feat(reasoning): auto-detect reasoning/tool-call parser from chat template (#23952)

.codespellrc

@@ -1,3 +1,3 @@
 [codespell]
-ignore-words-list = ans, als, hel, boostrap, childs, te, vas, hsa, ment, cann, thi, makro, wil, rouge, PRIS, ather, MIS, medias, allready, inout, nd, fo, visibles
+ignore-words-list = ans, als, hel, boostrap, childs, te, vas, hsa, ment, cann, thi, makro, wil, rouge, PRIS, ather, MIS, medias, allready, inout, nd, fo, visibles, nothink
 skip = *.json, *.jsonl, *.patch, *.txt, *.lock

python/sglang/srt/entrypoints/engine.py

@@ -82,6 +82,7 @@ from sglang.srt.managers.io_struct import (
 )
 from sglang.srt.managers.multi_tokenizer_mixin import MultiTokenizerRouter
 from sglang.srt.managers.scheduler import run_scheduler_process
+from sglang.srt.managers.template_detection import resolve_auto_parsers
 from sglang.srt.managers.template_manager import TemplateManager
 from sglang.srt.managers.tokenizer_manager import TokenizerManager
 from sglang.srt.observability.trace import process_tracing_init, trace_set_thread_info
@@ -140,6 +141,33 @@ def init_tokenizer_manager(
         completion_template=server_args.completion_template,
     )
 
+    # Resolve any remaining auto parsers using template manager's detection results
+    for attr, suggested, label in (
+        (
+            "reasoning_parser",
+            template_manager.suggested_reasoning_parser,
+            "reasoning parser",
+        ),
+        (
+            "tool_call_parser",
+            template_manager.suggested_tool_call_parser,
+            "tool-call parser",
+        ),
+    ):
+        if getattr(server_args, attr) != "auto":
+            continue
+        if suggested is not None:
+            setattr(server_args, attr, suggested)
+            logger.info(
+                f"Auto-detected --{attr.replace('_', '-')} as '{suggested}' from chat template"
+            )
+        else:
+            logger.warning(
+                f"--{attr.replace('_', '-')}=auto specified but could not detect "
+                f"{label} from chat template. Disabling {label}."
+            )
+            setattr(server_args, attr, None)
+
     return tokenizer_manager, template_manager
 
 
@@ -695,6 +723,12 @@ class Engine(EngineScoreMixin, EngineBase):
                 host=server_args.host, port=bootstrap_port
             )
 
+        if (
+            server_args.reasoning_parser == "auto"
+            or server_args.tool_call_parser == "auto"
+        ):
+            resolve_auto_parsers(server_args)
+
         # Launch scheduler processes
         scheduler_init_result, scheduler_procs = cls._launch_scheduler_processes(
             server_args, port_args, run_scheduler_process_func

python/sglang/srt/entrypoints/openai/serving_chat.py

@@ -193,6 +193,19 @@ class OpenAIServingChat(OpenAIServingBase):
         self.template_manager = template_manager
         self.tool_call_parser = self.tokenizer_manager.server_args.tool_call_parser
         self.reasoning_parser = self.tokenizer_manager.server_args.reasoning_parser
+        self._reasoning_detector = None
+        if self.reasoning_parser:
+            try:
+                rp = ReasoningParser(
+                    model_type=self.reasoning_parser, stream_reasoning=True
+                )
+                self._reasoning_detector = rp.detector
+            except ValueError as e:
+                logger.warning(
+                    "Failed to initialize reasoning detector for parser '%s': %s",
+                    self.reasoning_parser,
+                    e,
+                )
 
         # Get default sampling parameters from model's generation config
         self.default_sampling_params = (
@@ -683,10 +696,11 @@ class OpenAIServingChat(OpenAIServingBase):
                 prompt = prompt[: -len(conv.sep2)]
         else:
             prompt = conv.get_prompt()
-            if self._get_reasoning_from_request(
+            if self._get_reasoning_from_request(request) and (
-                request
+                self._reasoning_detector is None
-            ) and self.reasoning_parser not in ["qwen3", "qwen3-thinking", "glm4"]:
+                or not self._reasoning_detector.thinks_internally
-                # qwen3 and glm4 think internally without a leading <think> token
+            ):
+                # Models with thinks_internally=True think without a leading <think> token
                 prompt += "<think>"  # Note(Xinyuan): hard code thinking token
 
         image_data = conv.image_data if conv.image_data else None
@@ -1395,54 +1409,75 @@ class OpenAIServingChat(OpenAIServingBase):
             request.skip_special_tokens = False
 
     def _get_reasoning_from_request(self, request: ChatCompletionRequest) -> bool:
-        """Judge whether the request needs reasoning for hybrid reasoning models
+        """Determine whether reasoning mode should be enabled for this request.
+
         NOTE: This is predefined based on model's chat template
         """
         if not self.reasoning_parser:
             return False
 
-        if self.reasoning_parser == "deepseek-v3":
-            # Models that require explicit enable thinking (thinking=True)
-            return (
-                request.chat_template_kwargs is not None
-                and request.chat_template_kwargs.get("thinking") is True
-            )
-        if self.reasoning_parser == "gemma4":
-            return (
-                request.chat_template_kwargs is not None
-                and request.chat_template_kwargs.get("enable_thinking") is True
-            )
-        if self.reasoning_parser in ["kimi_k2"]:
-            # Models that thinking by default, and can be disabled by setting thinking=False
-            return (
-                not request.chat_template_kwargs
-                or request.chat_template_kwargs.get("thinking") is not False
-            )
-        if self.reasoning_parser in ["qwen3", "glm45", "nemotron_3", "interns1"]:
-            # Models that thinking by default, and can be disabled by setting enable_thinking=False
-            return (
-                not request.chat_template_kwargs
-                or request.chat_template_kwargs.get("enable_thinking") is not False
-            )
-        if self.reasoning_parser in ["mimo"]:
-            # Models that require explicit enable thinking (enable_thinking=True)
-            return (
-                request.chat_template_kwargs is not None
-                and request.chat_template_kwargs.get("enable_thinking") is True
-            )
         if self.reasoning_parser == "hunyuan":
             # Hy3-preview template emits no <think> when reasoning_effort is
             # "no_think" / "none" / unset; forcing reasoning would route all
             # output into reasoning_content.
             return request.reasoning_effort not in (None, "none", "no_think")
-        if self.reasoning_parser == "mistral":
+
-            # Mistral only reasons when reasoning_effort is explicitly set
+        config = self.template_manager.reasoning_config
-            # to a non-"none" value (typically "high").
+        if config is None:
+            # Fallback to parser-level defaults when template toggle config
+            # cannot be inferred (e.g., parser-only <think> templates).
+            mode = (
+                self._reasoning_detector.reasoning_default
+                if self._reasoning_detector is not None
+                else None
+            )
+            if mode is None:
+                return False
+            if mode == "always":
+                return True
+            if mode == "mistral":
+                return (
+                    request.reasoning_effort is not None
+                    and request.reasoning_effort != "none"
+                )
+            if mode in ("thinking", "enable_thinking"):
+                return (
+                    not request.chat_template_kwargs
+                    or request.chat_template_kwargs.get(mode) is not False
+                )
+            if mode in ("explicit_thinking", "explicit_enable_thinking"):
+                toggle = mode.replace("explicit_", "")
+                return (
+                    request.chat_template_kwargs is not None
+                    and request.chat_template_kwargs.get(toggle) is True
+                )
+            logger.warning(
+                "Unknown reasoning_default mode '%s', defaulting to reasoning disabled",
+                mode,
+            )
+            return False
+
+        if config.special_case == "always":
+            return True
+
+        if config.special_case == "mistral":
             return (
                 request.reasoning_effort is not None
                 and request.reasoning_effort != "none"
             )
-        return True  # default
+
+        if config.toggle_param is None or config.default_enabled is None:
+            return False
+
+        if config.default_enabled:
+            return (
+                not request.chat_template_kwargs
+                or request.chat_template_kwargs.get(config.toggle_param) is not False
+            )
+        return (
+            request.chat_template_kwargs is not None
+            and request.chat_template_kwargs.get(config.toggle_param) is True
+        )
 
     async def _process_tool_call_stream(
         self,

python/sglang/srt/managers/template_detection.py

@@ -0,0 +1,471 @@
+# Copyright 2026 SGLang Team
+# 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.
+# ==============================================================================
+"""
+Template detection utilities for auto-detecting reasoning and tool-call parsers.
+
+Provides rule-based detection of reasoning mode, reasoning parser, and tool-call
+parser from chat templates and tokenizer vocabularies.
+"""
+
+import logging
+import re
+from dataclasses import dataclass
+from typing import Callable, Optional, Tuple
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass(frozen=True)
+class TemplateDetectionContext:
+    template: str
+    reasoning_config: Optional["ReasoningToggleConfig"]
+    force_reasoning: bool
+    vocab: set[str]
+
+    def has_text(self, needle: str) -> bool:
+        return needle in self.template
+
+    def has_vocab(self, token: str) -> bool:
+        return token in self.vocab
+
+    def has_pattern(self, pattern: str, flags: int = 0) -> bool:
+        return re.search(pattern, self.template, flags) is not None
+
+
+@dataclass(frozen=True)
+class DetectionRule:
+    name: str
+    value: object
+    predicate: Callable[[TemplateDetectionContext], bool]
+
+
+@dataclass(frozen=True)
+class ReasoningToggleConfig:
+    toggle_param: Optional[str] = None
+    default_enabled: Optional[bool] = None
+    special_case: Optional[str] = None
+
+    @property
+    def always_on(self) -> bool:
+        return self.special_case == "always"
+
+
+# ---------------------------------------------------------------------------
+# Reasoning mode rules (detect toggle config from template)
+# ---------------------------------------------------------------------------
+
+REASONING_MODE_RULES = (
+    DetectionRule(
+        name="gpt_oss_channel_markers",
+        value=ReasoningToggleConfig(special_case="always"),
+        predicate=lambda ctx: ctx.has_text("<|channel|>"),
+    ),
+    DetectionRule(
+        name="force_reasoning_pattern",
+        value=ReasoningToggleConfig(special_case="always"),
+        predicate=lambda ctx: ctx.has_pattern(r"<\|im_start\|>assistant\\n<think>\\n")
+        and not ctx.has_text("enable_thinking")
+        and not ctx.has_text("thinking"),
+    ),
+    DetectionRule(
+        name="mistral_reasoning_effort",
+        value=ReasoningToggleConfig(special_case="mistral"),
+        predicate=lambda ctx: ctx.has_text("reasoning_effort")
+        and ctx.has_text("[THINK]"),
+    ),
+    DetectionRule(
+        name="explicit_enable_thinking_default_false",
+        value=ReasoningToggleConfig(
+            toggle_param="enable_thinking", default_enabled=False
+        ),
+        predicate=lambda ctx: ctx.has_pattern(
+            r"{%\s*if\s+not\s+enable_thinking\s+is\s+defined\s*%}.*?"
+            r"{%\s*set\s+enable_thinking\s*=\s*(?:false|False)\s*%}",
+            re.DOTALL,
+        ),
+    ),
+    DetectionRule(
+        name="enable_thinking_default_true",
+        value=ReasoningToggleConfig(
+            toggle_param="enable_thinking", default_enabled=True
+        ),
+        predicate=lambda ctx: ctx.has_pattern(
+            r"{%\s*if\s+not\s+enable_thinking\s+is\s+defined\s*%}.*?"
+            r"{%\s*set\s+enable_thinking\s*=\s*(?:true|True)\s*%}",
+            re.DOTALL,
+        )
+        or ctx.has_pattern(
+            r"set\s+enable_thinking\s*=\s*enable_thinking\s+if\s+enable_thinking\s+is\s+defined\s+else\s+(?:true|True)"
+        )
+        or ctx.has_pattern(
+            r"enable_thinking\s+is\s+defined\s+and\s+(?:enable_thinking\s+is\s+false|not\s+enable_thinking)"
+        )
+        or ctx.has_pattern(
+            r"enable_thinking\s+is\s+not\s+defined\s+or\s+enable_thinking"
+        )
+        or ctx.has_pattern(r"namespace\([^)]*enable_thinking\s*=\s*true"),
+    ),
+    DetectionRule(
+        name="explicit_thinking_default_false",
+        value=ReasoningToggleConfig(toggle_param="thinking", default_enabled=False),
+        predicate=lambda ctx: ctx.has_pattern(
+            r"{%\s*if\s+not\s+thinking\s+is\s+defined\s*%}.*?"
+            r"{%\s*set\s+thinking\s*=\s*(?:false|False)\s*%}",
+            re.DOTALL,
+        ),
+    ),
+    DetectionRule(
+        name="thinking_default_true",
+        value=ReasoningToggleConfig(toggle_param="thinking", default_enabled=True),
+        predicate=lambda ctx: ctx.has_pattern(
+            r"{%\s*if\s+not\s+thinking\s+is\s+defined\s*%}.*?"
+            r"{%\s*set\s+thinking\s*=\s*(?:true|True)\s*%}",
+            re.DOTALL,
+        )
+        or ctx.has_pattern(
+            r"set\s+thinking\s*=\s*thinking\s+if\s+thinking\s+is\s+defined\s+else\s+(?:true|True)"
+        )
+        or ctx.has_pattern(
+            r"thinking\s+is\s+defined\s+and\s+(?:thinking\s+is\s+false|not\s+thinking)"
+        )
+        or ctx.has_pattern(r"thinking\s+is\s+not\s+defined\s+or\s+thinking")
+        or ctx.has_pattern(r"namespace\([^)]*thinking\s*=\s*true"),
+    ),
+)
+
+
+# ---------------------------------------------------------------------------
+# Shared predicates for model-family detection
+# ---------------------------------------------------------------------------
+
+
+def _is_gemma4(ctx):
+    return ctx.has_text("<|channel>")
+
+
+def _is_kimi(ctx):
+    return ctx.has_text("◁think▷")
+
+
+def _is_interns1(ctx):
+    return ctx.has_text("default_thinking_sys") and ctx.reasoning_config == (
+        ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True)
+    )
+
+
+def _is_mistral(ctx):
+    return (
+        ctx.reasoning_config is not None
+        and ctx.reasoning_config.special_case == "mistral"
+    )
+
+
+def _is_gpt_oss(ctx):
+    return ctx.has_text("<|channel|>")
+
+
+def _is_kimi_k2(ctx):
+    return ctx.has_vocab("<|tool_calls_section_begin|>")
+
+
+def _is_nemotron_3(ctx):
+    return ctx.has_text("truncate_history_thinking") and ctx.reasoning_config == (
+        ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True)
+    )
+
+
+def _is_glm45(ctx):
+    return (
+        (
+            ctx.has_text("[gMASK]<sop>")
+            or ctx.has_pattern(r"(?<!<)/nothink")
+            or ctx.has_pattern(r"(?<!<)/think")
+        )
+        and ctx.has_vocab("<tool_call>")
+        and ctx.reasoning_config
+        == ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True)
+        and (ctx.has_vocab("<|user|>") or ctx.has_vocab("<|endoftext|>"))
+    )
+
+
+def _is_mimo(ctx):
+    return ctx.reasoning_config == ReasoningToggleConfig(
+        toggle_param="enable_thinking", default_enabled=False
+    )
+
+
+def _is_minimax(ctx):
+    return ctx.has_text("<minimax:tool_call>")
+
+
+def _is_qwen3(ctx):
+    return ctx.reasoning_config == ReasoningToggleConfig(
+        toggle_param="enable_thinking", default_enabled=True
+    )
+
+
+def _is_deepseek_v3(ctx):
+    return ctx.reasoning_config == ReasoningToggleConfig(
+        toggle_param="thinking", default_enabled=False
+    )
+
+
+def _is_deepseek_r1(ctx):
+    return ctx.force_reasoning
+
+
+def _is_deepseek_r1_think_tags(ctx):
+    return ctx.has_text("<think>") or ctx.has_text("</think>")
+
+
+# ---------------------------------------------------------------------------
+# Reasoning parser rules
+# ---------------------------------------------------------------------------
+
+REASONING_PARSER_RULES = (
+    DetectionRule(name="gemma4", value="gemma4", predicate=_is_gemma4),
+    DetectionRule(name="kimi", value="kimi", predicate=_is_kimi),
+    DetectionRule(name="interns1", value="interns1", predicate=_is_interns1),
+    DetectionRule(name="mistral", value="mistral", predicate=_is_mistral),
+    DetectionRule(name="gpt_oss", value="gpt-oss", predicate=_is_gpt_oss),
+    DetectionRule(name="kimi_k2", value="kimi_k2", predicate=_is_kimi_k2),
+    DetectionRule(name="nemotron_3", value="nemotron_3", predicate=_is_nemotron_3),
+    DetectionRule(name="glm45", value="glm45", predicate=_is_glm45),
+    DetectionRule(name="mimo", value="mimo", predicate=_is_mimo),
+    DetectionRule(name="minimax", value="minimax", predicate=_is_minimax),
+    DetectionRule(name="qwen3", value="qwen3", predicate=_is_qwen3),
+    DetectionRule(name="deepseek_v3", value="deepseek-v3", predicate=_is_deepseek_v3),
+    DetectionRule(
+        name="deepseek_r1_force", value="deepseek-r1", predicate=_is_deepseek_r1
+    ),
+    DetectionRule(
+        name="deepseek_r1_think_tags",
+        value="deepseek-r1",
+        predicate=_is_deepseek_r1_think_tags,
+    ),
+)
+
+# ---------------------------------------------------------------------------
+# Tool-call parser rules (reuse shared predicates, different values)
+# ---------------------------------------------------------------------------
+
+TOOL_CALL_PARSER_RULES = (
+    DetectionRule(name="gemma4", value="gemma4", predicate=_is_gemma4),
+    DetectionRule(name="gpt_oss", value="gpt-oss", predicate=_is_gpt_oss),
+    DetectionRule(name="kimi_k2", value="kimi_k2", predicate=_is_kimi_k2),
+    DetectionRule(name="minimax", value="minimax-m2", predicate=_is_minimax),
+    DetectionRule(name="interns1", value="interns1", predicate=_is_interns1),
+    DetectionRule(name="mistral", value="mistral", predicate=_is_mistral),
+    DetectionRule(name="glm45", value="glm45", predicate=_is_glm45),
+    DetectionRule(name="mimo", value="mimo", predicate=_is_mimo),
+    DetectionRule(name="qwen", value="qwen", predicate=_is_qwen3),
+    DetectionRule(name="deepseek_v3", value="deepseekv3", predicate=_is_deepseek_v3),
+    DetectionRule(name="deepseek_r1", value="deepseekv3", predicate=_is_deepseek_r1),
+)
+
+
+# ---------------------------------------------------------------------------
+# Detection functions
+# ---------------------------------------------------------------------------
+
+
+def build_detection_context(
+    template: Optional[str],
+    tokenizer,
+    reasoning_config: Optional[ReasoningToggleConfig] = None,
+    force_reasoning: bool = False,
+) -> Optional[TemplateDetectionContext]:
+    if template is None:
+        return None
+    vocab = set()
+    if tokenizer is not None:
+        try:
+            vocab = set(tokenizer.get_vocab().keys())
+        except Exception as e:
+            logger.warning(
+                "Failed to load tokenizer vocab for template detection: %s. "
+                "Vocab-dependent detection rules will be skipped.",
+                e,
+            )
+    return TemplateDetectionContext(
+        template=template,
+        reasoning_config=reasoning_config,
+        force_reasoning=force_reasoning,
+        vocab=vocab,
+    )
+
+
+def match_rules(
+    ctx: TemplateDetectionContext,
+    rules: Tuple[DetectionRule, ...],
+    label: str,
+) -> Optional[str]:
+    for rule in rules:
+        try:
+            if rule.predicate(ctx):
+                logger.info(
+                    "Detected %s '%s' from template rule '%s'.",
+                    label,
+                    rule.value,
+                    rule.name,
+                )
+                return rule.value
+        except Exception as e:
+            logger.warning(
+                "Detection rule '%s' for %s raised an exception: %s. Skipping.",
+                rule.name,
+                label,
+                e,
+                exc_info=True,
+            )
+    return None
+
+
+def detect_reasoning_pattern(
+    template: Optional[str],
+) -> Tuple[bool, Optional[ReasoningToggleConfig]]:
+    """Detect if the chat template contains reasoning/thinking patterns."""
+    if template is None:
+        return False, None
+
+    ctx = TemplateDetectionContext(
+        template=template,
+        reasoning_config=None,
+        force_reasoning=False,
+        vocab=set(),
+    )
+    for rule in REASONING_MODE_RULES:
+        if rule.predicate(ctx):
+            logger.info(
+                "Detected reasoning config '%s' from template rule '%s'.",
+                rule.value,
+                rule.name,
+            )
+            return rule.value.always_on, rule.value
+
+    return False, None
+
+
+def detect_reasoning_parser(
+    template: Optional[str],
+    tokenizer,
+    reasoning_config: Optional[ReasoningToggleConfig] = None,
+    force_reasoning: bool = False,
+) -> Optional[str]:
+    """Auto-detect which reasoning parser to use from the chat template."""
+    ctx = build_detection_context(
+        template, tokenizer, reasoning_config, force_reasoning
+    )
+    if ctx is None:
+        return None
+    return match_rules(ctx, REASONING_PARSER_RULES, "reasoning parser")
+
+
+def detect_tool_call_parser(
+    template: Optional[str],
+    tokenizer,
+    reasoning_config: Optional[ReasoningToggleConfig] = None,
+    force_reasoning: bool = False,
+) -> Optional[str]:
+    """Auto-detect which tool-call parser to use from the chat template."""
+    ctx = build_detection_context(
+        template, tokenizer, reasoning_config, force_reasoning
+    )
+    if ctx is None:
+        return None
+    return match_rules(ctx, TOOL_CALL_PARSER_RULES, "tool-call parser")
+
+
+def _resolve_auto_parser(
+    server_args,
+    attr: str,
+    ctx: TemplateDetectionContext,
+    rules: Tuple[DetectionRule, ...],
+    label: str,
+) -> None:
+    """Resolve a single auto parser, updating server_args in place."""
+    detected = match_rules(ctx, rules, label)
+    if detected:
+        setattr(server_args, attr, detected)
+        logger.info(
+            f"Auto-detected --{attr.replace('_', '-')} as '{detected}' from chat template"
+        )
+    else:
+        logger.warning(
+            f"--{attr.replace('_', '-')}=auto specified but could not detect "
+            f"{label} from chat template. Disabling {label}."
+        )
+        setattr(server_args, attr, None)
+
+
+def resolve_auto_parsers(server_args) -> None:
+    """Resolve --reasoning-parser=auto and --tool-call-parser=auto before scheduler.
+
+    This performs a lightweight tokenizer load to detect parsers from the chat
+    template. Called early in engine init before scheduler subprocesses are spawned.
+    """
+    needs_reasoning = server_args.reasoning_parser == "auto"
+    needs_tool_call = server_args.tool_call_parser == "auto"
+
+    if not needs_reasoning and not needs_tool_call:
+        return
+
+    from sglang.srt.utils.hf_transformers_utils import get_tokenizer
+
+    try:
+        tokenizer = get_tokenizer(
+            server_args.model_path,
+            trust_remote_code=server_args.trust_remote_code,
+        )
+        template = getattr(tokenizer, "chat_template", None)
+    except Exception as e:
+        logger.warning(f"Failed to load tokenizer for auto-detection: {e}")
+        if needs_reasoning:
+            logger.warning(
+                "--reasoning-parser=auto specified but could not detect "
+                "reasoning parser from chat template. Disabling reasoning parser."
+            )
+            server_args.reasoning_parser = None
+        if needs_tool_call:
+            logger.warning(
+                "--tool-call-parser=auto specified but could not detect "
+                "tool-call parser from chat template. Disabling tool-call parser."
+            )
+            server_args.tool_call_parser = None
+        return
+
+    force_reasoning, reasoning_config = detect_reasoning_pattern(template)
+    ctx = build_detection_context(
+        template, tokenizer, reasoning_config, force_reasoning
+    )
+    if ctx is None:
+        return
+
+    if needs_reasoning:
+        _resolve_auto_parser(
+            server_args,
+            "reasoning_parser",
+            ctx,
+            REASONING_PARSER_RULES,
+            "reasoning parser",
+        )
+
+    if needs_tool_call:
+        _resolve_auto_parser(
+            server_args,
+            "tool_call_parser",
+            ctx,
+            TOOL_CALL_PARSER_RULES,
+            "tool-call parser",
+        )

python/sglang/srt/managers/template_manager.py

@@ -21,9 +21,16 @@ and code completion templates, eliminating global state and improving modularity
 import json
 import logging
 import os
-import re
 from typing import Dict, Optional
 
+from sglang.srt.managers.template_detection import (
+    REASONING_PARSER_RULES,
+    TOOL_CALL_PARSER_RULES,
+    ReasoningToggleConfig,
+    build_detection_context,
+    detect_reasoning_pattern,
+    match_rules,
+)
 from sglang.srt.managers.tokenizer_manager import TokenizerManager
 from sglang.srt.parser.code_completion_parser import (
     CompletionTemplate,
@@ -58,6 +65,9 @@ class TemplateManager:
         self._completion_template_name: Optional[str] = None
         self._jinja_template_content_format: Optional[str] = "openai"
         self._force_reasoning: bool = False
+        self._reasoning_config: Optional[ReasoningToggleConfig] = None
+        self._suggested_reasoning_parser: Optional[str] = None
+        self._suggested_tool_call_parser: Optional[str] = None
 
     @property
     def chat_template_name(self) -> Optional[str]:
@@ -84,21 +94,39 @@ class TemplateManager:
         """
         return self._force_reasoning
 
-    def _detect_reasoning_pattern(self, template: str) -> bool:
+    @property
-        """
+    def reasoning_config(self) -> Optional[ReasoningToggleConfig]:
-        Detect if the chat template contains reasoning/thinking patterns.
+        """Get the reasoning toggle config inferred from chat template."""
-        """
+        return self._reasoning_config
-        if template is None:
-            return False
 
-        # TODO: remove this hard code the reasoning pattern
+    @property
-        force_reasoning_pattern = r"<\|im_start\|>assistant\\n<think>\\n"
+    def suggested_reasoning_parser(self) -> Optional[str]:
-        has_reasoning = re.search(force_reasoning_pattern, template) is not None
+        """Get the auto-detected reasoning parser name, or None."""
+        return self._suggested_reasoning_parser
 
-        if has_reasoning:
+    @property
-            logger.info("Detected the force reasoning pattern in chat template.")
+    def suggested_tool_call_parser(self) -> Optional[str]:
+        """Get the auto-detected tool-call parser name, or None."""
+        return self._suggested_tool_call_parser
 
-        return has_reasoning
+    def _run_template_detection(self, template, tokenizer) -> None:
+        """Run reasoning pattern and parser detection on a template."""
+        self._force_reasoning, self._reasoning_config = detect_reasoning_pattern(
+            template
+        )
+        # Build context once, reuse for both parser detections (avoids
+        # duplicate tokenizer.get_vocab() calls).
+        ctx = build_detection_context(
+            template, tokenizer, self._reasoning_config, self._force_reasoning
+        )
+        if ctx is None:
+            return
+        self._suggested_reasoning_parser = match_rules(
+            ctx, REASONING_PARSER_RULES, "reasoning parser"
+        )
+        self._suggested_tool_call_parser = match_rules(
+            ctx, TOOL_CALL_PARSER_RULES, "tool-call parser"
+        )
 
     def load_chat_template(
         self,
@@ -141,11 +169,18 @@ class TemplateManager:
                         "No chat template found, defaulting to 'string' content format"
                     )
 
-        # Detect reasoning pattern from chat template
+        # Detect reasoning pattern and suggest parser from chat template
         if tokenizer_manager.tokenizer:
-            self._force_reasoning = self._detect_reasoning_pattern(
+            template = tokenizer_manager.tokenizer.chat_template
-                tokenizer_manager.tokenizer.chat_template
+            self._run_template_detection(template, tokenizer_manager.tokenizer)
-            )
+            if self._suggested_reasoning_parser:
+                logger.info(
+                    f"Auto-detected reasoning parser: {self._suggested_reasoning_parser}"
+                )
+            if self._suggested_tool_call_parser:
+                logger.info(
+                    f"Auto-detected tool-call parser: {self._suggested_tool_call_parser}"
+                )
 
     def _load_explicit_chat_template(
         self, tokenizer_manager: TokenizerManager, chat_template_arg: str

python/sglang/srt/parser/reasoning_parser.py

@@ -28,12 +28,17 @@ class BaseReasoningFormatDetector:
         tool_start_token: Optional[str] = None,
         continue_final_message: bool = False,
         previous_content: str = "",
+        thinks_internally: bool = False,
+        reasoning_default: str = "always",
     ):
         self.think_start_token = think_start_token
         self.think_end_token = think_end_token
         self.tool_start_token = tool_start_token
+        self.force_reasoning = force_reasoning
         self._in_reasoning = force_reasoning
         self.stream_reasoning = stream_reasoning
+        self.thinks_internally = thinks_internally
+        self.reasoning_default = reasoning_default
 
         self._buffer = ""
         self.stripped_think_start = False
@@ -244,6 +249,8 @@ class Qwen3Detector(BaseReasoningFormatDetector):
             stream_reasoning=stream_reasoning,
             continue_final_message=continue_final_message,
             previous_content=previous_content,
+            thinks_internally=True,
+            reasoning_default="enable_thinking",
         )
 
 
@@ -298,6 +305,7 @@ class KimiK2Detector(BaseReasoningFormatDetector):
             tool_start_token="<|tool_calls_section_begin|>",
             continue_final_message=continue_final_message,
             previous_content=previous_content,
+            reasoning_default="thinking",
         )
 
 
@@ -321,6 +329,8 @@ class Glm45Detector(BaseReasoningFormatDetector):
             force_reasoning=force_reasoning,
             stream_reasoning=stream_reasoning,
             tool_start_token="<tool_call>",
+            thinks_internally=True,
+            reasoning_default="enable_thinking",
         )
 
 
@@ -445,6 +455,7 @@ class Nemotron3Detector(BaseReasoningFormatDetector):
             stream_reasoning=stream_reasoning,
             continue_final_message=continue_final_message,
             previous_content=previous_content,
+            reasoning_default="enable_thinking",
         )
         self._force_nonempty_content = force_nonempty_content
 
@@ -479,6 +490,7 @@ class MistralDetector(BaseReasoningFormatDetector):
             stream_reasoning=stream_reasoning,
             continue_final_message=continue_final_message,
             previous_content=previous_content,
+            reasoning_default="mistral",
         )
 
 
@@ -524,10 +536,27 @@ class Gemma4Detector(BaseReasoningFormatDetector):
             stream_reasoning=stream_reasoning,
             continue_final_message=continue_final_message,
             previous_content=previous_content,
+            reasoning_default="explicit_enable_thinking",
         )
         self.think_start_self_label = "thought\n"
 
 
+class _DeepSeekV3Detector(Qwen3Detector):
+    """DeepSeek-V3 reuses Qwen3 tokens but requires explicit thinking=True to enable."""
+
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self.reasoning_default = "explicit_thinking"
+
+
+class _MimoDetector(Qwen3Detector):
+    """MIMO reuses Qwen3 tokens but requires explicit enable_thinking=True to enable."""
+
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self.reasoning_default = "explicit_enable_thinking"
+
+
 class ReasoningParser:
     """
     Parser that handles both streaming and non-streaming scenarios for extracting
@@ -541,13 +570,13 @@ class ReasoningParser:
 
     DetectorMap: Dict[str, Type[BaseReasoningFormatDetector]] = {
         "deepseek-r1": DeepSeekR1Detector,
-        "deepseek-v3": Qwen3Detector,
+        "deepseek-v3": _DeepSeekV3Detector,
         "glm45": Glm45Detector,
         "hunyuan": HunyuanDetector,
         "gpt-oss": GptOssDetector,
         "kimi": KimiDetector,
         "kimi_k2": KimiK2Detector,
-        "mimo": Qwen3Detector,
+        "mimo": _MimoDetector,
         "qwen3": Qwen3Detector,
         "qwen3-thinking": Qwen3Detector,
         "minimax": Qwen3Detector,
@@ -575,7 +604,11 @@ class ReasoningParser:
             raise ValueError(f"Unsupported model type: {model_type}")
 
         # Special cases where we override force_reasoning
-        if model_type.lower() in {"qwen3-thinking", "gpt-oss", "minimax"}:
+        if model_type.lower() in {
+            "qwen3-thinking",
+            "gpt-oss",
+            "minimax",
+        }:
             force_reasoning = True
 
         # Only pass force_reasoning if explicitly set, let detectors use their defaults

python/sglang/srt/server_args.py

@@ -5110,12 +5110,15 @@ class ServerArgs:
             action="store_true",
             help="Return number of cached tokens in usage.prompt_tokens_details for each openai request.",
         )
+        reasoning_parser_choices = list(ReasoningParser.DetectorMap.keys())
         parser.add_argument(
             "--reasoning-parser",
             type=str,
-            choices=list(ReasoningParser.DetectorMap.keys()),
+            choices=["auto"] + reasoning_parser_choices,
             default=ServerArgs.reasoning_parser,
-            help=f"Specify the parser for reasoning models, supported parsers are: {list(ReasoningParser.DetectorMap.keys())}.",
+            help=f"Specify the parser for reasoning models. "
+            f"Use 'auto' to detect from chat template. "
+            f"Options include: {reasoning_parser_choices}.",
         )
         parser.add_argument(
             "--strip-thinking-cache",
@@ -5128,9 +5131,11 @@ class ServerArgs:
         parser.add_argument(
             "--tool-call-parser",
             type=str,
-            choices=tool_call_parser_choices,
+            choices=["auto"] + tool_call_parser_choices,
             default=ServerArgs.tool_call_parser,
-            help=f"Specify the parser for handling tool-call interactions. Options include: {tool_call_parser_choices}.",
+            help=f"Specify the parser for handling tool-call interactions. "
+            f"Use 'auto' to detect from chat template. "
+            f"Options include: {tool_call_parser_choices}.",
         )
         parser.add_argument(
             "--tool-server",

test/registered/unit/entrypoints/openai/test_serving_chat.py

@@ -28,6 +28,7 @@ from sglang.srt.entrypoints.openai.serving_chat import (
     normalize_tool_content,
 )
 from sglang.srt.managers.io_struct import GenerateReqInput
+from sglang.srt.managers.template_detection import ReasoningToggleConfig
 from sglang.srt.utils import get_or_create_event_loop
 from sglang.test.ci.ci_register import register_cpu_ci
 
@@ -86,6 +87,8 @@ class _MockTemplateManager:
         self.chat_template_name: Optional[str] = "llama-3"
         self.jinja_template_content_format: Optional[str] = None
         self.completion_template_name: Optional[str] = None
+        self.reasoning_config = None
+        self.force_reasoning = False
 
 
 class ServingChatTestCase(unittest.TestCase):
@@ -1039,6 +1042,175 @@ class ServingChatTestCase(unittest.TestCase):
                 req.reasoning_effort = effort
                 self.assertEqual(chat._get_reasoning_from_request(req), expected)
 
+    # ------------- reasoning config tests -------------
+    def test_get_reasoning_from_request_default_true_toggle(self):
+        self.tm.server_args.reasoning_parser = "qwen3"
+        self.chat.reasoning_parser = "qwen3"
+        self.template_manager.reasoning_config = ReasoningToggleConfig(
+            toggle_param="enable_thinking", default_enabled=True
+        )
+
+        enabled_by_default = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        disabled_explicitly = ChatCompletionRequest(
+            model="x",
+            messages=[{"role": "user", "content": "Hi?"}],
+            chat_template_kwargs={"enable_thinking": False},
+        )
+
+        self.assertTrue(self.chat._get_reasoning_from_request(enabled_by_default))
+        self.assertFalse(self.chat._get_reasoning_from_request(disabled_explicitly))
+
+    def test_get_reasoning_from_request_default_false_toggle(self):
+        self.tm.server_args.reasoning_parser = "deepseek-v3"
+        self.chat.reasoning_parser = "deepseek-v3"
+        self.template_manager.reasoning_config = ReasoningToggleConfig(
+            toggle_param="thinking", default_enabled=False
+        )
+
+        disabled_by_default = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        enabled_explicitly = ChatCompletionRequest(
+            model="x",
+            messages=[{"role": "user", "content": "Hi?"}],
+            chat_template_kwargs={"thinking": True},
+        )
+
+        self.assertFalse(self.chat._get_reasoning_from_request(disabled_by_default))
+        self.assertTrue(self.chat._get_reasoning_from_request(enabled_explicitly))
+
+    def test_get_reasoning_from_request_special_cases(self):
+        self.tm.server_args.reasoning_parser = "mistral"
+        self.chat.reasoning_parser = "mistral"
+        req = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+
+        self.template_manager.reasoning_config = ReasoningToggleConfig(
+            special_case="always"
+        )
+        self.assertTrue(self.chat._get_reasoning_from_request(req))
+
+        self.template_manager.reasoning_config = ReasoningToggleConfig(
+            special_case="mistral"
+        )
+        self.assertFalse(self.chat._get_reasoning_from_request(req))
+        req.reasoning_effort = "medium"
+        self.assertTrue(self.chat._get_reasoning_from_request(req))
+
+    # --- fallback path tests (config=None, uses reasoning_default) ---
+
+    def _setup_fallback(self, parser_name):
+        """Set up reasoning with config=None to exercise the fallback path."""
+        self.tm.server_args.reasoning_parser = parser_name
+        self.chat = OpenAIServingChat(self.tm, self.template_manager)
+        self.chat.reasoning_parser = parser_name
+        self.template_manager.reasoning_config = None
+
+    def test_fallback_always_mode(self):
+        self._setup_fallback("deepseek-r1")
+        req = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        self.assertTrue(self.chat._get_reasoning_from_request(req))
+
+    def test_fallback_mistral_mode(self):
+        self._setup_fallback("mistral")
+        req_no_effort = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        self.assertFalse(self.chat._get_reasoning_from_request(req_no_effort))
+
+        req_with_effort = ChatCompletionRequest(
+            model="x",
+            messages=[{"role": "user", "content": "Hi?"}],
+            reasoning_effort="high",
+        )
+        self.assertTrue(self.chat._get_reasoning_from_request(req_with_effort))
+
+    def test_fallback_enable_thinking_mode_default_on(self):
+        self._setup_fallback("qwen3")
+        req_default = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        self.assertTrue(self.chat._get_reasoning_from_request(req_default))
+
+        req_disabled = ChatCompletionRequest(
+            model="x",
+            messages=[{"role": "user", "content": "Hi?"}],
+            chat_template_kwargs={"enable_thinking": False},
+        )
+        self.assertFalse(self.chat._get_reasoning_from_request(req_disabled))
+
+    def test_fallback_explicit_thinking_mode_default_off(self):
+        self._setup_fallback("deepseek-v3")
+        req_default = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        self.assertFalse(self.chat._get_reasoning_from_request(req_default))
+
+        req_enabled = ChatCompletionRequest(
+            model="x",
+            messages=[{"role": "user", "content": "Hi?"}],
+            chat_template_kwargs={"thinking": True},
+        )
+        self.assertTrue(self.chat._get_reasoning_from_request(req_enabled))
+
+    def test_fallback_explicit_enable_thinking_mode_default_off(self):
+        self._setup_fallback("mimo")
+        req_default = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        self.assertFalse(self.chat._get_reasoning_from_request(req_default))
+
+        req_enabled = ChatCompletionRequest(
+            model="x",
+            messages=[{"role": "user", "content": "Hi?"}],
+            chat_template_kwargs={"enable_thinking": True},
+        )
+        self.assertTrue(self.chat._get_reasoning_from_request(req_enabled))
+
+    def test_fallback_no_detector_returns_false(self):
+        self.chat.reasoning_parser = "qwen3"
+        self.chat._reasoning_detector = None
+        self.template_manager.reasoning_config = None
+        req = ChatCompletionRequest(
+            model="x", messages=[{"role": "user", "content": "Hi?"}]
+        )
+        self.assertFalse(self.chat._get_reasoning_from_request(req))
+
+    def test_build_chat_response_qwen3_thinking_forces_reasoning(self):
+        self.tm.server_args.reasoning_parser = "qwen3-thinking"
+        self.chat.reasoning_parser = "qwen3-thinking"
+        self.template_manager.reasoning_config = ReasoningToggleConfig(
+            toggle_param="enable_thinking", default_enabled=True
+        )
+
+        req = ChatCompletionRequest(
+            model="Qwen/Qwen3-0.6B",
+            messages=[{"role": "user", "content": "Hi?"}],
+            separate_reasoning=True,
+            chat_template_kwargs={"enable_thinking": False},
+        )
+        ret_item = {
+            "text": "42",
+            "meta_info": {
+                "id": f"chatcmpl-{uuid.uuid4()}",
+                "prompt_tokens": 10,
+                "completion_tokens": 1,
+                "weight_version": "default",
+                "finish_reason": {"type": "stop", "matched": None},
+            },
+            "index": 0,
+        }
+
+        response = self.chat._build_chat_response(req, [ret_item], created=0)
+        msg = response.choices[0].message
+        self.assertIsNone(msg.content)
+        self.assertEqual(msg.reasoning_content, "42")
+
 
 class TestProcessToolCallsWithRequiredToolChoice(unittest.TestCase):
     """Test _process_tool_calls with tool_choice='required' uses model-specific parser."""

test/registered/unit/managers/test_template_manager.py

@@ -0,0 +1,334 @@
+import unittest
+from types import SimpleNamespace
+
+from sglang.srt.managers.template_detection import (
+    ReasoningToggleConfig,
+    detect_reasoning_parser,
+    detect_reasoning_pattern,
+    detect_tool_call_parser,
+    resolve_auto_parsers,
+)
+from sglang.test.ci.ci_register import register_cpu_ci
+
+register_cpu_ci(2.0, "stage-a-test-cpu")
+
+
+class _DummyTokenizer:
+    def __init__(self, vocab):
+        self._vocab = vocab
+
+    def get_vocab(self):
+        return {token: i for i, token in enumerate(self._vocab)}
+
+
+class TestTemplateManagerReasoningDetection(unittest.TestCase):
+
+    def _detect(self, template, vocab):
+        force, config = detect_reasoning_pattern(template)
+        parser = detect_reasoning_parser(
+            template, _DummyTokenizer(vocab), config, force
+        )
+        return force, config, parser
+
+    def test_qwen3_template_not_misclassified_as_glm45(self):
+        template = """
+        {% set enable_thinking = enable_thinking if enable_thinking is defined else true %}
+        {% if '</think>' in content %}
+        <tool_call>
+        """
+        _, config, parser = self._detect(
+            template, ["<tool_call>", "<|endoftext|>", "</think>"]
+        )
+
+        self.assertEqual(
+            config,
+            ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True),
+        )
+        self.assertEqual(parser, "qwen3")
+
+    def test_glm45_requires_glm_specific_template_markers(self):
+        template = """
+        [gMASK]<sop>
+        {% set enable_thinking = enable_thinking if enable_thinking is defined else true %}
+        /nothink
+        <tool_call>
+        """
+        _, config, parser = self._detect(
+            template, ["<tool_call>", "<|endoftext|>", "<|user|>"]
+        )
+
+        self.assertEqual(
+            config,
+            ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True),
+        )
+        self.assertEqual(parser, "glm45")
+
+    def test_interns1_detects_enable_thinking_default_true(self):
+        template = """
+        {% set default_thinking_sys %}...<think>...</think>{% endset %}
+        {% if enable_thinking is not defined or enable_thinking %}
+        """
+        _, config, parser = self._detect(template, ["<|endoftext|>"])
+
+        self.assertEqual(
+            config,
+            ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True),
+        )
+        self.assertEqual(parser, "interns1")
+
+    def test_nemotron_detects_uppercase_true_assignment(self):
+        template = """
+        {% set enable_thinking = enable_thinking if enable_thinking is defined else True %}
+        {% set truncate_history_thinking = truncate_history_thinking if truncate_history_thinking is defined else True %}
+        """
+        _, config, parser = self._detect(template, ["<|endoftext|>"])
+
+        self.assertEqual(
+            config,
+            ReasoningToggleConfig(toggle_param="enable_thinking", default_enabled=True),
+        )
+        self.assertEqual(parser, "nemotron_3")
+
+    def test_minimax_uses_template_signature_without_toggle_config(self):
+        template = """
+        {%- set toolcall_begin_token = '<minimax:tool_call>' -%}
+        """
+        _, config, parser = self._detect(template, ["<minimax:tool_call>"])
+
+        self.assertIsNone(config)
+        self.assertEqual(parser, "minimax")
+
+
+class TestTemplateDetectionRuleMatrix(unittest.TestCase):
+    """Table-driven tests for REASONING_PARSER_RULES and REASONING_MODE_RULES."""
+
+    def _detect(self, template, vocab=None):
+        if vocab is None:
+            vocab = []
+        force, config = detect_reasoning_pattern(template)
+        parser = detect_reasoning_parser(
+            template, _DummyTokenizer(vocab), config, force
+        )
+        return force, config, parser
+
+    PARSER_RULES_MATRIX = [
+        # (name, template_snippet, vocab, expected_parser, expected_toggle_param)
+        (
+            "deepseek_r1_think_tags",
+            "<think>\nLet me reason about this\n</think>\nAnswer here",
+            [],
+            "deepseek-r1",
+            None,  # matched by deepseek_r1_think_tags rule (has <think> text)
+        ),
+        (
+            "deepseek_v3",
+            "{% if not thinking is defined %}{% set thinking = false %}{% endif %}\n"
+            "<think>",
+            [],
+            "deepseek-v3",
+            "thinking",
+        ),
+        (
+            "qwen3_enable_thinking_true",
+            "{% set enable_thinking = enable_thinking if enable_thinking is defined else true %}\n",
+            [],
+            "qwen3",
+            "enable_thinking",
+        ),
+        (
+            "kimi_unicode_markers",
+            "\u25c1think\u25b7some text\u25c1/think\u25b7",
+            [],
+            "kimi",
+            None,
+        ),
+        (
+            "mistral_reasoning_effort",
+            "{% if reasoning_effort %}[THINK]{% endif %}",
+            [],
+            "mistral",
+            None,  # special_case="mistral"
+        ),
+        (
+            "gpt_oss_channel",
+            "<|channel|>analysis<|message|>",
+            [],
+            "gpt-oss",
+            None,  # special_case="always"
+        ),
+        (
+            "kimi_k2_with_tool_vocab",
+            "{% set thinking = thinking if thinking is defined else true %}\n<think>",
+            ["<|tool_calls_section_begin|>", "<|tool_calls_section_end|>"],
+            "kimi_k2",
+            "thinking",
+        ),
+        (
+            "mimo_enable_thinking_false",
+            "{% if not enable_thinking is defined %}{% set enable_thinking = false %}{% endif %}\n"
+            "enable_thinking",
+            [],
+            "mimo",
+            "enable_thinking",
+        ),
+    ]
+
+    def test_parser_rules_matrix(self):
+        for (
+            name,
+            template,
+            vocab,
+            expected_parser,
+            expected_toggle,
+        ) in self.PARSER_RULES_MATRIX:
+            with self.subTest(name=name):
+                _, config, parser = self._detect(template, vocab)
+                self.assertEqual(
+                    parser,
+                    expected_parser,
+                    f"Rule '{name}': expected parser '{expected_parser}', got '{parser}'",
+                )
+                if expected_toggle is not None:
+                    self.assertIsNotNone(
+                        config, f"Rule '{name}': expected config, got None"
+                    )
+                    self.assertEqual(
+                        config.toggle_param,
+                        expected_toggle,
+                        f"Rule '{name}': expected toggle '{expected_toggle}', "
+                        f"got '{config.toggle_param}'",
+                    )
+
+    def test_unrecognized_template_returns_none(self):
+        template = "Hello {{ user_message }}, how can I help you?"
+        _, config, parser = self._detect(template)
+
+        self.assertIsNone(config)
+        self.assertIsNone(parser)
+
+    def test_empty_template_returns_none(self):
+        _, config, parser = self._detect("")
+
+        self.assertIsNone(config)
+        self.assertIsNone(parser)
+
+    def test_qwen3_precedence_over_deepseek_r1(self):
+        """Template with enable_thinking=true but no <think> tag should be qwen3, not deepseek_r1."""
+        template = "{% set enable_thinking = enable_thinking if enable_thinking is defined else true %}"
+        _, config, parser = self._detect(template)
+
+        self.assertEqual(parser, "qwen3")
+        self.assertEqual(config.toggle_param, "enable_thinking")
+        self.assertTrue(config.default_enabled)
+
+
+class TestToolCallParserDetection(unittest.TestCase):
+    """Tests for detect_tool_call_parser() using real model tokenizers."""
+
+    def _detect_all(self, model_name):
+        from transformers import AutoTokenizer
+
+        tok = AutoTokenizer.from_pretrained(model_name, trust_remote_code=True)
+        template = tok.chat_template
+        force, config = detect_reasoning_pattern(template)
+        rp = detect_reasoning_parser(template, tok, config, force)
+        tcp = detect_tool_call_parser(template, tok, config, force)
+        return rp, tcp
+
+    def test_qwen3_detects_qwen_tool_call_parser(self):
+        rp, tcp = self._detect_all("Qwen/Qwen3-0.6B")
+        self.assertEqual(rp, "qwen3")
+        self.assertEqual(tcp, "qwen")
+
+    def test_tool_call_parser_rule_values_via_snippets(self):
+        """Table-driven: verify tool-call rule values differ from reasoning where expected."""
+        cases = [
+            # (name, template, vocab, expected_tool_call)
+            (
+                "qwen_maps_from_qwen3_config",
+                "{% set enable_thinking = enable_thinking if enable_thinking is defined else true %}",
+                [],
+                "qwen",
+            ),
+            ("gpt_oss", "<|channel|>analysis<|message|>", [], "gpt-oss"),
+            ("gemma4", "<|channel>content", [], "gemma4"),
+            ("minimax_maps_to_m2", "<minimax:tool_call>", [], "minimax-m2"),
+            (
+                "deepseekv3",
+                "{% if not thinking is defined %}{% set thinking = false %}{% endif %}",
+                [],
+                "deepseekv3",
+            ),
+            (
+                "kimi_k2",
+                "{% set thinking = thinking if thinking is defined else true %}\n<think>",
+                ["<|tool_calls_section_begin|>"],
+                "kimi_k2",
+            ),
+        ]
+        for name, template, vocab, expected in cases:
+            with self.subTest(name=name):
+                force, config = detect_reasoning_pattern(template)
+                result = detect_tool_call_parser(
+                    template, _DummyTokenizer(vocab), config, force
+                )
+                self.assertEqual(result, expected)
+
+    def test_none_template_returns_none(self):
+        self.assertIsNone(detect_tool_call_parser(None, None))
+
+    def test_unrecognized_template_returns_none(self):
+        force, config = detect_reasoning_pattern("Hello {{ user }}")
+        result = detect_tool_call_parser("Hello {{ user }}", None, config, force)
+        self.assertIsNone(result)
+
+
+class TestResolveAutoParsers(unittest.TestCase):
+    """Tests for resolve_auto_parsers() using real model tokenizers."""
+
+    def _make_server_args(self, reasoning_parser=None, tool_call_parser=None):
+        return SimpleNamespace(
+            reasoning_parser=reasoning_parser,
+            tool_call_parser=tool_call_parser,
+            model_path="Qwen/Qwen3-0.6B",
+            trust_remote_code=False,
+        )
+
+    def test_resolves_both_parsers_with_real_model(self):
+        args = self._make_server_args(reasoning_parser="auto", tool_call_parser="auto")
+        resolve_auto_parsers(args)
+        self.assertEqual(args.reasoning_parser, "qwen3")
+        self.assertEqual(args.tool_call_parser, "qwen")
+
+    def test_resolves_reasoning_parser_only(self):
+        args = self._make_server_args(reasoning_parser="auto", tool_call_parser=None)
+        resolve_auto_parsers(args)
+        self.assertEqual(args.reasoning_parser, "qwen3")
+        self.assertIsNone(args.tool_call_parser)
+
+    def test_resolves_tool_call_parser_only(self):
+        args = self._make_server_args(reasoning_parser="qwen3", tool_call_parser="auto")
+        resolve_auto_parsers(args)
+        self.assertEqual(args.reasoning_parser, "qwen3")
+        self.assertEqual(args.tool_call_parser, "qwen")
+
+    def test_neither_auto_is_noop(self):
+        args = self._make_server_args(reasoning_parser="qwen3", tool_call_parser="qwen")
+        resolve_auto_parsers(args)
+        self.assertEqual(args.reasoning_parser, "qwen3")
+        self.assertEqual(args.tool_call_parser, "qwen")
+
+    def test_nonexistent_model_disables_both_parsers(self):
+        args = SimpleNamespace(
+            reasoning_parser="auto",
+            tool_call_parser="auto",
+            model_path="nonexistent/model-does-not-exist-xyz",
+            trust_remote_code=False,
+        )
+        resolve_auto_parsers(args)
+        self.assertIsNone(args.reasoning_parser)
+        self.assertIsNone(args.tool_call_parser)
+
+
+if __name__ == "__main__":
+    unittest.main()