diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e03b4a6..f4e44ec 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: 7mind/github-env@minimal
       - name: Run test build
-        run: ./run --nix :test
+        run: nix develop --command mdl --github-actions :test
 
   publish-scala:
     runs-on: ubuntu-latest
@@ -45,7 +45,7 @@ jobs:
             popd
           fi
 
-          ./run --nix :publish-scala
+          nix develop --command mdl --github-actions :publish-scala
 
   publish-sjs:
     runs-on: ubuntu-latest
@@ -77,7 +77,7 @@ jobs:
             popd
           fi
 
-          ./run --nix :build-sjs
+          nix develop --command mdl --github-actions :build-sjs
       - uses: softprops/action-gh-release@v2
         id: create-release
         if: startsWith(github.ref, 'refs/tags/')
@@ -86,7 +86,7 @@ jobs:
             ./json-sick-scala/target/dist/**
       - name: Prepare and Publish to npm
         if: startsWith(github.ref, 'refs/tags/')
-        run: ./run --nix :publish-npm
+        run: nix develop --command mdl --github-actions :publish-npm
 
   publish-cs:
     runs-on: ubuntu-latest
@@ -101,4 +101,4 @@ jobs:
           secrets: |
             637c5cad-a680-4ea3-ac8b-b193010bee40 > TOKEN_NUGET
       - name: Build and Test
-        run: ./run --nix :publish-cs
+        run: nix develop --command mdl --github-actions :publish-cs
diff --git a/.gitignore b/.gitignore
index 236300f..f50a107 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@ target
 .bsp
 metals.sbt
 .direnv
+.mdl/runs
 
 npm-publish
 node_modules/
diff --git a/.mdl/defs/actions.md b/.mdl/defs/actions.md
new file mode 100644
index 0000000..f5d0637
--- /dev/null
+++ b/.mdl/defs/actions.md
@@ -0,0 +1,207 @@
+# SICK Build Actions
+
+# environment
+- `LANG=C.UTF-8`
+
+## passthrough
+- `HOME`
+- `USER`
+- `CI_BRANCH`
+- `CI_BRANCH_TAG`
+- `CI_BUILD_UNIQ_SUFFIX`
+- `CI_PULL_REQUEST`
+- `TOKEN_NUGET`
+- `NODE_AUTH_TOKEN`
+
+# action: clean-worktree
+
+```bash
+set -euo pipefail
+
+PROJECT_ROOT="${sys.project-root}"
+cd "$PROJECT_ROOT"
+
+git clean -fxd -e private -e .idea -e .mdl -e .mdl/runs
+
+ret cleaned:bool=true
+```
+
+# action: test-scala
+
+```bash
+dep action.clean-worktree
+
+set -euo pipefail
+
+SCALA_DIR="${sys.project-root}/json-sick-scala"
+cd "$SCALA_DIR"
+
+sbt +clean +test:compile +test
+
+ret success:bool=true
+```
+
+# action: test-csharp
+
+```bash
+dep action.test-scala
+
+set -euo pipefail
+
+CS_DIR="${sys.project-root}/json-sick-csharp"
+cd "$CS_DIR"
+
+dotnet build
+dotnet test
+
+ret success:bool=true
+```
+
+# action: test
+
+```bash
+dep action.test-csharp
+
+ret success:bool=true
+```
+
+# action: publish-scala
+
+```bash
+set -euo pipefail
+
+SCALA_DIR="${sys.project-root}/json-sick-scala"
+
+CI_PULL_REQUEST_VAL="${CI_PULL_REQUEST:-true}"
+CI_BRANCH_TAG_VAL="${CI_BRANCH_TAG:-}"
+
+if [[ "$CI_PULL_REQUEST_VAL" != "false" ]]; then
+  echo "Skipping Scala publish because this is a pull request."
+  ret skipped:bool=true
+  exit 0
+fi
+
+if [[ -z "$CI_BRANCH_TAG_VAL" ]]; then
+  echo "CI_BRANCH_TAG is required to publish Scala artifacts." >&2
+  exit 1
+fi
+
+cd "$SCALA_DIR"
+
+if [[ "$CI_BRANCH_TAG_VAL" =~ ^v.*$ ]]; then
+  sbt +clean +compile +publishSigned sonaUpload sonaRelease
+  sbt '++2.13 json-sickJS/fullOptJS'
+else
+  sbt +clean +compile +publishSigned
+fi
+
+ret success:bool=true
+```
+
+# action: build-sjs
+
+```bash
+set -euo pipefail
+
+SCALA_DIR="${sys.project-root}/json-sick-scala"
+DIST_DIR="${SCALA_DIR}/target/dist"
+
+CI_PULL_REQUEST_VAL="${CI_PULL_REQUEST:-true}"
+if [[ "$CI_PULL_REQUEST_VAL" != "false" ]]; then
+  echo "Skipping Scala.js build because this is a pull request."
+  mkdir -p "$DIST_DIR"
+  ret skipped:bool=true
+  ret dist-dir:directory="$DIST_DIR"
+  exit 0
+fi
+
+cd "$SCALA_DIR"
+sbt '++2.13 json-sickJS/fullOptJS'
+
+ret dist-dir:directory="$DIST_DIR"
+```
+
+# action: publish-cs
+
+```bash
+set -euo pipefail
+
+CI_PULL_REQUEST_VAL="${CI_PULL_REQUEST:-true}"
+TOKEN_NUGET_VAL="${TOKEN_NUGET:-}"
+CI_BUILD_UNIQ_SUFFIX_VAL="${CI_BUILD_UNIQ_SUFFIX:-}"
+CI_BRANCH_TAG_VAL="${CI_BRANCH_TAG:-}"
+
+if [[ "$CI_PULL_REQUEST_VAL" != "false" ]]; then
+  echo "Skipping C# publish because this is a pull request."
+  ret skipped:bool=true
+  exit 0
+fi
+
+if [[ -z "$TOKEN_NUGET_VAL" ]]; then
+  echo "TOKEN_NUGET is required to publish C# artifacts; skipping." >&2
+  ret skipped:bool=true
+  exit 0
+fi
+
+if [[ -z "$CI_BUILD_UNIQ_SUFFIX_VAL" ]]; then
+  echo "CI_BUILD_UNIQ_SUFFIX is required to publish C# artifacts; skipping." >&2
+  ret skipped:bool=true
+  exit 0
+fi
+
+CS_DIR="${sys.project-root}/json-sick-csharp"
+cd "$CS_DIR"
+
+if [[ "$CI_BRANCH_TAG_VAL" =~ ^v.*$ ]]; then
+  dotnet build -c Release
+else
+  dotnet build -c Release --version-suffix "alpha.${CI_BUILD_UNIQ_SUFFIX_VAL}"
+fi
+
+find . -name '*.nupkg' -type f -print0 | xargs -I % -n 1 -0 dotnet nuget push % -k "${TOKEN_NUGET_VAL}" --source https://api.nuget.org/v3/index.json
+
+ret success:bool=true
+```
+
+# action: publish-npm
+
+```bash
+dep action.build-sjs
+
+set -euo pipefail
+
+CI_PULL_REQUEST_VAL="${CI_PULL_REQUEST:-true}"
+if [[ "$CI_PULL_REQUEST_VAL" != "false" ]]; then
+  echo "Skipping npm publish because this is a pull request."
+  ret skipped:bool=true
+  exit 0
+fi
+
+PROJECT_ROOT="${sys.project-root}"
+DIST_DIR="${action.build-sjs.dist-dir}"
+PUBLISH_DIR="${PROJECT_ROOT}/npm-publish"
+VERSION_FILE="${PROJECT_ROOT}/version.txt"
+VERSION=$(tr -d '\n' < "$VERSION_FILE")
+
+if [[ ! -d "$DIST_DIR" ]]; then
+  echo "Scala.js distribution directory '$DIST_DIR' is missing." >&2
+  exit 1
+fi
+
+rm -rf "$PUBLISH_DIR"
+mkdir -p "$PUBLISH_DIR"
+
+cp "${DIST_DIR}"/* "$PUBLISH_DIR"/
+cp "${PROJECT_ROOT}/json-sick-scala/npm-template/"* "$PUBLISH_DIR"/
+
+sed -i "s/VERSION_PLACEHOLDER/$VERSION/g" "$PUBLISH_DIR/package.json"
+
+cd "$PUBLISH_DIR"
+
+npm install --save-dev ava
+npm test
+npm publish --provenance --access public
+
+ret success:bool=true
+ret publish-dir:directory="$PUBLISH_DIR"
+```
diff --git a/.mobala/env.sh b/.mobala/env.sh
deleted file mode 100755
index f81166f..0000000
--- a/.mobala/env.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-if [[ "${DO_VERBOSE}" == 1 ]] ; then set -x ; fi
-
-set_jvm_options
-debug_env
-
-# this script receives all the CLI args from the main script and may decide which flows should be enabled
-flow_enable do-build
\ No newline at end of file
diff --git a/.mobala/flows/do-build.sh b/.mobala/flows/do-build.sh
deleted file mode 100755
index f94a80a..0000000
--- a/.mobala/flows/do-build.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-function do-build() {
-  step_run_cond run-test
-  step_run_cond run-publish-scala
-  step_run_cond run-build-sjs
-  step_run_cond run-publish-cs
-  step_run_cond run-publish-npm
-}
diff --git a/.mobala/keep.env b/.mobala/keep.env
deleted file mode 100644
index 599c834..0000000
--- a/.mobala/keep.env
+++ /dev/null
@@ -1 +0,0 @@
-TOKEN_NUGET
\ No newline at end of file
diff --git a/.mobala/steps/run-build-sjs.sh b/.mobala/steps/run-build-sjs.sh
deleted file mode 100755
index f0bd6c1..0000000
--- a/.mobala/steps/run-build-sjs.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-function run-build-sjs() {
-  cd json-sick-scala
-
-  [[ "$CI_PULL_REQUEST" != "false"  ]] && exit 0
-
-  sbt '++2.13 json-sickJS/fullOptJS'
-}
diff --git a/.mobala/steps/run-publish-cs.sh b/.mobala/steps/run-publish-cs.sh
deleted file mode 100755
index 2502846..0000000
--- a/.mobala/steps/run-publish-cs.sh
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-function run-publish-cs() {
-  cd json-sick-csharp
-  
-  [[ "$CI_PULL_REQUEST" != "false"  ]] && exit 0
-  [[ -z "$TOKEN_NUGET" ]] && exit 0
-  [[ -z "$CI_BUILD_UNIQ_SUFFIX" ]] && exit 0
-  
-  if [[ "$CI_BRANCH_TAG" =~ ^v.*$ ]] ; then
-      dotnet build -c Release
-  else
-      dotnet build -c Release --version-suffix "alpha.${CI_BUILD_UNIQ_SUFFIX}"
-  fi
-  
-  find . -name '*.nupkg' -type f -print0 | xargs -I % -n 1 -0 dotnet nuget push % -k "${TOKEN_NUGET}" --source https://api.nuget.org/v3/index.json
-}
\ No newline at end of file
diff --git a/.mobala/steps/run-publish-npm.sh b/.mobala/steps/run-publish-npm.sh
deleted file mode 100644
index 7b8ad1c..0000000
--- a/.mobala/steps/run-publish-npm.sh
+++ /dev/null
@@ -1,23 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-function run-publish-npm() {
-  [[ "$CI_PULL_REQUEST" != "false"  ]] && exit 0
-
-  VERSION=$(cat version.txt | tr -d '\n')
-  mkdir -p npm-publish
-  cp ./json-sick-scala/target/dist/* npm-publish/
-  cp ./json-sick-scala/npm-template/* npm-publish/
-  sed -i "s/VERSION_PLACEHOLDER/$VERSION/g" npm-publish/package.json
-  ls -la npm-publish/
-  cat npm-publish/package.json
-
-  cd npm-publish
-
-  nix develop --command bash -c "
-    npm install --save-dev ava
-    npm test
-    npm publish --provenance --access public
-  "
-}
diff --git a/.mobala/steps/run-publish-scala.sh b/.mobala/steps/run-publish-scala.sh
deleted file mode 100755
index 4fbcbef..0000000
--- a/.mobala/steps/run-publish-scala.sh
+++ /dev/null
@@ -1,16 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-function run-publish-scala() {
-  cd json-sick-scala
-  
-  [[ "$CI_PULL_REQUEST" != "false"  ]] && exit 0
-
-  if [[ "$CI_BRANCH_TAG" =~ ^v.*$ ]] ; then
-      sbt +clean +compile +publishSigned sonaUpload sonaRelease
-      sbt '++2.13 json-sickJS/fullOptJS'
-  else
-      sbt +clean +compile +publishSigned
-  fi
-}
diff --git a/.mobala/steps/run-test.sh b/.mobala/steps/run-test.sh
deleted file mode 100755
index c1e6846..0000000
--- a/.mobala/steps/run-test.sh
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-function run-test() {
-  git clean -fxd -e private -e .idea
-  
-  pushd .
-  cd ./json-sick-scala
-  sbt +clean +test:compile +test
-  popd
-  
-  pushd .
-  cd ./json-sick-csharp
-  dotnet build
-  dotnet test
-  
-  popd
-}
\ No newline at end of file
diff --git a/.mobala/version-commit.lock b/.mobala/version-commit.lock
deleted file mode 100644
index cec2249..0000000
--- a/.mobala/version-commit.lock
+++ /dev/null
@@ -1,2 +0,0 @@
-87a6a202f917745e826d6f245f78db48cb92965b
-0
\ No newline at end of file
diff --git a/.mobala/version.txt b/.mobala/version.txt
deleted file mode 100644
index ce57f64..0000000
--- a/.mobala/version.txt
+++ /dev/null
@@ -1 +0,0 @@
-develop
\ No newline at end of file
diff --git a/flake.lock b/flake.lock
index 9eb9bcc..d16760f 100644
--- a/flake.lock
+++ b/flake.lock
@@ -18,6 +18,45 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "mudyla": {
+      "inputs": {
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1764278888,
+        "narHash": "sha256-RRmR6hLsW97AFoVJ3UCH//mcewTQpNrZHItIzxodzbs=",
+        "owner": "7mind",
+        "repo": "mudyla",
+        "rev": "aa1e86c5cbcc8c9b00e1cbf8a188a0ab36c42149",
+        "type": "github"
+      },
+      "original": {
+        "owner": "7mind",
+        "repo": "mudyla",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1761827546,
@@ -37,6 +76,7 @@
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
+        "mudyla": "mudyla",
         "nixpkgs": "nixpkgs"
       }
     },
@@ -54,6 +94,21 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",
diff --git a/flake.nix b/flake.nix
index 9a350d6..b220226 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,7 +5,10 @@
 
   inputs.flake-utils.url = "github:numtide/flake-utils";
 
-  outputs = { self, nixpkgs, flake-utils }:
+  inputs.mudyla.url = "github:7mind/mudyla";
+  inputs.mudyla.inputs.nixpkgs.follows = "nixpkgs";
+
+  outputs = { self, nixpkgs, flake-utils, mudyla }:
     flake-utils.lib.eachDefaultSystem
       (system:
         let
@@ -25,6 +28,8 @@
             openssl
 
             scala-cli
+          ] ++ [
+            mudyla.packages.${system}.default
           ];
         in
         {
@@ -32,8 +37,8 @@
 
           # use nix develop .#ide to enable JetBrains Rider from nixpkgs
           devShells.ide = pkgs.mkShell {
-            nativeBuildInputs = with pkgs.buildPackages; sharedPkgs ++ [
-              jetbrains.rider
+            nativeBuildInputs = sharedPkgs ++ [
+              pkgs.buildPackages.jetbrains.rider
             ];
             # LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath [ pkgs.stdenv.cc.cc.lib ];
           };
diff --git a/run b/run
index 1d6e53f..47d9dbd 100755
--- a/run
+++ b/run
@@ -2,84 +2,16 @@
 
 set -euo pipefail
 
-read_trimmed_string() { [[ -s "$1" ]] && sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//' "$1" || echo "$2"; }
+PROJECT_ROOT="$(cd "$(dirname "$0")" && pwd)"
+cd "$PROJECT_ROOT"
 
-export CACHE_DIR="${XDG_CACHE_HOME:-"${HOME}/.cache"}"
-export MOBALA_CACHE_MAIN="${CACHE_DIR}/mobala.sh"
-export MOBALA_CACHE_LIB="${CACHE_DIR}/mobala-lib.sh"
-export MOBALA_VERSION=$(read_trimmed_string ".mobala/version.txt" "release")
-export MOBALA_BASE="https://raw.githubusercontent.com/7mind/mobala/refs/heads/${MOBALA_VERSION}"
-export MOBALA_FILE="${MOBALA_BASE}/mobala.sh"
-export MOBALA_LIB_FILE="${MOBALA_BASE}/mobala-lib.sh"
-export MOBALA_SELF_UPDATE=${MOBALA_SELF_UPDATE:-1}
-export MOBALA_CACHE_UPDATE=${MOBALA_CACHE_UPDATE:-1}
+args=("$@")
+if [[ "${args[0]:-}" == "--nix" ]]; then
+  args=("${args[@]:1}")
+fi
 
-script_path="$(realpath "$0")"
-script_dirname="$(dirname "$script_path")"
+if command -v mdl >/dev/null 2>&1; then
+  exec mdl "${args[@]}"
+fi
 
-export MOBALA_PATH="${script_dirname}"
-export MOBALA_SUBDIR=${MOBALA_SUBDIR:-".mobala"}
-export MOBALA_KEEP=${MOBALA_KEEP:-"${MOBALA_PATH}/${MOBALA_SUBDIR}/keep.env"}
-export MOBALA_ENV=${MOBALA_ENV:-"${MOBALA_PATH}/${MOBALA_SUBDIR}/env.sh"}
-export MOBALA_MODS=${MOBALA_MODS:-"${MOBALA_PATH}/${MOBALA_SUBDIR}/mods"}
-export MOBALA_PARAMS=${MOBALA_PARAMS:-"${MOBALA_PATH}/${MOBALA_SUBDIR}/params"}
-
-function check-cache() {
-    if [[ -f "${MOBALA_CACHE_MAIN}" && -f "${MOBALA_CACHE_LIB}" ]]; then
-        echo "[info] mobala.sh cache found at '${MOBALA_CACHE_MAIN}'"
-    else
-        echo "[info] mobala.sh cache not found at '${MOBALA_CACHE_MAIN}'"
-    fi
-}
-
-function download-file() {
-    origin="${1}"
-    target="${2}"
-    mkdir -p "${CACHE_DIR}"
-    cache_name="$(basename "$target")"
-    cache_tmp="${CACHE_DIR}/${cache_name}.tmp"
-    rm -rf "${cache_tmp}"
-    download_response=$(curl -sLJ0 -H 'Cache-Control: no-cache, no-store' -o "${cache_tmp}" -w "%{response_code}" "${origin}" || true)
-    if [[ "${download_response}" == "200" ]]; then
-        rm -rf "${target}"
-        mv "${cache_tmp}" "${target}"
-        echo "[info] cache updated: ${target}"
-    else
-        echo "[warn] download failed with ${download_response} status code for ${target}"
-        rm "${cache_tmp}"
-    fi
-}
-
-
-function update-cache() {
-    if [[ "${MOBALA_CACHE_UPDATE}" == 1 ]] ; then
-        download-file "${MOBALA_LIB_FILE}" "${MOBALA_CACHE_LIB}"
-        download-file "${MOBALA_FILE}" "${MOBALA_CACHE_MAIN}"
-    fi
-}
-
-function verify-cache() {
-    if ! [[ -f "${MOBALA_CACHE_MAIN}" ]]; then
-        >&2 echo "[error] mobala.sh cache not found."
-        exit 1
-    fi
-    if ! [[ -f "${MOBALA_CACHE_LIB}" ]]; then
-        >&2 echo "[error] mobala-lib.sh cache not found."
-        exit 1
-    fi
-}
-
-function update-self(){
-  if [[ "${CI:-false}" == "false" && "${MOBALA_SELF_UPDATE}" == 1 ]] ; then
-    download-file "${MOBALA_BASE}/mobala-resolver.sh" "${script_path}"
-    chmod +x "${script_path}"
-  fi
-}
-
-trap 'update-self' EXIT
-
-check-cache
-update-cache
-verify-cache
-
-bash "${MOBALA_CACHE_MAIN}" "$@"
+exec nix run github:7mind/mudyla -- "${args[@]}"