refactor setup.py to extract stuff into build_rust.py

Signed-off-by: Bugen Zhao <i@bugenzhao.com>

.buildkite/scripts/run-rust-frontend-cargo-ci.sh

@@ -110,6 +110,36 @@ install_uv() {
     | env UV_INSTALL_DIR="$CARGO_HOME/bin" sh
 }
 
+setup_pyo3_python() {
+  local python_version="${PYO3_PYTHON_VERSION:-3.12}"
+
+  log_section "Installing Python ${python_version} for PyO3 tests"
+  uv python install "$python_version"
+  PYO3_PYTHON="$(uv python find \
+    --managed-python \
+    --no-project \
+    --resolve-links \
+    "$python_version")"
+  export PYO3_PYTHON
+
+  local python_libdir
+  python_libdir="$("$PYO3_PYTHON" - <<'PY'
+import pathlib
+import sysconfig
+
+libdir = pathlib.Path(sysconfig.get_config_var("LIBDIR"))
+ldlibrary = sysconfig.get_config_var("LDLIBRARY")
+assert sysconfig.get_config_var("Py_ENABLE_SHARED") == 1
+assert ldlibrary
+assert (libdir / ldlibrary).exists(), libdir / ldlibrary
+print(libdir)
+PY
+)"
+
+  export LD_LIBRARY_PATH="${python_libdir}:${LD_LIBRARY_PATH:-}"
+  export LIBRARY_PATH="${python_libdir}:${LIBRARY_PATH:-}"
+}
+
 run_style_clippy() {
   install_cargo_sort
 
@@ -132,6 +162,7 @@ run_style_clippy() {
 
 run_tests() {
   install_uv
+  setup_pyo3_python
   install_cargo_nextest
 
   log_section "Running cargo nextest"

.buildkite/test_areas/misc.yaml

@@ -300,9 +300,9 @@ steps:
   - tests/multimodal
   - tests/renderers
   - tests/standalone_tests/lazy_imports.py
-  - tests/tokenizers_
   - tests/reasoning
   - tests/tool_parsers
+  - tests/tokenizers_
   - tests/parser
   - tests/transformers_utils
   - tests/config
@@ -315,9 +315,9 @@ steps:
   - pytest -v -s test_ray_env.py
   - pytest -v -s -m 'cpu_test' multimodal
   - pytest -v -s renderers
-  - pytest -v -s tokenizers_
   - pytest -v -s reasoning --ignore=reasoning/test_seedoss_reasoning_parser.py --ignore=reasoning/test_glm4_moe_reasoning_parser.py
   - pytest -v -s tool_parsers
+  - pytest -v -s tokenizers_
   - pytest -v -s parser
   - pytest -v -s transformers_utils
   - pytest -v -s config

build_rust.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-# Build the vllm-rs Rust frontend binary.
+# Build vLLM Rust artifacts and install them into the vllm package.
 # Usage: ./build_rust.sh [--debug]
 #
 # By default builds in release mode. Pass --debug for faster compile times

docker/Dockerfile

@@ -281,7 +281,8 @@ COPY requirements/build/rust.txt requirements/build/rust.txt
 RUN --mount=type=cache,target=/opt/uv/cache \
     uv pip install --python /opt/venv/bin/python3 -r requirements/build/rust.txt
 
-# Copy only the Rust build inputs. The binary is the sole artifact we need.
+# Copy only the Rust build inputs; build_rust.sh publishes artifacts needed
+# by the wheel build stage.
 COPY rust rust
 COPY rust-toolchain.toml rust-toolchain.toml
 COPY tools/build_rust.py tools/build_rust.py
@@ -291,8 +292,9 @@ COPY build_rust.sh build_rust.sh
 # (rustc spawns enough concurrent processes to hit RLIMIT_NOFILE otherwise).
 ENV CARGO_BUILD_JOBS=4
 
-# Build the release binary. Cache cargo registry/git, but not target/, because
+# Build the release artifacts. Cache cargo registry/git, but not target/,
-# stale target metadata can outlive source updates across BuildKit cache reuse.
+# because stale target metadata can outlive source updates across BuildKit
+# cache reuse.
 RUN --mount=type=cache,target=/root/.cargo/registry \
     --mount=type=cache,target=/root/.cargo/git \
     bash build_rust.sh
@@ -503,9 +505,10 @@ WORKDIR /workspace
 COPY --from=csrc-build /workspace/dist /precompiled-wheels
 COPY . .
 
-# Drop the pre-built rust frontend binary into the source tree. setup.py
+# Drop the pre-built Rust artifacts into the source tree. setup.py detects
-# detects it and ships it as-is, skipping the local cargo build.
+# them and ships them as-is, skipping the local Rust build.
 COPY --from=rust-build /workspace/vllm/vllm-rs vllm/vllm-rs
+COPY --from=rust-build /workspace/vllm/_rust_*.so vllm/
 
 ARG GIT_REPO_CHECK=0
 RUN --mount=type=bind,source=.git,target=.git \

docker/Dockerfile.cpu

@@ -104,7 +104,8 @@ WORKDIR /workspace
 COPY requirements/build/rust.txt requirements/build/rust.txt
 RUN python3 -m pip install --no-cache-dir -r requirements/build/rust.txt
 
-# Copy only the Rust build inputs. The binary is the sole artifact we need.
+# Copy only the Rust build inputs; build_rust.sh publishes artifacts needed
+# by the wheel build stage.
 COPY rust rust
 COPY rust-toolchain.toml rust-toolchain.toml
 COPY tools/build_rust.py tools/build_rust.py
@@ -114,8 +115,9 @@ COPY build_rust.sh build_rust.sh
 # (rustc spawns enough concurrent processes to hit RLIMIT_NOFILE otherwise).
 ENV CARGO_BUILD_JOBS=4
 
-# Build the release binary. Cache cargo registry/git, but not target/, because
+# Build the release artifacts. Cache cargo registry/git, but not target/,
-# stale target metadata can outlive source updates across BuildKit cache reuse.
+# because stale target metadata can outlive source updates across BuildKit
+# cache reuse.
 RUN --mount=type=cache,target=/root/.cargo/registry,sharing=locked \
     --mount=type=cache,target=/root/.cargo/git,sharing=locked \
     bash build_rust.sh
@@ -151,9 +153,10 @@ RUN --mount=type=cache,target=/root/.cache/uv \
 
 COPY . .
 
-# Drop the pre-built rust frontend binary into the source tree. setup.py
+# Drop the pre-built Rust artifacts into the source tree. setup.py detects
-# detects it and ships it as-is, skipping the local cargo build.
+# them and ships them as-is, skipping the local Rust build.
 COPY --from=rust-build /workspace/vllm/vllm-rs vllm/vllm-rs
+COPY --from=rust-build /workspace/vllm/_rust_*.so vllm/
 
 RUN if [ "$GIT_REPO_CHECK" != 0 ]; then bash tools/check_repo.sh ; fi
 

docker/Dockerfile.nightly_torch

@@ -113,7 +113,8 @@ WORKDIR /workspace
 COPY requirements/build/rust.txt requirements/build/rust.txt
 RUN python3 -m pip install --no-cache-dir -r requirements/build/rust.txt
 
-# Copy only the Rust build inputs. The binary is the sole artifact we need.
+# Copy only the Rust build inputs; build_rust.sh publishes artifacts needed
+# by the wheel build stage.
 COPY rust rust
 COPY rust-toolchain.toml rust-toolchain.toml
 COPY tools/build_rust.py tools/build_rust.py
@@ -138,9 +139,10 @@ ENV UV_HTTP_TIMEOUT=500
 
 COPY . .
 
-# Drop the pre-built rust frontend binary into the source tree. setup.py
+# Drop the pre-built Rust artifacts into the source tree. setup.py detects
-# detects it and ships it as-is, skipping the local cargo build.
+# them and ships them as-is, skipping the local Rust build.
 COPY --from=rust-build /workspace/vllm/vllm-rs vllm/vllm-rs
+COPY --from=rust-build /workspace/vllm/_rust_*.so vllm/
 
 RUN python3 use_existing_torch.py
 

docker/Dockerfile.rocm

@@ -208,9 +208,10 @@ ENV VLLM_TARGET_DEVICE=rocm
 
 COPY --from=csrc-build ${COMMON_WORKDIR}/vllm/dist /precompiled-wheels
 
-# Drop the pre-built rust frontend binary into the source tree. setup.py
+# Drop the pre-built Rust artifacts into the source tree. setup.py detects
-# detects it and ships it as-is, skipping the local cargo build.
+# them and ships them as-is, skipping the local Rust build.
 COPY --from=rust-build ${COMMON_WORKDIR}/vllm/vllm/vllm-rs ${COMMON_WORKDIR}/vllm/vllm/vllm-rs
+COPY --from=rust-build ${COMMON_WORKDIR}/vllm/vllm/_rust_*.so ${COMMON_WORKDIR}/vllm/vllm/
 
 RUN --mount=type=cache,id=vllm-rocm-uv,target=/root/.cache/uv \
     cd vllm \
@@ -417,9 +418,10 @@ FROM fetch_vllm AS build_vllm_wheel_release
 
 ARG COMMON_WORKDIR
 
-# Drop the pre-built rust frontend binary into the source tree. setup.py
+# Drop the pre-built Rust artifacts into the source tree. setup.py detects
-# detects it and ships it as-is, skipping the local cargo build.
+# them and ships them as-is, skipping the local Rust build.
 COPY --from=rust-build ${COMMON_WORKDIR}/vllm/vllm/vllm-rs ${COMMON_WORKDIR}/vllm/vllm/vllm-rs
+COPY --from=rust-build ${COMMON_WORKDIR}/vllm/vllm/_rust_*.so ${COMMON_WORKDIR}/vllm/vllm/
 
 # Create /install directory for custom wheels
 RUN mkdir -p /install

docker/Dockerfile.xpu

@@ -17,7 +17,8 @@ WORKDIR /workspace
 COPY requirements/build/rust.txt requirements/build/rust.txt
 RUN python3 -m pip install --no-cache-dir -r requirements/build/rust.txt
 
-# Copy only the Rust build inputs. The binary is the sole artifact we need.
+# Copy only the Rust build inputs; build_rust.sh publishes artifacts needed
+# by the wheel build stage.
 COPY rust rust
 COPY rust-toolchain.toml rust-toolchain.toml
 COPY tools/build_rust.py tools/build_rust.py
@@ -212,9 +213,10 @@ RUN --mount=type=cache,target=/root/.cache/uv \
 # don't invalidate heavy dependency and UCX/NIXL layers.
 COPY . .
 
-# Drop the pre-built rust frontend binary into the source tree. setup.py
+# Drop the pre-built Rust artifacts into the source tree. setup.py detects
-# detects it and ships it as-is, skipping the local cargo build.
+# them and ships them as-is, skipping the local Rust build.
 COPY --from=rust-build /workspace/vllm/vllm-rs vllm/vllm-rs
+COPY --from=rust-build /workspace/vllm/_rust_*.so vllm/
 
 ARG GIT_REPO_CHECK=0
 RUN --mount=type=bind,source=.git,target=.git \

rust/Cargo.lock

@@ -3458,6 +3458,75 @@ version = "0.1.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e0c5ccf5294c6ccd63a74f1565028353830a9c2f5eb0c682c355c471726a6e3f"
 
+[[package]]
+name = "pyo3"
+version = "0.28.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91fd8e38a3b50ed1167fb981cd6fd60147e091784c427b8f7183a7ee32c31c12"
+dependencies = [
+ "libc",
+ "once_cell",
+ "portable-atomic",
+ "pyo3-build-config",
+ "pyo3-ffi",
+ "pyo3-macros",
+]
+
+[[package]]
+name = "pyo3-build-config"
+version = "0.28.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e368e7ddfdeb98c9bca7f8383be1648fd84ab466bf2bc015e94008db6d35611e"
+dependencies = [
+ "target-lexicon",
+]
+
+[[package]]
+name = "pyo3-ffi"
+version = "0.28.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f29e10af80b1f7ccaf7f69eace800a03ecd13e883acfacc1e5d0988605f651e"
+dependencies = [
+ "libc",
+ "pyo3-build-config",
+]
+
+[[package]]
+name = "pyo3-macros"
+version = "0.28.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df6e520eff47c45997d2fc7dd8214b25dd1310918bbb2642156ef66a67f29813"
+dependencies = [
+ "proc-macro2",
+ "pyo3-macros-backend",
+ "quote",
+ "syn 2.0.117",
+]
+
+[[package]]
+name = "pyo3-macros-backend"
+version = "0.28.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4cdc218d835738f81c2338f822078af45b4afdf8b2e33cbb5916f108b813acb"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "pyo3-build-config",
+ "quote",
+ "syn 2.0.117",
+]
+
+[[package]]
+name = "pythonize"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b79f670c9626c8b651c0581011b57b6ba6970bb69faf01a7c4c0cfc81c43f95"
+dependencies = [
+ "pyo3",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "qoi"
 version = "0.4.1"
@@ -4669,6 +4738,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "target-lexicon"
+version = "0.13.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adb6935a6f5c20170eeceb1a3835a49e12e19d792f6dd344ccc76a985ca5a6ca"
+
 [[package]]
 name = "task-local"
 version = "0.1.1"
@@ -5904,6 +5979,17 @@ dependencies = [
  "winnow",
 ]
 
+[[package]]
+name = "vllm-tool-parser-py"
+version = "0.1.0"
+dependencies = [
+ "pyo3",
+ "pythonize",
+ "serde_json",
+ "thiserror-ext",
+ "vllm-tool-parser",
+]
+
 [[package]]
 name = "walkdir"
 version = "2.5.0"

rust/Cargo.toml

@@ -12,6 +12,7 @@ members = [
     "src/text",
     "src/tokenizer",
     "src/tool-parser",
+    "src/tool-parser/python",
 ]
 resolver = "3"
 
@@ -60,6 +61,8 @@ prometheus-client = "0.24.0"
 prometheus-client-derive-encode = "0.5.0"
 prost = "0.14.3"
 prost-types = "0.14.3"
+pyo3 = "0.28.3"
+pythonize = "0.28.0"
 rand = "0.9.2"
 reasoning-parser = "1.2.2"
 reqwest = { version = "0.12.8", default-features = false, features = ["rustls-tls"] }

rust/src/tool-parser/python/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "vllm-tool-parser-py"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[lib]
+name = "_rust_tool_parser"
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+pyo3.workspace = true
+pythonize = { workspace = true, features = ["serde_json"] }
+serde_json.workspace = true
+thiserror-ext.workspace = true
+vllm-tool-parser.workspace = true
+
+[lints]
+workspace = true

rust/src/tool-parser/python/src/lib.rs

@@ -0,0 +1,366 @@
+//! Thin PyO3 bindings for `vllm_tool_parser`.
+//!
+//! This crate exposes the Rust tool parser trait and data shapes to Python
+//! while keeping parser state, grammar, and schema-aware argument conversion in
+//! Rust. Python callers should use this module as a typed bridge and keep any
+//! vLLM protocol adaptation outside the binding.
+
+use pyo3::exceptions::PyValueError;
+use pyo3::prelude::*;
+use pyo3::types::{PyAny, PyModule};
+use pythonize::{depythonize, pythonize};
+use serde_json::Value;
+use thiserror_ext::AsReport as _;
+use vllm_tool_parser::{Tool, ToolCallDelta, ToolParser, ToolParserOutput};
+
+macro_rules! tool_parser_factory {
+    ($($parser:ident),+ $(,)?) => {
+        fn create_tool_parser(
+            name: &str,
+            tools: &[Tool],
+        ) -> PyResult<Box<dyn ToolParser>> {
+            match name {
+                $(
+                    stringify!($parser) => {
+                        <vllm_tool_parser::$parser as ToolParser>::create(tools)
+                    }
+                )+
+                _ => {
+                    return Err(PyValueError::new_err(format!(
+                        "unsupported tool parser `{name}`"
+                    )));
+                }
+            }
+            .map_err(|error| PyValueError::new_err(error.to_report_string()))
+        }
+    };
+}
+
+// Export a tool parser to Python by registering it here.
+tool_parser_factory! {
+    DeepSeekV4ToolParser, // for testing on Python side
+}
+
+#[pyclass(name = "Tool", module = "vllm._rust_tool_parser", skip_from_py_object)]
+#[derive(Clone)]
+struct PyTool(Tool);
+
+#[pymethods]
+impl PyTool {
+    #[new]
+    #[pyo3(signature = (name, description, parameters, strict=None))]
+    fn new(
+        name: String,
+        description: Option<String>,
+        parameters: &Bound<'_, PyAny>,
+        strict: Option<bool>,
+    ) -> PyResult<Self> {
+        let parameters = depythonize::<Value>(parameters).map_err(|error| {
+            PyValueError::new_err(format!(
+                "failed to convert tool parameters from Python to JSON: {error}"
+            ))
+        })?;
+        Ok(Self(Tool {
+            name,
+            description,
+            parameters,
+            strict,
+        }))
+    }
+
+    #[getter]
+    fn name(&self) -> &str {
+        &self.0.name
+    }
+
+    #[getter]
+    fn description(&self) -> Option<&str> {
+        self.0.description.as_deref()
+    }
+
+    #[getter]
+    fn parameters(&self, py: Python<'_>) -> PyResult<Py<PyAny>> {
+        pythonize(py, &self.0.parameters).map(Bound::unbind).map_err(|error| {
+            PyValueError::new_err(format!(
+                "failed to convert tool parameters from JSON to Python: {error}"
+            ))
+        })
+    }
+
+    #[getter]
+    fn strict(&self) -> Option<bool> {
+        self.0.strict
+    }
+}
+
+#[pyclass(
+    name = "ToolCallDelta",
+    module = "vllm._rust_tool_parser",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyToolCallDelta(ToolCallDelta);
+
+#[pymethods]
+impl PyToolCallDelta {
+    #[new]
+    #[pyo3(signature = (tool_index, name, arguments))]
+    fn new(tool_index: usize, name: Option<String>, arguments: String) -> Self {
+        Self(ToolCallDelta {
+            tool_index,
+            name,
+            arguments,
+        })
+    }
+
+    #[getter]
+    fn tool_index(&self) -> usize {
+        self.0.tool_index
+    }
+
+    #[getter]
+    fn name(&self) -> Option<&str> {
+        self.0.name.as_deref()
+    }
+
+    #[getter]
+    fn arguments(&self) -> &str {
+        &self.0.arguments
+    }
+}
+
+#[pyclass(
+    name = "ToolParserOutput",
+    module = "vllm._rust_tool_parser",
+    skip_from_py_object
+)]
+#[derive(Clone)]
+struct PyToolParserOutput(ToolParserOutput);
+
+#[pymethods]
+impl PyToolParserOutput {
+    #[new]
+    #[pyo3(signature = (normal_text="", calls=None))]
+    fn new(py: Python<'_>, normal_text: &str, calls: Option<Vec<Py<PyToolCallDelta>>>) -> Self {
+        let calls =
+            calls.unwrap_or_default().iter().map(|call| call.borrow(py).0.clone()).collect();
+        Self(ToolParserOutput {
+            normal_text: normal_text.to_owned(),
+            calls,
+        })
+    }
+
+    #[getter]
+    fn normal_text(&self) -> &str {
+        &self.0.normal_text
+    }
+
+    #[getter]
+    fn calls(&self) -> Vec<PyToolCallDelta> {
+        self.0.calls.iter().cloned().map(PyToolCallDelta).collect()
+    }
+
+    fn append(&mut self, other: PyRef<'_, PyToolParserOutput>) {
+        self.0.append(other.0.clone());
+    }
+
+    fn coalesce_calls(&self) -> Self {
+        Self(self.0.clone().coalesce_calls())
+    }
+}
+
+#[pyclass(name = "ToolParser", module = "vllm._rust_tool_parser", unsendable)]
+struct PyToolParser(Box<dyn ToolParser>);
+
+impl PyToolParser {
+    fn parse_into_output(&mut self, chunk: &str, output: &mut PyToolParserOutput) -> PyResult<()> {
+        self.0
+            .parse_into(chunk, &mut output.0)
+            .map_err(|error| PyValueError::new_err(error.to_report_string()))
+    }
+}
+
+#[pymethods]
+impl PyToolParser {
+    #[new]
+    fn new(py: Python<'_>, parser_name: &str, tools: Vec<Py<PyTool>>) -> PyResult<Self> {
+        let tools = tools.iter().map(|tool| tool.borrow(py).0.clone()).collect::<Vec<_>>();
+        create_tool_parser(parser_name, &tools).map(Self)
+    }
+
+    fn parse_into(
+        &mut self,
+        chunk: &str,
+        mut output: PyRefMut<'_, PyToolParserOutput>,
+    ) -> PyResult<()> {
+        self.parse_into_output(chunk, &mut output)
+    }
+
+    fn finish(&mut self) -> PyResult<PyToolParserOutput> {
+        self.0
+            .finish()
+            .map(PyToolParserOutput)
+            .map_err(|error| PyValueError::new_err(error.to_report_string()))
+    }
+
+    fn reset(&mut self) -> String {
+        self.0.reset()
+    }
+
+    fn preserve_special_tokens(&self) -> bool {
+        self.0.preserve_special_tokens()
+    }
+}
+
+#[pymodule]
+fn _rust_tool_parser(m: &Bound<'_, PyModule>) -> PyResult<()> {
+    m.add_class::<PyTool>()?;
+    m.add_class::<PyToolCallDelta>()?;
+    m.add_class::<PyToolParserOutput>()?;
+    m.add_class::<PyToolParser>()?;
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    fn with_python<R>(f: impl for<'py> FnOnce(Python<'py>) -> R) -> R {
+        Python::initialize();
+        Python::attach(f)
+    }
+
+    fn tool_schema() -> Value {
+        json!({
+            "type": "object",
+            "properties": {
+                "user_id": {"type": "integer"},
+                "shipping": {
+                    "type": "object",
+                    "properties": {
+                        "city": {"type": "string"},
+                        "zip": {"type": "integer"}
+                    }
+                }
+            }
+        })
+    }
+
+    fn build_call() -> String {
+        r#"<｜DSML｜tool_calls>
+<｜DSML｜invoke name="create_order">
+<｜DSML｜parameter name="user_id" string="false">42</｜DSML｜parameter>
+<｜DSML｜parameter name="shipping" string="false">{"city":"Singapore","zip":18956}</｜DSML｜parameter>
+</｜DSML｜invoke>
+</｜DSML｜tool_calls>"#
+            .to_owned()
+    }
+
+    fn make_py_tool(py: Python<'_>) -> PyResult<Py<PyTool>> {
+        let parameters = pythonize(py, &tool_schema()).map_err(|error| {
+            PyValueError::new_err(format!(
+                "failed to convert test schema from JSON to Python: {error}"
+            ))
+        })?;
+        Py::new(
+            py,
+            PyTool::new(
+                "create_order".to_owned(),
+                Some("Create an order".to_owned()),
+                &parameters,
+                None,
+            )?,
+        )
+    }
+
+    #[test]
+    fn tool_round_trips_typed_fields() {
+        with_python(|py| {
+            let tool = make_py_tool(py)?;
+            let borrowed = tool.borrow(py);
+            assert_eq!(borrowed.name(), "create_order");
+            assert_eq!(borrowed.description(), Some("Create an order"));
+            assert_eq!(borrowed.strict(), None);
+
+            let parameters = borrowed.parameters(py)?;
+            let parameters = depythonize::<Value>(parameters.bind(py))?;
+            assert_eq!(parameters, tool_schema());
+            PyResult::Ok(())
+        })
+        .unwrap();
+    }
+
+    #[test]
+    fn output_append_and_coalesce_calls() {
+        with_python(|py| {
+            let first = Py::new(
+                py,
+                PyToolCallDelta::new(0, Some("create_order".to_owned()), "{\"a\"".to_owned()),
+            )?;
+            let second = Py::new(py, PyToolCallDelta::new(0, None, ":1}".to_owned()))?;
+            let mut output = PyToolParserOutput::new(py, "text", Some(vec![first]));
+            let other = Py::new(py, PyToolParserOutput::new(py, "", Some(vec![second])))?;
+            output.append(other.borrow(py));
+
+            let coalesced = output.coalesce_calls();
+            assert_eq!(coalesced.normal_text(), "text");
+            let calls = coalesced.calls();
+            assert_eq!(calls.len(), 1);
+            assert_eq!(calls[0].tool_index(), 0);
+            assert_eq!(calls[0].name(), Some("create_order"));
+            assert_eq!(calls[0].arguments(), "{\"a\":1}");
+            PyResult::Ok(())
+        })
+        .unwrap();
+    }
+
+    #[test]
+    fn parser_parse_finish_and_preserve_special_tokens() {
+        with_python(|py| {
+            let tool = make_py_tool(py)?;
+            let mut parser = PyToolParser::new(py, "DeepSeekV4ToolParser", vec![tool])?;
+            assert!(parser.preserve_special_tokens());
+
+            let mut output = PyToolParserOutput::new(py, "", None);
+            parser.parse_into_output(&build_call(), &mut output)?;
+            let finish = Py::new(py, parser.finish()?)?;
+            output.append(finish.borrow(py));
+            let output = output.coalesce_calls();
+
+            assert_eq!(output.normal_text(), "");
+            let calls = output.calls();
+            assert_eq!(calls.len(), 1);
+            assert_eq!(calls[0].name(), Some("create_order"));
+            assert_eq!(
+                serde_json::from_str::<Value>(calls[0].arguments()).unwrap(),
+                json!({
+                    "user_id": 42,
+                    "shipping": {
+                        "city": "Singapore",
+                        "zip": 18956
+                    }
+                })
+            );
+
+            assert_eq!(parser.reset(), "");
+            PyResult::Ok(())
+        })
+        .unwrap();
+    }
+
+    #[test]
+    fn parser_errors_for_unknown_name() {
+        with_python(|py| {
+            let tool = make_py_tool(py)?;
+            let error = match PyToolParser::new(py, "missing", vec![tool]) {
+                Ok(_) => panic!("missing parser name unexpectedly succeeded"),
+                Err(error) => error,
+            };
+            let message = format!("{error}");
+            assert!(message.contains("unsupported tool parser `missing`"));
+            PyResult::Ok(())
+        })
+        .unwrap();
+    }
+}

setup.py

@@ -18,7 +18,6 @@ import torch
 from packaging.version import Version, parse
 from setuptools import Extension, setup
 from setuptools.command.build_ext import build_ext
-from setuptools_rust.build import build_rust
 from setuptools_scm import get_version
 from torch.utils.cpp_extension import CUDA_HOME, ROCM_HOME
 
@@ -34,8 +33,6 @@ def load_module_from_path(module_name, path):
 ROOT_DIR = Path(__file__).parent
 logger = logging.getLogger(__name__)
 
-PRECOMPILED_RUST_FRONTEND_PATH = ROOT_DIR / "vllm" / "vllm-rs"
-
 # cannot import envs directly because it depends on vllm,
 #  which is not installed yet
 envs = load_module_from_path("envs", os.path.join(ROOT_DIR, "vllm", "envs.py"))
@@ -51,11 +48,6 @@ USE_PRECOMPILED_RUST_FRONTEND = (
 )
 
 
-def should_require_rust_frontend() -> bool:
-    value = os.getenv("VLLM_REQUIRE_RUST_FRONTEND", "")
-    return value.lower() not in ("", "0", "false", "no")
-
-
 if sys.platform.startswith("darwin") and VLLM_TARGET_DEVICE != "cpu":
     logger.warning("VLLM_TARGET_DEVICE automatically set to `cpu` due to macOS")
     VLLM_TARGET_DEVICE = "cpu"
@@ -422,24 +414,6 @@ class precompiled_build_ext(build_ext):
         return
 
 
-class precompiled_build_rust(build_rust):
-    """Skips local Rust builds when the precompiled wheel already ships vllm-rs."""
-
-    def run(self) -> None:
-        if PRECOMPILED_RUST_FRONTEND_PATH.exists():
-            logger.info(
-                "Skipping local Rust build: using precompiled %s",
-                PRECOMPILED_RUST_FRONTEND_PATH,
-            )
-            return
-
-        logger.warning(
-            "Precompiled wheel did not provide %s; falling back to local Rust build.",
-            PRECOMPILED_RUST_FRONTEND_PATH,
-        )
-        super().run()
-
-
 class precompiled_wheel_utils:
     """Extracts libraries and other files from an existing wheel."""
 
@@ -733,9 +707,6 @@ class precompiled_wheel_utils:
                             "vllm/_rocm_C.abi3.so",
                         }
                     )
-                if extract_rust_frontend:
-                    exact_members.add("vllm/vllm-rs")
-
                 flash_attn_regex = re.compile(
                     r"vllm/vllm_flash_attn/(?:[^/.][^/]*/)*(?!\.)[^/]*\.py"
                 )
@@ -758,6 +729,12 @@ class precompiled_wheel_utils:
                     if member.filename in exact_members:
                         file_members.append(member)
                         continue
+                    if (
+                        extract_rust_frontend
+                        and rust_build.is_precompiled_artifact_member(member.filename)
+                    ):
+                        file_members.append(member)
+                        continue
 
                     if not extract_extensions:
                         continue
@@ -1111,6 +1088,12 @@ package_data = {
 }
 
 
+def add_vllm_package_data(filename: str) -> None:
+    vllm_files = package_data.setdefault("vllm", [])
+    if filename not in vllm_files:
+        vllm_files.append(filename)
+
+
 # If using precompiled artifacts, extract and patch package_data in advance.
 if USE_PRECOMPILED_RUST_FRONTEND:
     wheel_url, download_filename = precompiled_wheel_utils.determine_wheel_url()
@@ -1123,12 +1106,10 @@ if USE_PRECOMPILED_RUST_FRONTEND:
     for pkg, files in patch.items():
         package_data.setdefault(pkg, []).extend(files)
 
-# If the rust frontend binary is already present in the source tree (e.g.,
+# Rust artifacts already present in the source tree (e.g., pre-built in a
-# pre-built in a separate Docker build stage), ship it as-is.
+# separate Docker build stage) are shipped as-is.
-if PRECOMPILED_RUST_FRONTEND_PATH.exists():
+for rust_artifact in rust_build.find_precompiled_artifacts():
-    vllm_files = package_data.setdefault("vllm", [])
+    add_vllm_package_data(rust_artifact.name)
-    if "vllm-rs" not in vllm_files:
-        vllm_files.append("vllm-rs")
 
 if _no_device():
     ext_modules = []
@@ -1141,15 +1122,13 @@ else:
         if USE_PRECOMPILED_EXTENSIONS
         else cmake_build_ext,
     }
-if USE_PRECOMPILED_RUST_FRONTEND or PRECOMPILED_RUST_FRONTEND_PATH.exists():
+if USE_PRECOMPILED_RUST_FRONTEND or rust_build.find_precompiled_artifacts():
-    cmdclass["build_rust"] = precompiled_build_rust
+    cmdclass["build_rust"] = rust_build.precompiled_build_rust
 
-# Rust frontend binary, built via setuptools-rust and installed into the
+# Rust artifacts, built via setuptools-rust and installed into the package
-# package directory alongside the Python modules.
+# directory alongside the Python modules.
-# TODO: we may use `RustBin` to directly install it into `bin` directory, but this
-# requires extra work on using precompiled binaries.
 rust_extensions = rust_build.rust_extensions(
-    optional=not should_require_rust_frontend()
+    optional=not rust_build.should_require_rust_frontend()
 )
 
 setup(

tests/tool_parsers/test_rust_tool_parser.py

@@ -0,0 +1,260 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import json
+from collections.abc import Sequence
+from unittest.mock import MagicMock
+
+import pytest
+
+from vllm.entrypoints.openai.chat_completion.protocol import (
+    ChatCompletionRequest,
+    ChatCompletionToolsParam,
+)
+from vllm.tool_parsers.rust_tool_parser import RustToolParser
+
+# The PyO3 extension is an optional build artifact; skip when absent.
+_rust_tool_parser = pytest.importorskip("vllm._rust_tool_parser")
+
+MOCK_TOKENIZER = MagicMock()
+MOCK_TOKENIZER.get_vocab.return_value = {}
+
+TC_START = "<｜DSML｜tool_calls>"
+TC_END = "</｜DSML｜tool_calls>"
+INV_START = '<｜DSML｜invoke name="'
+INV_END = "</｜DSML｜invoke>"
+PARAM_START = '<｜DSML｜parameter name="'
+PARAM_END = "</｜DSML｜parameter>"
+
+
+class DeepSeekV4RustToolParser(RustToolParser):
+    rust_parser_name = "DeepSeekV4ToolParser"
+    tool_call_start_token = TC_START
+
+
+def sample_tools() -> list[ChatCompletionToolsParam]:
+    return [
+        ChatCompletionToolsParam(
+            type="function",
+            function={
+                "name": "get_weather",
+                "description": "Get weather for a location",
+                "parameters": {
+                    "type": "object",
+                    "properties": {
+                        "location": {"type": "string"},
+                        "date": {"type": "string"},
+                    },
+                },
+            },
+        ),
+        ChatCompletionToolsParam(
+            type="function",
+            function={
+                "name": "add",
+                "description": "Add two integers",
+                "parameters": {
+                    "type": "object",
+                    "properties": {
+                        "x": {"type": "integer"},
+                        "y": {"type": "integer"},
+                    },
+                },
+            },
+        ),
+    ]
+
+
+EXPECTED_CALLS = [
+    ("get_weather", {"location": "SF", "date": "2024-01-16"}),
+    ("add", {"x": 3, "y": 5}),
+]
+
+
+def build_invoke(
+    function_name: str,
+    params: Sequence[tuple[str, str, bool]],
+) -> str:
+    param_text = "\n".join(
+        f'{PARAM_START}{name}" string="{str(is_string).lower()}">{value}{PARAM_END}'
+        for name, value, is_string in params
+    )
+    return f'{INV_START}{function_name}">\n{param_text}\n{INV_END}\n'
+
+
+def build_tool_call() -> str:
+    weather = build_invoke(
+        "get_weather",
+        [
+            ("location", "SF", True),
+            ("date", "2024-01-16", True),
+        ],
+    )
+    add = build_invoke(
+        "add",
+        [
+            ("x", "3", False),
+            ("y", "5", False),
+        ],
+    )
+    return f"{TC_START}\n{weather}{add}{TC_END}"
+
+
+def parse_streaming(
+    parser: DeepSeekV4RustToolParser,
+    text: str,
+    chunk_size: int,
+) -> list:
+    deltas = []
+    previous_text = ""
+    for start in range(0, len(text), chunk_size):
+        delta_text = text[start : start + chunk_size]
+        current_text = previous_text + delta_text
+        delta = parser.extract_tool_calls_streaming(
+            previous_text=previous_text,
+            current_text=current_text,
+            delta_text=delta_text,
+            previous_token_ids=[],
+            current_token_ids=[],
+            delta_token_ids=[1],
+            request=MagicMock(),
+        )
+        previous_text = current_text
+        if delta is not None:
+            deltas.append(delta)
+
+    delta = parser.extract_tool_calls_streaming(
+        previous_text=previous_text,
+        current_text=previous_text,
+        delta_text="",
+        previous_token_ids=[],
+        current_token_ids=[],
+        delta_token_ids=[2],
+        request=MagicMock(),
+    )
+    if delta is not None:
+        deltas.append(delta)
+
+    return deltas
+
+
+def collect_streamed_arguments(deltas: Sequence, tool_index: int = 0) -> str:
+    return "".join(
+        tool_call.function.arguments
+        for delta in deltas
+        for tool_call in delta.tool_calls or []
+        if (
+            tool_call.index == tool_index
+            and tool_call.function is not None
+            and tool_call.function.arguments is not None
+        )
+    )
+
+
+def test_rust_tool_parser_extension_typed_api() -> None:
+    tools = [
+        _rust_tool_parser.Tool(
+            tool.function.name,
+            tool.function.description,
+            tool.function.parameters,
+            None,
+        )
+        for tool in sample_tools()
+    ]
+    parser = _rust_tool_parser.ToolParser("DeepSeekV4ToolParser", tools)
+    output = _rust_tool_parser.ToolParserOutput()
+
+    parser.parse_into(build_tool_call(), output)
+    output.append(parser.finish())
+    output = output.coalesce_calls()
+
+    assert parser.preserve_special_tokens()
+    assert output.normal_text == ""
+    assert len(output.calls) == 2
+    for call, (name, arguments) in zip(output.calls, EXPECTED_CALLS):
+        assert call.name == name
+        assert json.loads(call.arguments) == arguments
+
+
+def test_rust_tool_parser_adapter_extracts_complete_output() -> None:
+    tools = sample_tools()
+    parser = DeepSeekV4RustToolParser(MOCK_TOKENIZER, tools=tools)
+
+    result = parser.extract_tool_calls(
+        "Let me create it. " + build_tool_call(),
+        ChatCompletionRequest(messages=[], model="m", tools=tools),
+    )
+
+    assert result.tools_called
+    assert result.content == "Let me create it. "
+    assert len(result.tool_calls) == 2
+    for tool_call, (name, arguments) in zip(result.tool_calls, EXPECTED_CALLS):
+        assert tool_call.function.name == name
+        assert json.loads(tool_call.function.arguments) == arguments
+
+
+def test_rust_tool_parser_adapter_streaming_handles_multiple_calls() -> None:
+    parser = DeepSeekV4RustToolParser(MOCK_TOKENIZER, tools=sample_tools())
+
+    deltas = parse_streaming(parser, build_tool_call(), chunk_size=5)
+
+    names = [
+        tool_call.function.name
+        for delta in deltas
+        for tool_call in delta.tool_calls or []
+        if tool_call.function is not None and tool_call.function.name is not None
+    ]
+    assert names == [name for name, _ in EXPECTED_CALLS]
+    for index, (_, arguments) in enumerate(EXPECTED_CALLS):
+        assert json.loads(collect_streamed_arguments(deltas, index)) == arguments
+
+
+def test_rust_tool_parser_adapter_ignores_midstream_empty_delta() -> None:
+    parser = DeepSeekV4RustToolParser(MOCK_TOKENIZER, tools=sample_tools())
+    text = build_tool_call()
+    split_at = len(TC_START) + 8
+    deltas = []
+    previous_text = ""
+
+    for delta_text in (text[:split_at], "", text[split_at:], ""):
+        current_text = previous_text + delta_text
+        delta = parser.extract_tool_calls_streaming(
+            previous_text=previous_text,
+            current_text=current_text,
+            delta_text=delta_text,
+            previous_token_ids=[],
+            current_token_ids=[],
+            delta_token_ids=[1],
+            request=MagicMock(),
+        )
+        previous_text = current_text
+        if delta is not None:
+            deltas.append(delta)
+
+    names = [
+        tool_call.function.name
+        for delta in deltas
+        for tool_call in delta.tool_calls or []
+        if tool_call.function is not None and tool_call.function.name is not None
+    ]
+    assert names == [name for name, _ in EXPECTED_CALLS]
+    for index, (_, arguments) in enumerate(EXPECTED_CALLS):
+        assert json.loads(collect_streamed_arguments(deltas, index)) == arguments
+
+
+def test_rust_tool_parser_adapter_adjust_request_is_opaque() -> None:
+    tools = sample_tools()
+    parser = DeepSeekV4RustToolParser(MOCK_TOKENIZER, tools=tools)
+    request = ChatCompletionRequest(
+        messages=[],
+        model="m",
+        tools=tools,
+        tool_choice="required",
+        skip_special_tokens=True,
+    )
+
+    adjusted = parser.adjust_request(request)
+
+    assert adjusted is request
+    assert adjusted.skip_special_tokens is False
+    assert adjusted.structured_outputs is None

tools/build_rust.py

@@ -1,21 +1,31 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
-"""Shared setuptools-rust build entry for the vllm-rs binary."""
+"""Rust build support shared by `setup.py` and the standalone `build_rust.sh`.
+
+This module is the single source of truth for the Rust artifacts shipped in
+the vllm package: which crates are built, where their artifacts land, and how
+precompiled artifacts are detected.
+"""
 
 from __future__ import annotations
 
+import logging
 import os
 import sys
 from pathlib import Path
 
 from setuptools import setup
 from setuptools_rust import Binding, RustExtension
+from setuptools_rust.build import build_rust
+
+logger = logging.getLogger(__name__)
 
 ROOT_DIR = Path(__file__).resolve().parents[1]
+PACKAGE_DIR = ROOT_DIR / "vllm"
 
 
-def rust_extensions(*, optional: bool) -> list[RustExtension]:
+def rust_extensions(*, optional: bool = False) -> list[RustExtension]:
     return [
         RustExtension(
             target="vllm.vllm-rs",
@@ -25,12 +35,92 @@ def rust_extensions(*, optional: bool) -> list[RustExtension]:
             binding=Binding.Exec,
             optional=optional,
         ),
+        RustExtension(
+            target="vllm._rust_tool_parser",
+            path="rust/src/tool-parser/python/Cargo.toml",
+            features=["pyo3/abi3-py38"],
+            binding=Binding.PyO3,
+            optional=optional,
+            py_limited_api=True,
+        ),
     ]
 
 
-def build_binary(build_rust_args: list[str]) -> None:
+def should_require_rust_frontend() -> bool:
+    value = os.getenv("VLLM_REQUIRE_RUST_FRONTEND", "")
+    return value.lower() not in ("", "0", "false", "no")
+
+
+def _expected_artifacts() -> list[tuple[str, Binding]]:
+    """(basename, binding) of each artifact installed into the package."""
+    artifacts = []
+    for extension in rust_extensions():
+        for target in extension.target.values():
+            package, _, name = target.rpartition(".")
+            assert package == "vllm", f"unexpected Rust target: {target}"
+            artifacts.append((name, extension.binding))
+    return artifacts
+
+
+def _is_artifact_file(filename: str, name: str, binding: Binding) -> bool:
+    # setuptools-rust installs Exec binaries under their bare name, and PyO3
+    # modules as `<module>.<ext-suffix>` where the suffix ends with `.so` on
+    # Linux and macOS alike (e.g. `_rust_foo.abi3.so`).
+    if binding == Binding.Exec:
+        return filename == name
+    return filename.endswith(".so") and filename.split(".", 1)[0] == name
+
+
+def find_precompiled_artifacts() -> list[Path]:
+    """Rust artifacts already present in the package directory."""
+    return sorted(
+        path
+        for path in PACKAGE_DIR.iterdir()
+        if any(_is_artifact_file(path.name, *spec) for spec in _expected_artifacts())
+    )
+
+
+def missing_precompiled_artifacts() -> list[str]:
+    """Expected-but-absent artifacts, as file patterns for diagnostics."""
+    present = [path.name for path in find_precompiled_artifacts()]
+    return [
+        str(PACKAGE_DIR / (name if binding == Binding.Exec else f"{name}.*.so"))
+        for name, binding in _expected_artifacts()
+        if not any(_is_artifact_file(filename, name, binding) for filename in present)
+    ]
+
+
+def is_precompiled_artifact_member(member_name: str) -> bool:
+    """Whether a wheel member is a Rust artifact (e.g. `vllm/vllm-rs`)."""
+    package, _, filename = member_name.rpartition("/")
+    return package == "vllm" and any(
+        _is_artifact_file(filename, *spec) for spec in _expected_artifacts()
+    )
+
+
+class precompiled_build_rust(build_rust):
+    """Skips the local Rust build when all precompiled artifacts are present."""
+
+    def run(self) -> None:
+        missing = missing_precompiled_artifacts()
+        if not missing:
+            logger.info(
+                "Skipping local Rust build: using precompiled %s",
+                find_precompiled_artifacts(),
+            )
+            return
+
+        logger.warning(
+            "Precompiled Rust artifacts missing (%s); "
+            "falling back to local Rust build.",
+            ", ".join(missing),
+        )
+        super().run()
+
+
+def build_artifacts(build_rust_args: list[str]) -> None:
     os.chdir(ROOT_DIR)
-    (ROOT_DIR / "vllm").mkdir(exist_ok=True)
+    PACKAGE_DIR.mkdir(exist_ok=True)
     setup(
         name="vllm-rust-frontend-build",
         packages=[],
@@ -40,7 +130,7 @@ def build_binary(build_rust_args: list[str]) -> None:
 
 
 def main() -> None:
-    build_binary(sys.argv[1:])
+    build_artifacts(sys.argv[1:])
 
 
 if __name__ == "__main__":

vllm/tool_parsers/rust_tool_parser.py

@@ -0,0 +1,310 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import importlib
+from collections.abc import Sequence
+from typing import Any
+
+from openai.types.responses.function_tool import FunctionTool
+
+from vllm.entrypoints.chat_utils import make_tool_call_id
+from vllm.entrypoints.openai.chat_completion.protocol import (
+    ChatCompletionRequest,
+    ChatCompletionToolsParam,
+)
+from vllm.entrypoints.openai.engine.protocol import (
+    DeltaFunctionCall,
+    DeltaMessage,
+    DeltaToolCall,
+    ExtractedToolCallInformation,
+    FunctionCall,
+    ToolCall,
+)
+from vllm.entrypoints.openai.responses.protocol import ResponsesRequest
+from vllm.logger import init_logger
+from vllm.tokenizers import TokenizerLike
+from vllm.tool_parsers.abstract_tool_parser import Tool, ToolParser
+
+logger = init_logger(__name__)
+
+
+def _rust_tool_parser_module() -> Any:
+    try:
+        return importlib.import_module("vllm._rust_tool_parser")
+    except ImportError as exc:
+        raise RuntimeError(
+            "Rust tool parsing requires the vllm._rust_tool_parser PyO3 "
+            "extension. Rebuild vLLM with Rust frontend/extensions enabled."
+        ) from exc
+
+
+class RustToolParser(ToolParser):
+    """Adapter from an opaque Rust parser to the vLLM ToolParser API.
+
+    Subclasses provide only model-specific configuration: the exact Rust parser
+    name and an optional tool-call start marker for fast complete-output
+    rejection.
+
+    This class keeps the vLLM-specific bridge work:
+    - convert vLLM tool definitions into the Rust ``Tool`` shape;
+    - translate typed Rust parser outputs into vLLM protocol objects; and
+    - maintain vLLM streaming bookkeeping used by finish-reason handling.
+
+    The parser grammar and incremental parser state stay in Rust.
+    """
+
+    # Rust-backed parsers are opaque to Python by default. Do not use vLLM's
+    # standard JSON required/named handling; let the Rust parser consume the
+    # model's native tool-call syntax.
+    supports_required_and_named = False
+
+    rust_parser_name: str
+    tool_call_start_token: str | None = None
+
+    def __init__(self, tokenizer: TokenizerLike, tools: list[Tool] | None = None):
+        super().__init__(tokenizer, tools)
+        self._parser: Any | None = None
+        self._error: Exception | None = None
+        self._tool_call_ids: dict[int, str] = {}
+
+        if not self.model_tokenizer:
+            raise ValueError(
+                "The model tokenizer must be passed to the ToolParser "
+                "constructor during construction."
+            )
+
+        logger.debug(
+            "vLLM successfully imported tool parser %s", self.__class__.__name__
+        )
+
+    def adjust_request(
+        self, request: ChatCompletionRequest | ResponsesRequest
+    ) -> ChatCompletionRequest | ResponsesRequest:
+        """Adjust request options without installing Python-side constraints.
+
+        Rust-backed parsers are treated as source-of-truth opaque parsers.  The
+        bridge intentionally avoids ``super().adjust_request()`` so Python does
+        not install JSON schema guidance or structural-tag constraints that may
+        conflict with the Rust parser's native grammar.
+        """
+        if self._get_parser().preserve_special_tokens():
+            request.skip_special_tokens = False
+        return request
+
+    def _rust_tools(self) -> list[Any]:
+        """Build Rust ``Tool`` objects from vLLM tool definitions."""
+        if not self.tools:
+            return []
+
+        tools: list[Any] = []
+        for tool in self.tools:
+            if isinstance(tool, FunctionTool):
+                name = tool.name
+                description = tool.description
+                parameters = tool.parameters or {}
+                strict = getattr(tool, "strict", None)
+            elif isinstance(tool, ChatCompletionToolsParam):
+                name = tool.function.name
+                description = tool.function.description
+                parameters = tool.function.parameters or {}
+                strict = getattr(tool.function, "strict", None)
+            else:
+                continue
+            tools.append(
+                _rust_tool_parser_module().Tool(name, description, parameters, strict)
+            )
+        return tools
+
+    def _new_parser(self) -> Any:
+        """Create a fresh Rust parser with the current tool schemas."""
+        return _rust_tool_parser_module().ToolParser(
+            self.rust_parser_name, self._rust_tools()
+        )
+
+    def _get_parser(self) -> Any:
+        if self._parser is None:
+            self._parser = self._new_parser()
+        return self._parser
+
+    def _reset_streaming_state(self) -> None:
+        """Reset parser state for a new request on a reused parser instance."""
+        self._parser = self._new_parser()
+        self._error = None
+        self._tool_call_ids.clear()
+        self.prev_tool_call_arr.clear()
+        self.streamed_args_for_tool.clear()
+        self.current_tool_id = -1
+        self.current_tool_name_sent = False
+
+    def _ensure_tool_state(self, index: int) -> None:
+        """Grow vLLM streaming state arrays to contain ``index``."""
+        while len(self.prev_tool_call_arr) <= index:
+            self.prev_tool_call_arr.append({})
+        while len(self.streamed_args_for_tool) <= index:
+            self.streamed_args_for_tool.append("")
+
+    def _record_delta(
+        self, index: int, name: str | None, arguments: str | None
+    ) -> str | None:
+        """Mirror a Rust parser delta into vLLM streaming bookkeeping.
+
+        ``prev_tool_call_arr`` and ``streamed_args_for_tool`` are read later by
+        the chat serving layer to decide the final ``tool_calls`` finish reason
+        and to flush any remaining argument bytes.
+        """
+        tool_call_id = None
+        self._ensure_tool_state(index)
+
+        if name is not None:
+            tool_call_id = make_tool_call_id()
+            self._tool_call_ids[index] = tool_call_id
+            self.prev_tool_call_arr[index] = {"name": name, "arguments": {}}
+            self.current_tool_name_sent = True
+
+        if arguments is not None:
+            self.streamed_args_for_tool[index] += arguments
+            self.prev_tool_call_arr[index]["arguments"] = self.streamed_args_for_tool[
+                index
+            ]
+            self.current_tool_id = index
+
+        return tool_call_id
+
+    def _delta_message_from_parser_output(
+        self, parser_output: Any | None
+    ) -> DeltaMessage | None:
+        """Translate one Rust parser output into a vLLM ``DeltaMessage``."""
+        if parser_output is None:
+            return None
+
+        normal_text = parser_output.normal_text or None
+        tool_calls: list[DeltaToolCall] = []
+        for tool_call in parser_output.calls:
+            index = tool_call.tool_index
+            name = tool_call.name
+            arguments: str | None = tool_call.arguments
+            if name is None and arguments is None:
+                continue
+
+            tool_call_id = self._record_delta(index, name, arguments)
+            tool_calls.append(
+                DeltaToolCall(
+                    index=index,
+                    id=tool_call_id,
+                    type="function" if name is not None else None,
+                    function=DeltaFunctionCall(
+                        name=name,
+                        arguments=arguments,
+                    ),
+                )
+            )
+
+        if normal_text is None and not tool_calls:
+            return None
+        return DeltaMessage(content=normal_text, tool_calls=tool_calls)
+
+    def _parse_complete(self, model_output: str) -> Any | None:
+        """Parse complete model output with a throwaway Rust parser instance."""
+        parser = self._new_parser()
+        output = _rust_tool_parser_module().ToolParserOutput()
+        try:
+            parser.parse_into(model_output, output)
+            output.append(parser.finish())
+        except Exception:
+            logger.exception(
+                "Error parsing %s tool call output.", self.rust_parser_name
+            )
+            return None
+        return output.coalesce_calls()
+
+    def extract_tool_calls(
+        self,
+        model_output: str,
+        request: ChatCompletionRequest,
+    ) -> ExtractedToolCallInformation:
+        """Extract tool calls from complete model output (non-streaming)."""
+        if (
+            self.tool_call_start_token is not None
+            and self.tool_call_start_token not in model_output
+        ):
+            return ExtractedToolCallInformation(
+                tools_called=False,
+                tool_calls=[],
+                content=model_output,
+            )
+
+        parsed = self._parse_complete(model_output)
+        if parsed is None:
+            return ExtractedToolCallInformation(
+                tools_called=False,
+                tool_calls=[],
+                content=model_output,
+            )
+
+        tool_calls: list[ToolCall] = []
+        self.prev_tool_call_arr.clear()
+        for parsed_tool_call in parsed.calls:
+            name = parsed_tool_call.name
+            arguments = parsed_tool_call.arguments or "{}"
+            if name is None:
+                continue
+            tool_calls.append(
+                ToolCall(
+                    type="function",
+                    function=FunctionCall(name=name, arguments=arguments),
+                )
+            )
+            self.prev_tool_call_arr.append({"name": name, "arguments": arguments})
+
+        if not tool_calls:
+            return ExtractedToolCallInformation(
+                tools_called=False,
+                tool_calls=[],
+                content=model_output,
+            )
+
+        content = parsed.normal_text or None
+        return ExtractedToolCallInformation(
+            tools_called=True,
+            tool_calls=tool_calls,
+            content=content,
+        )
+
+    def extract_tool_calls_streaming(
+        self,
+        previous_text: str,
+        current_text: str,
+        delta_text: str,
+        previous_token_ids: Sequence[int],  # pylint: disable=unused-argument
+        current_token_ids: Sequence[int],  # pylint: disable=unused-argument
+        delta_token_ids: Sequence[int],  # pylint: disable=unused-argument
+        request: ChatCompletionRequest,  # pylint: disable=unused-argument
+    ) -> DeltaMessage | None:
+        """Extract tool calls from streaming model output.
+
+        The Rust parser owns the incremental buffer, so this adapter feeds only
+        the newest text delta and lets the serving layer handle final empty
+        chunks.
+        """
+        # TODO: Add a final-chunk hook if streaming needs to call Rust finish().
+        if not previous_text:
+            self._reset_streaming_state()
+
+        if self._error is not None:
+            return None
+
+        parser_output = _rust_tool_parser_module().ToolParserOutput()
+        try:
+            self._get_parser().parse_into(delta_text, parser_output)
+        except Exception as error:
+            self._error = error
+            logger.exception(
+                "Error parsing %s streaming tool call output.",
+                self.rust_parser_name,
+            )
+
+        delta_message = self._delta_message_from_parser_output(parser_output)
+        if delta_message is not None:
+            return delta_message
+
+        return None