feat: Xml coder tool parser (#4415) (#4859)

Signed-off-by: ayushag <[email protected]>
Co-authored-by: William Zhang <[email protected]>

Author: ayushag-nv

Cargo.lock

@@ -38,3 +38,6 @@ openai-harmony = "0.0.3"
 lazy_static = "1.5.0"
 rustpython-parser = "0.4.0"
 num-traits = "0.2"
+
+[dev-dependencies]
+rstest = "0.25"

lib/parsers/Cargo.toml

@@ -55,6 +55,7 @@ impl Default for JsonParserConfig {
 }
 
 /// Configuration for parsing tool calls with different formats
+// TODO(2ez4bz): refactor to allow other parser configs than `JsonParserConfig`.
 #[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 pub struct ToolCallConfig {
     /// The format type for tool calls
@@ -192,4 +193,12 @@ impl ToolCallConfig {
             },
         }
     }
+
+    pub fn qwen3_coder() -> Self {
+        // <tool_call><function=name><parameter=key>value</parameter></function></tool_call>
+        Self {
+            format: ToolCallParserType::Xml,
+            json: JsonParserConfig::default(), // Not used for qwen3_coder but kept for consistency.
+        }
+    }
 }

lib/parsers/src/tool_calling/config.rs

@@ -10,6 +10,7 @@ pub mod response;
 #[cfg(test)]
 pub mod tests;
 pub mod tools;
+pub mod xml;
 
 // Re-export main types and functions for convenience
 pub use config::{JsonParserConfig, ToolCallConfig, ToolCallParserType};
@@ -22,3 +23,4 @@ pub use parsers::{
 pub use pythonic::try_tool_call_parse_pythonic;
 pub use response::{CalledFunction, ToolCallResponse, ToolCallType};
 pub use tools::{try_tool_call_parse_aggregate, try_tool_call_parse_stream};
+pub use xml::try_tool_call_parse_xml;