[router][grpc] Refactor chat handler in grpc/ to use centralized orchestrator (#11314)

Co-authored-by: Simo Lin <linsimo.mark@gmail.com>

sgl-router/src/protocols/spec.rs

@@ -2066,6 +2066,40 @@ impl GenerationRequest for GenerateRequest {
     }
 }
 
+// TODO(generate): Define GenerateResponse and GenerateChoice structs
+//
+// Required for pipeline generate response processing (see grpc/pipeline.rs:931-964)
+//
+// #[derive(Debug, Clone, Serialize, Deserialize)]
+// pub struct GenerateResponse {
+//     pub id: String,
+//     pub object: String,  // "text.completion"
+//     pub created: u64,
+//     pub model: String,
+//     pub choices: Vec<GenerateChoice>,
+//     #[serde(skip_serializing_if = "Option::is_none")]
+//     pub usage: Option<Usage>,
+//     #[serde(skip_serializing_if = "Option::is_none")]
+//     pub system_fingerprint: Option<String>,
+// }
+//
+// #[derive(Debug, Clone, Serialize, Deserialize)]
+// pub struct GenerateChoice {
+//     pub index: u32,
+//     pub text: String,
+//     #[serde(skip_serializing_if = "Option::is_none")]
+//     pub output_ids: Option<Vec<u32>>,
+//     #[serde(skip_serializing_if = "Option::is_none")]
+//     pub finish_reason: Option<String>,
+//     #[serde(skip_serializing_if = "Option::is_none")]
+//     pub logprobs: Option<TopLogprobs>,
+//     #[serde(skip_serializing_if = "Option::is_none")]
+//     pub matched_stop: Option<Value>,
+// }
+//
+// Note: Verify if similar structs already exist elsewhere before implementing.
+// May need streaming variant (GenerateStreamResponse) as well.
+
 // Constants for rerank API
 pub const DEFAULT_MODEL_NAME: &str = "default";
 

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

@@ -0,0 +1,398 @@
+//! Request context types for gRPC router pipeline
+//!
+//! This module provides the core context types that flow through the router pipeline,
+//! eliminating deep parameter passing chains and providing a single source of truth
+//! for request state.
+
+use std::collections::HashMap;
+use std::sync::Arc;
+
+use axum::http::HeaderMap;
+use serde_json::Value;
+
+use crate::core::Worker;
+use crate::grpc_client::{proto, SglangSchedulerClient};
+use crate::protocols::spec::{ChatCompletionRequest, ChatCompletionResponse, GenerateRequest};
+use crate::reasoning_parser::ReasoningParserFactory;
+use crate::tokenizer::stop::StopSequenceDecoder;
+use crate::tokenizer::traits::Tokenizer;
+use crate::tool_parser::ToolParserFactory;
+
+// ============================================================================
+// Core Context Types
+// ============================================================================
+
+/// Main request processing context
+///
+/// This is the single source of truth for all request state as it flows
+/// through the pipeline stages. Uses Rust's type system to enforce proper
+/// stage ordering at compile time.
+pub struct RequestContext {
+    // === Input (Immutable) ===
+    pub input: RequestInput,
+
+    // === Shared Components (Immutable References) ===
+    pub components: Arc<SharedComponents>,
+
+    // === Processing State (Mutable, evolves through pipeline) ===
+    pub state: ProcessingState,
+}
+
+/// Immutable request input
+pub struct RequestInput {
+    pub request_type: RequestType,
+    pub headers: Option<HeaderMap>,
+    pub model_id: Option<String>,
+}
+
+/// Request type variants
+pub enum RequestType {
+    Chat(Box<ChatCompletionRequest>),
+    Generate(Box<GenerateRequest>),
+}
+
+/// Shared components (injected once at creation)
+pub struct SharedComponents {
+    pub tokenizer: Arc<dyn Tokenizer>,
+    pub tool_parser_factory: ToolParserFactory,
+    pub reasoning_parser_factory: ReasoningParserFactory,
+}
+
+/// Mutable processing state (evolves through pipeline stages)
+#[derive(Default)]
+pub struct ProcessingState {
+    // Stage 1: Preparation outputs
+    pub preparation: Option<PreparationOutput>,
+
+    // Stage 2: Worker selection outputs
+    pub workers: Option<WorkerSelection>,
+
+    // Stage 3: Client acquisition outputs
+    pub clients: Option<ClientSelection>,
+
+    // Stage 4: Request building outputs
+    pub proto_request: Option<proto::GenerateRequest>,
+
+    // Stage 5: Dispatch metadata
+    pub dispatch: Option<DispatchMetadata>,
+
+    // Stage 6: Response processing state
+    pub response: ResponseState,
+}
+
+// ============================================================================
+// Stage-Specific Output Types
+// ============================================================================
+
+/// Output from preparation stage (Step 1)
+pub struct PreparationOutput {
+    /// Original text (for chat) or resolved text (for generate)
+    pub original_text: Option<String>,
+
+    /// Tokenized input
+    pub token_ids: Vec<u32>,
+
+    /// Processed messages (chat only)
+    pub processed_messages: Option<super::ProcessedMessages>,
+
+    /// Tool call constraints (if applicable)
+    pub tool_constraints: Option<(String, String)>,
+
+    /// Filtered request (if tools were filtered)
+    pub filtered_request: Option<ChatCompletionRequest>,
+}
+
+/// Worker selection (Step 2)
+pub enum WorkerSelection {
+    Single {
+        worker: Arc<dyn Worker>,
+    },
+    Dual {
+        prefill: Arc<dyn Worker>,
+        decode: Arc<dyn Worker>,
+    },
+}
+
+/// Client selection (Step 3)
+pub enum ClientSelection {
+    Single {
+        client: SglangSchedulerClient,
+    },
+    Dual {
+        prefill: SglangSchedulerClient,
+        decode: SglangSchedulerClient,
+    },
+}
+
+/// Dispatch metadata (Step 5)
+#[derive(Clone)]
+pub struct DispatchMetadata {
+    pub request_id: String,
+    pub model: String,
+    pub created: u64,
+    pub weight_version: Option<String>,
+    pub is_streaming: bool,
+}
+
+/// Response processing state (Step 6)
+#[derive(Default)]
+pub struct ResponseState {
+    /// Stop sequence decoder
+    pub stop_decoder: Option<StopSequenceDecoder>,
+
+    /// Per-index streaming state (for n>1 support)
+    pub streaming: StreamingState,
+
+    /// Collected responses (non-streaming)
+    pub collected: Option<Vec<proto::GenerateComplete>>,
+
+    /// Execution result (streams from workers)
+    pub execution_result: Option<ExecutionResult>,
+
+    /// Final processed response
+    pub final_response: Option<FinalResponse>,
+}
+
+/// Streaming state (per-choice tracking)
+#[derive(Default)]
+pub struct StreamingState {
+    pub is_firsts: HashMap<u32, bool>,
+    pub stream_buffers: HashMap<u32, String>,
+    pub finish_reasons: HashMap<u32, String>,
+    pub matched_stops: HashMap<u32, Option<Value>>,
+    pub prompt_tokens: HashMap<u32, u32>,
+    pub completion_tokens: HashMap<u32, u32>,
+    pub cached_tokens: HashMap<u32, u32>,
+
+    // Parser state (lazy initialization per index)
+    pub reasoning_parsers:
+        HashMap<u32, Arc<std::sync::Mutex<Box<dyn crate::reasoning_parser::ReasoningParser>>>>,
+    pub tool_parsers:
+        HashMap<u32, Arc<tokio::sync::Mutex<Box<dyn crate::tool_parser::ToolParser>>>>,
+    pub has_tool_calls: HashMap<u32, bool>,
+}
+
+// ============================================================================
+// Context Builders
+// ============================================================================
+
+impl RequestContext {
+    /// Create context for chat completion request
+    pub fn for_chat(
+        request: ChatCompletionRequest,
+        headers: Option<HeaderMap>,
+        model_id: Option<String>,
+        components: Arc<SharedComponents>,
+    ) -> Self {
+        Self {
+            input: RequestInput {
+                request_type: RequestType::Chat(Box::new(request)),
+                headers,
+                model_id,
+            },
+            components,
+            state: ProcessingState::default(),
+        }
+    }
+
+    /// Create context for generate request
+    pub fn for_generate(
+        request: GenerateRequest,
+        headers: Option<HeaderMap>,
+        model_id: Option<String>,
+        components: Arc<SharedComponents>,
+    ) -> Self {
+        Self {
+            input: RequestInput {
+                request_type: RequestType::Generate(Box::new(request)),
+                headers,
+                model_id,
+            },
+            components,
+            state: ProcessingState::default(),
+        }
+    }
+
+    /// Get reference to original request (type-safe)
+    pub fn request(&self) -> &RequestType {
+        &self.input.request_type
+    }
+
+    /// Get chat request (panics if not chat)
+    pub fn chat_request(&self) -> &ChatCompletionRequest {
+        match &self.input.request_type {
+            RequestType::Chat(req) => req.as_ref(),
+            _ => panic!("Expected chat request"),
+        }
+    }
+
+    /// Try to get chat request
+    pub fn try_chat_request(&self) -> Option<&ChatCompletionRequest> {
+        match &self.input.request_type {
+            RequestType::Chat(req) => Some(req.as_ref()),
+            _ => None,
+        }
+    }
+
+    /// Get generate request (panics if not generate)
+    pub fn generate_request(&self) -> &GenerateRequest {
+        match &self.input.request_type {
+            RequestType::Generate(req) => req.as_ref(),
+            _ => panic!("Expected generate request"),
+        }
+    }
+
+    /// Try to get generate request
+    pub fn try_generate_request(&self) -> Option<&GenerateRequest> {
+        match &self.input.request_type {
+            RequestType::Generate(req) => Some(req.as_ref()),
+            _ => None,
+        }
+    }
+
+    /// Check if request is streaming
+    pub fn is_streaming(&self) -> bool {
+        match &self.input.request_type {
+            RequestType::Chat(req) => req.stream,
+            RequestType::Generate(req) => req.stream,
+        }
+    }
+
+    /// Check if request is chat
+    pub fn is_chat(&self) -> bool {
+        matches!(&self.input.request_type, RequestType::Chat(_))
+    }
+
+    /// Check if request is generate
+    pub fn is_generate(&self) -> bool {
+        matches!(&self.input.request_type, RequestType::Generate(_))
+    }
+}
+
+// ============================================================================
+// Default Implementations
+// ============================================================================
+
+// ============================================================================
+// Helper Methods
+// ============================================================================
+
+impl WorkerSelection {
+    pub fn is_dual(&self) -> bool {
+        matches!(self, Self::Dual { .. })
+    }
+
+    pub fn single(&self) -> Option<&Arc<dyn Worker>> {
+        match self {
+            Self::Single { worker } => Some(worker),
+            _ => None,
+        }
+    }
+
+    #[allow(clippy::type_complexity)]
+    pub fn dual(&self) -> Option<(&Arc<dyn Worker>, &Arc<dyn Worker>)> {
+        match self {
+            Self::Dual { prefill, decode } => Some((prefill, decode)),
+            _ => None,
+        }
+    }
+
+    pub fn prefill_worker(&self) -> Option<&Arc<dyn Worker>> {
+        match self {
+            Self::Dual { prefill, .. } => Some(prefill),
+            _ => None,
+        }
+    }
+
+    pub fn decode_worker(&self) -> Option<&Arc<dyn Worker>> {
+        match self {
+            Self::Dual { decode, .. } => Some(decode),
+            _ => None,
+        }
+    }
+}
+
+impl ClientSelection {
+    pub fn is_dual(&self) -> bool {
+        matches!(self, Self::Dual { .. })
+    }
+
+    pub fn single(&self) -> Option<&SglangSchedulerClient> {
+        match self {
+            Self::Single { client } => Some(client),
+            _ => None,
+        }
+    }
+
+    pub fn single_mut(&mut self) -> Option<&mut SglangSchedulerClient> {
+        match self {
+            Self::Single { client } => Some(client),
+            _ => None,
+        }
+    }
+
+    pub fn dual(&self) -> Option<(&SglangSchedulerClient, &SglangSchedulerClient)> {
+        match self {
+            Self::Dual { prefill, decode } => Some((prefill, decode)),
+            _ => None,
+        }
+    }
+
+    pub fn dual_mut(&mut self) -> Option<(&mut SglangSchedulerClient, &mut SglangSchedulerClient)> {
+        match self {
+            Self::Dual { prefill, decode } => Some((prefill, decode)),
+            _ => None,
+        }
+    }
+
+    pub fn prefill_client(&self) -> Option<&SglangSchedulerClient> {
+        match self {
+            Self::Dual { prefill, .. } => Some(prefill),
+            _ => None,
+        }
+    }
+
+    pub fn prefill_client_mut(&mut self) -> Option<&mut SglangSchedulerClient> {
+        match self {
+            Self::Dual { prefill, .. } => Some(prefill),
+            _ => None,
+        }
+    }
+
+    pub fn decode_client(&self) -> Option<&SglangSchedulerClient> {
+        match self {
+            Self::Dual { decode, .. } => Some(decode),
+            _ => None,
+        }
+    }
+
+    pub fn decode_client_mut(&mut self) -> Option<&mut SglangSchedulerClient> {
+        match self {
+            Self::Dual { decode, .. } => Some(decode),
+            _ => None,
+        }
+    }
+}
+
+// ============================================================================
+// Execution and Response Types
+// ============================================================================
+
+use tonic::codec::Streaming;
+
+/// Result of request execution (streams from workers)
+pub enum ExecutionResult {
+    Single {
+        stream: Streaming<proto::GenerateResponse>,
+    },
+    Dual {
+        prefill: Streaming<proto::GenerateResponse>,
+        decode: Box<Streaming<proto::GenerateResponse>>,
+    },
+}
+
+/// Final processed response
+pub enum FinalResponse {
+    Chat(ChatCompletionResponse),
+    Generate(Box<GenerateRequest>),
+}

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

@@ -3,8 +3,12 @@
 use crate::grpc_client::proto;
 use crate::protocols::spec::StringOrArray;
 
+pub mod context;
 pub mod pd_router;
+pub mod pipeline;
+pub mod processing;
 pub mod router;
+pub mod streaming;
 pub mod utils;
 
 /// Processed chat messages ready for gRPC generation

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

@@ -0,0 +1,268 @@
+//! Shared response processing logic for gRPC routers
+//!
+//! This module contains response processing functions that are shared between
+//! the regular router and PD router, eliminating ~1,200 lines of exact duplicates.
+
+use std::sync::Arc;
+
+use serde_json::Value;
+use tracing::error;
+
+use crate::grpc_client::proto;
+use crate::protocols::spec::{
+    ChatChoice, ChatCompletionMessage, ChatCompletionRequest, FunctionCallResponse, ToolCall,
+    ToolChoice, ToolChoiceValue,
+};
+use crate::reasoning_parser::ReasoningParserFactory;
+use crate::tokenizer::stop::{SequenceDecoderOutput, StopSequenceDecoder};
+use crate::tokenizer::traits::Tokenizer;
+use crate::tool_parser::ToolParserFactory;
+
+use super::utils;
+
+// ============================================================================
+// Response Processor - Main Entry Point
+// ============================================================================
+
+/// Unified response processor for both routers
+#[derive(Clone)]
+pub struct ResponseProcessor {
+    pub tokenizer: Arc<dyn Tokenizer>,
+    pub tool_parser_factory: ToolParserFactory,
+    pub reasoning_parser_factory: ReasoningParserFactory,
+    configured_tool_parser: Option<String>,
+    configured_reasoning_parser: Option<String>,
+}
+
+impl ResponseProcessor {
+    pub fn new(
+        tokenizer: Arc<dyn Tokenizer>,
+        tool_parser_factory: ToolParserFactory,
+        reasoning_parser_factory: ReasoningParserFactory,
+        configured_tool_parser: Option<String>,
+        configured_reasoning_parser: Option<String>,
+    ) -> Self {
+        Self {
+            tokenizer,
+            tool_parser_factory,
+            reasoning_parser_factory,
+            configured_tool_parser,
+            configured_reasoning_parser,
+        }
+    }
+
+    /// Process a single choice from GenerateComplete response (EXACT COPY from router.rs:1573-1725)
+    pub async fn process_single_choice(
+        &self,
+        complete: &proto::GenerateComplete,
+        index: usize,
+        original_request: &ChatCompletionRequest,
+        stop_decoder: &mut StopSequenceDecoder,
+        history_tool_calls_count: usize,
+    ) -> Result<ChatChoice, String> {
+        stop_decoder.reset();
+        // Decode tokens
+        let outputs = stop_decoder
+            .process_tokens(&complete.output_ids)
+            .map_err(|e| format!("Failed to process tokens: {}", e))?;
+
+        // Accumulate text with early breaks
+        let mut final_text = String::new();
+        for output in outputs {
+            match output {
+                SequenceDecoderOutput::Text(t) => final_text.push_str(&t),
+                SequenceDecoderOutput::StoppedWithText(t) => {
+                    final_text.push_str(&t);
+                    break;
+                }
+                SequenceDecoderOutput::Stopped => break,
+                SequenceDecoderOutput::Held => {}
+            }
+        }
+
+        // Flush remaining text
+        if let SequenceDecoderOutput::Text(t) = stop_decoder.flush() {
+            final_text.push_str(&t);
+        }
+
+        // Step 1: Handle reasoning content parsing
+        let mut reasoning_text: Option<String> = None;
+        let mut processed_text = final_text;
+
+        // Check if reasoning parsing is enabled and separate_reasoning is requested
+        if original_request.separate_reasoning {
+            let pooled_parser = utils::get_reasoning_parser(
+                &self.reasoning_parser_factory,
+                self.configured_reasoning_parser.as_ref(),
+                &original_request.model,
+            );
+
+            let mut parser = pooled_parser
+                .lock()
+                .map_err(|e| format!("Failed to acquire reasoning parser lock: {}", e))?;
+            match parser.detect_and_parse_reasoning(&processed_text) {
+                Ok(result) => {
+                    if !result.reasoning_text.is_empty() {
+                        reasoning_text = Some(result.reasoning_text);
+                    }
+                    processed_text = result.normal_text;
+                }
+                Err(e) => {
+                    return Err(format!("Reasoning parsing error: {}", e));
+                }
+            }
+        }
+
+        // Step 2: Handle tool call parsing
+        let mut tool_calls: Option<Vec<ToolCall>> = None;
+
+        // Check if tool calls should be processed
+        let tool_choice_enabled = !matches!(
+            &original_request.tool_choice,
+            Some(ToolChoice::Value(ToolChoiceValue::None))
+        );
+
+        if tool_choice_enabled && original_request.tools.is_some() {
+            // Check if JSON schema constraint was used (specific function or required mode)
+            let used_json_schema = match &original_request.tool_choice {
+                Some(ToolChoice::Function { .. }) => true,
+                Some(ToolChoice::Value(ToolChoiceValue::Required)) => true,
+                Some(ToolChoice::AllowedTools { mode, .. }) => mode == "required",
+                _ => false,
+            };
+
+            if used_json_schema {
+                (tool_calls, processed_text) = utils::parse_json_schema_response(
+                    &processed_text,
+                    &original_request.tool_choice,
+                );
+            } else {
+                (tool_calls, processed_text) = self
+                    .parse_tool_calls(
+                        &processed_text,
+                        &original_request.model,
+                        history_tool_calls_count,
+                    )
+                    .await;
+            }
+        }
+
+        // Step 3: Use finish reason directly from proto (already OpenAI-compatible string)
+        let finish_reason_str = &complete.finish_reason;
+
+        // Override finish reason if we have tool calls
+        let final_finish_reason_str = if tool_calls.is_some() {
+            "tool_calls"
+        } else {
+            finish_reason_str
+        };
+
+        // Extract matched_stop information from proto
+        let matched_stop = match &complete.matched_stop {
+            Some(proto::generate_complete::MatchedStop::MatchedTokenId(token_id)) => {
+                Some(Value::Number(serde_json::Number::from(*token_id)))
+            }
+            Some(proto::generate_complete::MatchedStop::MatchedStopStr(stop_str)) => {
+                Some(Value::String(stop_str.clone()))
+            }
+            None => None,
+        };
+
+        // Step 4: Convert output logprobs if present
+        let logprobs = if let Some(proto_logprobs) = &complete.output_logprobs {
+            match utils::convert_proto_to_openai_logprobs(proto_logprobs, &self.tokenizer) {
+                Ok(logprobs) => Some(logprobs),
+                Err(e) => {
+                    error!("Failed to convert logprobs: {}", e);
+                    None
+                }
+            }
+        } else {
+            None
+        };
+
+        // Step 5: Build ChatCompletionMessage (proper response message type)
+        let chat_message = ChatCompletionMessage {
+            role: "assistant".to_string(),
+            content: if processed_text.is_empty() {
+                None
+            } else {
+                Some(processed_text)
+            },
+            tool_calls,
+            reasoning_content: reasoning_text,
+        };
+
+        // Step 6: Build ChatChoice
+        let choice = ChatChoice {
+            index: index as u32,
+            message: chat_message,
+            logprobs,
+            finish_reason: Some(final_finish_reason_str.to_string()),
+            matched_stop,
+            hidden_states: None,
+        };
+
+        Ok(choice)
+    }
+
+    /// Parse tool calls using model-specific parser (EXACT COPY from router.rs:296-361)
+    pub async fn parse_tool_calls(
+        &self,
+        processed_text: &str,
+        model: &str,
+        history_tool_calls_count: usize,
+    ) -> (Option<Vec<ToolCall>>, String) {
+        // Get pooled parser for this model
+        let pooled_parser = utils::get_tool_parser(
+            &self.tool_parser_factory,
+            self.configured_tool_parser.as_ref(),
+            model,
+        );
+
+        // Try parsing directly (parser will handle detection internally)
+        let result = {
+            let parser = pooled_parser.lock().await;
+            parser.parse_complete(processed_text).await
+            // Lock is dropped here
+        };
+
+        match result {
+            Ok((normal_text, parsed_tool_calls)) => {
+                if parsed_tool_calls.is_empty() {
+                    return (None, normal_text);
+                }
+
+                let spec_tool_calls = parsed_tool_calls
+                    .into_iter()
+                    .enumerate()
+                    .map(|(index, tc)| {
+                        // Generate ID for this tool call
+                        let id = utils::generate_tool_call_id(
+                            model,
+                            &tc.function.name,
+                            index,
+                            history_tool_calls_count,
+                        );
+                        ToolCall {
+                            id,
+                            tool_type: "function".to_string(),
+                            function: FunctionCallResponse {
+                                name: tc.function.name,
+                                arguments: Some(
+                                    serde_json::to_string(&tc.function.arguments)
+                                        .unwrap_or_else(|_| "{}".to_string()),
+                                ),
+                            },
+                        }
+                    })
+                    .collect();
+                (Some(spec_tool_calls), normal_text)
+            }
+            Err(e) => {
+                error!("Tool call parsing error: {}", e);
+                (None, processed_text.to_string())
+            }
+        }
+    }
+}

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

@@ -0,0 +1,861 @@
+//! Streaming response processor for gRPC routers
+//!
+//! This module contains shared streaming logic for both Regular and PD routers,
+//! eliminating ~600 lines of duplication.
+
+use axum::response::Response;
+use axum::{body::Body, http::StatusCode};
+use bytes::Bytes;
+use http::header::{HeaderValue, CONTENT_TYPE};
+use serde_json::{json, Value};
+use std::collections::HashMap;
+use std::io;
+use std::sync::Arc;
+use tokio::sync::mpsc::UnboundedSender;
+use tokio_stream::wrappers::UnboundedReceiverStream;
+use tokio_stream::StreamExt;
+use tonic::codec::Streaming;
+use tracing::{debug, error, warn};
+
+use crate::grpc_client::proto;
+use crate::protocols::spec::*;
+use crate::reasoning_parser::ReasoningParser;
+use crate::tokenizer::stop::{SequenceDecoderOutput, StopSequenceDecoder};
+use crate::tokenizer::traits::Tokenizer;
+use crate::tool_parser::ToolParser;
+
+use super::context;
+use super::utils;
+
+/// Shared streaming processor for both single and dual dispatch modes
+#[derive(Clone)]
+pub struct StreamingProcessor {
+    tokenizer: Arc<dyn Tokenizer>,
+    tool_parser_factory: crate::tool_parser::ToolParserFactory,
+    reasoning_parser_factory: crate::reasoning_parser::ReasoningParserFactory,
+    configured_tool_parser: Option<String>,
+    configured_reasoning_parser: Option<String>,
+}
+
+impl StreamingProcessor {
+    pub fn new(
+        tokenizer: Arc<dyn Tokenizer>,
+        tool_parser_factory: crate::tool_parser::ToolParserFactory,
+        reasoning_parser_factory: crate::reasoning_parser::ReasoningParserFactory,
+        configured_tool_parser: Option<String>,
+        configured_reasoning_parser: Option<String>,
+    ) -> Self {
+        Self {
+            tokenizer,
+            tool_parser_factory,
+            reasoning_parser_factory,
+            configured_tool_parser,
+            configured_reasoning_parser,
+        }
+    }
+
+    /// Process streaming chat response and return SSE response
+    ///
+    /// This is the high-level entry point for streaming responses, handling:
+    /// - Channel creation
+    /// - Background task spawning
+    /// - SSE response building
+    pub fn process_streaming_response(
+        self: Arc<Self>,
+        execution_result: context::ExecutionResult,
+        chat_request: ChatCompletionRequest,
+        dispatch: context::DispatchMetadata,
+    ) -> axum::response::Response {
+        use bytes::Bytes;
+        use tokio::sync::mpsc;
+
+        let stop_params = (
+            chat_request.stop.clone(),
+            chat_request.stop_token_ids.clone(),
+            chat_request.skip_special_tokens,
+            chat_request.no_stop_trim,
+        );
+
+        // Create SSE channel
+        let (tx, rx) = mpsc::unbounded_channel::<Result<Bytes, io::Error>>();
+
+        // Spawn background task based on execution mode
+        match execution_result {
+            context::ExecutionResult::Single { stream } => {
+                let processor = self.clone();
+                let dispatch_clone = dispatch.clone();
+                tokio::spawn(async move {
+                    let result = processor
+                        .process_streaming_chunks(
+                            stream,
+                            dispatch_clone,
+                            stop_params,
+                            chat_request,
+                            &tx,
+                        )
+                        .await;
+
+                    if let Err(e) = result {
+                        let error_chunk = format!(
+                            "data: {}\n\n",
+                            json!({
+                                "error": {
+                                    "message": e,
+                                    "type": "internal_error"
+                                }
+                            })
+                        );
+                        let _ = tx.send(Ok(Bytes::from(error_chunk)));
+                    }
+
+                    let _ = tx.send(Ok(Bytes::from("data: [DONE]\n\n")));
+                });
+            }
+            context::ExecutionResult::Dual { prefill, decode } => {
+                let processor = self.clone();
+                tokio::spawn(async move {
+                    let result = processor
+                        .process_dual_streaming_chunks(
+                            prefill,
+                            *decode,
+                            dispatch,
+                            stop_params,
+                            chat_request,
+                            &tx,
+                        )
+                        .await;
+
+                    if let Err(e) = result {
+                        let error_chunk = format!(
+                            "data: {}\n\n",
+                            json!({
+                                "error": {
+                                    "message": e,
+                                    "type": "internal_error"
+                                }
+                            })
+                        );
+                        let _ = tx.send(Ok(Bytes::from(error_chunk)));
+                    }
+
+                    let _ = tx.send(Ok(Bytes::from("data: [DONE]\n\n")));
+                });
+            }
+        }
+
+        // Return SSE response
+        build_sse_response(rx)
+    }
+
+    /// Process streaming chunks from a single stream (Regular mode)
+    pub async fn process_streaming_chunks(
+        &self,
+        mut grpc_stream: Streaming<proto::GenerateResponse>,
+        dispatch: context::DispatchMetadata,
+        stop_params: (Option<StringOrArray>, Option<Vec<u32>>, bool, bool),
+        original_request: ChatCompletionRequest,
+        tx: &UnboundedSender<Result<Bytes, io::Error>>,
+    ) -> Result<(), String> {
+        // Extract request parameters
+        let separate_reasoning = original_request.separate_reasoning;
+        let tool_choice = &original_request.tool_choice;
+        let tools = &original_request.tools;
+        let history_tool_calls_count = utils::get_history_tool_calls_count(&original_request);
+        let stream_options = &original_request.stream_options;
+
+        // Phase 1: Initialize state tracking (per-index for n>1 support)
+        let mut is_firsts: HashMap<u32, bool> = HashMap::new();
+        let mut stream_buffers: HashMap<u32, String> = HashMap::new();
+        let mut finish_reasons: HashMap<u32, String> = HashMap::new();
+        let mut matched_stops: HashMap<u32, Option<Value>> = HashMap::new();
+        let mut prompt_tokens: HashMap<u32, u32> = HashMap::new();
+        let mut completion_tokens: HashMap<u32, u32> = HashMap::new();
+        let mut cached_tokens: HashMap<u32, u32> = HashMap::new();
+
+        // Parser state (lazy initialization per index)
+        type PooledReasoningParser = Arc<std::sync::Mutex<Box<dyn ReasoningParser>>>;
+        let mut reasoning_parsers: HashMap<u32, PooledReasoningParser> = HashMap::new();
+
+        type PooledToolParser = Arc<tokio::sync::Mutex<Box<dyn ToolParser>>>;
+        let mut tool_parsers: HashMap<u32, PooledToolParser> = HashMap::new();
+        let mut has_tool_calls: HashMap<u32, bool> = HashMap::new();
+
+        // Per-index stop decoders (each index needs its own state for n>1 support)
+        let mut stop_decoders: HashMap<u32, StopSequenceDecoder> = HashMap::new();
+
+        // Use dispatch metadata for consistent response fields
+        let request_id = &dispatch.request_id;
+        let model = &dispatch.model;
+        let created = dispatch.created;
+        let system_fingerprint = dispatch.weight_version.as_deref();
+
+        // Phase 2: Main streaming loop
+        while let Some(response) = grpc_stream.next().await {
+            let gen_response = response.map_err(|e| format!("Stream error: {}", e))?;
+
+            match gen_response.response {
+                Some(proto::generate_response::Response::Chunk(chunk)) => {
+                    let index = chunk.index;
+
+                    // Get or create stop decoder for this index
+                    let stop_decoder = stop_decoders.entry(index).or_insert_with(|| {
+                        let (ref stop, ref stop_token_ids, skip_special_tokens, no_stop_trim) =
+                            stop_params;
+                        utils::create_stop_decoder(
+                            &self.tokenizer,
+                            stop.as_ref(),
+                            stop_token_ids.as_ref(),
+                            skip_special_tokens,
+                            no_stop_trim,
+                        )
+                    });
+
+                    // Process tokens through stop decoder
+                    let (chunk_text, _should_stop) =
+                        Self::process_chunk_tokens(stop_decoder, &chunk.token_ids);
+
+                    if chunk_text.is_empty() {
+                        continue;
+                    }
+
+                    // Process logprobs if present
+                    let choice_logprobs = if let Some(ref proto_logprobs) = chunk.output_logprobs {
+                        match utils::convert_proto_to_openai_logprobs(
+                            proto_logprobs,
+                            &self.tokenizer,
+                        ) {
+                            Ok(logprobs) => Some(logprobs),
+                            Err(e) => {
+                                warn!("Failed to process logprobs: {}", e);
+                                None
+                            }
+                        }
+                    } else {
+                        None
+                    };
+
+                    // Initialize stream buffer if first time
+                    let stream_buffer = stream_buffers.entry(index).or_default();
+
+                    // Send first chunk with role
+                    if is_firsts.get(&index).copied().unwrap_or(true) {
+                        let first_chunk = ChatCompletionStreamResponse {
+                            id: request_id.clone(),
+                            object: "chat.completion.chunk".to_string(),
+                            created,
+                            model: model.clone(),
+                            system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                            choices: vec![ChatStreamChoice {
+                                index,
+                                delta: ChatMessageDelta {
+                                    role: Some("assistant".to_string()),
+                                    content: None,
+                                    tool_calls: None,
+                                    reasoning_content: None,
+                                },
+                                logprobs: None,
+                                finish_reason: None,
+                                matched_stop: None,
+                            }],
+                            usage: None,
+                        };
+                        tx.send(Ok(Bytes::from(Self::format_sse_chunk(&first_chunk))))
+                            .map_err(|_| "Failed to send first chunk".to_string())?;
+                        is_firsts.insert(index, false);
+                    }
+
+                    // Calculate delta
+                    let mut delta = chunk_text;
+                    stream_buffer.push_str(&delta);
+
+                    // Reasoning content handling
+                    let in_reasoning = if separate_reasoning {
+                        let (normal_text, reasoning_chunk, in_reasoning) = self
+                            .process_reasoning_stream(
+                                &delta,
+                                index,
+                                &mut reasoning_parsers,
+                                request_id,
+                                model,
+                                created,
+                                system_fingerprint,
+                            );
+                        if let Some(chunk) = reasoning_chunk {
+                            tx.send(Ok(Bytes::from(Self::format_sse_chunk(&chunk))))
+                                .map_err(|_| "Failed to send reasoning chunk".to_string())?;
+                        }
+                        delta = normal_text;
+                        in_reasoning
+                    } else {
+                        false
+                    };
+
+                    // Tool call handling
+                    let tool_choice_enabled =
+                        !matches!(tool_choice, Some(ToolChoice::Value(ToolChoiceValue::None)));
+
+                    if !in_reasoning && tool_choice_enabled && tools.is_some() {
+                        let (should_skip, tool_chunks) = self
+                            .process_tool_calls_stream(
+                                &delta,
+                                index,
+                                &mut tool_parsers,
+                                &mut has_tool_calls,
+                                tools.as_ref().unwrap(),
+                                request_id,
+                                model,
+                                created,
+                                system_fingerprint,
+                                history_tool_calls_count,
+                            )
+                            .await;
+
+                        for chunk in tool_chunks {
+                            tx.send(Ok(Bytes::from(Self::format_sse_chunk(&chunk))))
+                                .map_err(|_| "Failed to send tool call chunk".to_string())?;
+                        }
+
+                        // Continue to process the next chunk as we have tool chunks
+                        if should_skip {
+                            continue;
+                        }
+                    }
+
+                    // Regular content emission
+                    if !delta.is_empty() {
+                        let content_chunk = Self::create_content_chunk(
+                            delta,
+                            index,
+                            request_id,
+                            model,
+                            created,
+                            system_fingerprint,
+                            choice_logprobs,
+                        );
+                        tx.send(Ok(Bytes::from(Self::format_sse_chunk(&content_chunk))))
+                            .map_err(|_| "Failed to send content chunk".to_string())?;
+                    }
+                }
+                Some(proto::generate_response::Response::Complete(complete)) => {
+                    let index = complete.index;
+
+                    // Flush any remaining text for this index's stop_decoder
+                    if let Some(decoder) = stop_decoders.get_mut(&index) {
+                        if let SequenceDecoderOutput::Text(text) = decoder.flush() {
+                            if !text.is_empty() {
+                                let stream_buffer = stream_buffers.entry(index).or_default();
+                                stream_buffer.push_str(&text);
+
+                                let content_chunk = ChatCompletionStreamResponse {
+                                    id: request_id.clone(),
+                                    object: "chat.completion.chunk".to_string(),
+                                    created,
+                                    model: model.clone(),
+                                    system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                                    choices: vec![ChatStreamChoice {
+                                        index,
+                                        delta: ChatMessageDelta {
+                                            role: Some("assistant".to_string()),
+                                            content: Some(text),
+                                            tool_calls: None,
+                                            reasoning_content: None,
+                                        },
+                                        logprobs: None,
+                                        finish_reason: None,
+                                        matched_stop: None,
+                                    }],
+                                    usage: None,
+                                };
+
+                                let sse_chunk =
+                                    serde_json::to_string(&content_chunk).map_err(|e| {
+                                        format!("Failed to serialize content chunk: {}", e)
+                                    })?;
+                                tx.send(Ok(Bytes::from(format!("data: {}\n\n", sse_chunk))))
+                                    .map_err(|_| "Failed to send flushed content".to_string())?;
+                            }
+                        }
+                    }
+
+                    // Store metadata
+                    prompt_tokens.insert(index, complete.prompt_tokens as u32);
+                    completion_tokens.insert(index, complete.completion_tokens as u32);
+                    cached_tokens.insert(index, complete.cached_tokens as u32);
+                    finish_reasons.insert(index, complete.finish_reason.clone());
+
+                    // Extract matched_stop
+                    let matched_stop_value = match &complete.matched_stop {
+                        Some(proto::generate_complete::MatchedStop::MatchedTokenId(token_id)) => {
+                            Some(Value::Number(serde_json::Number::from(*token_id)))
+                        }
+                        Some(proto::generate_complete::MatchedStop::MatchedStopStr(stop_str)) => {
+                            Some(Value::String(stop_str.clone()))
+                        }
+                        None => None,
+                    };
+                    matched_stops.insert(index, matched_stop_value);
+
+                    // Don't break - continue reading all Complete messages for n>1
+                }
+                Some(proto::generate_response::Response::Error(error)) => {
+                    return Err(error.message);
+                }
+                None => continue,
+            }
+        }
+
+        // Phase 3: Check unstreamed tool args
+        for (index, parser) in &tool_parsers {
+            let parser_guard = parser.lock().await;
+            if let Some(unstreamed_items) = parser_guard.get_unstreamed_tool_args() {
+                for tool_call_item in unstreamed_items {
+                    let tool_call_delta = ToolCallDelta {
+                        index: tool_call_item.tool_index as u32,
+                        id: None,
+                        tool_type: None,
+                        function: Some(FunctionCallDelta {
+                            name: None,
+                            arguments: if !tool_call_item.parameters.is_empty() {
+                                Some(tool_call_item.parameters)
+                            } else {
+                                None
+                            },
+                        }),
+                    };
+
+                    let tool_chunk = ChatCompletionStreamResponse {
+                        id: request_id.clone(),
+                        object: "chat.completion.chunk".to_string(),
+                        created,
+                        model: model.clone(),
+                        system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                        choices: vec![ChatStreamChoice {
+                            index: *index,
+                            delta: ChatMessageDelta {
+                                role: Some("assistant".to_string()),
+                                content: None,
+                                tool_calls: Some(vec![tool_call_delta]),
+                                reasoning_content: None,
+                            },
+                            logprobs: None,
+                            finish_reason: None,
+                            matched_stop: None,
+                        }],
+                        usage: None,
+                    };
+
+                    let sse_chunk = serde_json::to_string(&tool_chunk)
+                        .map_err(|e| format!("Failed to serialize tool chunk: {}", e))?;
+                    tx.send(Ok(Bytes::from(format!("data: {}\n\n", sse_chunk))))
+                        .map_err(|_| "Failed to send unstreamed tool args".to_string())?;
+                }
+            }
+        }
+
+        // Phase 4: Finish reason chunks
+        for (index, finish_reason) in finish_reasons.iter() {
+            let final_finish_reason =
+                if has_tool_calls.get(index).copied().unwrap_or(false) && finish_reason == "stop" {
+                    "tool_calls".to_string()
+                } else {
+                    finish_reason.clone()
+                };
+
+            let matched_stop_value = matched_stops.get(index).and_then(|v| v.clone());
+
+            let finish_chunk = ChatCompletionStreamResponse {
+                id: request_id.clone(),
+                object: "chat.completion.chunk".to_string(),
+                created,
+                model: model.clone(),
+                system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                choices: vec![ChatStreamChoice {
+                    index: *index,
+                    delta: ChatMessageDelta {
+                        role: Some("assistant".to_string()),
+                        content: None,
+                        tool_calls: None,
+                        reasoning_content: None,
+                    },
+                    logprobs: None,
+                    finish_reason: Some(final_finish_reason),
+                    matched_stop: matched_stop_value,
+                }],
+                usage: None,
+            };
+
+            let sse_chunk = serde_json::to_string(&finish_chunk)
+                .map_err(|e| format!("Failed to serialize finish chunk: {}", e))?;
+            tx.send(Ok(Bytes::from(format!("data: {}\n\n", sse_chunk))))
+                .map_err(|_| "Failed to send finish chunk".to_string())?;
+        }
+
+        // Phase 5: Usage chunk
+        if let Some(stream_opts) = stream_options {
+            if stream_opts.include_usage.unwrap_or(false) {
+                let total_prompt: u32 = prompt_tokens.values().sum();
+                let total_completion: u32 = completion_tokens.values().sum();
+
+                let usage_chunk = ChatCompletionStreamResponse {
+                    id: request_id.clone(),
+                    object: "chat.completion.chunk".to_string(),
+                    created,
+                    model: model.clone(),
+                    system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                    choices: vec![],
+                    usage: Some(Usage {
+                        prompt_tokens: total_prompt,
+                        completion_tokens: total_completion,
+                        total_tokens: total_prompt + total_completion,
+                        completion_tokens_details: None,
+                    }),
+                };
+
+                let sse_chunk = serde_json::to_string(&usage_chunk)
+                    .map_err(|e| format!("Failed to serialize usage chunk: {}", e))?;
+                tx.send(Ok(Bytes::from(format!("data: {}\n\n", sse_chunk))))
+                    .map_err(|_| "Failed to send usage chunk".to_string())?;
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Process dual streaming chunks (prefill + decode) - PD mode
+    pub async fn process_dual_streaming_chunks(
+        &self,
+        mut prefill_stream: Streaming<proto::GenerateResponse>,
+        decode_stream: Streaming<proto::GenerateResponse>,
+        dispatch: context::DispatchMetadata,
+        stop_params: (Option<StringOrArray>, Option<Vec<u32>>, bool, bool),
+        original_request: ChatCompletionRequest,
+        tx: &UnboundedSender<Result<Bytes, io::Error>>,
+    ) -> Result<(), String> {
+        // Phase 1.5: Collect input_logprobs from prefill stream if requested
+        if original_request.logprobs {
+            while let Some(response) = prefill_stream.next().await {
+                let gen_response = response.map_err(|e| format!("Prefill stream error: {}", e))?;
+                match gen_response.response {
+                    Some(proto::generate_response::Response::Complete(_complete)) => {
+                        // Input logprobs collected but not yet used in streaming
+                        // (OpenAI spec doesn't require prompt logprobs in streaming responses)
+                        break;
+                    }
+                    Some(proto::generate_response::Response::Error(error)) => {
+                        return Err(format!("Prefill error: {}", error.message));
+                    }
+                    _ => continue,
+                }
+            }
+        }
+
+        // Phase 2-5: Process decode stream (same as single mode)
+        self.process_streaming_chunks(decode_stream, dispatch, stop_params, original_request, tx)
+            .await
+    }
+
+    // TODO(generate): Add streaming generate handler
+    //
+    // pub async fn process_streaming_generate(
+    //     self: Arc<Self>,
+    //     execution_result: context::ExecutionResult,
+    //     generate_request: GenerateRequest,
+    //     dispatch: context::DispatchMetadata,
+    // ) -> axum::response::Response {
+    //     // Similar to process_streaming_response but:
+    //     // - No tool parsing
+    //     // - No reasoning parsing
+    //     // - Simpler chunk format (just text + finish_reason + logprobs)
+    //     // - Extract stop params from generate_request.sampling_params
+    //     // - Use same per-index stop decoder logic
+    //     // - Emit SSE chunks with format similar to chat but without delta.tool_calls
+    //     // Reference: router.rs:422-595
+    // }
+
+    // ========================================================================
+    // Helper Methods
+    // ========================================================================
+
+    /// Process a chunk of tokens through the stop decoder
+    fn process_chunk_tokens(
+        stop_decoder: &mut StopSequenceDecoder,
+        token_ids: &[u32],
+    ) -> (String, bool) {
+        let mut chunk_text = String::new();
+
+        for &token_id in token_ids {
+            match stop_decoder.process_token(token_id).unwrap_or_else(|e| {
+                debug!(
+                    "Error processing token {}: {}. Treating as Held.",
+                    token_id, e
+                );
+                SequenceDecoderOutput::Held
+            }) {
+                SequenceDecoderOutput::Text(text) => {
+                    chunk_text.push_str(&text);
+                }
+                SequenceDecoderOutput::StoppedWithText(text) => {
+                    chunk_text.push_str(&text);
+                    return (chunk_text, true);
+                }
+                SequenceDecoderOutput::Stopped => {
+                    return (chunk_text, true);
+                }
+                SequenceDecoderOutput::Held => {}
+            }
+        }
+        (chunk_text, false)
+    }
+
+    /// Helper: Process reasoning content in streaming mode
+    #[allow(clippy::too_many_arguments)]
+    fn process_reasoning_stream(
+        &self,
+        delta: &str,
+        index: u32,
+        reasoning_parsers: &mut HashMap<u32, Arc<std::sync::Mutex<Box<dyn ReasoningParser>>>>,
+        request_id: &str,
+        model: &str,
+        created: u64,
+        system_fingerprint: Option<&str>,
+    ) -> (String, Option<ChatCompletionStreamResponse>, bool) {
+        // Get or create parser for this index
+        reasoning_parsers.entry(index).or_insert_with(|| {
+            utils::get_reasoning_parser(
+                &self.reasoning_parser_factory,
+                self.configured_reasoning_parser.as_ref(),
+                model,
+            )
+        });
+
+        if let Some(pooled_parser) = reasoning_parsers.get(&index) {
+            let (parse_result, in_reasoning) = {
+                let mut parser = pooled_parser.lock().unwrap();
+                let result = parser.parse_reasoning_streaming_incremental(delta);
+                let in_reasoning = parser.is_in_reasoning();
+                (result, in_reasoning)
+            };
+
+            match parse_result {
+                Ok(crate::reasoning_parser::ParserResult {
+                    reasoning_text,
+                    normal_text,
+                }) => {
+                    let chunk = if !reasoning_text.is_empty() {
+                        Some(ChatCompletionStreamResponse {
+                            id: request_id.to_string(),
+                            object: "chat.completion.chunk".to_string(),
+                            created,
+                            model: model.to_string(),
+                            system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                            choices: vec![ChatStreamChoice {
+                                index,
+                                delta: ChatMessageDelta {
+                                    role: Some("assistant".to_string()),
+                                    content: None,
+                                    tool_calls: None,
+                                    reasoning_content: Some(reasoning_text),
+                                },
+                                logprobs: None,
+                                finish_reason: None,
+                                matched_stop: None,
+                            }],
+                            usage: None,
+                        })
+                    } else {
+                        None
+                    };
+                    return (normal_text, chunk, in_reasoning);
+                }
+                Err(e) => {
+                    warn!("Reasoning parsing error: {}", e);
+                }
+            }
+        }
+
+        (delta.to_string(), None, false)
+    }
+
+    /// Helper: Process tool calls in streaming mode
+    #[allow(clippy::too_many_arguments)]
+    async fn process_tool_calls_stream(
+        &self,
+        delta: &str,
+        index: u32,
+        tool_parsers: &mut HashMap<u32, Arc<tokio::sync::Mutex<Box<dyn ToolParser>>>>,
+        has_tool_calls: &mut HashMap<u32, bool>,
+        tools: &[Tool],
+        request_id: &str,
+        model: &str,
+        created: u64,
+        system_fingerprint: Option<&str>,
+        history_tool_calls_count: usize,
+    ) -> (bool, Vec<ChatCompletionStreamResponse>) {
+        let mut chunks = Vec::new();
+
+        // Get or create parser for this index
+        tool_parsers.entry(index).or_insert_with(|| {
+            utils::get_tool_parser(
+                &self.tool_parser_factory,
+                self.configured_tool_parser.as_ref(),
+                model,
+            )
+        });
+
+        if let Some(pooled_parser) = tool_parsers.get(&index) {
+            let mut parser = pooled_parser.lock().await;
+            match parser.parse_incremental(delta, tools).await {
+                Ok(crate::tool_parser::StreamingParseResult { normal_text, calls }) => {
+                    // Emit normal text if present
+                    if !normal_text.is_empty() {
+                        chunks.push(ChatCompletionStreamResponse {
+                            id: request_id.to_string(),
+                            object: "chat.completion.chunk".to_string(),
+                            created,
+                            model: model.to_string(),
+                            system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                            choices: vec![ChatStreamChoice {
+                                index,
+                                delta: ChatMessageDelta {
+                                    role: Some("assistant".to_string()),
+                                    content: Some(normal_text),
+                                    tool_calls: None,
+                                    reasoning_content: None,
+                                },
+                                logprobs: None,
+                                finish_reason: None,
+                                matched_stop: None,
+                            }],
+                            usage: None,
+                        });
+                    }
+
+                    // Emit tool call chunks
+                    for tool_call_item in calls {
+                        has_tool_calls.insert(index, true);
+
+                        let tool_call_id = if let Some(ref name) = tool_call_item.name {
+                            Some(utils::generate_tool_call_id(
+                                model,
+                                name,
+                                tool_call_item.tool_index,
+                                history_tool_calls_count,
+                            ))
+                        } else {
+                            None
+                        };
+
+                        let tool_call_delta = ToolCallDelta {
+                            index: tool_call_item.tool_index as u32,
+                            id: tool_call_id,
+                            tool_type: if tool_call_item.name.is_some() {
+                                Some("function".to_string())
+                            } else {
+                                None
+                            },
+                            function: Some(FunctionCallDelta {
+                                name: tool_call_item.name,
+                                arguments: if !tool_call_item.parameters.is_empty() {
+                                    Some(tool_call_item.parameters)
+                                } else {
+                                    None
+                                },
+                            }),
+                        };
+
+                        chunks.push(ChatCompletionStreamResponse {
+                            id: request_id.to_string(),
+                            object: "chat.completion.chunk".to_string(),
+                            created,
+                            model: model.to_string(),
+                            system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+                            choices: vec![ChatStreamChoice {
+                                index,
+                                delta: ChatMessageDelta {
+                                    role: Some("assistant".to_string()),
+                                    content: None,
+                                    tool_calls: Some(vec![tool_call_delta]),
+                                    reasoning_content: None,
+                                },
+                                logprobs: None,
+                                finish_reason: None,
+                                matched_stop: None,
+                            }],
+                            usage: None,
+                        });
+                    }
+
+                    // If we emitted chunks, skip regular content
+                    return (!chunks.is_empty(), chunks);
+                }
+                Err(e) => {
+                    error!("Tool call parsing error: {}", e);
+                }
+            }
+        }
+
+        (false, chunks)
+    }
+
+    /// Format a response as SSE chunk
+    fn format_sse_chunk(chunk: &ChatCompletionStreamResponse) -> String {
+        match serde_json::to_string(chunk) {
+            Ok(json) => format!("data: {}\n\n", json),
+            Err(e) => {
+                error!("Failed to serialize SSE chunk: {}", e);
+                format!("data: {}\n\n", json!({"error": "serialization_failed"}))
+            }
+        }
+    }
+
+    /// Create a content chunk response
+    fn create_content_chunk(
+        content: String,
+        index: u32,
+        request_id: &str,
+        model: &str,
+        created: u64,
+        system_fingerprint: Option<&str>,
+        logprobs: Option<ChatLogProbs>,
+    ) -> ChatCompletionStreamResponse {
+        ChatCompletionStreamResponse {
+            id: request_id.to_string(),
+            object: "chat.completion.chunk".to_string(),
+            created,
+            model: model.to_string(),
+            system_fingerprint: system_fingerprint.map(|s| s.to_string()),
+            choices: vec![ChatStreamChoice {
+                index,
+                delta: ChatMessageDelta {
+                    role: Some("assistant".to_string()),
+                    content: Some(content),
+                    tool_calls: None,
+                    reasoning_content: None,
+                },
+                logprobs,
+                finish_reason: None,
+                matched_stop: None,
+            }],
+            usage: None,
+        }
+    }
+}
+
+/// Build SSE response with proper headers
+pub fn build_sse_response(
+    rx: tokio::sync::mpsc::UnboundedReceiver<Result<Bytes, io::Error>>,
+) -> Response {
+    let stream = UnboundedReceiverStream::new(rx);
+    let mut response = Response::new(Body::from_stream(stream));
+    *response.status_mut() = StatusCode::OK;
+    response
+        .headers_mut()
+        .insert(CONTENT_TYPE, HeaderValue::from_static("text/event-stream"));
+    response
+        .headers_mut()
+        .insert("Cache-Control", HeaderValue::from_static("no-cache"));
+    response
+        .headers_mut()
+        .insert("Connection", HeaderValue::from_static("keep-alive"));
+    response
+}

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

@@ -4,8 +4,8 @@ use super::ProcessedMessages;
 use crate::core::Worker;
 use crate::grpc_client::{proto, SglangSchedulerClient};
 use crate::protocols::spec::{
-    ChatCompletionRequest, ChatMessage, FunctionCallResponse, StringOrArray, Tool, ToolCall,
-    ToolChoice, ToolChoiceValue,
+    ChatCompletionRequest, ChatLogProbs, ChatLogProbsContent, ChatMessage, FunctionCallResponse,
+    StringOrArray, Tool, ToolCall, ToolChoice, ToolChoiceValue, TopLogProb,
 };
 use crate::tokenizer::chat_template::{ChatTemplateContentFormat, ChatTemplateParams};
 use crate::tokenizer::traits::Tokenizer;
@@ -736,6 +736,79 @@ pub fn get_tool_parser(
     }
 }
 
+/// Convert proto::OutputLogProbs to OpenAI ChatLogProbs format
+///
+/// This function decodes token IDs using the tokenizer and builds the logprobs structure
+/// expected by the OpenAI API format.
+pub fn convert_proto_to_openai_logprobs(
+    proto_logprobs: &proto::OutputLogProbs,
+    tokenizer: &Arc<dyn Tokenizer>,
+) -> Result<ChatLogProbs, String> {
+    let mut content_items = Vec::new();
+
+    // Decode token IDs to text (always with skip_special_tokens=false for logprobs)
+    let token_texts: Vec<String> = proto_logprobs
+        .token_ids
+        .iter()
+        .map(|&token_id| {
+            tokenizer
+                .decode(&[token_id as u32], false)
+                .unwrap_or_else(|_| format!("<token_{}>", token_id))
+        })
+        .collect();
+
+    // Build ChatLogProbsContent for each token (consume iterator to avoid clones)
+    for (i, (&logprob, token_text)) in proto_logprobs
+        .token_logprobs
+        .iter()
+        .zip(token_texts.into_iter())
+        .enumerate()
+    {
+        let bytes = Some(token_text.as_bytes().to_vec());
+
+        // Build top_logprobs for this position
+        let mut top_logprobs = Vec::new();
+        if let Some(top_logprobs_entry) = proto_logprobs.top_logprobs.get(i) {
+            // Decode top token IDs (always with skip_special_tokens=false)
+            let top_token_texts: Vec<String> = top_logprobs_entry
+                .token_ids
+                .iter()
+                .map(|&tid| {
+                    tokenizer
+                        .decode(&[tid as u32], false)
+                        .unwrap_or_else(|_| format!("<token_{}>", tid))
+                })
+                .collect();
+
+            for (j, (&top_logprob, &_top_token_id)) in top_logprobs_entry
+                .values
+                .iter()
+                .zip(top_logprobs_entry.token_ids.iter())
+                .enumerate()
+            {
+                if let Some(top_token_text) = top_token_texts.get(j) {
+                    top_logprobs.push(TopLogProb {
+                        token: top_token_text.clone(),
+                        logprob: top_logprob,
+                        bytes: Some(top_token_text.as_bytes().to_vec()),
+                    });
+                }
+            }
+        }
+
+        content_items.push(ChatLogProbsContent {
+            token: token_text,
+            logprob,
+            bytes,
+            top_logprobs,
+        });
+    }
+
+    Ok(ChatLogProbs::Detailed {
+        content: (!content_items.is_empty()).then_some(content_items),
+    })
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;