+                            float_param_value)  # type: ignore
+                except (ValueError, TypeError):
+                    logger.warning(
+                        "Parsed value '%s' of parameter '%s' is not a float in tool "
+                        "'%s', degenerating to string.", param_value,
+                        param_name, func_name)
+                return param_value
+            elif param_type in ["boolean", "bool", "binary"]:
+                param_value = param_value.lower()
+                if param_value not in ["true", "false"]:
+                    logger.warning(
+                        "Parsed value '%s' of parameter '%s' is not a boolean "
+                        "(`true` of `false`) in tool '%s', degenerating to false.",
+                        param_value, param_name, func_name)
+                return param_value == "true"
+            else:
+                if param_type == "object" or param_type.startswith("dict"):
+                    try:
+                        param_value = json.loads(param_value)
+                        return param_value
+                    except (ValueError, TypeError, json.JSONDecodeError):
+                        logger.warning(
+                            "Parsed value '%s' of parameter '%s' is not a valid JSON "
+                            "object in tool '%s', will try other methods to parse it.",
+                            param_value, param_name, func_name)
+                try:
+                    param_value = ast.literal_eval(param_value)
+                except (ValueError, SyntaxError):
+                    logger.warning(
+                        "Parsed value '%s' of parameter '%s' cannot be converted via "
+                        "Python `ast.literal_eval()` in tool '%s', degenerating to string.",
+                        param_value, param_name, func_name)
+                return param_value
+
+        # Extract function name
+        end_index = function_call_str.index(">")
+        function_name = function_call_str[:end_index]
+        param_config = get_arguments_config(function_name)
+        parameters = function_call_str[end_index + 1:]
+        param_dict = {}
+        for match in self.tool_call_parameter_regex.findall(parameters):
+            match_text = match[0] if match[0] else match[1]
+            idx = match_text.index(">")
+            param_name = match_text[:idx]
+            param_value = str(match_text[idx + 1:])
+            # Remove prefix and trailing \n
+            if param_value.startswith("\n"):
+                param_value = param_value[1:]
+            if param_value.endswith("\n"):
+                param_value = param_value[:-1]
+
+            param_dict[param_name] = convert_param_value(
+                param_value, param_name, param_config, function_name)
+        return ToolCall(
+            type="function",
+            function=FunctionCall(name=function_name,
+                                  arguments=json.dumps(param_dict,
+                                                       ensure_ascii=False)),
+        )
+
+    def _get_function_calls(self, model_output: str) -> list[str]:
+        # Find all tool calls
+        matched_ranges = self.tool_call_regex.findall(model_output)
+        raw_tool_calls = [
+            match[0] if match[0] else match[1] for match in matched_ranges
+        ]
+
+        # Back-off strategy if no tool_call tags found
+        if len(raw_tool_calls) == 0:
+            raw_tool_calls = [model_output]
+
+        raw_function_calls = []
+        for tool_call in raw_tool_calls:
+            raw_function_calls.extend(
+                self.tool_call_function_regex.findall(tool_call))
+
+        function_calls = [
+            match[0] if match[0] else match[1] for match in raw_function_calls
+        ]
+        return function_calls
+
+    def extract_tool_calls(
+        self,
+        model_output: str,
+        request: ChatCompletionRequest,
+    ) -> ExtractedToolCallInformation:
+        # Quick check to avoid unnecessary processing
+        if self.tool_call_prefix not in model_output:
+            return ExtractedToolCallInformation(tools_called=False,
+                                                tool_calls=[],
+                                                content=model_output)
+
+        # Check if both think start and end tokens are present
+        if (self.think_start_token in model_output
+                and self.think_end_token in model_output):
+            # Find the position of think end token
+            think_end_index = model_output.find(self.think_end_token) + len(
+                self.think_end_token)
+            # Extract content after think end token
+            result_content = model_output[think_end_index:]
+            thinking_content = model_output[:think_end_index]
+
+        try:
+            function_calls = self._get_function_calls(result_content)
+            if len(function_calls) == 0:
+                return ExtractedToolCallInformation(tools_called=False,
+                                                    tool_calls=[],
+                                                    content=model_output)
+
+            tool_calls = [
+                self._parse_xml_function_call(function_call_str, request.tools)
+                for function_call_str in function_calls
+            ]
+
+            # Populate prev_tool_call_arr for serving layer to set finish_reason
+            self.prev_tool_call_arr.clear()  # Clear previous calls
+            for tool_call in tool_calls:
+                if tool_call:
+                    self.prev_tool_call_arr.append({
+                        "name":
+                        tool_call.function.name,
+                        "arguments":
+                        tool_call.function.arguments,
+                    })
+
+            # Extract content before tool calls
+            tool_call_start_index = result_content.find(
+                self.tool_call_start_token)
+            tool_call_start_index = (
+                tool_call_start_index if tool_call_start_index >= 0 else
+                result_content.find(self.tool_call_prefix))
+            content = thinking_content + result_content[:tool_call_start_index]
+
+            return ExtractedToolCallInformation(
+                tools_called=(len(tool_calls) > 0),
+                tool_calls=tool_calls,
+                content=content if content else None,
+            )
+
+        except Exception:
+            logger.exception("Error in extracting tool call from response.")
+            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]:
+        # If no delta text, return None unless
+        # it's an EOS token after tool calls
+        if not delta_text:
+            # Check if this is an EOS token after all tool calls are complete
+            # We check for tool calls in the text even if is_tool_call_started
+            # is False because it might have been reset after processing all tools
+            if (delta_token_ids
+                    and self.tool_call_end_token_id not in delta_token_ids):
+                # Count complete tool calls
+                complete_calls = len(
+                    self.tool_call_complete_regex.findall(current_text))
+
+                # If we have completed tool calls and populated prev_tool_call_arr
+                if complete_calls > 0 and len(self.prev_tool_call_arr) > 0:
+                    # Check if all tool calls are closed
+                    open_calls = current_text.count(
+                        self.tool_call_start_token) - current_text.count(
+                            self.tool_call_end_token)
+                    if open_calls == 0:
+                        # Return empty delta message to allow finish_reason processing
+                        return DeltaMessage(content="")
+                elif not self.is_tool_call_started and current_text:
+                    # This is a regular content response that's now complete
+                    return DeltaMessage(content="")
+            return None
+
+        # Check if this is the first call (reset state if needed)
+        if not previous_text:
+            self._reset_streaming_state()
+
+        # Update accumulated text
+        self.accumulated_text = current_text
+
+        # Check if we need to advance to next tool
+        if self.json_closed and not self.in_function:
+            # Check if this tool call has ended
+            tool_ends = current_text.count(self.tool_call_end_token)
+            if tool_ends > self.current_tool_index:
+                # This tool has ended, advance to next
+                self.current_tool_index += 1
+                self.header_sent = False
+                self.param_count = 0
+                self.json_started = False
+                self.json_closed = False
+
+                # Check if there are more tool calls
+                if self.current_tool_index >= current_text.count(
+                        self.tool_call_start_token):
+                    # No more tool calls
+                    self.is_tool_call_started = False
+                # Continue processing next tool
+                return None
+
+        # Check if end thinking
+        if (not self.is_thinking_end
+                and (self.think_end_token_id in delta_token_ids
+                     or self.think_end_token in delta_text)):
+            self.is_thinking_end = True
+
+        # If thinking hasn't ended yet, don't process any tool calls
+        if not self.is_thinking_end:
+            return DeltaMessage(content=delta_text)
+
+        # Handle normal content before tool calls
+        if not self.is_tool_call_started:
+            # Check if tool call is starting
+            if (self.tool_call_start_token_id in delta_token_ids
+                    or self.tool_call_start_token in delta_text):
+                self.is_tool_call_started = True
+                # Return any content before the tool call
+                if self.tool_call_start_token in delta_text:
+                    content_before = delta_text[:delta_text.index(
+                        self.tool_call_start_token)]
+                    if content_before:
+                        return DeltaMessage(content=content_before)
+                return None
+            else:
+                # Check if we're between tool calls - skip whitespace
+                if (current_text.rstrip().endswith(self.tool_call_end_token)
+                        and delta_text.strip() == ""):
+                    # We just ended a tool call, skip whitespace
+                    return None
+                # Normal content, no tool call
+                return DeltaMessage(content=delta_text)
+
+        # Check if we're between tool calls (waiting for next one)
+        # Count tool calls we've seen vs processed
+        tool_starts_count = current_text.count(self.tool_call_start_token)
+        if self.current_tool_index >= tool_starts_count:
+            # We're past all tool calls, shouldn't be here
+            return None
+
+        # We're in a tool call, find the current tool call portion
+        # Need to find the correct tool call based on current_tool_index
+        # Only process tool calls after think_end_token
+        think_end_index = current_text.find(self.think_end_token) + len(
+            self.think_end_token
+        ) if self.think_end_token in current_text else 0
+        tool_starts: list[int] = []
+        idx = think_end_index
+        while True:
+            idx = current_text.find(self.tool_call_start_token, idx)
+            if idx == -1:
+                break
+            tool_starts.append(idx)
+            idx += len(self.tool_call_start_token)
+
+        if self.current_tool_index >= len(tool_starts):
+            # No more tool calls to process yet
+            return None
+
+        tool_start_idx = tool_starts[self.current_tool_index]
+        # Find where this tool call ends (or current position if not ended yet)
+        tool_end_idx = current_text.find(self.tool_call_end_token,
+                                         tool_start_idx)
+        if tool_end_idx == -1:
+            tool_text = current_text[tool_start_idx:]
+        else:
+            tool_text = current_text[tool_start_idx:tool_end_idx +
+                                     len(self.tool_call_end_token)]
+
+        # Looking for function header
+        if not self.header_sent:
+            if self.tool_call_prefix in tool_text:
+                func_start = tool_text.find(self.tool_call_prefix) + len(
+                    self.tool_call_prefix)
+                func_end = tool_text.find(">", func_start)
+
+                if func_end != -1:
+                    # Found complete function name
+                    self.current_function_name = tool_text[func_start:func_end]
+                    self.current_tool_id = self._generate_tool_call_id(
+                    )  # type: ignore
+                    self.header_sent = True
+                    self.in_function = True
+
+                    # IMPORTANT: Add to prev_tool_call_arr immediately when we detect a tool call
+                    # This ensures finish_reason="tool_calls" even if parsing isn't complete
+                    already_added = any(
+                        tool.get("name") == self.current_function_name
+                        for tool in self.prev_tool_call_arr)
+                    if not already_added:
+                        self.prev_tool_call_arr.append({
+                            "name": self.current_function_name,
+                            "arguments":
+                            "{}",  # Placeholder, will be updated later
+                        })
+
+                    # Send header with function info
+                    return DeltaMessage(tool_calls=[
+                        DeltaToolCall(
+                            index=self.current_tool_index,
+                            id=self.current_tool_id,
+                            function=DeltaFunctionCall(
+                                name=self.current_function_name, arguments=""),
+                            type="function",
+                        )
+                    ])
+            return None
+
+        # We've sent header, now handle function body
+        if self.in_function:
+            # Send opening brace if not sent yet
+            if (not self.json_started
+                    and self.parameter_prefix not in delta_text):
+                self.json_started = True
+                return DeltaMessage(tool_calls=[
+                    DeltaToolCall(
+                        index=self.current_tool_index,
+                        function=DeltaFunctionCall(arguments="{"),
+                    )
+                ])
+
+            # Make sure json_started is set if we're processing parameters
+            if not self.json_started:
+                self.json_started = True
+
+            # Check for function end in accumulated text
+            if not self.json_closed and self.function_end_token in tool_text:
+                # Close JSON
+                self.json_closed = True
+
+                # Extract the complete tool call to update prev_tool_call_arr with final arguments
+                # Find the function content
+                func_start = tool_text.find(self.tool_call_prefix) + len(
+                    self.tool_call_prefix)
+                func_content_end = tool_text.find(self.function_end_token,
+                                                  func_start)
+                if func_content_end != -1:
+                    func_content = tool_text[func_start:func_content_end]
+                    # Parse to get the complete arguments
+                    try:
+                        parsed_tool = self._parse_xml_function_call(
+                            func_content, request.tools if request else None)
+                        if parsed_tool:
+                            # Update existing entry in prev_tool_call_arr with complete arguments
+                            for i, tool in enumerate(self.prev_tool_call_arr):
+                                if tool.get(
+                                        "name") == parsed_tool.function.name:
+                                    self.prev_tool_call_arr[i]["arguments"] = (
+                                        parsed_tool.function.arguments)
+                                    break
+                    except Exception:
+                        logger.warning(
+                            "Failed to parse tool arguments during streaming.",
+                            exc_info=True)
+
+                result = DeltaMessage(tool_calls=[
+                    DeltaToolCall(
+                        index=self.current_tool_index,
+                        function=DeltaFunctionCall(arguments="}"),
+                    )
+                ])
+
+                # Reset state for next tool
+                self.in_function = False
+                self.json_closed = True
+
+                return result
+
+            # Look for parameters
+            # Count how many complete parameters we have processed
+            complete_params = tool_text.count(self.parameter_end_token)
+
+            # Check if we should start a new parameter
+            if not self.in_param and self.param_count < complete_params:
+                # Find the unprocessed parameter
+                # Count parameter starts
+                param_starts = []
+                idx = 0
+                while True:
+                    idx = tool_text.find(self.parameter_prefix, idx)
+                    if idx == -1:
+                        break
+                    param_starts.append(idx)
+                    idx += len(self.parameter_prefix)
+
+                if len(param_starts) > self.param_count:
+                    # Process the next parameter
+                    param_idx = param_starts[self.param_count]
+                    param_start = param_idx + len(self.parameter_prefix)
+                    remaining = tool_text[param_start:]
+
+                    if ">" in remaining:
+                        # We have the complete parameter name
+                        name_end = remaining.find(">")
+                        self.current_param_name = remaining[:name_end]
+
+                        # Find the parameter value
+                        value_start = param_start + name_end + 1
+                        value_text = tool_text[value_start:]
+                        if value_text.startswith("\n"):
+                            value_text = value_text[1:]
+
+                        # Find where this parameter ends
+                        param_end_idx = value_text.find(
+                            self.parameter_end_token)
+                        if param_end_idx != -1:
+                            # Complete parameter found
+                            param_value = value_text[:param_end_idx]
+                            if param_value.endswith("\n"):
+                                param_value = param_value[:-1]
+
+                            # Build complete JSON fragment for this parameter
+                            if self.param_count == 0:
+                                json_fragment = (
+                                    '"' + self.current_param_name + '": "' +
+                                    json.dumps(param_value)[1:-1] + '"')
+                            else:
+                                json_fragment = (
+                                    ', "' + self.current_param_name + '": "' +
+                                    json.dumps(param_value)[1:-1] + '"')
+
+                            self.param_count += 1
+
+                            return DeltaMessage(tool_calls=[
+                                DeltaToolCall(
+                                    index=self.current_tool_index,
+                                    function=DeltaFunctionCall(
+                                        arguments=json_fragment),
+                                )
+                            ])
+
+            # Continue parameter value
+            if self.in_param:
+                if self.parameter_end_token in delta_text:
+                    # End of parameter
+                    end_idx = delta_text.find(self.parameter_end_token)
+                    value_chunk = delta_text[:end_idx]
+
+                    # Skip past > if at start
+                    if not self.current_param_value and ">" in value_chunk:
+                        gt_idx = value_chunk.find(">")
+                        value_chunk = value_chunk[gt_idx + 1:]
+
+                    if not self.current_param_value and value_chunk.startswith(
+                            "\n"):
+                        value_chunk = value_chunk[1:]
+
+                    # Calculate incremental JSON
+                    full_value = self.current_param_value + value_chunk
+                    prev_escaped = (json.dumps(self.current_param_value)[1:-1]
+                                    if self.current_param_value else "")
+                    full_escaped = json.dumps(full_value)[1:-1]
+                    delta_escaped = full_escaped[len(prev_escaped):]
+
+                    self.in_param = False
+                    self.current_param_value = ""
+
+                    return DeltaMessage(tool_calls=[
+                        DeltaToolCall(
+                            index=self.current_tool_index,
+                            function=DeltaFunctionCall(
+                                arguments=delta_escaped + '"'),
+                        )
+                    ])
+                else:
+                    # Continue accumulating value
+                    value_chunk = delta_text
+
+                    # Handle first chunk after param name
+                    if not self.current_param_value and ">" in value_chunk:
+                        gt_idx = value_chunk.find(">")
+                        value_chunk = value_chunk[gt_idx + 1:]
+
+                    if not self.current_param_value and value_chunk.startswith(
+                            "\n"):
+                        value_chunk = value_chunk[1:]
+
+                    if value_chunk:
+                        # Stream the escaped delta
+                        prev_escaped = (json.dumps(
+                            self.current_param_value)[1:-1]
+                                        if self.current_param_value else "")
+                        self.current_param_value += value_chunk
+                        full_escaped = json.dumps(
+                            self.current_param_value)[1:-1]
+                        delta_escaped = full_escaped[len(prev_escaped):]
+
+                        if delta_escaped:
+                            return DeltaMessage(tool_calls=[
+                                DeltaToolCall(
+                                    index=self.current_tool_index,
+                                    function=DeltaFunctionCall(
+                                        arguments=delta_escaped),
+                                )
+                            ])
+
+        return None

vllm/model_executor/models/registry.py

@@ -130,6 +130,7 @@ _TEXT_GENERATION_MODELS = {
     "Qwen3ForCausalLM": ("qwen3", "Qwen3ForCausalLM"),
     "Qwen3MoeForCausalLM": ("qwen3_moe", "Qwen3MoeForCausalLM"),
     "RWForCausalLM": ("falcon", "FalconForCausalLM"),
+    "SeedOssForCausalLM": ("seed_oss", "SeedOssForCausalLM"),
     "Step3TextForCausalLM": ("step3_text", "Step3TextForCausalLM"),
     "StableLMEpochForCausalLM": ("stablelm", "StablelmForCausalLM"),
     "StableLmForCausalLM": ("stablelm", "StablelmForCausalLM"),

vllm/model_executor/models/seed_oss.py

@@ -0,0 +1,487 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+# Copyright 2025 The Seed team.
+# Copyright 2023 The vLLM team.
+# Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved.
+#
+# This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX
+# and OPT implementations in this library. It has been modified from its
+# original forms to accommodate minor architectural differences compared
+# to GPT-NeoX and OPT used by the Meta AI team that trained the model.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Inference-only SeedOss model compatible with HuggingFace weights."""
+from collections.abc import Iterable
+from typing import Optional, Union
+
+import torch
+from torch import nn
+from transformers import PretrainedConfig as SeedOssConfig
+
+from vllm.attention import Attention, AttentionType
+from vllm.compilation.decorators import support_torch_compile
+from vllm.config import CacheConfig, VllmConfig
+from vllm.distributed import get_pp_group, get_tensor_model_parallel_world_size
+from vllm.logger import init_logger
+from vllm.model_executor.layers.activation import SiluAndMul
+from vllm.model_executor.layers.layernorm import RMSNorm
+from vllm.model_executor.layers.linear import (MergedColumnParallelLinear,
+                                               QKVParallelLinear,
+                                               RowParallelLinear)
+from vllm.model_executor.layers.logits_processor import LogitsProcessor
+from vllm.model_executor.layers.quantization import QuantizationConfig
+from vllm.model_executor.layers.rotary_embedding import get_rope
+from vllm.model_executor.layers.vocab_parallel_embedding import (
+    ParallelLMHead, VocabParallelEmbedding)
+from vllm.model_executor.model_loader.weight_utils import (
+    default_weight_loader, maybe_remap_kv_scale_name)
+from vllm.model_executor.sampling_metadata import SamplingMetadata
+from vllm.sequence import IntermediateTensors
+
+from .interfaces import SupportsLoRA, SupportsPP
+from .utils import (AutoWeightsLoader, PPMissingLayer, is_pp_missing_parameter,
+                    make_empty_intermediate_tensors_factory, make_layers,
+                    maybe_prefix)
+
+logger = init_logger(__name__)
+
+
+class SeedOssMLP(nn.Module):
+
+    def __init__(
+        self,
+        hidden_size: int,
+        intermediate_size: int,
+        hidden_act: str,
+        quant_config: Optional[QuantizationConfig] = None,
+        prefix: str = "",
+    ) -> None:
+        super().__init__()
+        self.gate_up_proj = MergedColumnParallelLinear(
+            hidden_size,
+            [intermediate_size] * 2,
+            bias=False,
+            quant_config=quant_config,
+            prefix=f"{prefix}.gate_up_proj",
+        )
+        self.down_proj = RowParallelLinear(
+            intermediate_size,
+            hidden_size,
+            bias=False,
+            quant_config=quant_config,
+            prefix=f"{prefix}.down_proj",
+        )
+        if hidden_act != "silu":
+            raise ValueError(f"Unsupported activation: {hidden_act}. "
+                             "Only silu is supported for now.")
+        self.act_fn = SiluAndMul()
+
+    def forward(self, x):
+        gate_up, _ = self.gate_up_proj(x)
+        x = self.act_fn(gate_up)
+        x, _ = self.down_proj(x)
+        return x
+
+
+class SeedOssAttention(nn.Module):
+
+    def __init__(
+        self,
+        hidden_size: int,
+        num_heads: int,
+        num_kv_heads: int,
+        head_dim: int,
+        max_position: int = 4096 * 32,
+        rope_theta: float = 10000,
+        cache_config: Optional[CacheConfig] = None,
+        quant_config: Optional[QuantizationConfig] = None,
+        rope_scaling: Optional[tuple] = None,
+        prefix: str = "",
+        attn_type: str = AttentionType.DECODER,
+    ) -> None:
+        super().__init__()
+        self.hidden_size = hidden_size
+        tp_size = get_tensor_model_parallel_world_size()
+        self.total_num_heads = num_heads
+        assert self.total_num_heads % tp_size == 0
+        self.num_heads = self.total_num_heads // tp_size
+        self.total_num_kv_heads = num_kv_heads
+        self.head_dim = head_dim
+        if self.total_num_kv_heads >= tp_size:
+            # Number of KV heads is greater than TP size, so we partition
+            # the KV heads across multiple tensor parallel GPUs.
+            assert self.total_num_kv_heads % tp_size == 0
+        else:
+            # Number of KV heads is less than TP size, so we replicate
+            # the KV heads across multiple tensor parallel GPUs.
+            assert tp_size % self.total_num_kv_heads == 0
+        self.num_kv_heads = max(1, self.total_num_kv_heads // tp_size)
+        self.q_size = self.num_heads * self.head_dim
+        self.kv_size = self.num_kv_heads * self.head_dim
+        self.scaling = self.head_dim**-0.5
+        self.rope_theta = rope_theta
+
+        self.qkv_proj = QKVParallelLinear(
+            hidden_size,
+            self.head_dim,
+            self.total_num_heads,
+            self.total_num_kv_heads,
+            bias=True,
+            quant_config=quant_config,
+            prefix=f"{prefix}.qkv_proj",
+        )
+        self.o_proj = RowParallelLinear(
+            self.total_num_heads * self.head_dim,
+            hidden_size,
+            bias=False,
+            quant_config=quant_config,
+            prefix=f"{prefix}.o_proj",
+        )
+
+        self.rotary_emb = get_rope(
+            self.head_dim,
+            rotary_dim=self.head_dim,
+            max_position=max_position,
+            base=self.rope_theta,
+            rope_scaling=rope_scaling,
+        )
+        self.attn = Attention(
+            self.num_heads,
+            self.head_dim,
+            self.scaling,
+            num_kv_heads=self.num_kv_heads,
+            cache_config=cache_config,
+            quant_config=quant_config,
+            attn_type=attn_type,
+            prefix=f"{prefix}.attn",
+        )
+
+    def forward(
+        self,
+        positions: torch.Tensor,
+        hidden_states: torch.Tensor,
+    ) -> torch.Tensor:
+        qkv, _ = self.qkv_proj(hidden_states)
+        q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size], dim=-1)
+        q, k = self.rotary_emb(positions, q, k)
+        attn_output = self.attn(q, k, v)
+        output, _ = self.o_proj(attn_output)
+        return output
+
+
+class SeedOssDecoderLayer(nn.Module):
+
+    def __init__(
+        self,
+        config: SeedOssConfig,
+        cache_config: Optional[CacheConfig] = None,
+        quant_config: Optional[QuantizationConfig] = None,
+        prefix: str = "",
+    ) -> None:
+        super().__init__()
+        self.hidden_size = config.hidden_size
+        # Requires transformers > 4.32.0
+        rope_theta = getattr(config, "rope_theta", 1000000)
+        rope_scaling = getattr(config, "rope_scaling", None)
+
+        # By default, SeedOss uses causal attention as it is a
+        # decoder-only model.
+        # You can override the HF config with `is_causal=False` to enable
+        # bidirectional attention, which is used in some embedding models
+        if getattr(config, "is_causal", True):
+            attn_type = AttentionType.DECODER
+        else:
+            attn_type = AttentionType.ENCODER_ONLY
+
+        self.self_attn = SeedOssAttention(
+            hidden_size=self.hidden_size,
+            num_heads=config.num_attention_heads,
+            max_position=config.max_position_embeddings,
+            num_kv_heads=config.num_key_value_heads,
+            head_dim=config.head_dim,
+            rope_theta=rope_theta,
+            cache_config=cache_config,
+            quant_config=quant_config,
+            rope_scaling=rope_scaling,
+            prefix=f"{prefix}.self_attn",
+            attn_type=attn_type,
+        )
+        self.mlp = SeedOssMLP(
+            hidden_size=self.hidden_size,
+            intermediate_size=config.intermediate_size,
+            hidden_act=config.hidden_act,
+            quant_config=quant_config,
+            prefix=f"{prefix}.mlp",
+        )
+        self.input_layernorm = RMSNorm(config.hidden_size,
+                                       eps=config.rms_norm_eps)
+        self.post_attention_layernorm = RMSNorm(config.hidden_size,
+                                                eps=config.rms_norm_eps)
+
+    def forward(
+        self,
+        positions: torch.Tensor,
+        hidden_states: torch.Tensor,
+        residual: Optional[torch.Tensor],
+    ) -> tuple[torch.Tensor, torch.Tensor]:
+        # Self Attention
+        if residual is None:
+            residual = hidden_states
+            hidden_states = self.input_layernorm(hidden_states)
+        else:
+            hidden_states, residual = self.input_layernorm(
+                hidden_states, residual)
+        hidden_states = self.self_attn(
+            positions=positions,
+            hidden_states=hidden_states,
+        )
+
+        # Fully Connected
+        hidden_states, residual = self.post_attention_layernorm(
+            hidden_states, residual)
+        hidden_states = self.mlp(hidden_states)
+        return hidden_states, residual
+
+
+@support_torch_compile(
+    dynamic_arg_dims={
+        "input_ids": 0,
+        "positions": -1,
+        "intermediate_tensors": 0,
+        "inputs_embeds": 0,
+    })
+class SeedOssModel(nn.Module):
+
+    def __init__(self,
+                 *,
+                 vllm_config: VllmConfig,
+                 prefix: str = "",
+                 decoder_layer_type: type[nn.Module] = SeedOssDecoderLayer):
+        super().__init__()
+
+        config = vllm_config.model_config.hf_config
+        cache_config = vllm_config.cache_config
+        quant_config = vllm_config.quant_config
+
+        # TODO (@robertgshaw2): see if this can be moved out
+        if (cache_config.sliding_window is not None
+                and hasattr(config, "max_window_layers")):
+            assert config.max_window_layers == config.num_hidden_layers, (
+                "Sliding window for some but all layers is not supported. "
+                "This model uses sliding window but `max_window_layers` = {} "
+                "is less than `num_hidden_layers` = {}. Please open an issue "
+                "to discuss this feature.".format(
+                    config.max_window_layers,
+                    config.num_hidden_layers,
+                ))
+
+        self.config = config
+        self.quant_config = quant_config
+        self.vocab_size = config.vocab_size
+
+        if get_pp_group().is_first_rank or (config.tie_word_embeddings
+                                            and get_pp_group().is_last_rank):
+            self.embed_tokens = VocabParallelEmbedding(
+                config.vocab_size,
+                config.hidden_size,
+                quant_config=quant_config,
+                prefix=f"{prefix}.embed_tokens",
+            )
+        else:
+            self.embed_tokens = PPMissingLayer()
+
+        # Use the provided decoder layer type or default to SeedDecoderLayer
+        decoder_layer_type = decoder_layer_type or SeedOssDecoderLayer
+        self.start_layer, self.end_layer, self.layers = make_layers(
+            config.num_hidden_layers,
+            lambda prefix: decoder_layer_type(config=config,
+                                              cache_config=cache_config,
+                                              quant_config=quant_config,
+                                              prefix=prefix),
+            prefix=f"{prefix}.layers",
+        )
+
+        self.make_empty_intermediate_tensors = (
+            make_empty_intermediate_tensors_factory(
+                ["hidden_states", "residual"], config.hidden_size))
+        if get_pp_group().is_last_rank:
+            self.norm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
+        else:
+            self.norm = PPMissingLayer()
+
+    def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
+        return self.embed_tokens(input_ids)
+
+    def forward(
+        self,
+        input_ids: torch.Tensor,
+        positions: torch.Tensor,
+        intermediate_tensors: Optional[IntermediateTensors] = None,
+        inputs_embeds: Optional[torch.Tensor] = None,
+    ) -> Union[torch.Tensor, IntermediateTensors]:
+        if get_pp_group().is_first_rank:
+            if inputs_embeds is not None:
+                hidden_states = inputs_embeds
+            else:
+                hidden_states = self.get_input_embeddings(input_ids)
+            residual = None
+        else:
+            assert intermediate_tensors is not None
+            hidden_states = intermediate_tensors["hidden_states"]
+            residual = intermediate_tensors["residual"]
+        for layer in self.layers[self.start_layer:self.end_layer]:
+            hidden_states, residual = layer(
+                positions,
+                hidden_states,
+                residual,
+            )
+        if not get_pp_group().is_last_rank:
+            return IntermediateTensors({
+                "hidden_states": hidden_states,
+                "residual": residual
+            })
+        hidden_states, _ = self.norm(hidden_states, residual)
+        return hidden_states
+
+    def load_weights(self, weights: Iterable[tuple[str,
+                                                   torch.Tensor]]) -> set[str]:
+        stacked_params_mapping = [
+            # (param_name, shard_name, shard_id)
+            ("qkv_proj", "q_proj", "q"),
+            ("qkv_proj", "k_proj", "k"),
+            ("qkv_proj", "v_proj", "v"),
+            ("gate_up_proj", "gate_proj", 0),
+            ("gate_up_proj", "up_proj", 1),
+        ]
+        params_dict = dict(self.named_parameters(remove_duplicate=False))
+        loaded_params: set[str] = set()
+        for name, loaded_weight in weights:
+            if "rotary_emb.inv_freq" in name:
+                continue
+            if (self.quant_config is not None and
+                (scale_name := self.quant_config.get_cache_scale(name))):
+                # Loading kv cache quantization scales
+                param = params_dict[scale_name]
+                weight_loader = getattr(param, "weight_loader",
+                                        default_weight_loader)
+                loaded_weight = (loaded_weight if loaded_weight.dim() == 0 else
+                                 loaded_weight[0])
+                weight_loader(param, loaded_weight)
+                loaded_params.add(scale_name)
+                continue
+            for (param_name, weight_name, shard_id) in stacked_params_mapping:
+                if weight_name not in name:
+                    continue
+                name = name.replace(weight_name, param_name)
+                # Skip loading extra bias for GPTQ models.
+                if name.endswith(".bias") and name not in params_dict:
+                    continue
+                if is_pp_missing_parameter(name, self):
+                    continue
+                param = params_dict[name]
+                weight_loader = param.weight_loader
+                weight_loader(param, loaded_weight, shard_id)
+                break
+            else:
+                # Skip loading extra bias for GPTQ models.
+                if name.endswith(".bias") and name not in params_dict:
+                    continue
+                # Remapping the name of FP8 kv-scale.
+                name = maybe_remap_kv_scale_name(name, params_dict)
+                if name is None:
+                    continue
+                if is_pp_missing_parameter(name, self):
+                    continue
+                param = params_dict[name]
+                weight_loader = getattr(param, "weight_loader",
+                                        default_weight_loader)
+                weight_loader(param, loaded_weight)
+            loaded_params.add(name)
+        return loaded_params
+
+
+class SeedOssForCausalLM(nn.Module, SupportsLoRA, SupportsPP):
+    packed_modules_mapping = {
+        "qkv_proj": [
+            "q_proj",
+            "k_proj",
+            "v_proj",
+        ],
+        "gate_up_proj": [
+            "gate_proj",
+            "up_proj",
+        ],
+    }
+
+    def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
+        super().__init__()
+        config = vllm_config.model_config.hf_config
+        quant_config = vllm_config.quant_config
+        lora_config = vllm_config.lora_config
+
+        self.config = config
+        self.lora_config = lora_config
+
+        self.quant_config = quant_config
+        self.model = SeedOssModel(vllm_config=vllm_config,
+                                  prefix=maybe_prefix(prefix, "model"))
+
+        if get_pp_group().is_last_rank:
+            if config.tie_word_embeddings:
+                self.lm_head = self.model.embed_tokens
+            else:
+                self.lm_head = ParallelLMHead(config.vocab_size,
+                                              config.hidden_size,
+                                              quant_config=quant_config,
+                                              prefix=maybe_prefix(
+                                                  prefix, "lm_head"))
+        else:
+            self.lm_head = PPMissingLayer()
+
+        self.logits_processor = LogitsProcessor(config.vocab_size)
+
+        self.make_empty_intermediate_tensors = (
+            self.model.make_empty_intermediate_tensors)
+
+    def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
+        return self.model.get_input_embeddings(input_ids)
+
+    def forward(
+        self,
+        input_ids: torch.Tensor,
+        positions: torch.Tensor,
+        intermediate_tensors: Optional[IntermediateTensors] = None,
+        inputs_embeds: Optional[torch.Tensor] = None,
+    ) -> Union[torch.Tensor, IntermediateTensors]:
+        hidden_states = self.model(input_ids, positions, intermediate_tensors,
+                                   inputs_embeds)
+        return hidden_states
+
+    def compute_logits(
+        self,
+        hidden_states: torch.Tensor,
+        sampling_metadata: SamplingMetadata,
+    ) -> Optional[torch.Tensor]:
+        logits = self.logits_processor(self.lm_head, hidden_states,
+                                       sampling_metadata)
+        return logits
+
+    def load_weights(self, weights: Iterable[tuple[str,
+                                                   torch.Tensor]]) -> set[str]:
+        loader = AutoWeightsLoader(
+            self,
+            skip_prefixes=(["lm_head."]
+                           if self.config.tie_word_embeddings else None),
+        )
+        return loader.load_weights(weights)