[{"slug":"ZV-2026-0643","server_name":"quantum-expectations.com","severity":"breaking","title":"quantum-expectations.com: Type of distanceSurfaceCode on compare_hardware_scenarios changed integer → number.","summary":"[breaking] Type of distanceSurfaceCode on compare_hardware_scenarios changed integer → number. [breaking] Type of distanceSurfaceCode on compute_expectation changed integer → number. [risky] Description of compute_required_error_rate changed (39% word delta). [risky] Description of list_hardware_timings changed (51% word delta).","changes":[{"kind":"input_type_changed","path":"inputSchema.properties.distanceSurfaceCode","tool":"compare_hardware_scenarios","after":"number","before":"integer","detail":"Type of `distanceSurfaceCode` on `compare_hardware_scenarios` changed integer → number.","severity":"breaking"},{"kind":"input_type_changed","path":"inputSchema.properties.distanceSurfaceCode","tool":"compute_expectation","after":"number","before":"integer","detail":"Type of `distanceSurfaceCode` on `compute_expectation` changed integer → number.","severity":"breaking"},{"kind":"description_changed","tool":"compute_required_error_rate","after":"Inverse of compute_expectation. Given a circuit (numQubits, compDepth) and an acceptable effective error rate, return the required per-gate logical error rate (requiredLogicalErrorRatePerGate: a number, or null only when the target is genuinely unreachable; never 0) and, for every EC option (no-EC, surface-code per distance, every qLDPC code), the required physical error rate plus the subset of current SOTA hardware that already qualifies. An option whose inverse lands above the code threshold is capped at min(MAX_P, threshold) and carries a `note` (any sub-threshold p satisfies it); `unreachableReason` is reserved for genuinely unreachable options. Answers \"what hardware do I need to run this algorithm?\".","before":"Inverse of compute_expectation. Given a circuit (numQubits, compDepth) and an acceptable effective error rate, return the required per-gate logical error rate and, for every EC option (no-EC, surface-code per distance, every qLDPC code), the required physical error rate plus the subset of current SOTA hardware that already qualifies. Answers \"what hardware do I need to run this algorithm?\".","detail":"Description of `compute_required_error_rate` changed (39% word delta).","severity":"risky","descriptionDelta":0.38961038961038963},{"kind":"description_changed","tool":"list_hardware_timings","after":"Return per-platform gate-cycle timings (2Q gate time, readout time, in SI seconds) plus the testbed they were measured on (`representativeDevice`) and the native 2Q gate name, with source URLs. Joins list_current_quantum_computers via `hardwareType`, but the numbers are BEST-CASE DEMONSTRATIONS from small testbeds, not measurements on the joined devices, which run their gates and array readout orders of magnitude slower. Use for ratio analysis or as optimistic lower-bound inputs to runtime estimates and compute_quantum_volume_rate, and say so when you quote a runtime.","before":"Return per-platform gate-cycle timings (2Q gate time, readout time, in SI seconds) plus the representative device and native 2Q gate name, with source URLs. Joins list_current_quantum_computers via `hardwareType`. Use for runtime estimates, ratio analysis, or as inputs to compute_quantum_volume_rate. Values are representative current-generation numbers, not records.","detail":"Description of `list_hardware_timings` changed (51% word delta).","severity":"risky","descriptionDelta":0.5128205128205128}],"published_at":"2026-09-02T20:46:41.078Z"}]