diff --git a/.github/workflows/test-pr.yml b/.github/workflows/test-pr.yml
index 99e98a9b9..5e8cf2181 100644
--- a/.github/workflows/test-pr.yml
+++ b/.github/workflows/test-pr.yml
@@ -39,7 +39,7 @@ jobs:
     steps:
       - name: 'Check out code'
         uses: actions/checkout@v3
-        with:    
+        with:
           submodules: recursive
       - name: 'Install Poetry'
         uses: Gr1N/setup-poetry@v8
@@ -53,7 +53,7 @@ jobs:
     steps:
       - name: 'Check out code'
         uses: actions/checkout@v3
-        with:    
+        with:
           submodules: recursive
       - name: 'Install Poetry'
         uses: Gr1N/setup-poetry@v8
@@ -67,23 +67,24 @@ jobs:
     steps:
       - name: 'Check out code'
         uses: actions/checkout@v3
-        with:    
+        with:
           submodules: recursive
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with:
           username: rvdockerhub
-          password: ${{ secrets.DOCKERHUB_PASSWORD }} 
+          password: ${{ secrets.DOCKERHUB_PASSWORD }}
 
       - name: 'Set up Docker'
         uses: ./.github/actions/with-docker
         with:
           container-name: kwasm-ci-integration-${{ github.sha }}
-      - name: 'Build LLVM Backend and pykwasm'
-        run: docker exec -u user kwasm-ci-integration-${GITHUB_SHA} make -j2 build-llvm
+      - name: 'Build pykwasm'
+        run: docker exec -u user kwasm-ci-integration-${GITHUB_SHA} poetry -C pykwasm install
+      - name: 'Build LLVM definition'
+        run: docker exec -u user kwasm-ci-integration-${GITHUB_SHA} poetry -C pykwasm run kdist -v build wasm-semantics.llvm
       - name: 'Build and run integration tests'
-        run: docker exec -u user kwasm-ci-integration-${GITHUB_SHA} make -C pykwasm cov-integration \
-                 TEST_ARGS='--llvm-dir ../.build/defn/llvm/test-kompiled'
+        run: docker exec -u user kwasm-ci-integration-${GITHUB_SHA} make -C pykwasm cov-integration
       - name: 'Tear down Docker'
         if: always()
         run: |
@@ -105,13 +106,15 @@ jobs:
         with:
           username: rvdockerhub
           password: ${{ secrets.DOCKERHUB_PASSWORD }}
-        
+
       - name: 'Set up Docker'
         uses: ./.github/actions/with-docker
         with:
           container-name: kwasm-ci-parse-${{ github.sha }}
-      - name: 'Build LLVM Backend and pykwasm'
-        run: docker exec -u user kwasm-ci-parse-${GITHUB_SHA} make -j2 build-llvm RELEASE=true
+      - name: 'Build pykwasm'
+        run: docker exec -u user kwasm-ci-parse-${GITHUB_SHA} poetry -C pykwasm install
+      - name: 'Build LLVM definition'
+        run: docker exec -u user kwasm-ci-parse-${GITHUB_SHA} poetry -C pykwasm run kdist -v build wasm-semantics.llvm
       - name: 'Conformance parse'
         run: docker exec -u user kwasm-ci-parse-${GITHUB_SHA} make test-conformance-parse
       - name: 'Tear down Docker'
@@ -129,23 +132,25 @@ jobs:
         uses: actions/checkout@v3
         with:
           submodules: recursive
- 
+
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with:
           username: rvdockerhub
           password: ${{ secrets.DOCKERHUB_PASSWORD }}
-   
+
       - name: 'Set up Docker'
         uses: ./.github/actions/with-docker
         with:
           container-name: kwasm-ci-conformance-${{ github.sha }}
-      - name: 'Build LLVM Backend'
-        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} make -j2 build-llvm RELEASE=true
+      - name: 'Build pykwasm'
+        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} poetry -C pykwasm install
+      - name: 'Build LLVM definition'
+        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} poetry -C pykwasm run kdist -v build wasm-semantics.llvm
       - name: 'Simple tests'
-        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} make -j2 TEST_CONCRETE_BACKEND=llvm test-simple
+        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} make -j2 test-simple
       - name: 'Conformance run'
-        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} make -j2 TEST_CONCRETE_BACKEND=llvm test-conformance-supported
+        run: docker exec -u user kwasm-ci-conformance-${GITHUB_SHA} make -j2 test-conformance-supported
       - name: 'Tear down Docker'
         if: always()
         run: |
@@ -165,8 +170,10 @@ jobs:
         uses: ./.github/actions/with-docker
         with:
           container-name: kwasm-ci-prove-${{ github.sha }}
-      - name: 'Build Haskell Backend'
-        run: docker exec -u user kwasm-ci-prove-${GITHUB_SHA} make -j2 build-haskell build-wrc20
+      - name: 'Build pykwasm'
+        run: docker exec -u user kwasm-ci-prove-${GITHUB_SHA} poetry -C pykwasm install
+      - name: 'Build Haskell definitions'
+        run: docker exec -u user kwasm-ci-prove-${GITHUB_SHA} poetry -C pykwasm run kdist -v build wasm-semantics.{kwasm-lemmas,wrc20} -j2
       - name: 'Prove'
         run: docker exec -u user kwasm-ci-prove-${GITHUB_SHA} make -j6 test-prove
       - name: 'Tear down Docker'
diff --git a/Makefile b/Makefile
index dd0fa2db5..c9242d2d1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,109 +1,29 @@
-# Settings
-# --------
-
-BUILD_DIR := .build
-DEFN_DIR  := $(BUILD_DIR)/defn
-K_INCLUDE_DIR ?= $(CURDIR)
-
 .PHONY: all                                                                \
-        build build-llvm build-haskell build-wrc20                         \
         test test-execution test-simple test-prove                         \
         test-conformance test-conformance-parse test-conformance-supported \
         media presentations reports
 
+
 all: build
 
+
 # Building Definition
 # -------------------
 
-KOMPILE_OPTS         :=
-LLVM_KOMPILE_OPTS    :=
-HASKELL_KOMPILE_OPTS :=
-
-tangle_selector := k
-
-SOURCE_FILES       := data         \
-                      kwasm-lemmas \
-                      numeric      \
-                      test         \
-                      wasm         \
-                      wasm-text    \
-                      wrc20
-EXTRA_SOURCE_FILES :=
-ALL_SOURCE_FILES   := $(patsubst %, %.md, $(SOURCE_FILES)) $(EXTRA_SOURCE_FILES)
-
-build: build-llvm build-haskell build-wrc20
-
-ifneq (,$(RELEASE))
-    KOMPILE_OPTS += -O2 --gen-glr-bison-parser
-else
-    KOMPILE_OPTS += --debug
-endif
-
-ifeq (,$(RELEASE))
-    LLVM_KOMPILE_OPTS += -g
-endif
-
-KOMPILE_LLVM := kompile --backend llvm --md-selector "$(tangle_selector)" \
-                $(KOMPILE_OPTS)                                           \
-                $(addprefix -ccopt ,$(LLVM_KOMPILE_OPTS))
-
-KOMPILE_HASKELL := kompile --backend haskell --md-selector "$(tangle_selector)" \
-                   $(KOMPILE_OPTS)                                              \
-                   $(HASKELL_KOMPILE_OPTS)                                      \
-                   --warnings-to-errors
-
-### LLVM
-
-llvm_files         := $(ALL_SOURCE_FILES)
-llvm_main_module   := WASM-TEST
-llvm_syntax_module := $(llvm_main_module)-SYNTAX
-llvm_main_file     := test
-llvm_dir           := $(DEFN_DIR)/llvm/$(llvm_main_file)-kompiled
-llvm_kompiled      := $(llvm_dir)/interpreter
-
-build-llvm: $(llvm_kompiled)
-
-$(llvm_kompiled): $(llvm_files)
-	$(KOMPILE_LLVM) $(llvm_main_file).md      \
-	    --output-definition $(llvm_dir) -I $(K_INCLUDE_DIR)  \
-	    --main-module $(llvm_main_module)     \
-	    --syntax-module $(llvm_syntax_module) \
-	    --emit-json
-
-### Haskell
-
-haskell_files         := $(ALL_SOURCE_FILES)
-haskell_main_module   := KWASM-LEMMAS
-haskell_syntax_module := WASM-TEXT-SYNTAX
-haskell_main_file     := kwasm-lemmas
-haskell_dir           := $(DEFN_DIR)/haskell/$(haskell_main_file)-kompiled
-haskell_kompiled      := $(haskell_dir)/definition.kore
-
-build-haskell: $(haskell_kompiled)
-
-$(haskell_kompiled): $(haskell_files)
-	$(KOMPILE_HASKELL) $(haskell_main_file).md   \
-	    --output-definition $(haskell_dir) -I $(K_INCLUDE_DIR)  \
-	    --main-module $(haskell_main_module)     \
-	    --syntax-module $(haskell_syntax_module)
-
-### WRC-20 Verification
-
-wrc20_files         := $(haskell_files) wrc20.md
-wrc20_main_module   := WRC20-LEMMAS
-wrc20_syntax_module := WASM-TEXT-SYNTAX
-wrc20_main_file     := wrc20
-wrc20_dir           := $(DEFN_DIR)/haskell/$(wrc20_main_file)-kompiled
-wrc20_kompiled      := $(wrc20_dir)/definition.kore
-
-build-wrc20: $(wrc20_kompiled)
-
-$(wrc20_kompiled): $(wrc20_files)
-	$(KOMPILE_HASKELL) $(wrc20_main_file).md   \
-	    --output-definition $(wrc20_dir) -I $(K_INCLUDE_DIR)  \
-	    --main-module $(wrc20_main_module)     \
-	    --syntax-module $(wrc20_syntax_module)
+POETRY := poetry -C pykwasm
+
+.PHONY: pykwasm
+pykwasm:
+	$(POETRY) install
+
+.PHONY: build
+build: pykwasm
+	$(POETRY) run kdist -v build -j3
+
+.PHONY: clean
+clean: pykwasm
+	$(POETRY) run kdist clean
+
 
 # Testing
 # -------
@@ -114,31 +34,33 @@ CHECK := git --no-pager diff --no-index --ignore-all-space -R
 TEST_CONCRETE_BACKEND := llvm
 TEST_SYMBOLIC_BACKEND := haskell
 
+SOURCE_DIR := pykwasm/src/pykwasm/kdist
+
 test: test-execution test-prove
 
 # Generic Test Harnesses
 
-tests/%.run: tests/% $(llvm_kompiled)
+tests/%.run: tests/%
 	$(TEST) run --backend $(TEST_CONCRETE_BACKEND) $< > tests/$*.$(TEST_CONCRETE_BACKEND)-out
 	$(CHECK) tests/$*.$(TEST_CONCRETE_BACKEND)-out tests/success-$(TEST_CONCRETE_BACKEND).out
 	rm -rf tests/$*.$(TEST_CONCRETE_BACKEND)-out
 
-tests/%.run-term: tests/% $(llvm_kompiled)
+tests/%.run-term: tests/%
 	$(TEST) run --backend $(TEST_CONCRETE_BACKEND) $< > tests/$*.$(TEST_CONCRETE_BACKEND)-out
 	grep --after-context=2 "<instrs>" tests/$*.$(TEST_CONCRETE_BACKEND)-out > tests/$*.$(TEST_CONCRETE_BACKEND)-out-term
 	$(CHECK) tests/$*.$(TEST_CONCRETE_BACKEND)-out-term tests/success-k.out
 	rm -rf tests/$*.$(TEST_CONCRETE_BACKEND)-out
 	rm -rf tests/$*.$(TEST_CONCRETE_BACKEND)-out-term
 
-tests/%.parse: tests/% $(llvm_kompiled)
+tests/%.parse: tests/%
 	$(TEST) kast --backend $(TEST_CONCRETE_BACKEND) $< kast > $@-out
 	rm -rf $@-out
 
-tests/%.prove: tests/% $(haskell_kompiled)
-	$(TEST) prove --backend $(TEST_SYMBOLIC_BACKEND) $< $(haskell_main_file)
+tests/%.prove: tests/%
+	$(TEST) prove --backend $(TEST_SYMBOLIC_BACKEND) $< kwasm-lemmas -I $(SOURCE_DIR)
 
-tests/proofs/wrc20-spec.k.prove: tests/proofs/wrc20-spec.k $(wrc20_kompiled)
-	$(TEST) prove --backend $(TEST_SYMBOLIC_BACKEND) $< $(wrc20_main_file)
+tests/proofs/wrc20-spec.k.prove: tests/proofs/wrc20-spec.k
+	$(TEST) prove --backend $(TEST_SYMBOLIC_BACKEND) $< wrc20 -I $(SOURCE_DIR)
 
 ### Execution Tests
 
@@ -169,8 +91,10 @@ proof_tests:=$(wildcard tests/proofs/*-spec.k)
 
 test-prove: $(proof_tests:=.prove)
 
+
 # Analysis
 # --------
+
 json_build := $(haskell_dir)/parsed.json
 
 $(json_build):
@@ -179,6 +103,7 @@ $(json_build):
 graph-imports: $(json_build)
 	kpyk $(haskell_dir) graph-imports
 
+
 # Presentation
 # ------------
 
diff --git a/kbuild.toml b/kbuild.toml
deleted file mode 100644
index 3a909ea98..000000000
--- a/kbuild.toml
+++ /dev/null
@@ -1,13 +0,0 @@
-[project]
-name = "wasm-semantics"
-version = "1.0.0"
-source = "."
-
-[targets.llvm]
-main-file = 'test.md'
-main-module = 'WASM-TEST'
-backend='llvm'
-
-[targets.haskell]
-main-file = 'kwasm-lemmas.md'
-backend='haskell'
diff --git a/kwasm b/kwasm
index bb3d12ac6..89b499801 100755
--- a/kwasm
+++ b/kwasm
@@ -8,7 +8,8 @@ fatal() { echo "[FATAL] $@" ; exit 1 ; }
 
 kwasm_dir="${KWASM_DIR:-$(dirname $0)}"
 build_dir="$kwasm_dir/.build"
-defn_dir="${KWASM_DEFN_DIR:-$build_dir/defn}"
+kdist_dir="$(poetry -C pykwasm run -- kdist which)"
+defn_dir="${KWASM_DEFN_DIR:-$kdist_dir}/wasm-semantics"
 lib_dir="$build_dir/local/lib"
 k_release_dir="${K_RELEASE:-$kwasm_dir/deps/k/k-distribution/target/release/k}"
 if [[ ! -f "${k_release_dir}/bin/kompile" ]]; then
@@ -45,13 +46,8 @@ preprocess() {
 # -------
 
 run_krun() {
-    local additional_run_args
-
-    additional_run_args=()
-    ! $bug_report || additional_run_args+=(--haskell-backend-command "kore-exec --bug-report $bug_report_name")
-
     preprocess
-    krun --definition "$backend_dir/test-kompiled" "$run_file" "${additional_run_args[@]}" "$@"
+    krun --definition "$defn_dir/llvm" "$run_file" "$@"
 }
 
 run_kast() {
@@ -59,7 +55,7 @@ run_kast() {
 
     preprocess
     output_mode="${1:-kast}" ; shift
-    kast --definition "$backend_dir/test-kompiled" "$run_file" --output "$output_mode" "$@"
+    kast --definition "$defn_dir/llvm" "$run_file" --output "$output_mode" "$@"
 }
 
 run_prove() {
@@ -71,7 +67,7 @@ run_prove() {
     ! $repl       || additional_proof_args+=(--debugger)
     ! $bug_report || additional_proof_args+=(--haskell-backend-command "kore-exec --bug-report $bug_report_name")
 
-    kprove --definition "$backend_dir/$def_module-kompiled" -I "$kwasm_dir" "$run_file" "${additional_proof_args[@]}" "$@"
+    kprove --definition "$defn_dir/$def_module" -I "$kwasm_dir" "$run_file" "${additional_proof_args[@]}" "$@"
 }
 
 # Main
@@ -146,8 +142,6 @@ set -- "${args[@]}"
 ! $repl       || [[ "$backend" == "haskell" ]] || fatal "--repl option only available for Haskell backend."
 ! $bug_report || [[ "$backend" == "haskell" ]] || fatal "--bug-report option only available for Haskell backend."
 
-backend_dir="$defn_dir/$backend"
-
 # get the run file
 [[ ! -z ${1:-} ]] || usage_fatal "Must supply a file to run on."
 run_file="$1" ; shift
diff --git a/package/version b/package/version
index 7db267292..a2e1aa9d9 100644
--- a/package/version
+++ b/package/version
@@ -1 +1 @@
-0.1.26
+0.1.27
diff --git a/pykwasm/pyproject.toml b/pykwasm/pyproject.toml
index 06e5a2d4b..bcb6e8b60 100644
--- a/pykwasm/pyproject.toml
+++ b/pykwasm/pyproject.toml
@@ -4,12 +4,15 @@ build-backend = "poetry.core.masonry.api"
 
 [tool.poetry]
 name = "pykwasm"
-version = "0.1.26"
+version = "0.1.27"
 description = ""
 authors = [
     "Runtime Verification, Inc. <contact@runtimeverification.com>",
 ]
 
+[tool.poetry.plugins.kdist]
+wasm-semantics = "pykwasm.kdist.plugin"
+
 [tool.poetry.dependencies]
 python = "^3.10"
 cytoolz = "^0.12.1"
diff --git a/pykwasm/src/pykwasm/kdist/__init__.py b/pykwasm/src/pykwasm/kdist/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/auxil.md b/pykwasm/src/pykwasm/kdist/auxil.md
similarity index 100%
rename from auxil.md
rename to pykwasm/src/pykwasm/kdist/auxil.md
diff --git a/data.md b/pykwasm/src/pykwasm/kdist/data.md
similarity index 100%
rename from data.md
rename to pykwasm/src/pykwasm/kdist/data.md
diff --git a/data/int-type.k b/pykwasm/src/pykwasm/kdist/data/int-type.k
similarity index 100%
rename from data/int-type.k
rename to pykwasm/src/pykwasm/kdist/data/int-type.k
diff --git a/data/list-int.k b/pykwasm/src/pykwasm/kdist/data/list-int.k
similarity index 100%
rename from data/list-int.k
rename to pykwasm/src/pykwasm/kdist/data/list-int.k
diff --git a/data/list-ref.k b/pykwasm/src/pykwasm/kdist/data/list-ref.k
similarity index 100%
rename from data/list-ref.k
rename to pykwasm/src/pykwasm/kdist/data/list-ref.k
diff --git a/data/map-int-to-int.k b/pykwasm/src/pykwasm/kdist/data/map-int-to-int.k
similarity index 100%
rename from data/map-int-to-int.k
rename to pykwasm/src/pykwasm/kdist/data/map-int-to-int.k
diff --git a/data/sparse-bytes.k b/pykwasm/src/pykwasm/kdist/data/sparse-bytes.k
similarity index 100%
rename from data/sparse-bytes.k
rename to pykwasm/src/pykwasm/kdist/data/sparse-bytes.k
diff --git a/data/tools.k b/pykwasm/src/pykwasm/kdist/data/tools.k
similarity index 100%
rename from data/tools.k
rename to pykwasm/src/pykwasm/kdist/data/tools.k
diff --git a/kwasm-lemmas.md b/pykwasm/src/pykwasm/kdist/kwasm-lemmas.md
similarity index 100%
rename from kwasm-lemmas.md
rename to pykwasm/src/pykwasm/kdist/kwasm-lemmas.md
diff --git a/numeric.md b/pykwasm/src/pykwasm/kdist/numeric.md
similarity index 100%
rename from numeric.md
rename to pykwasm/src/pykwasm/kdist/numeric.md
diff --git a/pykwasm/src/pykwasm/kdist/plugin.py b/pykwasm/src/pykwasm/kdist/plugin.py
new file mode 100644
index 000000000..dbf95582d
--- /dev/null
+++ b/pykwasm/src/pykwasm/kdist/plugin.py
@@ -0,0 +1,71 @@
+from __future__ import annotations
+
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+from pyk.kbuild.utils import k_version
+from pyk.kdist.api import Target
+from pyk.ktool.kompile import KompileBackend, kompile
+
+if TYPE_CHECKING:
+    from collections.abc import Mapping
+    from typing import Any, Final
+
+
+SOURCE_DIR: Final = Path(__file__).parent
+
+
+class KompileTarget(Target):
+    _kompile_args: dict[str, Any]
+
+    def __init__(self, kompile_args: Mapping[str, Any]):
+        self._kompile_args = dict(kompile_args)
+
+    def build(self, output_dir: Path, deps: dict[str, Path], args: dict[str, Any], verbose: bool) -> None:
+        kompile(
+            output_dir=output_dir,
+            verbose=verbose,
+            **self._kompile_args,
+        )
+
+    def source(self) -> tuple[Path, ...]:
+        return (SOURCE_DIR,)
+
+    def context(self) -> dict[str, str]:
+        return {'k-version': k_version().text}
+
+
+__TARGETS__: Final = {
+    'llvm': KompileTarget(
+        {
+            'backend': KompileBackend.LLVM,
+            'main_file': SOURCE_DIR / 'test.md',
+            'main_module': 'WASM-TEST',
+            'syntax_module': 'WASM-TEST-SYNTAX',
+            'md_selector': 'k',
+            'gen_glr_bison_parser': True,
+            'opt_level': 2,
+            'ccopts': ['-g'],
+        },
+    ),
+    'kwasm-lemmas': KompileTarget(
+        {
+            'backend': KompileBackend.HASKELL,
+            'main_file': SOURCE_DIR / 'kwasm-lemmas.md',
+            'main_module': 'KWASM-LEMMAS',
+            'syntax_module': 'WASM-TEXT-SYNTAX',
+            'md_selector': 'k',
+            'warning_to_error': True,
+        },
+    ),
+    'wrc20': KompileTarget(
+        {
+            'backend': KompileBackend.HASKELL,
+            'main_file': SOURCE_DIR / 'wrc20.md',
+            'main_module': 'WRC20-LEMMAS',
+            'syntax_module': 'WASM-TEXT-SYNTAX',
+            'md_selector': 'k',
+            'warning_to_error': True,
+        },
+    ),
+}
diff --git a/test.md b/pykwasm/src/pykwasm/kdist/test.md
similarity index 100%
rename from test.md
rename to pykwasm/src/pykwasm/kdist/test.md
diff --git a/wasm-text.md b/pykwasm/src/pykwasm/kdist/wasm-text.md
similarity index 100%
rename from wasm-text.md
rename to pykwasm/src/pykwasm/kdist/wasm-text.md
diff --git a/wasm.md b/pykwasm/src/pykwasm/kdist/wasm.md
similarity index 100%
rename from wasm.md
rename to pykwasm/src/pykwasm/kdist/wasm.md
diff --git a/wrc20.md b/pykwasm/src/pykwasm/kdist/wrc20.md
similarity index 100%
rename from wrc20.md
rename to pykwasm/src/pykwasm/kdist/wrc20.md
diff --git a/pykwasm/src/tests/conftest.py b/pykwasm/src/tests/conftest.py
index d452bb084..fa3446575 100644
--- a/pykwasm/src/tests/conftest.py
+++ b/pykwasm/src/tests/conftest.py
@@ -2,6 +2,7 @@
 
 import pytest
 from pyk.cli.utils import dir_path
+from pyk.kdist import kdist
 from pyk.ktool.krun import KRun
 from pytest import Config, Parser
 
@@ -16,12 +17,17 @@ def pytest_addoption(parser: Parser) -> None:
 
 
 @pytest.fixture(scope='session')
-def llvm_dir(pytestconfig: Config) -> Path:
-    ldir = pytestconfig.getoption('llvm_dir')
-    assert isinstance(ldir, Path)
-    return ldir
+def llvm_dir(pytestconfig: Config) -> Path | None:
+    return pytestconfig.getoption('llvm_dir')
 
 
 @pytest.fixture(scope='session')
-def krun_llvm(llvm_dir: Path) -> KRun:
+def krun_llvm(llvm_dir: Path | None) -> KRun:
+    if llvm_dir is not None:
+        return KRun(llvm_dir)
+
+    llvm_dir = kdist.which('wasm-semantics.llvm')
+    if not llvm_dir.is_dir():
+        raise ValueError('LLVM definition not found. Run make from the repository root, or pass --llvm-dir')
+
     return KRun(llvm_dir)