QDSV Bridge

QDSV Bridge is the QDSV interoperability service for circuit-based quantum workflows. Applications submit a bounded decision request and receive a portable OpenQASM or Qiskit-ready artifact when the request is within the service's supported scope.

Version 0.7.x uses a deliberately narrow public boundary. The SDK contains domain request builders, an HTTP client and artifact adapters. The QDSV translation and implementation that derive an artifact run only in the Bridge service.

• Documentation
• PyPI
• Source

Business-First Quickstart

Describe the prepared candidates and decision rule; Bridge returns a portable artifact without requiring the application to author a quantum circuit.

from qdsv_bridge import (
    QDSVBridge,
    const,
    field,
    predicate_request,
)

suppliers = [
    {"supplier_id": 101, "quality": 820, "compliance": 1},
    {"supplier_id": 102, "quality": 680, "compliance": 1},
    {"supplier_id": 103, "quality": 760, "compliance": 0},
]

request = predicate_request(
    candidates=suppliers,
    rule={
        "op": "and",
        "args": [
            {"op": "gte", "left": field("quality"), "right": const(700)},
            {"op": "eq", "left": field("compliance"), "right": const(1)},
        ],
    },
    format="qasm2",
)

artifact = QDSVBridge().export(request)

print(artifact.format)
print(artifact.artifact_digest)

The candidates keep their business identifiers. The SDK sends the bounded public request to Bridge; it does not construct a circuit locally.

Qiskit integration

Install the optional adapter:

pip install "qdsv-bridge[qiskit]"

Then load the recommended artifact into your own Qiskit workflow:

from qdsv_bridge import QDSVBridge

bridge = QDSVBridge()
artifact = bridge.export(request)
qc = artifact.to_quantum_circuit()

export() is explicit: it sends only the public domain request to Bridge. Before Qiskit parses anything, the adapter confirms that artifact_digest matches the exact returned OpenQASM bytes and that the public verification status passed. to_quantum_circuit() makes no network request.

Bridge does not select a backend, transpile for a device, execute a simulator or QPU, or interpret execution results. Those remain under the user's Qiskit or provider workflow. The SDK has no local construction or circuit-generation fallback.

Semantic composition candidates

The official Bridge backend can also report the status of QDSV's Semantic Composition Engine (SCE). SCE generates composite operation candidates from bounded structured expressions and only marks them OFFICIAL_CANDIDATE when the backend evidence includes both operation-program verification and semantic cross-check over the declared finite domain.

from qdsv_bridge import QDSVBridgeClient

client = QDSVBridgeClient()
capabilities = client.composition_capabilities()

candidate = client.generate_composition_candidate(
    name="policy_gate_score_v1",
    expression={
        "op": "select_if",
        "args": [
            {"op": "gte", "args": [{"var": "risk"}, 5]},
            {"op": "add", "args": [{"op": "mul", "args": [{"var": "risk"}, 2]}, {"var": "impact"}]},
            {"var": "impact"},
        ],
    },
    domains=[
        {"type": "int_range", "variable": "risk", "start": 0, "end": 7},
        {"type": "int_range", "variable": "impact", "start": 0, "end": 7},
    ],
)

print(candidate["candidate"]["state"])
print(candidate["evidence"]["semantic_cross_check"]["status"])

Reference outputs may be used by the backend to verify candidate semantics, but the evidence must report reference_answers_used_for_materialization = false. The SDK does not include the private compiler or operation synthesis internals.

Public boundary

The SDK's stable contracts are qdsv_bridge_domain.v1 for requests and qdsv_bridge_public.v1 for responses. The Qiskit adapter accepts qasm2 and qasm3 artifacts.

The public service does not return internal intermediate representations, lowering plans, private build identities, or compilation diagnostics. Do not send confidential, regulated or secret data to a public endpoint.

The distributable wheel and source package are checked before release against the 0.7 public-distribution policy. The check fails when an unexpected module, historical documentation, implementation marker or unapproved package file is present.

Migration from 0.6.x

Release 0.7.0 was intentionally breaking. Replace legacy request builders with predicate_request() or score_request(), and receive a verified public artifact through QDSVBridge().export(request). See the 0.7 migration guide in the documentation before upgrading an existing integration.