* Create cicuit module and circuit/library submodule

* Add MidCircuitMeasure(Instruction) to new circuit library

* Add unit tests

* Add release note

* Modify convert_to_target to support additional instructions through "instruction_signatures", add arguments supported in original implementation. Allow to provide a custom_name_mapping, which was referenced in the error messages but not actually enabled. Update typing style.

Author: ElePT

qiskit_ibm_runtime/circuit/__init__.py

@@ -0,0 +1,15 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2025.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Module for vendor-specific circuit objects."""
+
+from .library import *

qiskit_ibm_runtime/circuit/library/__init__.py

@@ -0,0 +1,16 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2025.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Module for vendor-specific instructions."""
+
+
+from .mid_circuit_measure import MidCircuitMeasure

qiskit_ibm_runtime/circuit/library/mid_circuit_measure.py

@@ -0,0 +1,32 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2025.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""MidCircuitMeasure gate."""
+
+from qiskit.circuit import Instruction
+
+
+class MidCircuitMeasure(Instruction):
+    """
+    This instruction implements an alternative 'named' measurement definition
+    (1 classical bit, 1 quantum bit), whose name can be used to map to a corresponding
+    mid-circuit measurement instruction implementation on hardware.
+    """
+
+    def __init__(self, name: str = "measure_2", label: str = None) -> None:
+        if not name.startswith("measure_"):
+            raise ValueError(
+                "Invalid name for mid-circuit measure instruction."
+                "The provided name must start with `measure_`"
+            )
+
+        super().__init__(name, 1, 1, [], label=label)

qiskit_ibm_runtime/utils/backend_converter.py

@@ -10,13 +10,16 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""Converters for migration from IBM Quantum BackendV1 to BackendV2."""
+"""
+Converters from BackendConfiguration and BackendProperties
+model (BackendV1) to Target model (BackendV2).
+"""
 
 from __future__ import annotations
 
 import logging
 import warnings
-from typing import Any, Dict, List
+from typing import Any
 
 from qiskit.circuit.controlflow import (
     CONTROL_FLOW_OP_NAMES,
@@ -26,17 +29,15 @@
     WhileLoopOp,
 )
 from qiskit.circuit.gate import Gate
+from qiskit.circuit import Instruction
 from qiskit.circuit.library.standard_gates import get_standard_gate_name_mapping
 from qiskit.circuit.parameter import Parameter
 from qiskit.providers.backend import QubitProperties
 from qiskit.transpiler.target import InstructionProperties, Target
 
-from ..models import BackendConfiguration, BackendProperties
-from ..models.exceptions import BackendPropertyError
-
-# is_fractional_gate used to be defined in this module and might be referenced
-# from here externally
-from .utils import is_fractional_gate  # See comment above before removing
+from qiskit_ibm_runtime.models import BackendConfiguration, BackendProperties
+from qiskit_ibm_runtime.models.exceptions import BackendPropertyError
+from qiskit_ibm_runtime.utils.utils import is_fractional_gate
 
 
 logger = logging.getLogger(__name__)
@@ -48,34 +49,42 @@ def convert_to_target(  # type: ignore[no-untyped-def]
     *,
     include_control_flow: bool = True,
     include_fractional_gates: bool = True,
+    custom_name_mapping: dict[str, Any] | None = None,
+    add_delay: bool = True,
+    filter_faulty: bool = True,
     **kwargs,
 ) -> Target:
     """Decode transpiler target from backend data set.
 
     This function generates :class:`.Target`` instance from intermediate
     legacy objects such as :class:`.BackendProperties` and :class:`.BackendConfiguration`.
+    These objects were components of the legacy :class:`.BackendV1` model.
 
     Args:
         configuration: Backend configuration as ``BackendConfiguration``
         properties: Backend property dictionary or ``BackendProperties``
         include_control_flow: Set True to include control flow instructions.
         include_fractional_gates: Set True to include fractioanl gates.
+        custom_name_mapping: A name mapping must be supplied for the operation
+            not included in Qiskit Standard Gate name mapping, otherwise the operation
+            will be dropped in the resulting ``Target`` object.
+        add_delay: If True, adds delay to the instruction set.
+        filter_faulty: If True, this filters the non-operational qubits.
 
     Returns:
         A ``Target`` instance.
     """
-    add_delay = True
-    filter_faulty = True
-
     if "defaults" in kwargs:
         warnings.warn(
             "Backend defaults have been completely from removed IBM Backends. They will be ignored."
         )
 
     required = ["measure", "delay", "reset"]
 
-    # Load Qiskit object representation
+    # Load qiskit object representation
     qiskit_inst_mapping = get_standard_gate_name_mapping()
+    if custom_name_mapping:
+        qiskit_inst_mapping.update(custom_name_mapping)
 
     qiskit_control_flow_mapping = {
         "if_else": IfElseOp,
@@ -95,9 +104,12 @@ def convert_to_target(  # type: ignore[no-untyped-def]
     # Create instruction property placeholder from backend configuration
     basis_gates = set(getattr(configuration, "basis_gates", []))
     supported_instructions = set(getattr(configuration, "supported_instructions", []))
+    instruction_signatures = getattr(configuration, "instruction_signatures", [])
     gate_configs = {gate.name: gate for gate in configuration.gates}
     all_instructions = set.union(
-        basis_gates, set(required), supported_instructions.intersection(CONTROL_FLOW_OP_NAMES)
+        basis_gates,
+        set(required),
+        supported_instructions.intersection(CONTROL_FLOW_OP_NAMES),
     )
 
     inst_name_map = {}
@@ -106,7 +118,7 @@ def convert_to_target(  # type: ignore[no-untyped-def]
     faulty_qubits = set()
     unsupported_instructions = []
 
-    # Create name to Qiskit instruction object repr mapping
+    # Create name to qiskit instruction object repr mapping
     for name in all_instructions:
         if name in qiskit_control_flow_mapping:
             if not include_control_flow:
@@ -132,9 +144,9 @@ def convert_to_target(  # type: ignore[no-untyped-def]
             inst_name_map[name] = qiskit_gate
         elif name in gate_configs:
             # GateConfig model is a translator of QASM opcode.
-            # This doesn't have quantum definition, so Qiskit transpiler doesn't perform
+            # This doesn't have quantum definition, so qiskit transpiler doesn't perform
             # any optimization in quantum domain.
-            # Usually GateConfig counterpart should exist in Qiskit namespace so this is rarely called.
+            # Usually GateConfig counterpart should exist in qiskit namespace so this is rarely called.
             this_config = gate_configs[name]
             params = list(map(Parameter, getattr(this_config, "parameters", [])))
             coupling_map = getattr(this_config, "coupling_map", [])
@@ -155,12 +167,29 @@ def convert_to_target(  # type: ignore[no-untyped-def]
     for name in unsupported_instructions:
         all_instructions.remove(name)
 
+    # Create name to qiskit-ibm-runtime instruction object repr mapping
+
+    for signature in instruction_signatures:
+        name = signature.get("name")
+        num_qubits = signature.get("num_qubits")
+        num_clbits = signature.get("num_clbits")
+        param_names = signature.get("parameters")
+        # Add generic parameter name
+        params = [Parameter(name) for name in param_names]
+
+        instruction = Instruction(
+            name=name, num_qubits=num_qubits, num_clbits=num_clbits, params=params
+        )
+        inst_name_map[name] = instruction
+        all_instructions.add(name)
+
     # Create inst properties placeholder
     # Without any assignment, properties value is None,
     # which defines a global instruction that can be applied to any qubit(s).
     # The None value behaves differently from an empty dictionary.
     # See API doc of Target.add_instruction for details.
     prop_name_map = dict.fromkeys(all_instructions)
+
     for name in all_instructions:
         if name in gate_configs:
             if coupling_map := getattr(gate_configs[name], "coupling_map", None):
@@ -173,7 +202,7 @@ def convert_to_target(  # type: ignore[no-untyped-def]
     # Populate instruction properties
     if properties:
 
-        def _get_value(prop_dict: Dict, prop_name: str) -> Any:
+        def _get_value(prop_dict: dict, prop_name: str) -> Any:
             if ndval := prop_dict.get(prop_name, None):
                 return ndval[0]
             return None
@@ -285,11 +314,9 @@ def _get_value(prop_dict: Dict, prop_name: str) -> Any:
 
 def qubit_props_list_from_props(
     properties: BackendProperties,
-) -> List[QubitProperties]:
-    """Uses BackendProperties to construct
-    and return a list of QubitProperties.
-    """
-    qubit_props: List[QubitProperties] = []
+) -> list[QubitProperties]:
+    """Uses BackendProperties to construct and return a list of QubitProperties."""
+    qubit_props: list[QubitProperties] = []
     for qubit, _ in enumerate(properties.qubits):
         try:
             t_1 = properties.t1(qubit)

release-notes/unreleased/2316.feat.rst

@@ -0,0 +1,57 @@
+The :mod:`qiskit_ibm_runtime` package has been extended with two new modules: :mod:`.circuit` and 
+:mod:`.circuit.library`. These modules are designed to mirror the structure of the 
+corresponding `qiskit` SDK modules, while providing vendor-specific implementations of 
+circuit objects and instructions. 
+
+The first addition to this new circuit library is the :class:`.MidCircuitMeasure` class. 
+This class enables the creation of instructions that follow the naming convention 
+`measure_<identifier>`, which are mapped to specific mid-circuit measurement
+ hardware instructions matching that pattern. The default name for this instruction is `"measure_2"`.
+ Example usage::
+
+    from qiskit import QuantumCircuit
+    from qiskit_ibm_runtime.circuit import MidCircuitMeasure
+
+    measure_2 = MidCircuitMeasure()
+    measure_reset = MidCircuitMeasure("measure_3")
+    qc = QuantumCircuit(1, 1)
+    qc.append(measure_2, [0], [0])
+    qc.append(measure_reset, [0], [0])
+    qc.measure([0], [0])
+
+Output::
+
+       ┌────────────┐┌────────────────┐┌─┐
+    q: ┤0           ├┤0               ├┤M├
+       │  Measure_2 ││  Measure_reset │└╥┘
+    c: ╡0           ╞╡0               ╞═╩═
+       └────────────┘└────────────────┘
+
+
+The :func:`.convert_to_target` utility has been updated to support an additional ``"instruction_signatures"`` field in 
+backend configuration files (``configuration.json``). This field is intended to represent non-unitary, non-standard instructions 
+reported by the backend and should respect the following schema::
+
+    "instruction_signatures" = [
+        {
+            "name": "measure_2",
+            "num_qubits": 1,
+            "num_clbits": 1,
+            "parameters": [],
+            "return_type": "Bool",
+            "description": "An alternative measurement. This can be used as a mid-circuit measurement in a dynamic circuit. ",
+        },
+        {
+            "name": "reset_2",
+            "num_qubits": 1,
+            "num_clbits": 1,
+            "parameters": [],
+            "return_type": "Bool",
+            "description": "An alternative reset instruction.",
+        }
+    ]
+
+
+
+In addition to this change, the :func:`.convert_to_target` function now accepts a ``custom_name_mapping`` argument
+and exposes the ``add_delay`` and ``filter_faulty`` flags from the original core implementation.

test/unit/circuit/__init__.py

@@ -0,0 +1,11 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2025.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.