[router][grpc] Fix streaming bugs: empty tool names, state pollution, and panics (#11373)

sgl-router/benches/tool_parser_benchmark.rs

@@ -10,7 +10,7 @@
 use criterion::{black_box, criterion_group, BenchmarkId, Criterion, Throughput};
 use serde_json::json;
 use sglang_router_rs::protocols::spec::{Function, Tool};
-use sglang_router_rs::tool_parser::{JsonParser, ToolParser, ToolParserFactory};
+use sglang_router_rs::tool_parser::{JsonParser, ParserFactory as ToolParserFactory, ToolParser};
 use std::collections::BTreeMap;
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
 use std::sync::{Arc, Mutex};

sgl-router/src/reasoning_parser/factory.rs

@@ -82,9 +82,15 @@ impl ParserRegistry {
         }
     }
 
-    /// Get a parser by exact name (creates new instance, not pooled).
-    /// Use this for compatibility or when you need a fresh instance.
-    pub fn get_parser(&self, name: &str) -> Option<Box<dyn ReasoningParser>> {
+    /// Check if a parser with the given name is registered.
+    pub fn has_parser(&self, name: &str) -> bool {
+        let creators = self.creators.read().unwrap();
+        creators.contains_key(name)
+    }
+
+    /// Create a fresh parser instance by exact name (not pooled).
+    /// Returns a new parser instance for each call - useful for streaming where state isolation is needed.
+    pub fn create_parser(&self, name: &str) -> Option<Box<dyn ReasoningParser>> {
         let creators = self.creators.read().unwrap();
         creators.get(name).map(|creator| creator())
     }
@@ -102,14 +108,30 @@ impl ParserRegistry {
         None
     }
 
-    /// Find a parser for a given model ID by pattern matching (creates new instance).
-    pub fn find_parser_for_model(&self, model_id: &str) -> Option<Box<dyn ReasoningParser>> {
+    /// Check if a parser can be created for a specific model without actually creating it.
+    /// Returns true if a parser is available (registered) for this model.
+    pub fn has_parser_for_model(&self, model_id: &str) -> bool {
+        let patterns = self.patterns.read().unwrap();
+        let model_lower = model_id.to_lowercase();
+
+        for (pattern, parser_name) in patterns.iter() {
+            if model_lower.contains(&pattern.to_lowercase()) {
+                let creators = self.creators.read().unwrap();
+                return creators.contains_key(parser_name);
+            }
+        }
+        false
+    }
+
+    /// Create a fresh parser instance for a given model ID by pattern matching (not pooled).
+    /// Returns a new parser instance for each call - useful for streaming where state isolation is needed.
+    pub fn create_for_model(&self, model_id: &str) -> Option<Box<dyn ReasoningParser>> {
         let patterns = self.patterns.read().unwrap();
         let model_lower = model_id.to_lowercase();
 
         for (pattern, parser_name) in patterns.iter() {
             if model_lower.contains(&pattern.to_lowercase()) {
-                return self.get_parser(parser_name);
+                return self.create_parser(parser_name);
             }
         }
         None
@@ -131,11 +153,11 @@ impl Default for ParserRegistry {
 
 /// Factory for creating reasoning parsers based on model type.
 #[derive(Clone)]
-pub struct ReasoningParserFactory {
+pub struct ParserFactory {
     registry: ParserRegistry,
 }
 
-impl ReasoningParserFactory {
+impl ParserFactory {
     /// Create a new factory with default parsers registered.
     pub fn new() -> Self {
         let registry = ParserRegistry::new();
@@ -211,7 +233,7 @@ impl ReasoningParserFactory {
     /// Use this when you need an isolated parser instance.
     pub fn create(&self, model_id: &str) -> Result<Box<dyn ReasoningParser>, ParseError> {
         // First try to find by pattern
-        if let Some(parser) = self.registry.find_parser_for_model(model_id) {
+        if let Some(parser) = self.registry.create_for_model(model_id) {
             return Ok(parser);
         }
 
@@ -240,7 +262,7 @@ impl ReasoningParserFactory {
     }
 }
 
-impl Default for ReasoningParserFactory {
+impl Default for ParserFactory {
     fn default() -> Self {
         Self::new()
     }
@@ -252,35 +274,35 @@ mod tests {
 
     #[test]
     fn test_factory_creates_deepseek_r1() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let parser = factory.create("deepseek-r1-distill").unwrap();
         assert_eq!(parser.model_type(), "deepseek_r1");
     }
 
     #[test]
     fn test_factory_creates_qwen3() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let parser = factory.create("qwen3-7b").unwrap();
         assert_eq!(parser.model_type(), "qwen3");
     }
 
     #[test]
     fn test_factory_creates_kimi() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let parser = factory.create("kimi-chat").unwrap();
         assert_eq!(parser.model_type(), "kimi");
     }
 
     #[test]
     fn test_factory_fallback_to_passthrough() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let parser = factory.create("unknown-model").unwrap();
         assert_eq!(parser.model_type(), "passthrough");
     }
 
     #[test]
     fn test_case_insensitive_matching() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let parser1 = factory.create("DeepSeek-R1").unwrap();
         let parser2 = factory.create("QWEN3").unwrap();
         let parser3 = factory.create("Kimi").unwrap();
@@ -292,21 +314,21 @@ mod tests {
 
     #[test]
     fn test_step3_model() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let step3 = factory.create("step3-model").unwrap();
         assert_eq!(step3.model_type(), "step3");
     }
 
     #[test]
     fn test_glm45_model() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let glm45 = factory.create("glm45-v2").unwrap();
         assert_eq!(glm45.model_type(), "glm45");
     }
 
     #[tokio::test]
     async fn test_pooled_parser_reuse() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
 
         // Get the same parser twice - should be the same instance
         let parser1 = factory.get_pooled("deepseek-r1");
@@ -322,7 +344,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_pooled_parser_concurrent_access() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let parser = factory.get_pooled("deepseek-r1");
 
         // Spawn multiple async tasks that use the same parser
@@ -348,7 +370,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_pool_clearing() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
 
         // Get a pooled parser
         let parser1 = factory.get_pooled("deepseek-r1");
@@ -365,7 +387,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_passthrough_parser_pooling() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
 
         // Unknown models should get passthrough parser
         let parser1 = factory.get_pooled("unknown-model-1");
@@ -383,7 +405,7 @@ mod tests {
         use std::sync::atomic::{AtomicUsize, Ordering};
         use std::time::Instant;
 
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let num_tasks = 100;
         let requests_per_task = 50;
         let models = vec!["deepseek-r1", "qwen3", "kimi", "qwen3-thinking"];
@@ -512,7 +534,7 @@ mod tests {
 
     #[tokio::test(flavor = "multi_thread", worker_threads = 4)]
     async fn test_concurrent_pool_modifications() {
-        let factory = ReasoningParserFactory::new();
+        let factory = ParserFactory::new();
         let mut handles = vec![];
 
         // Task 1: Continuously get parsers

sgl-router/src/reasoning_parser/mod.rs

@@ -2,7 +2,7 @@ pub mod factory;
 pub mod parsers;
 pub mod traits;
 
-pub use factory::{ParserRegistry, PooledParser, ReasoningParserFactory};
+pub use factory::{ParserFactory, ParserRegistry, PooledParser};
 pub use parsers::{
     BaseReasoningParser, DeepSeekR1Parser, Glm45Parser, KimiParser, Qwen3Parser,
     QwenThinkingParser, Step3Parser,

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

@@ -15,10 +15,10 @@ use crate::grpc_client::{proto, SglangSchedulerClient};
 use crate::protocols::spec::{
     ChatCompletionRequest, ChatCompletionResponse, GenerateRequest, GenerateResponse,
 };
-use crate::reasoning_parser::ReasoningParserFactory;
+use crate::reasoning_parser::ParserFactory as ReasoningParserFactory;
 use crate::tokenizer::stop::StopSequenceDecoder;
 use crate::tokenizer::traits::Tokenizer;
-use crate::tool_parser::ToolParserFactory;
+use crate::tool_parser::ParserFactory as ToolParserFactory;
 
 // ============================================================================
 // Core Context Types

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

@@ -7,11 +7,11 @@ use crate::protocols::spec::{
     ChatCompletionRequest, CompletionRequest, EmbeddingRequest, GenerateRequest, RerankRequest,
     ResponsesGetParams, ResponsesRequest,
 };
-use crate::reasoning_parser::ReasoningParserFactory;
+use crate::reasoning_parser::ParserFactory as ReasoningParserFactory;
 use crate::routers::RouterTrait;
 use crate::server::AppContext;
 use crate::tokenizer::traits::Tokenizer;
-use crate::tool_parser::ToolParserFactory;
+use crate::tool_parser::ParserFactory as ToolParserFactory;
 use async_trait::async_trait;
 use axum::{
     body::Body,

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

@@ -13,10 +13,10 @@ use crate::protocols::spec::{
     ChatChoice, ChatCompletionMessage, ChatCompletionRequest, FunctionCallResponse, ToolCall,
     ToolChoice, ToolChoiceValue,
 };
-use crate::reasoning_parser::ReasoningParserFactory;
+use crate::reasoning_parser::ParserFactory as ReasoningParserFactory;
 use crate::tokenizer::stop::{SequenceDecoderOutput, StopSequenceDecoder};
 use crate::tokenizer::traits::Tokenizer;
-use crate::tool_parser::ToolParserFactory;
+use crate::tool_parser::ParserFactory as ToolParserFactory;
 
 use super::utils;
 

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

@@ -18,11 +18,11 @@ use crate::protocols::spec::{
     ChatCompletionRequest, CompletionRequest, EmbeddingRequest, GenerateRequest, RerankRequest,
     ResponsesGetParams, ResponsesRequest,
 };
-use crate::reasoning_parser::ReasoningParserFactory;
+use crate::reasoning_parser::ParserFactory as ReasoningParserFactory;
 use crate::routers::RouterTrait;
 use crate::server::AppContext;
 use crate::tokenizer::traits::Tokenizer;
-use crate::tool_parser::ToolParserFactory;
+use crate::tool_parser::ParserFactory as ToolParserFactory;
 
 /// gRPC router implementation for SGLang
 #[derive(Clone)]

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

@@ -34,8 +34,8 @@ use tokio::sync::mpsc;
 #[derive(Clone)]
 pub struct StreamingProcessor {
     tokenizer: Arc<dyn Tokenizer>,
-    tool_parser_factory: crate::tool_parser::ToolParserFactory,
-    reasoning_parser_factory: crate::reasoning_parser::ReasoningParserFactory,
+    tool_parser_factory: crate::tool_parser::ParserFactory,
+    reasoning_parser_factory: crate::reasoning_parser::ParserFactory,
     configured_tool_parser: Option<String>,
     configured_reasoning_parser: Option<String>,
 }
@@ -43,8 +43,8 @@ pub struct StreamingProcessor {
 impl StreamingProcessor {
     pub fn new(
         tokenizer: Arc<dyn Tokenizer>,
-        tool_parser_factory: crate::tool_parser::ToolParserFactory,
-        reasoning_parser_factory: crate::reasoning_parser::ReasoningParserFactory,
+        tool_parser_factory: crate::tool_parser::ParserFactory,
+        reasoning_parser_factory: crate::reasoning_parser::ParserFactory,
         configured_tool_parser: Option<String>,
         configured_reasoning_parser: Option<String>,
     ) -> Self {
@@ -195,6 +195,47 @@ impl StreamingProcessor {
         let created = dispatch.created;
         let system_fingerprint = dispatch.weight_version.as_deref();
 
+        // Check parser availability once upfront (log warning only once per request)
+        let reasoning_parser_available = if separate_reasoning {
+            if let Some(parser_name) = self.configured_reasoning_parser.as_ref() {
+                self.reasoning_parser_factory
+                    .registry()
+                    .has_parser(parser_name)
+            } else {
+                self.reasoning_parser_factory
+                    .registry()
+                    .has_parser_for_model(model)
+            }
+        } else {
+            false
+        };
+
+        let tool_parser_available = if tools.is_some() {
+            if let Some(parser_name) = self.configured_tool_parser.as_ref() {
+                self.tool_parser_factory.registry().has_parser(parser_name)
+            } else {
+                self.tool_parser_factory
+                    .registry()
+                    .has_parser_for_model(model)
+            }
+        } else {
+            false
+        };
+
+        if separate_reasoning && !reasoning_parser_available {
+            warn!(
+                "No reasoning parser found for model '{}', skipping reasoning parsing",
+                model
+            );
+        }
+
+        if tools.is_some() && !tool_parser_available {
+            warn!(
+                "No tool parser found for model '{}', skipping tool call parsing",
+                model
+            );
+        }
+
         // Phase 2: Main streaming loop
         while let Some(response) = grpc_stream.next().await {
             let gen_response = response.map_err(|e| format!("Stream error: {}", e))?;
@@ -276,7 +317,7 @@ impl StreamingProcessor {
                     stream_buffer.push_str(&delta);
 
                     // Reasoning content handling
-                    let in_reasoning = if separate_reasoning {
+                    let in_reasoning = if separate_reasoning && reasoning_parser_available {
                         let (normal_text, reasoning_chunk, in_reasoning) = self
                             .process_reasoning_stream(
                                 &delta,
@@ -303,8 +344,12 @@ impl StreamingProcessor {
                     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
+                    if !in_reasoning
+                        && tool_choice_enabled
+                        && tools.is_some()
+                        && tool_parser_available
+                    {
+                        let tool_chunks = self
                             .process_tool_calls_stream(
                                 &delta,
                                 index,
@@ -325,10 +370,9 @@ impl StreamingProcessor {
                                 .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;
-                        }
+                        // Always skip regular content when tool parsing is active
+                        // Parser either emitted chunks or buffered content
+                        continue;
                     }
 
                     // Regular content emission
@@ -963,13 +1007,15 @@ impl StreamingProcessor {
         created: u64,
         system_fingerprint: Option<&str>,
     ) -> (String, Option<ChatCompletionStreamResponse>, bool) {
-        // Get or create parser for this index
+        // Create fresh parser for this index (not pooled, to avoid state pollution)
         reasoning_parsers.entry(index).or_insert_with(|| {
-            utils::get_reasoning_parser(
+            let parser = utils::create_reasoning_parser(
                 &self.reasoning_parser_factory,
                 self.configured_reasoning_parser.as_ref(),
                 model,
             )
+            .expect("Parser should be available - checked upfront");
+            Arc::new(tokio::sync::Mutex::new(parser))
         });
 
         if let Some(pooled_parser) = reasoning_parsers.get(&index) {
@@ -1034,20 +1080,23 @@ impl StreamingProcessor {
         created: u64,
         system_fingerprint: Option<&str>,
         history_tool_calls_count: usize,
-    ) -> (bool, Vec<ChatCompletionStreamResponse>) {
+    ) -> Vec<ChatCompletionStreamResponse> {
         let mut chunks = Vec::new();
 
-        // Get or create parser for this index
+        // Create fresh parser for this index (not pooled, to avoid state pollution)
         tool_parsers.entry(index).or_insert_with(|| {
-            utils::get_tool_parser(
+            let parser = utils::create_tool_parser(
                 &self.tool_parser_factory,
                 self.configured_tool_parser.as_ref(),
                 model,
             )
+            .expect("Parser should be available - checked upfront");
+            Arc::new(tokio::sync::Mutex::new(parser))
         });
 
         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
@@ -1129,8 +1178,7 @@ impl StreamingProcessor {
                         });
                     }
 
-                    // If we emitted chunks, skip regular content
-                    return (!chunks.is_empty(), chunks);
+                    return chunks;
                 }
                 Err(e) => {
                     error!("Tool call parsing error: {}", e);
@@ -1138,7 +1186,7 @@ impl StreamingProcessor {
             }
         }
 
-        (false, chunks)
+        chunks
     }
 
     /// Format a response as SSE chunk into a reusable buffer

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

@@ -677,13 +677,12 @@ pub fn generate_tool_call_id(
 ///
 /// If a parser name is explicitly configured, use that parser.
 /// Otherwise, auto-detect based on the model name.
+/// Get a pooled reasoning parser (for non-streaming where state doesn't matter)
 pub fn get_reasoning_parser(
-    reasoning_parser_factory: &crate::reasoning_parser::ReasoningParserFactory,
+    reasoning_parser_factory: &crate::reasoning_parser::ParserFactory,
     configured_parser: Option<&String>,
     model: &str,
 ) -> crate::reasoning_parser::PooledParser {
-    use tracing::warn;
-
     if let Some(parser_name) = configured_parser {
         // Use configured parser if specified
         reasoning_parser_factory
@@ -702,17 +701,40 @@ pub fn get_reasoning_parser(
     }
 }
 
+/// Create a fresh reasoning parser instance (for streaming where state isolation is needed)
+pub fn create_reasoning_parser(
+    reasoning_parser_factory: &crate::reasoning_parser::ParserFactory,
+    configured_parser: Option<&String>,
+    model: &str,
+) -> Option<Box<dyn crate::reasoning_parser::ReasoningParser>> {
+    if let Some(parser_name) = configured_parser {
+        // Use configured parser if specified
+        reasoning_parser_factory
+            .registry()
+            .create_parser(parser_name)
+            .or_else(|| {
+                warn!(
+                    "Configured reasoning parser '{}' not found, falling back to model-based selection",
+                    parser_name
+                );
+                reasoning_parser_factory.registry().create_for_model(model)
+            })
+    } else {
+        // Auto-detect based on model
+        reasoning_parser_factory.registry().create_for_model(model)
+    }
+}
+
 /// Get the appropriate tool parser for a model
 ///
 /// If a parser name is explicitly configured, use that parser.
 /// Otherwise, auto-detect based on the model name.
+/// Get a pooled tool parser (for non-streaming where state doesn't matter)
 pub fn get_tool_parser(
-    tool_parser_factory: &crate::tool_parser::ToolParserFactory,
+    tool_parser_factory: &crate::tool_parser::ParserFactory,
     configured_parser: Option<&String>,
     model: &str,
-) -> crate::tool_parser::PooledToolParser {
-    use tracing::warn;
-
+) -> crate::tool_parser::PooledParser {
     if let Some(parser_name) = configured_parser {
         // Use configured parser if specified
         tool_parser_factory
@@ -731,6 +753,30 @@ pub fn get_tool_parser(
     }
 }
 
+/// Create a fresh tool parser instance (for streaming where state isolation is needed)
+pub fn create_tool_parser(
+    tool_parser_factory: &crate::tool_parser::ParserFactory,
+    configured_parser: Option<&String>,
+    model: &str,
+) -> Option<Box<dyn crate::tool_parser::ToolParser>> {
+    if let Some(parser_name) = configured_parser {
+        // Use configured parser if specified
+        tool_parser_factory
+            .registry()
+            .create_parser(parser_name)
+            .or_else(|| {
+                warn!(
+                    "Configured tool parser '{}' not found, falling back to model-based selection",
+                    parser_name
+                );
+                tool_parser_factory.registry().create_for_model(model)
+            })
+    } else {
+        // Auto-detect based on model
+        tool_parser_factory.registry().create_for_model(model)
+    }
+}
+
 /// Convert proto::OutputLogProbs to OpenAI ChatLogProbs format
 ///
 /// This function decodes token IDs using the tokenizer and builds the logprobs structure

sgl-router/src/server.rs

@@ -18,11 +18,11 @@ use crate::{
         },
         worker_spec::{WorkerApiResponse, WorkerConfigRequest, WorkerErrorResponse},
     },
-    reasoning_parser::ReasoningParserFactory,
+    reasoning_parser::ParserFactory as ReasoningParserFactory,
     routers::{router_manager::RouterManager, RouterTrait},
     service_discovery::{start_service_discovery, ServiceDiscoveryConfig},
     tokenizer::{factory as tokenizer_factory, traits::Tokenizer},
-    tool_parser::ToolParserFactory,
+    tool_parser::ParserFactory as ToolParserFactory,
 };
 use axum::{
     extract::{Path, Query, Request, State},
@@ -88,8 +88,8 @@ impl AppContext {
                     tokenizer_factory::create_tokenizer(&tokenizer_path)
                         .map_err(|e| format!("Failed to create tokenizer: {e}"))?,
                 );
-                let reasoning_parser_factory = Some(ReasoningParserFactory::new());
-                let tool_parser_factory = Some(ToolParserFactory::new());
+                let reasoning_parser_factory = Some(crate::reasoning_parser::ParserFactory::new());
+                let tool_parser_factory = Some(crate::tool_parser::ParserFactory::new());
 
                 (tokenizer, reasoning_parser_factory, tool_parser_factory)
             } else {

sgl-router/src/tool_parser/errors.rs

 use thiserror::Error;
 
 /// Result type for tool parser operations
-pub type ToolParserResult<T> = Result<T, ToolParserError>;
+pub type ParserResult<T> = Result<T, ParserError>;
 
 /// Errors that can occur during tool parsing
 #[derive(Debug, Error)]
-pub enum ToolParserError {
+pub enum ParserError {
     #[error("Parsing failed: {0}")]
     ParsingFailed(String),
 

sgl-router/src/tool_parser/factory.rs

@@ -11,25 +11,25 @@ use crate::tool_parser::parsers::{
 use crate::tool_parser::traits::ToolParser;
 
 /// Type alias for pooled parser instances.
-pub type PooledToolParser = Arc<Mutex<Box<dyn ToolParser>>>;
+pub type PooledParser = Arc<Mutex<Box<dyn ToolParser>>>;
 
 /// Type alias for parser creator functions.
 type ParserCreator = Arc<dyn Fn() -> Box<dyn ToolParser> + Send + Sync>;
 
 /// Registry for model-specific tool parsers with pooling support.
 #[derive(Clone)]
-pub struct ToolParserRegistry {
+pub struct ParserRegistry {
     /// Creator functions for parsers (used when pool is empty)
     creators: Arc<RwLock<HashMap<String, ParserCreator>>>,
     /// Pooled parser instances for reuse
-    pool: Arc<RwLock<HashMap<String, PooledToolParser>>>,
+    pool: Arc<RwLock<HashMap<String, PooledParser>>>,
     /// Model pattern to parser name mappings
     model_mapping: Arc<RwLock<HashMap<String, String>>>,
     /// Default parser name
     default_parser: Arc<RwLock<String>>,
 }
 
-impl ToolParserRegistry {
+impl ParserRegistry {
     /// Create a new empty registry.
     pub fn new() -> Self {
         Self {
@@ -57,7 +57,7 @@ impl ToolParserRegistry {
 
     /// Get a pooled parser by exact name.
     /// Returns a shared parser instance from the pool, creating one if needed.
-    pub fn get_pooled_parser(&self, name: &str) -> Option<PooledToolParser> {
+    pub fn get_pooled_parser(&self, name: &str) -> Option<PooledParser> {
         // First check if we have a pooled instance
         {
             let pool = self.pool.read().unwrap();
@@ -81,8 +81,91 @@ impl ToolParserRegistry {
         }
     }
 
+    /// Check if a parser with the given name is registered.
+    pub fn has_parser(&self, name: &str) -> bool {
+        let creators = self.creators.read().unwrap();
+        creators.contains_key(name)
+    }
+
+    /// Create a fresh (non-pooled) parser instance by exact name.
+    /// Returns a new parser instance for each call - useful for streaming where state isolation is needed.
+    pub fn create_parser(&self, name: &str) -> Option<Box<dyn ToolParser>> {
+        let creators = self.creators.read().unwrap();
+        creators.get(name).map(|creator| creator())
+    }
+
+    /// Check if a parser can be created for a specific model without actually creating it.
+    /// Returns true if a parser is available (registered) for this model.
+    pub fn has_parser_for_model(&self, model: &str) -> bool {
+        // Try exact match first
+        {
+            let mapping = self.model_mapping.read().unwrap();
+            if let Some(parser_name) = mapping.get(model) {
+                let creators = self.creators.read().unwrap();
+                if creators.contains_key(parser_name) {
+                    return true;
+                }
+            }
+        }
+
+        // Try prefix matching
+        let model_mapping = self.model_mapping.read().unwrap();
+        let best_match = model_mapping
+            .iter()
+            .filter(|(pattern, _)| {
+                pattern.ends_with('*') && model.starts_with(&pattern[..pattern.len() - 1])
+            })
+            .max_by_key(|(pattern, _)| pattern.len());
+
+        if let Some((_, parser_name)) = best_match {
+            let creators = self.creators.read().unwrap();
+            if creators.contains_key(parser_name) {
+                return true;
+            }
+        }
+
+        // Check if default parser exists
+        let default = self.default_parser.read().unwrap().clone();
+        let creators = self.creators.read().unwrap();
+        creators.contains_key(&default)
+    }
+
+    /// Create a fresh (non-pooled) parser instance for a specific model.
+    /// Returns a new parser instance for each call - useful for streaming where state isolation is needed.
+    pub fn create_for_model(&self, model: &str) -> Option<Box<dyn ToolParser>> {
+        // Try exact match first
+        {
+            let mapping = self.model_mapping.read().unwrap();
+            if let Some(parser_name) = mapping.get(model) {
+                if let Some(parser) = self.create_parser(parser_name) {
+                    return Some(parser);
+                }
+            }
+        }
+
+        // Try prefix matching with more specific patterns first
+        let model_mapping = self.model_mapping.read().unwrap();
+        let best_match = model_mapping
+            .iter()
+            .filter(|(pattern, _)| {
+                pattern.ends_with('*') && model.starts_with(&pattern[..pattern.len() - 1])
+            })
+            .max_by_key(|(pattern, _)| pattern.len());
+
+        // Return the best matching parser
+        if let Some((_, parser_name)) = best_match {
+            if let Some(parser) = self.create_parser(parser_name) {
+                return Some(parser);
+            }
+        }
+
+        // Fall back to default parser
+        let default = self.default_parser.read().unwrap().clone();
+        self.create_parser(&default)
+    }
+
     /// Get parser for a specific model
-    pub fn get_pooled_for_model(&self, model: &str) -> Option<PooledToolParser> {
+    pub fn get_pooled_for_model(&self, model: &str) -> Option<PooledParser> {
         // Try exact match first
         {
             let mapping = self.model_mapping.read().unwrap();
@@ -127,7 +210,7 @@ impl ToolParserRegistry {
     }
 }
 
-impl Default for ToolParserRegistry {
+impl Default for ParserRegistry {
     fn default() -> Self {
         Self::new()
     }
@@ -135,14 +218,14 @@ impl Default for ToolParserRegistry {
 
 /// Factory for creating tool parsers based on model type.
 #[derive(Clone)]
-pub struct ToolParserFactory {
-    registry: ToolParserRegistry,
+pub struct ParserFactory {
+    registry: ParserRegistry,
 }
 
-impl ToolParserFactory {
+impl ParserFactory {
     /// Create a new factory with default parsers registered.
     pub fn new() -> Self {
-        let registry = ToolParserRegistry::new();
+        let registry = ParserRegistry::new();
 
         // Register default parsers
         registry.register_parser("json", || Box::new(JsonParser::new()));
@@ -172,7 +255,7 @@ impl ToolParserFactory {
         Self { registry }
     }
 
-    fn register_default_mappings(registry: &ToolParserRegistry) {
+    fn register_default_mappings(registry: &ParserRegistry) {
         // OpenAI models
         registry.map_model("gpt-4*", "json");
         registry.map_model("gpt-3.5*", "json");
@@ -229,7 +312,7 @@ impl ToolParserFactory {
     /// Get a pooled parser for the given model ID.
     /// Returns a shared instance that can be used concurrently.
     /// Falls back to JSON parser if model is not recognized.
-    pub fn get_pooled(&self, model_id: &str) -> PooledToolParser {
+    pub fn get_pooled(&self, model_id: &str) -> PooledParser {
         self.registry
             .get_pooled_for_model(model_id)
             .unwrap_or_else(|| {
@@ -241,7 +324,7 @@ impl ToolParserFactory {
     }
 
     /// Get the internal registry for custom registration.
-    pub fn registry(&self) -> &ToolParserRegistry {
+    pub fn registry(&self) -> &ParserRegistry {
         &self.registry
     }
 
@@ -299,7 +382,7 @@ impl ToolParserFactory {
     }
 }
 
-impl Default for ToolParserFactory {
+impl Default for ParserFactory {
     fn default() -> Self {
         Self::new()
     }

sgl-router/src/tool_parser/mod.rs

@@ -16,8 +16,8 @@ pub mod parsers;
 mod tests;
 
 // Re-export commonly used types
-pub use errors::{ToolParserError, ToolParserResult};
-pub use factory::{PooledToolParser, ToolParserFactory, ToolParserRegistry};
+pub use errors::{ParserError, ParserResult};
+pub use factory::{ParserFactory, ParserRegistry, PooledParser};
 pub use traits::{PartialJsonParser, ToolParser};
 pub use types::{FunctionCall, PartialToolCall, StreamingParseResult, ToolCall};
 

sgl-router/src/tool_parser/parsers/deepseek_parser.rs

@@ -5,7 +5,7 @@ use serde_json::Value;
 use crate::protocols::spec::Tool;
 
 use crate::tool_parser::{
-    errors::{ToolParserError, ToolParserResult},
+    errors::{ParserError, ParserResult},
     parsers::helpers,
     traits::ToolParser,
     types::{FunctionCall, StreamingParseResult, ToolCall, ToolCallItem},
@@ -78,15 +78,15 @@ impl DeepSeekParser {
     }
 
     /// Parse a single tool call block - throws error if parsing fails
-    fn parse_tool_call(&self, block: &str) -> ToolParserResult<ToolCall> {
+    fn parse_tool_call(&self, block: &str) -> ParserResult<ToolCall> {
         let captures = self.func_detail_extractor.captures(block).ok_or_else(|| {
-            ToolParserError::ParsingFailed("Failed to match tool call pattern".to_string())
+            ParserError::ParsingFailed("Failed to match tool call pattern".to_string())
         })?;
 
         // Get function type (should be "function")
         let func_type = captures.get(1).map_or("", |m| m.as_str());
         if func_type != "function" {
-            return Err(ToolParserError::ParsingFailed(format!(
+            return Err(ParserError::ParsingFailed(format!(
                 "Invalid function type: {}",
                 func_type
             )));
@@ -95,7 +95,7 @@ impl DeepSeekParser {
         // Get function name
         let func_name = captures.get(2).map_or("", |m| m.as_str()).trim();
         if func_name.is_empty() {
-            return Err(ToolParserError::ParsingFailed(
+            return Err(ParserError::ParsingFailed(
                 "Empty function name".to_string(),
             ));
         }
@@ -105,7 +105,7 @@ impl DeepSeekParser {
 
         // Parse JSON arguments
         let value = serde_json::from_str::<Value>(json_args)
-            .map_err(|e| ToolParserError::ParsingFailed(format!("Invalid JSON: {}", e)))?;
+            .map_err(|e| ParserError::ParsingFailed(format!("Invalid JSON: {}", e)))?;
 
         // Create arguments object
         let args = if value.is_object() {
@@ -115,8 +115,8 @@ impl DeepSeekParser {
             serde_json::json!({ "value": value })
         };
 
-        let arguments = serde_json::to_string(&args)
-            .map_err(|e| ToolParserError::ParsingFailed(e.to_string()))?;
+        let arguments =
+            serde_json::to_string(&args).map_err(|e| ParserError::ParsingFailed(e.to_string()))?;
 
         Ok(ToolCall {
             function: FunctionCall {
@@ -135,7 +135,7 @@ impl Default for DeepSeekParser {
 
 #[async_trait]
 impl ToolParser for DeepSeekParser {
-    async fn parse_complete(&self, text: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    async fn parse_complete(&self, text: &str) -> ParserResult<(String, Vec<ToolCall>)> {
         if !self.has_tool_markers(text) {
             return Ok((text.to_string(), vec![]));
         }
@@ -168,7 +168,7 @@ impl ToolParser for DeepSeekParser {
         &mut self,
         chunk: &str,
         tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         self.buffer.push_str(chunk);
         let current_text = &self.buffer.clone();
 
@@ -314,4 +314,12 @@ impl ToolParser for DeepSeekParser {
     fn get_unstreamed_tool_args(&self) -> Option<Vec<ToolCallItem>> {
         helpers::get_unstreamed_args(&self.prev_tool_call_arr, &self.streamed_args_for_tool)
     }
+
+    fn reset(&mut self) {
+        self.buffer.clear();
+        self.prev_tool_call_arr.clear();
+        self.current_tool_id = -1;
+        self.current_tool_name_sent = false;
+        self.streamed_args_for_tool.clear();
+    }
 }

sgl-router/src/tool_parser/parsers/glm4_moe_parser.rs

@@ -5,7 +5,7 @@ use serde_json::Value;
 use crate::protocols::spec::Tool;
 
 use crate::tool_parser::{
-    errors::{ToolParserError, ToolParserResult},
+    errors::{ParserError, ParserResult},
     parsers::helpers,
     traits::ToolParser,
     types::{FunctionCall, StreamingParseResult, ToolCall, ToolCallItem},
@@ -72,7 +72,7 @@ impl Glm4MoeParser {
     }
 
     /// Parse arguments from key-value pairs
-    fn parse_arguments(&self, args_text: &str) -> ToolParserResult<serde_json::Map<String, Value>> {
+    fn parse_arguments(&self, args_text: &str) -> ParserResult<serde_json::Map<String, Value>> {
         let mut arguments = serde_json::Map::new();
 
         for capture in self.arg_extractor.captures_iter(args_text) {
@@ -110,7 +110,7 @@ impl Glm4MoeParser {
     }
 
     /// Parse a single tool call block
-    fn parse_tool_call(&self, block: &str) -> ToolParserResult<Option<ToolCall>> {
+    fn parse_tool_call(&self, block: &str) -> ParserResult<Option<ToolCall>> {
         if let Some(captures) = self.func_detail_extractor.captures(block) {
             // Get function name
             let func_name = captures.get(1).map_or("", |m| m.as_str()).trim();
@@ -122,7 +122,7 @@ impl Glm4MoeParser {
             let arguments = self.parse_arguments(args_text)?;
 
             let arguments_str = serde_json::to_string(&arguments)
-                .map_err(|e| ToolParserError::ParsingFailed(e.to_string()))?;
+                .map_err(|e| ParserError::ParsingFailed(e.to_string()))?;
 
             Ok(Some(ToolCall {
                 function: FunctionCall {
@@ -137,7 +137,7 @@ impl Glm4MoeParser {
 
     /// Parse and return StreamingParseResult (mirrors Python's detect_and_parse)
     /// Parse all tool calls from text (shared logic for complete and incremental parsing)
-    fn parse_tool_calls_from_text(&self, text: &str) -> ToolParserResult<Vec<ToolCall>> {
+    fn parse_tool_calls_from_text(&self, text: &str) -> ParserResult<Vec<ToolCall>> {
         let mut tools = Vec::new();
 
         for mat in self.tool_call_extractor.find_iter(text) {
@@ -163,7 +163,7 @@ impl Default for Glm4MoeParser {
 
 #[async_trait]
 impl ToolParser for Glm4MoeParser {
-    async fn parse_complete(&self, text: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    async fn parse_complete(&self, text: &str) -> ParserResult<(String, Vec<ToolCall>)> {
         // Check if text contains GLM-4 MoE format
         if !self.has_tool_markers(text) {
             return Ok((text.to_string(), vec![]));
@@ -188,7 +188,7 @@ impl ToolParser for Glm4MoeParser {
         &mut self,
         chunk: &str,
         tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         // Python logic: Wait for complete tool call, then parse it all at once
         self.buffer.push_str(chunk);
         let current_text = &self.buffer.clone();
@@ -315,4 +315,11 @@ impl ToolParser for Glm4MoeParser {
     fn get_unstreamed_tool_args(&self) -> Option<Vec<ToolCallItem>> {
         helpers::get_unstreamed_args(&self.prev_tool_call_arr, &self.streamed_args_for_tool)
     }
+
+    fn reset(&mut self) {
+        self.buffer.clear();
+        self.prev_tool_call_arr.clear();
+        self.current_tool_id = -1;
+        self.streamed_args_for_tool.clear();
+    }
 }

sgl-router/src/tool_parser/parsers/gpt_oss_harmony_parser.rs

@@ -3,7 +3,7 @@ use async_trait::async_trait;
 use crate::protocols::spec::Tool;
 
 use crate::tool_parser::{
-    errors::ToolParserResult,
+    errors::ParserResult,
     traits::{TokenToolParser, ToolParser},
     types::{StreamingParseResult, ToolCall},
 };
@@ -23,7 +23,7 @@ impl GptOssHarmonyParser {
 
 #[async_trait]
 impl ToolParser for GptOssHarmonyParser {
-    async fn parse_complete(&self, output: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    async fn parse_complete(&self, output: &str) -> ParserResult<(String, Vec<ToolCall>)> {
         // Temporary stub: fall back to returning the raw text with no tool calls.
         // Later phases will decode Harmony tokens into structured tool calls.
         Ok((output.to_string(), Vec::new()))
@@ -33,7 +33,7 @@ impl ToolParser for GptOssHarmonyParser {
         &mut self,
         _chunk: &str,
         _tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         // Temporary stub until the Harmony streaming pipeline is implemented.
         Ok(StreamingParseResult::default())
     }
@@ -54,7 +54,7 @@ impl TokenToolParser for GptOssHarmonyParser {
     async fn parse_complete_tokens(
         &self,
         _tokens: &[u32],
-    ) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    ) -> ParserResult<(String, Vec<ToolCall>)> {
         // Placeholder until Harmony integration lands. Returning an empty tool list ensures
         // that enabling the parser without full implementation results in a no-op rather
         // than a runtime panic.
@@ -65,7 +65,7 @@ impl TokenToolParser for GptOssHarmonyParser {
         &mut self,
         _tokens: &[u32],
         _tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         Ok(StreamingParseResult::default())
     }
 }

sgl-router/src/tool_parser/parsers/gpt_oss_parser.rs

@@ -5,7 +5,7 @@ use serde_json::Value;
 use crate::protocols::spec::Tool;
 
 use crate::tool_parser::{
-    errors::{ToolParserError, ToolParserResult},
+    errors::{ParserError, ParserResult},
     parsers::helpers,
     partial_json::PartialJson,
     traits::ToolParser,
@@ -76,7 +76,7 @@ impl Default for GptOssParser {
 
 #[async_trait]
 impl ToolParser for GptOssParser {
-    async fn parse_complete(&self, text: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    async fn parse_complete(&self, text: &str) -> ParserResult<(String, Vec<ToolCall>)> {
         // Check if text contains GPT-OSS format
         if !self.has_tool_markers(text) {
             return Ok((text.to_string(), vec![]));
@@ -100,7 +100,7 @@ impl ToolParser for GptOssParser {
                 } else {
                     match serde_json::from_str::<Value>(args_content) {
                         Ok(value) => serde_json::to_string(&value)
-                            .map_err(|e| ToolParserError::ParsingFailed(e.to_string()))?,
+                            .map_err(|e| ParserError::ParsingFailed(e.to_string()))?,
                         Err(_) => {
                             // Skip malformed JSON
                             continue;
@@ -126,7 +126,7 @@ impl ToolParser for GptOssParser {
         &mut self,
         chunk: &str,
         tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         self.buffer.push_str(chunk);
 
         // Check for tool markers
@@ -211,7 +211,7 @@ impl ToolParser for GptOssParser {
                             partial_args
                         };
 
-                        match self.partial_json.parse_value(json_part) {
+                        match self.partial_json.parse_value(json_part, true) {
                             Ok((value, _consumed)) => {
                                 let args_str = serde_json::to_string(&value)
                                     .unwrap_or_else(|_| "{}".to_string());

sgl-router/src/tool_parser/parsers/helpers.rs

@@ -2,7 +2,7 @@ use crate::protocols::spec::Tool;
 use serde_json::Value;
 use std::collections::HashMap;
 
-use crate::tool_parser::errors::{ToolParserError, ToolParserResult};
+use crate::tool_parser::errors::{ParserError, ParserResult};
 use crate::tool_parser::types::{StreamingParseResult, ToolCallItem};
 
 /// Get a mapping of tool names to their indices
@@ -14,6 +14,16 @@ pub fn get_tool_indices(tools: &[Tool]) -> HashMap<String, usize> {
         .collect()
 }
 
+/// Find the common prefix of two strings
+/// Used for incremental argument streaming when partial JSON returns different intermediate states
+pub fn find_common_prefix(s1: &str, s2: &str) -> String {
+    s1.chars()
+        .zip(s2.chars())
+        .take_while(|(c1, c2)| c1 == c2)
+        .map(|(c1, _)| c1)
+        .collect()
+}
+
 /// Get unstreamed tool call arguments
 /// Returns tool call items for arguments that have been parsed but not yet streamed
 /// This ensures tool calls are properly completed even if the model generates final arguments in the last chunk
@@ -96,7 +106,7 @@ pub fn reset_parser_state(
 ) {
     buffer.clear();
     prev_tool_call_arr.clear();
-    *current_tool_id = 0;
+    *current_tool_id = -1;
     *current_tool_name_sent = false;
     streamed_args_for_tool.clear();
 }
@@ -169,7 +179,7 @@ pub fn normalize_arguments_field(mut obj: Value) -> Value {
 ///
 /// # Returns
 /// - `Ok(StreamingParseResult)` with any tool call items to stream
-/// - `Err(ToolParserError)` if JSON parsing or serialization fails
+/// - `Err(ParserError)` if JSON parsing or serialization fails
 #[allow(clippy::too_many_arguments)]
 pub fn handle_json_tool_streaming(
     current_text: &str,
@@ -181,7 +191,7 @@ pub fn handle_json_tool_streaming(
     current_tool_name_sent: &mut bool,
     streamed_args_for_tool: &mut Vec<String>,
     prev_tool_call_arr: &mut Vec<Value>,
-) -> ToolParserResult<StreamingParseResult> {
+) -> ParserResult<StreamingParseResult> {
     // Check if we have content to parse
     if start_idx >= current_text.len() {
         return Ok(StreamingParseResult::default());
@@ -190,8 +200,12 @@ pub fn handle_json_tool_streaming(
     // Extract JSON string from current position
     let json_str = &current_text[start_idx..];
 
+    // When current_tool_name_sent is false, don't allow partial strings to avoid
+    // parsing incomplete tool names as empty strings
+    let allow_partial_strings = *current_tool_name_sent;
+
     // Parse partial JSON
-    let (obj, end_idx) = match partial_json.parse_value(json_str) {
+    let (obj, end_idx) = match partial_json.parse_value(json_str, allow_partial_strings) {
         Ok(result) => result,
         Err(_) => {
             return Ok(StreamingParseResult::default());
@@ -252,49 +266,68 @@ pub fn handle_json_tool_streaming(
             .map(|s| s.len())
             .unwrap_or(0);
         let cur_args_json = serde_json::to_string(cur_arguments)
-            .map_err(|e| ToolParserError::ParsingFailed(e.to_string()))?;
+            .map_err(|e| ParserError::ParsingFailed(e.to_string()))?;
+
+        // Get prev_arguments (matches Python's structure)
+        let prev_arguments = if tool_id < prev_tool_call_arr.len() {
+            prev_tool_call_arr[tool_id].get("arguments")
+        } else {
+            None
+        };
 
-        // Compute diff: everything after what we've already sent
-        let diff = cur_args_json[sent..].to_string();
+        // Calculate diff: everything after we've already sent
+        let mut argument_diff = None;
 
-        // Send diff if there's new content
-        if !diff.is_empty() {
-            // Only accumulate if not complete
-            if !is_complete && tool_id < streamed_args_for_tool.len() {
-                streamed_args_for_tool[tool_id].push_str(&diff);
+        if is_complete {
+            // Python: argument_diff = cur_args_json[sent:]
+            // Rust needs bounds check (Python returns "" automatically)
+            argument_diff = if sent < cur_args_json.len() {
+                Some(cur_args_json[sent..].to_string())
+            } else {
+                Some(String::new())
+            };
+        } else if let Some(prev_args) = prev_arguments {
+            let prev_args_json = serde_json::to_string(prev_args)
+                .map_err(|e| ParserError::ParsingFailed(e.to_string()))?;
+
+            if cur_args_json != prev_args_json {
+                let prefix = find_common_prefix(&prev_args_json, &cur_args_json);
+                argument_diff = if sent < prefix.len() {
+                    Some(prefix[sent..].to_string())
+                } else {
+                    Some(String::new())
+                };
             }
+        }
 
-            result.calls.push(ToolCallItem {
-                tool_index: tool_id,
-                name: None,
-                parameters: diff,
-            });
+        // Send diff if present
+        if let Some(diff) = argument_diff {
+            if !diff.is_empty() {
+                if tool_id < streamed_args_for_tool.len() {
+                    streamed_args_for_tool[tool_id].push_str(&diff);
+                }
+                result.calls.push(ToolCallItem {
+                    tool_index: tool_id,
+                    name: None,
+                    parameters: diff,
+                });
+            }
         }
 
-        // If JSON is complete, advance to next tool
-        if is_complete {
-            // Remove processed portion, keep unprocessed content
-            *buffer = current_text[start_idx + end_idx..].to_string();
+        // Update prev_tool_call_arr with current state
+        if *current_tool_id >= 0 {
+            ensure_capacity(*current_tool_id, prev_tool_call_arr, streamed_args_for_tool);
 
-            // Clear completed tool data
             if tool_id < prev_tool_call_arr.len() {
-                prev_tool_call_arr[tool_id] = Value::Null;
-            }
-            *current_tool_name_sent = false;
-            if tool_id < streamed_args_for_tool.len() {
-                streamed_args_for_tool[tool_id].clear();
+                prev_tool_call_arr[tool_id] = current_tool_call;
             }
-            *current_tool_id += 1;
         }
-    }
 
-    // Update prev_tool_call_arr with current state
-    if *current_tool_id >= 0 {
-        ensure_capacity(*current_tool_id, prev_tool_call_arr, streamed_args_for_tool);
-        let tool_id = *current_tool_id as usize;
-
-        if tool_id < prev_tool_call_arr.len() {
-            prev_tool_call_arr[tool_id] = current_tool_call;
+        // If complete, advance to next tool
+        if is_complete {
+            *buffer = current_text[start_idx + end_idx..].to_string();
+            *current_tool_name_sent = false;
+            *current_tool_id += 1;
         }
     }
 
@@ -371,7 +404,7 @@ mod tests {
 
         assert_eq!(buffer, "");
         assert_eq!(prev_tools.len(), 0);
-        assert_eq!(current_tool_id, 0);
+        assert_eq!(current_tool_id, -1);
         assert!(!current_tool_name_sent);
         assert_eq!(streamed_args.len(), 0);
     }

sgl-router/src/tool_parser/parsers/json_parser.rs

@@ -4,7 +4,7 @@ use serde_json::Value;
 use crate::protocols::spec::Tool;
 
 use crate::tool_parser::{
-    errors::{ToolParserError, ToolParserResult},
+    errors::{ParserError, ParserResult},
     parsers::helpers,
     partial_json::PartialJson,
     traits::ToolParser,
@@ -117,7 +117,7 @@ impl JsonParser {
     }
 
     /// Parse a single JSON object into a ToolCall
-    fn parse_single_object(&self, obj: &Value) -> ToolParserResult<Option<ToolCall>> {
+    fn parse_single_object(&self, obj: &Value) -> ParserResult<Option<ToolCall>> {
         // Check if this looks like a tool call
         let name = obj
             .get("name")
@@ -134,7 +134,7 @@ impl JsonParser {
 
             // Convert arguments to JSON string
             let arguments = serde_json::to_string(args)
-                .map_err(|e| ToolParserError::ParsingFailed(e.to_string()))?;
+                .map_err(|e| ParserError::ParsingFailed(e.to_string()))?;
 
             Ok(Some(ToolCall {
                 function: FunctionCall {
@@ -148,7 +148,7 @@ impl JsonParser {
     }
 
     /// Parse JSON value(s) into tool calls
-    fn parse_json_value(&self, value: &Value) -> ToolParserResult<Vec<ToolCall>> {
+    fn parse_json_value(&self, value: &Value) -> ParserResult<Vec<ToolCall>> {
         let mut tools = Vec::new();
 
         match value {
@@ -184,11 +184,11 @@ impl Default for JsonParser {
 
 #[async_trait]
 impl ToolParser for JsonParser {
-    async fn parse_complete(&self, text: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    async fn parse_complete(&self, text: &str) -> ParserResult<(String, Vec<ToolCall>)> {
         // Always use extract_json_from_text to handle both pure JSON and mixed content
         if let Some((extracted_json, normal_text)) = self.extract_json_from_text(text) {
             let parsed = serde_json::from_str::<Value>(&extracted_json)
-                .map_err(|e| ToolParserError::ParsingFailed(e.to_string()))
+                .map_err(|e| ParserError::ParsingFailed(e.to_string()))
                 .and_then(|v| self.parse_json_value(&v));
 
             match parsed {
@@ -205,7 +205,7 @@ impl ToolParser for JsonParser {
         &mut self,
         chunk: &str,
         tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         // Append new text to buffer
         self.buffer.push_str(chunk);
         let current_text = &self.buffer.clone();
@@ -264,4 +264,14 @@ impl ToolParser for JsonParser {
     fn get_unstreamed_tool_args(&self) -> Option<Vec<ToolCallItem>> {
         helpers::get_unstreamed_args(&self.prev_tool_call_arr, &self.streamed_args_for_tool)
     }
+
+    fn reset(&mut self) {
+        helpers::reset_parser_state(
+            &mut self.buffer,
+            &mut self.prev_tool_call_arr,
+            &mut self.current_tool_id,
+            &mut self.current_tool_name_sent,
+            &mut self.streamed_args_for_tool,
+        );
+    }
 }

sgl-router/src/tool_parser/parsers/kimik2_parser.rs

@@ -5,7 +5,7 @@ use serde_json::Value;
 use crate::protocols::spec::Tool;
 
 use crate::tool_parser::{
-    errors::ToolParserResult,
+    errors::ParserResult,
     parsers::helpers,
     traits::ToolParser,
     types::{FunctionCall, StreamingParseResult, ToolCall, ToolCallItem},
@@ -102,7 +102,7 @@ impl Default for KimiK2Parser {
 
 #[async_trait]
 impl ToolParser for KimiK2Parser {
-    async fn parse_complete(&self, text: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
+    async fn parse_complete(&self, text: &str) -> ParserResult<(String, Vec<ToolCall>)> {
         if !self.has_tool_markers(text) {
             return Ok((text.to_string(), vec![]));
         }
@@ -161,7 +161,7 @@ impl ToolParser for KimiK2Parser {
         &mut self,
         chunk: &str,
         tools: &[Tool],
-    ) -> ToolParserResult<StreamingParseResult> {
+    ) -> ParserResult<StreamingParseResult> {
         self.buffer.push_str(chunk);
         let current_text = &self.buffer.clone();
 
@@ -333,4 +333,13 @@ impl ToolParser for KimiK2Parser {
     fn get_unstreamed_tool_args(&self) -> Option<Vec<ToolCallItem>> {
         helpers::get_unstreamed_args(&self.prev_tool_call_arr, &self.streamed_args_for_tool)
     }
+
+    fn reset(&mut self) {
+        self.buffer.clear();
+        self.prev_tool_call_arr.clear();
+        self.current_tool_id = -1;
+        self.current_tool_name_sent = false;
+        self.streamed_args_for_tool.clear();
+        self.last_arguments.clear();
+    }
 }