[misc] add model arch and type to server info and use it for harmony (#14456)

python/sglang/srt/entrypoints/grpc_server.py

@@ -22,6 +22,7 @@ from grpc_health.v1 import health_pb2_grpc
 from grpc_reflection.v1alpha import reflection
 
 import sglang
+from sglang.srt.configs.model_config import ModelConfig
 from sglang.srt.disaggregation.utils import FAKE_BOOTSTRAP_HOST, DisaggregationMode
 from sglang.srt.grpc import sglang_scheduler_pb2, sglang_scheduler_pb2_grpc
 from sglang.srt.grpc.grpc_request_manager import GrpcRequestManager
@@ -321,7 +322,8 @@ class SGLangSchedulerServicer(sglang_scheduler_pb2_grpc.SglangSchedulerServicer)
             max_context_length=self.model_info["max_context_length"],
             vocab_size=self.model_info["vocab_size"],
             supports_vision=self.model_info["supports_vision"],
-            model_type=self.model_info["model_type"],
+            model_type=self.model_info.get("model_type") or "",
+            architectures=self.model_info.get("architectures") or [],
             eos_token_ids=self.model_info["eos_token_ids"],
             pad_token_id=self.model_info["pad_token_id"],
             bos_token_id=self.model_info["bos_token_id"],
@@ -718,7 +720,10 @@ async def serve_grpc(
         server_args=server_args,
     )
 
-    # Update model info from scheduler info
+    # Load model config to get HF config info (same as TokenizerManager does)
+    model_config = ModelConfig.from_server_args(server_args)
+
+    # Update model info from scheduler info and model config
     if model_info is None:
         model_info = {
             "model_name": server_args.model_path,
@@ -727,7 +732,8 @@ async def serve_grpc(
             ),
             "vocab_size": scheduler_info.get("vocab_size", 128256),
             "supports_vision": scheduler_info.get("supports_vision", False),
-            "model_type": scheduler_info.get("model_type", "transformer"),
+            "model_type": getattr(model_config.hf_config, "model_type", None),
+            "architectures": getattr(model_config.hf_config, "architectures", None),
             "max_req_input_len": scheduler_info.get("max_req_input_len", 8192),
             "eos_token_ids": scheduler_info.get("eos_token_ids", []),
             "pad_token_id": scheduler_info.get("pad_token_id", 0),

python/sglang/srt/entrypoints/http_server.py

@@ -497,14 +497,17 @@ async def get_model_info():
 @app.get("/model_info")
 async def model_info():
     """Get the model information."""
+    model_config = _global_state.tokenizer_manager.model_config
     result = {
         "model_path": _global_state.tokenizer_manager.model_path,
         "tokenizer_path": _global_state.tokenizer_manager.server_args.tokenizer_path,
         "is_generation": _global_state.tokenizer_manager.is_generation,
         "preferred_sampling_params": _global_state.tokenizer_manager.server_args.preferred_sampling_params,
         "weight_version": _global_state.tokenizer_manager.server_args.weight_version,
-        "has_image_understanding": _global_state.tokenizer_manager.model_config.is_image_understandable_model,
+        "has_image_understanding": model_config.is_image_understandable_model,
-        "has_audio_understanding": _global_state.tokenizer_manager.model_config.is_audio_understandable_model,
+        "has_audio_understanding": model_config.is_audio_understandable_model,
+        "model_type": getattr(model_config.hf_config, "model_type", None),
+        "architectures": getattr(model_config.hf_config, "architectures", None),
     }
     return result
 

python/sglang/srt/grpc/sglang_scheduler.proto

@@ -427,6 +427,7 @@ message GetModelInfoResponse {
   int32 pad_token_id = 12;
   int32 bos_token_id = 13;
   int32 max_req_input_len = 14;
+  repeated string architectures = 15;
 }
 
 // Get server information

python/sglang/srt/grpc/sglang_scheduler_pb2.pyi

@@ -432,7 +432,7 @@ class GetModelInfoRequest(_message.Message):
     def __init__(self) -> None: ...
 
 class GetModelInfoResponse(_message.Message):
-    __slots__ = ("model_path", "tokenizer_path", "is_generation", "preferred_sampling_params", "weight_version", "served_model_name", "max_context_length", "vocab_size", "supports_vision", "model_type", "eos_token_ids", "pad_token_id", "bos_token_id", "max_req_input_len")
+    __slots__ = ("model_path", "tokenizer_path", "is_generation", "preferred_sampling_params", "weight_version", "served_model_name", "max_context_length", "vocab_size", "supports_vision", "model_type", "eos_token_ids", "pad_token_id", "bos_token_id", "max_req_input_len", "architectures")
     MODEL_PATH_FIELD_NUMBER: _ClassVar[int]
     TOKENIZER_PATH_FIELD_NUMBER: _ClassVar[int]
     IS_GENERATION_FIELD_NUMBER: _ClassVar[int]
@@ -447,6 +447,7 @@ class GetModelInfoResponse(_message.Message):
     PAD_TOKEN_ID_FIELD_NUMBER: _ClassVar[int]
     BOS_TOKEN_ID_FIELD_NUMBER: _ClassVar[int]
     MAX_REQ_INPUT_LEN_FIELD_NUMBER: _ClassVar[int]
+    ARCHITECTURES_FIELD_NUMBER: _ClassVar[int]
     model_path: str
     tokenizer_path: str
     is_generation: bool
@@ -461,7 +462,8 @@ class GetModelInfoResponse(_message.Message):
     pad_token_id: int
     bos_token_id: int
     max_req_input_len: int
-    def __init__(self, model_path: _Optional[str] = ..., tokenizer_path: _Optional[str] = ..., is_generation: bool = ..., preferred_sampling_params: _Optional[str] = ..., weight_version: _Optional[str] = ..., served_model_name: _Optional[str] = ..., max_context_length: _Optional[int] = ..., vocab_size: _Optional[int] = ..., supports_vision: bool = ..., model_type: _Optional[str] = ..., eos_token_ids: _Optional[_Iterable[int]] = ..., pad_token_id: _Optional[int] = ..., bos_token_id: _Optional[int] = ..., max_req_input_len: _Optional[int] = ...) -> None: ...
+    architectures: _containers.RepeatedScalarFieldContainer[str]
+    def __init__(self, model_path: _Optional[str] = ..., tokenizer_path: _Optional[str] = ..., is_generation: bool = ..., preferred_sampling_params: _Optional[str] = ..., weight_version: _Optional[str] = ..., served_model_name: _Optional[str] = ..., max_context_length: _Optional[int] = ..., vocab_size: _Optional[int] = ..., supports_vision: bool = ..., model_type: _Optional[str] = ..., eos_token_ids: _Optional[_Iterable[int]] = ..., pad_token_id: _Optional[int] = ..., bos_token_id: _Optional[int] = ..., max_req_input_len: _Optional[int] = ..., architectures: _Optional[_Iterable[str]] = ...) -> None: ...
 
 class GetServerInfoRequest(_message.Message):
     __slots__ = ()

sgl-router/src/core/model_card.rs

@@ -123,6 +123,15 @@ pub struct ModelCard {
     #[serde(default = "default_model_type")]
     pub model_type: ModelType,
 
+    /// HuggingFace model type string (e.g., "llama", "qwen2", "gpt-oss")
+    /// This is different from `model_type` which is capability bitflags.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub hf_model_type: Option<String>,
+
+    /// Model architectures from HuggingFace config (e.g., ["LlamaForCausalLM"])
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub architectures: Vec<String>,
+
     /// Provider hint for API transformations.
     /// `None` means native/passthrough (no transformation needed).
     #[serde(default, skip_serializing_if = "Option::is_none")]
@@ -172,6 +181,8 @@ impl ModelCard {
             display_name: None,
             aliases: Vec::new(),
             model_type: ModelType::LLM,
+            hf_model_type: None,
+            architectures: Vec::new(),
             provider: None,
             context_length: None,
             tokenizer_path: None,
@@ -208,6 +219,18 @@ impl ModelCard {
         self
     }
 
+    /// Set the HuggingFace model type string
+    pub fn with_hf_model_type(mut self, hf_model_type: impl Into<String>) -> Self {
+        self.hf_model_type = Some(hf_model_type.into());
+        self
+    }
+
+    /// Set the model architectures
+    pub fn with_architectures(mut self, architectures: Vec<String>) -> Self {
+        self.architectures = architectures;
+        self
+    }
+
     /// Set the provider type (for external API transformations)
     pub fn with_provider(mut self, provider: ProviderType) -> Self {
         self.provider = Some(provider);

sgl-router/src/core/workflow/steps/worker_registration.rs

@@ -55,6 +55,18 @@ struct ServerInfo {
     max_num_reqs: Option<usize>,
 }
 
+/// Model information returned from /model_info endpoint
+#[derive(Debug, Clone, Deserialize, Serialize)]
+struct ModelInfo {
+    model_path: Option<String>,
+    tokenizer_path: Option<String>,
+    is_generation: Option<bool>,
+    /// HuggingFace model type string (e.g., "llama", "qwen2", "gpt_oss")
+    model_type: Option<String>,
+    /// Model architectures from HuggingFace config (e.g., ["LlamaForCausalLM"])
+    architectures: Option<Vec<String>>,
+}
+
 #[derive(Debug, Clone)]
 pub struct DpInfo {
     pub dp_size: usize,
@@ -69,7 +81,7 @@ fn parse_server_info(json: Value) -> Result<ServerInfo, String> {
 /// Get server info from /get_server_info endpoint
 async fn get_server_info(url: &str, api_key: Option<&str>) -> Result<ServerInfo, String> {
     let base_url = url.trim_end_matches('/');
-    let server_info_url = format!("{}/get_server_info", base_url);
+    let server_info_url = format!("{}/server_info", base_url);
 
     let mut req = HTTP_CLIENT.get(&server_info_url);
     if let Some(key) = api_key {
@@ -97,6 +109,35 @@ async fn get_server_info(url: &str, api_key: Option<&str>) -> Result<ServerInfo,
     parse_server_info(json)
 }
 
+/// Get model info from /model_info endpoint
+async fn get_model_info(url: &str, api_key: Option<&str>) -> Result<ModelInfo, String> {
+    let base_url = url.trim_end_matches('/');
+    let model_info_url = format!("{}/model_info", base_url);
+
+    let mut req = HTTP_CLIENT.get(&model_info_url);
+    if let Some(key) = api_key {
+        req = req.bearer_auth(key);
+    }
+
+    let response = req
+        .send()
+        .await
+        .map_err(|e| format!("Failed to connect to {}: {}", model_info_url, e))?;
+
+    if !response.status().is_success() {
+        return Err(format!(
+            "Server returned status {} from {}",
+            response.status(),
+            model_info_url
+        ));
+    }
+
+    response
+        .json::<ModelInfo>()
+        .await
+        .map_err(|e| format!("Failed to parse response from {}: {}", model_info_url, e))
+}
+
 /// Get DP info for a worker URL
 async fn get_dp_info(url: &str, api_key: Option<&str>) -> Result<DpInfo, String> {
     let info = get_server_info(url, api_key).await?;
@@ -319,21 +360,37 @@ impl StepExecutor for DiscoverMetadataStep {
 
         let (discovered_labels, detected_runtime) = match connection_mode.as_ref() {
             ConnectionMode::Http => {
-                match get_server_info(&config.url, config.api_key.as_deref()).await {
+                let mut labels = HashMap::new();
-                    Ok(server_info) => {
+
-                        let mut labels = HashMap::new();
+                // Fetch from /get_server_info for server-related metadata
-                        if let Some(model_path) = server_info.model_path.filter(|s| !s.is_empty()) {
+                if let Ok(server_info) =
-                            labels.insert("model_path".to_string(), model_path);
+                    get_server_info(&config.url, config.api_key.as_deref()).await
-                        }
+                {
-                        if let Some(served_model_name) =
+                    if let Some(model_path) = server_info.model_path.filter(|s| !s.is_empty()) {
-                            server_info.served_model_name.filter(|s| !s.is_empty())
+                        labels.insert("model_path".to_string(), model_path);
-                        {
+                    }
-                            labels.insert("served_model_name".to_string(), served_model_name);
+                    if let Some(served_model_name) =
-                        }
+                        server_info.served_model_name.filter(|s| !s.is_empty())
-                        Ok((labels, None))
+                    {
+                        labels.insert("served_model_name".to_string(), served_model_name);
                     }
-                    Err(e) => Err(e),
                 }
+
+                // Fetch from /model_info for model-related metadata (model_type, architectures)
+                if let Ok(model_info) = get_model_info(&config.url, config.api_key.as_deref()).await
+                {
+                    if let Some(model_type) = model_info.model_type.filter(|s| !s.is_empty()) {
+                        labels.insert("model_type".to_string(), model_type);
+                    }
+                    if let Some(architectures) = model_info.architectures.filter(|a| !a.is_empty())
+                    {
+                        if let Ok(json_str) = serde_json::to_string(&architectures) {
+                            labels.insert("architectures".to_string(), json_str);
+                        }
+                    }
+                }
+
+                Ok((labels, None))
             }
             ConnectionMode::Grpc { .. } => {
                 let runtime_type = config.runtime.as_deref();
@@ -481,6 +538,16 @@ impl StepExecutor for CreateWorkerStep {
             if let Some(ref chat_template) = config.chat_template {
                 card = card.with_chat_template(chat_template.clone());
             }
+            // Set HuggingFace model type from discovered labels
+            if let Some(model_type_str) = final_labels.get("model_type") {
+                card = card.with_hf_model_type(model_type_str.clone());
+            }
+            // Set architectures from discovered labels (JSON array string)
+            if let Some(architectures_json) = final_labels.get("architectures") {
+                if let Ok(architectures) = serde_json::from_str::<Vec<String>>(architectures_json) {
+                    card = card.with_architectures(architectures);
+                }
+            }
             card
         };
 

sgl-router/src/proto/sglang_scheduler.proto

@@ -427,6 +427,7 @@ message GetModelInfoResponse {
   int32 pad_token_id = 12;
   int32 bos_token_id = 13;
   int32 max_req_input_len = 14;
+  repeated string architectures = 15;
 }
 
 // Get server information

sgl-router/src/routers/grpc/client.rs

@@ -166,7 +166,13 @@ impl ModelInfo {
                     serde_json::Value::Bool(true) => {
                         labels.insert(key, "true".to_string());
                     }
-                    // Skip empty strings, zeros, false, nulls, arrays, objects
+                    // Insert non-empty arrays as JSON strings (for architectures, etc.)
+                    serde_json::Value::Array(arr) if !arr.is_empty() => {
+                        if let Ok(json_str) = serde_json::to_string(&arr) {
+                            labels.insert(key, json_str);
+                        }
+                    }
+                    // Skip empty strings, zeros, false, nulls, empty arrays, objects
                     _ => {}
                 }
             }

sgl-router/src/routers/grpc/harmony/detector.rs

@@ -1,11 +1,48 @@
 //! Harmony model detection
 
+use crate::core::{Worker, WorkerRegistry};
+
 /// Harmony model detector
 ///
 /// Detects if a model name indicates support for Harmony encoding/parsing.
 pub struct HarmonyDetector;
 
 impl HarmonyDetector {
+    /// Check if a worker is a Harmony/GPT-OSS model.
+    ///
+    /// Detection priority:
+    /// 1. Check if any model card has architectures containing "GptOssForCausalLM"
+    /// 2. Check if any model card has hf_model_type equal to "gpt_oss"
+    /// 3. Check if model_id contains "gpt-oss" substring (case-insensitive)
+    pub fn is_harmony_worker(worker: &dyn Worker) -> bool {
+        for model_card in worker.models() {
+            // 1. Check architectures for GptOssForCausalLM
+            if model_card
+                .architectures
+                .iter()
+                .any(|arch| arch == "GptOssForCausalLM")
+            {
+                return true;
+            }
+
+            // 2. Check hf_model_type for gpt_oss
+            if let Some(ref model_type) = model_card.hf_model_type {
+                if model_type == "gpt_oss" {
+                    return true;
+                }
+            }
+
+            // 3. Check model id for gpt-oss substring
+            if Self::is_harmony_model(&model_card.id) {
+                return true;
+            }
+        }
+
+        // Fallback: check worker's model_id directly
+        Self::is_harmony_model(worker.model_id())
+    }
+
+    /// Check if a model name contains "gpt-oss" (case-insensitive).
     pub fn is_harmony_model(model_name: &str) -> bool {
         // Case-insensitive substring search without heap allocation
         // More efficient than to_lowercase() which allocates a new String
@@ -14,4 +51,27 @@ impl HarmonyDetector {
             .windows(7) // "gpt-oss".len()
             .any(|window| window.eq_ignore_ascii_case(b"gpt-oss"))
     }
+
+    /// Check if any worker for the given model is a Harmony/GPT-OSS worker.
+    ///
+    /// This method looks up workers from the registry by model name and checks
+    /// if any of them are Harmony workers based on their metadata (architectures,
+    /// hf_model_type).
+    ///
+    /// Falls back to string-based detection if no workers are registered for
+    /// the model (e.g., during startup before workers are discovered).
+    pub fn is_harmony_model_in_registry(registry: &WorkerRegistry, model_name: &str) -> bool {
+        // Get workers for this model
+        let workers = registry.get_by_model_fast(model_name);
+
+        if workers.is_empty() {
+            // No workers found - fall back to string-based detection
+            return Self::is_harmony_model(model_name);
+        }
+
+        // Check if any worker is a Harmony worker
+        workers
+            .iter()
+            .any(|worker| Self::is_harmony_worker(worker.as_ref()))
+    }
 }

sgl-router/src/routers/grpc/router.rs

@@ -142,8 +142,9 @@ impl GrpcRouter {
         body: &ChatCompletionRequest,
         model_id: Option<&str>,
     ) -> Response {
-        // Choose Harmony pipeline if model indicates Harmony
+        // Choose Harmony pipeline if workers indicate Harmony (checks architectures, hf_model_type)
-        let is_harmony = HarmonyDetector::is_harmony_model(&body.model);
+        let is_harmony =
+            HarmonyDetector::is_harmony_model_in_registry(&self.worker_registry, &body.model);
 
         debug!(
             "Processing chat completion request for model: {:?}, using_harmony={}",
@@ -203,8 +204,9 @@ impl GrpcRouter {
             return error_response;
         }
 
-        // Choose implementation based on Harmony model detection
+        // Choose implementation based on Harmony model detection (checks worker metadata)
-        let is_harmony = HarmonyDetector::is_harmony_model(&body.model);
+        let is_harmony =
+            HarmonyDetector::is_harmony_model_in_registry(&self.worker_registry, &body.model);
 
         if is_harmony {
             debug!(