Your formal tool just "proved" your chip is correct. The catch: the proof is worthless. Here's the failure mode quietly killing silicon in 2026. An LLM writes a SystemVerilog assertion — "grant must follow request." The formal engine runs it and returns PROVEN. You tape out. But the assertion was vacuously true. The antecedent — request — never fired, so the engine "proved" a property that could never be violated. You shipped a buggy design with a certificate that says correct. Siemens has been warning about vacuous proofs since 2017. The field still ships formal flows without vacuity checks. That isn't verification — it's theater. This matters now because first-silicon success has collapsed to 14% (Wilson/Siemens 2024), the lowest in 20 years of tracking, down from 32% in 2020. A 5nm mask respin runs $10-20M and climbs past $40M at 3nm. Your team is already running LLMs on Verilog, and the bug classes they can't catch — vacuity, protocol violations like AXI WVALID asserted before AWREADY, clock-domain crossings — are exactly the ones that pass simulation and die in silicon. Our position: don't rip out JasperGold or VC Formal. Wrap a fine-tuned open-weight LLM around the formal engine you already own, run it entirely on your own hardware so no RTL leaves your network, and put vacuity and coverage metrics in front of every "proven" result. If you verify RISC-V cores or AXI-based IP before tape-out, save this for your next formal review. Vacuity, protocol, or CDC — which hallucination class has bitten you worst in LLM-generated RTL? #SemiconductorVerification #FormalVerification #RISCV #ChipDesign #RTLDesign