diff --git a/Cargo.toml b/Cargo.toml
index f827b969..edf12f98 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,6 +33,8 @@ portgraph = { workspace = true }
 pyo3 = { workspace = true, optional = true, features = [
     "multiple-pymethods",
 ] }
+strum_macros = "0.25.2"
+strum = "0.25.0"
 
 [features]
 pyo3 = ["dep:pyo3", "tket-json-rs/pyo3", "tket-json-rs/tket2ops", "portgraph/pyo3", "quantinuum-hugr/pyo3"]
@@ -57,4 +59,4 @@ members = ["pyrs"]
 
 quantinuum-hugr = { git = "https://github.com/CQCL-DEV/hugr", branch = "fix/no-resource-validation" }
 portgraph = "0.8"
-pyo3 = { version = "0.19" }
\ No newline at end of file
+pyo3 = { version = "0.19" }
diff --git a/src/lib.rs b/src/lib.rs
index 600714d9..2f0ada9c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,7 +10,9 @@
 pub mod circuit;
 pub mod extension;
 pub mod json;
+mod ops;
 pub mod passes;
+pub use ops::{Pauli, T2Op};
 
 #[cfg(feature = "portmatching")]
 pub mod portmatching;
diff --git a/src/ops.rs b/src/ops.rs
new file mode 100644
index 00000000..fd2a186a
--- /dev/null
+++ b/src/ops.rs
@@ -0,0 +1,232 @@
+use std::collections::HashMap;
+
+use hugr::{
+    extension::{
+        prelude::{BOOL_T, QB_T},
+        ExtensionBuildError, ExtensionId, OpDef,
+    },
+    ops::{custom::ExternalOp, LeafOp, OpType},
+    std_extensions::arithmetic::float_types::FLOAT64_TYPE,
+    type_row,
+    types::FunctionType,
+    Extension,
+};
+use lazy_static::lazy_static;
+use serde::{Deserialize, Serialize};
+use std::str::FromStr;
+use strum::IntoEnumIterator;
+use strum_macros::{Display, EnumIter, EnumString, IntoStaticStr};
+
+/// Name of tket 2 extension.
+pub const EXTENSION_ID: ExtensionId = ExtensionId::new_inline("quantum.tket2");
+
+#[derive(
+    Clone, Copy, Debug, Serialize, Deserialize, EnumIter, IntoStaticStr, EnumString, PartialEq,
+)]
+#[allow(missing_docs)]
+/// Simple enum of tket 2 quantum operations.
+pub enum T2Op {
+    H,
+    CX,
+    T,
+    S,
+    X,
+    Y,
+    Z,
+    Tadj,
+    Sadj,
+    ZZMax,
+    Measure,
+    RzF64,
+}
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, EnumIter, Display, PartialEq, PartialOrd)]
+#[allow(missing_docs)]
+/// Simple enum representation of Pauli matrices.
+pub enum Pauli {
+    I,
+    X,
+    Y,
+    Z,
+}
+
+// this trait could be implemented in Hugr
+trait SimpleOpEnum: Into<&'static str> + FromStr + Copy + IntoEnumIterator {
+    fn signature(&self) -> FunctionType;
+    fn name(&self) -> &str {
+        (*self).into()
+    }
+    fn try_from_op_def(op_def: &OpDef) -> Result<Self, <Self as FromStr>::Err> {
+        Self::from_str(op_def.name())
+    }
+    fn add_to_extension<'e>(
+        &self,
+        ext: &'e mut Extension,
+    ) -> Result<&'e OpDef, ExtensionBuildError>;
+
+    fn all_variants() -> <Self as IntoEnumIterator>::Iterator {
+        <Self as IntoEnumIterator>::iter()
+    }
+}
+
+impl Pauli {
+    /// Check if this pauli commutes with another.
+    pub fn commutes_with(&self, other: Self) -> bool {
+        *self == Pauli::I || other == Pauli::I || *self == other
+    }
+}
+impl SimpleOpEnum for T2Op {
+    fn signature(&self) -> FunctionType {
+        use T2Op::*;
+        let one_qb_row = type_row![QB_T];
+        let two_qb_row = type_row![QB_T, QB_T];
+        match self {
+            H | T | S | X | Y | Z | Tadj | Sadj => {
+                FunctionType::new(one_qb_row.clone(), one_qb_row)
+            }
+            CX | ZZMax => FunctionType::new(two_qb_row.clone(), two_qb_row),
+            Measure => FunctionType::new(one_qb_row, type_row![QB_T, BOOL_T]),
+            RzF64 => FunctionType::new(type_row![QB_T, FLOAT64_TYPE], one_qb_row),
+        }
+    }
+
+    fn add_to_extension<'e>(
+        &self,
+        ext: &'e mut Extension,
+    ) -> Result<&'e OpDef, ExtensionBuildError> {
+        let name = self.name().into();
+        let FunctionType { input, output, .. } = self.signature();
+        ext.add_op_custom_sig(
+            name,
+            format!("TKET 2 quantum op: {}", self.name()),
+            vec![],
+            HashMap::from_iter([(
+                "commutation".to_string(),
+                serde_yaml::to_value(self.qubit_commutation()).unwrap(),
+            )]),
+            vec![],
+            move |_: &_| Ok(FunctionType::new(input.clone(), output.clone())),
+        )
+    }
+}
+
+impl T2Op {
+    pub(crate) fn qubit_commutation(&self) -> Vec<(usize, Pauli)> {
+        use T2Op::*;
+
+        match self {
+            X => vec![(0, Pauli::X)],
+            T | Z | S | Tadj | Sadj | RzF64 => vec![(0, Pauli::Z)],
+            CX => vec![(0, Pauli::Z), (1, Pauli::X)],
+            ZZMax => vec![(0, Pauli::Z), (1, Pauli::Z)],
+            // by default, no commutation
+            _ => vec![],
+        }
+    }
+}
+
+fn extension() -> Extension {
+    let mut e = Extension::new(EXTENSION_ID);
+    load_all_ops::<T2Op>(&mut e).expect("add fail");
+
+    e
+}
+
+lazy_static! {
+    static ref EXTENSION: Extension = extension();
+}
+
+// From implementations could be made generic over SimpleOpEnum
+impl From<T2Op> for LeafOp {
+    fn from(op: T2Op) -> Self {
+        EXTENSION
+            .instantiate_extension_op(op.name(), [])
+            .unwrap()
+            .into()
+    }
+}
+
+impl From<T2Op> for OpType {
+    fn from(op: T2Op) -> Self {
+        let l: LeafOp = op.into();
+        l.into()
+    }
+}
+
+impl TryFrom<OpType> for T2Op {
+    type Error = &'static str;
+
+    fn try_from(op: OpType) -> Result<Self, Self::Error> {
+        let leaf: LeafOp = op.try_into().map_err(|_| "not a leaf.")?;
+        match leaf {
+            LeafOp::CustomOp(b) => match *b {
+                ExternalOp::Extension(e) => {
+                    Self::try_from_op_def(e.def()).map_err(|_| "not a T2Op")
+                }
+                ExternalOp::Opaque(_) => todo!(),
+            },
+            _ => Err("not a custom."),
+        }
+    }
+}
+fn load_all_ops<T: SimpleOpEnum>(extension: &mut Extension) -> Result<(), ExtensionBuildError> {
+    for op in T::all_variants() {
+        op.add_to_extension(extension)?;
+    }
+    Ok(())
+}
+#[cfg(test)]
+pub(crate) mod test {
+
+    use std::sync::Arc;
+
+    use hugr::{
+        builder::{BuildError, CircuitBuilder, DFGBuilder, Dataflow, DataflowHugr},
+        extension::{prelude::QB_T, OpDef},
+        types::FunctionType,
+        Hugr,
+    };
+    use rstest::fixture;
+
+    use crate::ops::SimpleOpEnum;
+
+    use super::{T2Op, EXTENSION, EXTENSION_ID};
+    fn get_opdef(op: impl SimpleOpEnum) -> Option<&'static Arc<OpDef>> {
+        EXTENSION.get_op(op.name())
+    }
+    #[test]
+    fn create_extension() {
+        assert_eq!(EXTENSION.name(), &EXTENSION_ID);
+
+        for o in T2Op::all_variants() {
+            assert_eq!(T2Op::try_from_op_def(get_opdef(o.clone()).unwrap()), Ok(o));
+        }
+    }
+
+    pub(crate) fn build_simple_circuit(
+        num_qubits: usize,
+        f: impl FnOnce(&mut CircuitBuilder<DFGBuilder<Hugr>>) -> Result<(), BuildError>,
+    ) -> Result<Hugr, BuildError> {
+        let qb_row = vec![QB_T; num_qubits];
+        let mut h = DFGBuilder::new(FunctionType::new(qb_row.clone(), qb_row))?;
+
+        let qbs = h.input_wires();
+
+        let mut circ = h.as_circuit(qbs.into_iter().collect());
+
+        f(&mut circ)?;
+
+        let qbs = circ.finish();
+        h.finish_hugr_with_outputs(qbs)
+    }
+
+    #[fixture]
+    pub(crate) fn t2_bell_circuit() -> Hugr {
+        let h = build_simple_circuit(2, |circ| {
+            circ.append(T2Op::H, [0])?;
+            circ.append(T2Op::CX, [0, 1])?;
+            Ok(())
+        });
+
+        h.unwrap()
+    }
+}