diff --git a/.github/workflows/build-pyslang.yml b/.github/workflows/build-pyslang.yml
index fe4291bb7d3a..c09785d0cfb0 100644
--- a/.github/workflows/build-pyslang.yml
+++ b/.github/workflows/build-pyslang.yml
@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: MIT
 ---
 # This workflow is based on the `build_wheels` job of
-# https://github.com/MikePopoloski/slang/blob/v11.0/.github/workflows/python-dist.yml
+# https://github.com/MikePopoloski/slang/blob/v12.0/.github/workflows/python-dist.yml
 name: Build pyslang wheels (riscv64)
 
 on:
@@ -45,17 +45,30 @@ jobs:
       package: pyslang
       version: ${{ inputs.version }}
 
+  # v12.0.0 moved bindings/CMakeLists.txt from pybind11 to nanobind's split mode
+  # (nanobind_add_module(... BACKEND_MODULE nanobind_backend STABLE_ABI_VERSION
+  # 3.11)): pyproject.toml now sets `wheel.py-api = "cp311"`, so cibuildwheel
+  # produces a single cp311-abi3 wheel that covers every newer non-free-threaded
+  # interpreter (CLAUDE.md gotcha 11), and upstream's own python-dist.yml builds
+  # it once per OS with no interpreter matrix at all. Building it on cp312+
+  # here (as the old per-interpreter pybind11 matrix did) would tag the wheel
+  # cp311-abi3 while compiling it against newer headers than the tag claims
+  # (gotcha 96), so build on cp311, the floor the tag actually promises.
+  #
+  # Free-threaded (cp314t) is dropped: nanobind-backend>=1.0 publishes no
+  # cp313t/cp314t wheel on *any* platform (only cp315t), so pyslang ships no
+  # free-threaded wheel upstream either (the litellm/gotcha-11 "abi3-only, no
+  # cp314t variant" shape) -- this is an upstream gap, not riscv64-specific.
   build_wheels:
     needs: [setup]
     if: needs.setup.outputs.versions != '[]'
-    name: Build pyslang ${{ matrix.version }} ${{ matrix.python }}-manylinux_riscv64
+    name: Build pyslang ${{ matrix.version }} cp311-abi3-manylinux_riscv64
     runs-on: ubuntu-24.04-riscv
     timeout-minutes: 360
     strategy:
       fail-fast: false
       matrix:
         version: ${{ fromJSON(needs.setup.outputs.versions) }}
-        python: ["cp312", "cp313", "cp314", "cp314t"]
 
     env:
       PYSLANG_VERSION: ${{ matrix.version }}
@@ -90,7 +103,7 @@ jobs:
         uses: pypa/cibuildwheel@1828c10ab37f080699c7b81cea34097c684a7074  # v4.2.0
         with:
           output-dir: wheelhouse/
-          only: ${{ matrix.python }}-manylinux_riscv64
+          only: cp311-manylinux_riscv64
         env:
           CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
           CIBW_ENVIRONMENT: 'SKBUILD_WHEEL_LICENSE_FILES="LICENSE;LICENSE.boost-headers;LICENSE.bs-thread-pool;LICENSE.fmt;LICENSE.pybind11"'
@@ -101,8 +114,10 @@ jobs:
           import sys, zipfile
           names = zipfile.ZipFile(sys.argv[1]).namelist()
           exts = [n for n in names if n.endswith(".so")]
-          assert len(exts) == 1 and exts[0].startswith("pyslang/pyslang.cpython-"), exts
-          assert exts[0].endswith("-riscv64-linux-gnu.so"), exts
+          # nanobind's split mode (stable ABI) names the extension
+          # "<module>.abi3.so" with no interpreter/platform tag baked in -- that
+          # information already lives in the wheel's own filename instead.
+          assert exts == ["pyslang/pyslang.abi3.so"], exts
           assert any(n.endswith(".pyi") for n in names), names
           licences = {n.split(".dist-info/licenses/", 1)[1] for n in names
                       if ".dist-info/licenses/" in n and not n.endswith("/")}
@@ -112,7 +127,7 @@ jobs:
 
       - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
         with:
-          name: pyslang-${{ env.PYSLANG_VERSION }}-${{ matrix.python }}-manylinux_riscv64
+          name: pyslang-${{ env.PYSLANG_VERSION }}-cp311-abi3-manylinux_riscv64
           path: wheelhouse/*.whl
           if-no-files-found: error
 
diff --git a/docs/packages/pyslang.yaml b/docs/packages/pyslang.yaml
index 6eaa773b1e07..e0e5816e6353 100644
--- a/docs/packages/pyslang.yaml
+++ b/docs/packages/pyslang.yaml
@@ -13,3 +13,4 @@ versions:
     sha256: 4a7afec71fefc257b7e5c8ef21afd4cafab307e996cab86028f78f8b9676764f
   - filename: pyslang-11.0.0-cp314-cp314t-manylinux_2_39_riscv64.whl
     sha256: 594be7f4426650552dd3e58803d2b5bd7c0582c6a90bdee1899270edc0e722b7
+- version: 12.0.0