diff --git a/.github/workflows/pr-checks.yml b/.github/workflows/pr-checks.yml
index 3915fddf53..ed514c9cd9 100644
--- a/.github/workflows/pr-checks.yml
+++ b/.github/workflows/pr-checks.yml
@@ -45,7 +45,7 @@ jobs:
         uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
         with:
           node-version: ${{ matrix.node-version }}
-          cache: 'npm'
+          cache: "npm"
 
       - name: Install dependencies
         run: |
@@ -77,33 +77,6 @@ jobs:
           sarif_file: eslint.sarif
           category: eslint
 
-  changetool-tests:
-    name: changetool unit tests
-    permissions:
-      contents: read
-    runs-on: ubuntu-slim
-    timeout-minutes: 10
-
-    concurrency:
-      cancel-in-progress: ${{ github.event_name == 'pull_request' || false }}
-      group: pr-checks-changetool-tests-${{ github.ref }}-${{ github.event_name }}
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-
-      - name: Set up Node.js
-        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
-        with:
-          node-version: 24
-          cache: 'npm'
-
-      - name: Install dependencies
-        run: npm ci
-
-      - name: Run changetool unit tests
-        run: npm --workspace changetool test
-
   # These checks do not need to be run as part of the same matrix that we use for the `unit-tests`
   # job.
   other-checks:
@@ -126,7 +99,7 @@ jobs:
         uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
         with:
           node-version: 24
-          cache: 'npm'
+          cache: "npm"
 
       - name: Install dependencies
         id: install-deps
@@ -190,14 +163,14 @@ jobs:
           path: ${{ runner.temp }}/repo-size/
           if-no-files-found: error
 
-      - name: 'Backport: Check out base ref'
+      - name: "Backport: Check out base ref"
         id: checkout-base
         if: ${{ startsWith(github.head_ref, 'backport-') }}
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           ref: ${{ github.base_ref }}
 
-      - name: 'Backport: Verify Node versions unchanged'
+      - name: "Backport: Verify Node versions unchanged"
         if: steps.checkout-base.outcome == 'success'
         env:
           HEAD_VERSION: ${{ steps.head-version.outputs.node_version }}
diff --git a/eslint.config.mjs b/eslint.config.mjs
index f82f071321..a64e92701d 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -180,7 +180,7 @@ export default [
     },
   },
   {
-    files: ["pr-checks/**/*.ts"],
+    files: ["pr-checks/**/*.ts", "pr-checks/**/*.mts"],
 
     languageOptions: {
       parserOptions: {
@@ -209,18 +209,4 @@ export default [
       ],
     },
   },
-  {
-    files: ["scripts/changetool/**/*.ts"],
-
-    languageOptions: {
-      parserOptions: {
-        project: "./scripts/changetool/tsconfig.json",
-      },
-    },
-
-    rules: {
-      "no-console": "off",
-      "import/extensions": "off",
-    },
-  },
 ];
diff --git a/package-lock.json b/package-lock.json
index da14fd0ed6..354dc58bde 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,8 +9,7 @@
       "version": "4.37.10",
       "license": "MIT",
       "workspaces": [
-        "pr-checks",
-        "scripts/changetool"
+        "pr-checks"
       ],
       "dependencies": {
         "@actions/artifact": "^5.0.3",
@@ -3010,346 +3009,6 @@
         "url": "https://opencollective.com/eslint"
       }
     },
-    "node_modules/@typescript/typescript-aix-ppc64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-aix-ppc64/-/typescript-aix-ppc64-7.0.2.tgz",
-      "integrity": "sha1-zcfOgdYPHgkDSWDd+x+4gNendrY=",
-      "cpu": [
-        "ppc64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "aix"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-darwin-arm64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-darwin-arm64/-/typescript-darwin-arm64-7.0.2.tgz",
-      "integrity": "sha1-pV/fz6WN9Y0n2yI3zealweNacjU=",
-      "cpu": [
-        "arm64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-darwin-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-darwin-x64/-/typescript-darwin-x64-7.0.2.tgz",
-      "integrity": "sha1-ONHJFygAqR1we+xk0qNwoBZjTbQ=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-freebsd-arm64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-2.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-freebsd-arm64/-/typescript-freebsd-arm64-7.0.2.tgz",
-      "integrity": "sha1-8f+IEAMLNdK1vg22otxlBGDqlPo=",
-      "cpu": [
-        "arm64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "freebsd"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-freebsd-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-2.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-freebsd-x64/-/typescript-freebsd-x64-7.0.2.tgz",
-      "integrity": "sha1-PYawPzU8WxupUWLrbONVM7/ClL0=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "freebsd"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-arm": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-arm/-/typescript-linux-arm-7.0.2.tgz",
-      "integrity": "sha1-rZS0HhruKk3MaimMe2fEM0X94y4=",
-      "cpu": [
-        "arm"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-arm64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-arm64/-/typescript-linux-arm64-7.0.2.tgz",
-      "integrity": "sha1-2TNNltbaxv+F2pyGVYiUjek56R8=",
-      "cpu": [
-        "arm64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-loong64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-loong64/-/typescript-linux-loong64-7.0.2.tgz",
-      "integrity": "sha1-KWWu5PyHM2ATnYk9qv5jl6KROK0=",
-      "cpu": [
-        "loong64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-mips64el": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-mips64el/-/typescript-linux-mips64el-7.0.2.tgz",
-      "integrity": "sha1-Goh6MRvtOoM/gL/Uqe03wnGTbPA=",
-      "cpu": [
-        "mips64el"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-ppc64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-ppc64/-/typescript-linux-ppc64-7.0.2.tgz",
-      "integrity": "sha1-i2PJsvRFs5PrTkPsIdoiXa3jV30=",
-      "cpu": [
-        "ppc64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-riscv64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-2.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-riscv64/-/typescript-linux-riscv64-7.0.2.tgz",
-      "integrity": "sha1-tuijXCibPql6kqQdRhqu7Q07NuE=",
-      "cpu": [
-        "riscv64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-s390x": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-s390x/-/typescript-linux-s390x-7.0.2.tgz",
-      "integrity": "sha1-Lvlmk75IYfbReWVCflsAnLvtGj4=",
-      "cpu": [
-        "s390x"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-linux-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-linux-x64/-/typescript-linux-x64-7.0.2.tgz",
-      "integrity": "sha1-cyacsLq6UK6gygYERaa4jlg/HOI=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-netbsd-arm64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-2.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-netbsd-arm64/-/typescript-netbsd-arm64-7.0.2.tgz",
-      "integrity": "sha1-OjZJ+X+vohC05uN5jBXgZgXIqQE=",
-      "cpu": [
-        "arm64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "netbsd"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-netbsd-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-netbsd-x64/-/typescript-netbsd-x64-7.0.2.tgz",
-      "integrity": "sha1-R+xZSRpAxHDSgH3E0rglUo/Zeas=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "netbsd"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-openbsd-arm64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-17.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-openbsd-arm64/-/typescript-openbsd-arm64-7.0.2.tgz",
-      "integrity": "sha1-eWvo2gvZidij+5bygB44qDZbS68=",
-      "cpu": [
-        "arm64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "openbsd"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-openbsd-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-2.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-openbsd-x64/-/typescript-openbsd-x64-7.0.2.tgz",
-      "integrity": "sha1-03/ipynrlCwHbEVO5/GBX699Vg8=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "openbsd"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-sunos-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-17.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-sunos-x64/-/typescript-sunos-x64-7.0.2.tgz",
-      "integrity": "sha1-q6jTRkw1ZacER4m6upaRa9SrLIg=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "sunos"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-win32-arm64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-win32-arm64/-/typescript-win32-arm64-7.0.2.tgz",
-      "integrity": "sha1-ud5QoXGWOD9iYgtfnQovNK07YNc=",
-      "cpu": [
-        "arm64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "win32"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
-    "node_modules/@typescript/typescript-win32-x64": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-2.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@typescript/typescript-win32-x64/-/typescript-win32-x64-7.0.2.tgz",
-      "integrity": "sha1-zzt7DWzlY12spMjgHBic3N5H7Dw=",
-      "cpu": [
-        "x64"
-      ],
-      "dev": true,
-      "license": "Apache-2.0",
-      "optional": true,
-      "os": [
-        "win32"
-      ],
-      "engines": {
-        "node": ">=16.20.0"
-      }
-    },
     "node_modules/@typespec/ts-http-runtime": {
       "version": "0.3.2",
       "resolved": "https://registry.npmjs.org/@typespec/ts-http-runtime/-/ts-http-runtime-0.3.2.tgz",
@@ -4496,10 +4155,6 @@
         "url": "https://github.com/chalk/chalk?sponsor=1"
       }
     },
-    "node_modules/changetool": {
-      "resolved": "scripts/changetool",
-      "link": true
-    },
     "node_modules/character-entities": {
       "version": "2.0.2",
       "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/character-entities/-/character-entities-2.0.2.tgz",
@@ -7582,8 +7237,8 @@
     },
     "node_modules/lite-matter": {
       "version": "0.1.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/lite-matter/-/lite-matter-0.1.2.tgz",
-      "integrity": "sha1-NlO1r/xDs8OnKQcf/kw4/a4O1Ws=",
+      "resolved": "https://registry.npmjs.org/lite-matter/-/lite-matter-0.1.2.tgz",
+      "integrity": "sha512-cGSYxO6vcipYZBSF5dUtDF3IqbkNxSjVQuvs5Ol3fO35URzHEvG2Ml0KbH5kvXXsx33SgbfwiVp6afwovarD8A==",
       "license": "MIT",
       "dependencies": {
         "yaml": "^2.9.0"
@@ -7717,8 +7372,8 @@
     },
     "node_modules/mdast-util-from-markdown": {
       "version": "2.0.3",
-      "resolved": "https://ms-feed-17.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/mdast-util-from-markdown/-/mdast-util-from-markdown-2.0.3.tgz",
-      "integrity": "sha1-yVgiuRqrdfGKTL6LL1G4c+0s8Mc=",
+      "resolved": "https://registry.npmjs.org/mdast-util-from-markdown/-/mdast-util-from-markdown-2.0.3.tgz",
+      "integrity": "sha512-W4mAWTvSlKvf8L6J+VN9yLSqQ9AOAAvHuoDAmPkz4dHf553m5gVj2ejadHJhoJmcmxEnOv6Pa8XJhpxE93kb8Q==",
       "license": "MIT",
       "dependencies": {
         "@types/mdast": "^4.0.0",
@@ -10724,6 +10379,8 @@
         "@octokit/core": "^7.0.7",
         "@octokit/plugin-paginate-rest": ">=15.0.0",
         "@octokit/plugin-rest-endpoint-methods": "^18.0.0",
+        "lite-matter": "^0.1.2",
+        "mdast-util-from-markdown": "^2.0.3",
         "semver": "^7.8.5",
         "yaml": "^2.9.0"
       },
@@ -10731,71 +10388,6 @@
         "@types/node": "^20.19.43",
         "tsx": "^4.23.12"
       }
-    },
-    "scripts/changetool": {
-      "version": "1.0.0",
-      "license": "MIT",
-      "dependencies": {
-        "lite-matter": "^0.1.2",
-        "mdast-util-from-markdown": "^2.0.3"
-      },
-      "devDependencies": {
-        "@types/node": "^26.2.0",
-        "tsx": "^4.23.12",
-        "typescript": "^7.0.2"
-      }
-    },
-    "scripts/changetool/node_modules/@types/node": {
-      "version": "26.2.0",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@types/node/-/node-26.2.0.tgz",
-      "integrity": "sha1-Wkh1qGL9qP3Ffej6pXm7gey6FoU=",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "undici-types": "~8.3.0"
-      }
-    },
-    "scripts/changetool/node_modules/typescript": {
-      "version": "7.0.2",
-      "resolved": "https://ms-feed-12.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/typescript/-/typescript-7.0.2.tgz",
-      "integrity": "sha1-nsdz15VKjBgsF8xbvVdaoovFFYI=",
-      "dev": true,
-      "license": "Apache-2.0",
-      "bin": {
-        "tsc": "bin/tsc"
-      },
-      "engines": {
-        "node": ">=16.20.0"
-      },
-      "optionalDependencies": {
-        "@typescript/typescript-aix-ppc64": "7.0.2",
-        "@typescript/typescript-darwin-arm64": "7.0.2",
-        "@typescript/typescript-darwin-x64": "7.0.2",
-        "@typescript/typescript-freebsd-arm64": "7.0.2",
-        "@typescript/typescript-freebsd-x64": "7.0.2",
-        "@typescript/typescript-linux-arm": "7.0.2",
-        "@typescript/typescript-linux-arm64": "7.0.2",
-        "@typescript/typescript-linux-loong64": "7.0.2",
-        "@typescript/typescript-linux-mips64el": "7.0.2",
-        "@typescript/typescript-linux-ppc64": "7.0.2",
-        "@typescript/typescript-linux-riscv64": "7.0.2",
-        "@typescript/typescript-linux-s390x": "7.0.2",
-        "@typescript/typescript-linux-x64": "7.0.2",
-        "@typescript/typescript-netbsd-arm64": "7.0.2",
-        "@typescript/typescript-netbsd-x64": "7.0.2",
-        "@typescript/typescript-openbsd-arm64": "7.0.2",
-        "@typescript/typescript-openbsd-x64": "7.0.2",
-        "@typescript/typescript-sunos-x64": "7.0.2",
-        "@typescript/typescript-win32-arm64": "7.0.2",
-        "@typescript/typescript-win32-x64": "7.0.2"
-      }
-    },
-    "scripts/changetool/node_modules/undici-types": {
-      "version": "8.3.0",
-      "resolved": "https://ms-feed-17.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/undici-types/-/undici-types-8.3.0.tgz",
-      "integrity": "sha1-ROn8nzJEZIzeo15Pm7LWgelBCAk=",
-      "dev": true,
-      "license": "MIT"
     }
   }
 }
diff --git a/package.json b/package.json
index 0e8fc4bb2a..c77b851044 100644
--- a/package.json
+++ b/package.json
@@ -17,8 +17,7 @@
   },
   "license": "MIT",
   "workspaces": [
-    "pr-checks",
-    "scripts/changetool"
+    "pr-checks"
   ],
   "dependencies": {
     "@actions/artifact": "^5.0.3",
diff --git a/scripts/changetool/cli/validate.ts b/pr-checks/changelog/validate.mts
similarity index 100%
rename from scripts/changetool/cli/validate.ts
rename to pr-checks/changelog/validate.mts
diff --git a/scripts/changetool/cli/validate.test.ts b/pr-checks/changelog/validate.test.mts
similarity index 84%
rename from scripts/changetool/cli/validate.test.ts
rename to pr-checks/changelog/validate.test.mts
index ac54972fdf..a5ad97e97a 100644
--- a/scripts/changetool/cli/validate.test.ts
+++ b/pr-checks/changelog/validate.test.mts
@@ -10,12 +10,12 @@ import {
   isValidChangenoteFilename,
   hasValidChangenoteCategory,
   VALID_CHANGE_NOTE_CATEGORIES,
-} from "./validate.ts";
+} from "./validate.mjs";
 
 async function withTmpFile<T>(
   baseFileName: string,
   contents: string,
-  body: (filePath: string) => Promise<T>,
+  body: (filePath: string) => Promise<T> | T,
 ): Promise<T> {
   const tmpDir = fs.mkdtempSync(
     path.join(os.tmpdir(), "changetool-validate-test-"),
@@ -23,14 +23,14 @@ async function withTmpFile<T>(
   try {
     const filePath = path.join(tmpDir, baseFileName);
     fs.writeFileSync(filePath, contents);
-    return await body(filePath);
+    return await Promise.resolve(body(filePath));
   } finally {
     fs.rmSync(tmpDir, { recursive: true, force: true });
   }
 }
 
 await describe("isValidChangenoteContent", async () => {
-  await it("recognizes an unordered Markdown list", async () => {
+  await it("recognizes an unordered Markdown list", () => {
     const inputs = [
       "- One changenote entry",
       "- First item\n- Second item",
@@ -42,7 +42,7 @@ await describe("isValidChangenoteContent", async () => {
     }
   });
 
-  await it("does not recognize non-Markdown text", async () => {
+  await it("does not recognize non-Markdown text", () => {
     const inputs = [
       "This is not a list.",
       '["this", "is", "JSON"]',
@@ -57,7 +57,7 @@ await describe("isValidChangenoteContent", async () => {
     }
   });
 
-  await it("does not recognize ordered Markdown lists", async () => {
+  await it("does not recognize ordered Markdown lists", () => {
     const inputs = [
       "1. First item\n2. Second item",
       "\n\n\n1. First item\n1. Second item",
@@ -68,7 +68,7 @@ await describe("isValidChangenoteContent", async () => {
     }
   });
 
-  await it("requires all list items to use a hyphen bullet", async () => {
+  await it("requires all list items to use a hyphen bullet", () => {
     const inputs = [
       "* Fixed a bug\n* Added feature",
       "+ Fixed a bug\n+ Added feature",
@@ -85,7 +85,7 @@ await describe("isValidChangenoteContent", async () => {
     }
   });
 
-  await it("does not contain other Markdown elements", async () => {
+  await it("does not contain other Markdown elements", () => {
     const inputs = [
       "- Fixed a bug\n\nParagraph of text",
       "- Fixed a bug\n\n* Added a feature",
@@ -100,7 +100,7 @@ await describe("isValidChangenoteContent", async () => {
 });
 
 await describe("isValidChangenoteFilename", async () => {
-  await it("accepts valid filenames", async () => {
+  await it("accepts valid filenames", () => {
     const inputs = [
       "2023-01-01-fix-bug.md",
       "2023-12-31-add-feature.md",
@@ -112,7 +112,7 @@ await describe("isValidChangenoteFilename", async () => {
     }
   });
 
-  await it("rejects invalid filenames", async () => {
+  await it("rejects invalid filenames", () => {
     const inputs = [
       "missing-date-from-filename.md",
       "2021-01-01.md",
@@ -126,14 +126,14 @@ await describe("isValidChangenoteFilename", async () => {
 });
 
 await describe("hasValidChangenoteCategory", async () => {
-  await it("accepts valid categories", async () => {
+  await it("accepts valid categories", () => {
     for (const category of Object.keys(VALID_CHANGE_NOTE_CATEGORIES)) {
       const frontmatter = { category };
       assert.equal(hasValidChangenoteCategory(frontmatter), true);
     }
   });
 
-  await it("rejects invalid categories", async () => {
+  await it("rejects invalid categories", () => {
     const inputs = [
       "",
       "invalid-category",
@@ -150,7 +150,7 @@ await describe("hasValidChangenoteCategory", async () => {
     }
   });
 
-  await it("reject missing category", async () => {
+  await it("reject missing category", () => {
     assert.equal(hasValidChangenoteCategory({}), false);
     assert.equal(hasValidChangenoteCategory({ category: null }), false);
     assert.equal(hasValidChangenoteCategory({ category: undefined }), false);
@@ -162,7 +162,7 @@ await describe("isValidChangenoteFile", async () => {
     await withTmpFile(
       "2026-01-01-fix-bug.md",
       "---\ncategory: fix\n---\n- Fixed a bug\n",
-      async (filePath) => {
+      (filePath) => {
         assert.equal(isValidChangenoteFile(filePath), true);
       },
     );
@@ -172,7 +172,7 @@ await describe("isValidChangenoteFile", async () => {
     await withTmpFile(
       "fix-bug.md",
       "---\ncategory: fix\n---\n- Fixed a bug\n",
-      async (filePath) => {
+      (filePath) => {
         assert.equal(isValidChangenoteFile(filePath), false);
       },
     );
@@ -182,7 +182,7 @@ await describe("isValidChangenoteFile", async () => {
     await withTmpFile(
       "2026-01-01-fix-bug.md",
       "- Fixed a bug\n",
-      async (filePath) => {
+      (filePath) => {
         assert.equal(isValidChangenoteFile(filePath), false);
       },
     );
@@ -192,7 +192,7 @@ await describe("isValidChangenoteFile", async () => {
     await withTmpFile(
       "2026-01-01-fix-bug.md",
       "---\ncategory: fix\n---\n* Fixed a bug\n",
-      async (filePath) => {
+      (filePath) => {
         assert.equal(isValidChangenoteFile(filePath), false);
       },
     );
diff --git a/pr-checks/package.json b/pr-checks/package.json
index 00f4b813c2..b211d91898 100644
--- a/pr-checks/package.json
+++ b/pr-checks/package.json
@@ -1,12 +1,14 @@
 {
   "private": true,
-  "description": "Dependencies for the sync.ts",
+  "description": "Dependencies for codeql-action scripts",
   "dependencies": {
     "@actions/core": "^2.0.3",
     "@actions/github": "^8.0.1",
     "@octokit/core": "^7.0.7",
     "@octokit/plugin-paginate-rest": ">=15.0.0",
     "@octokit/plugin-rest-endpoint-methods": "^18.0.0",
+    "lite-matter": "^0.1.2",
+    "mdast-util-from-markdown": "^2.0.3",
     "semver": "^7.8.5",
     "yaml": "^2.9.0"
   },
diff --git a/pr-checks/tsconfig.json b/pr-checks/tsconfig.json
index b010827cf5..67f31d2cdb 100644
--- a/pr-checks/tsconfig.json
+++ b/pr-checks/tsconfig.json
@@ -6,8 +6,8 @@
     "module": "preserve",
     "rootDir": "..",
     "sourceMap": false,
-    "noEmit": true,
+    "noEmit": true
   },
-  "include": ["./*.ts", "../src/**/*.ts"],
+  "include": ["./**/*.ts", "./**/*.mts", "../src/**/*.ts"],
   "exclude": ["node_modules"]
 }
diff --git a/scripts/changetool/index.ts b/pr-checks/validate-changelog.mts
old mode 100644
new mode 100755
similarity index 86%
rename from scripts/changetool/index.ts
rename to pr-checks/validate-changelog.mts
index 249448b3fb..6990fa6944
--- a/scripts/changetool/index.ts
+++ b/pr-checks/validate-changelog.mts
@@ -1,7 +1,9 @@
+#!/usr/bin/env npx tsx
+
 import { pathToFileURL } from "node:url";
 import { parseArgs } from "node:util";
 
-import { isValidChangenoteFile } from "./cli/validate.ts";
+import { isValidChangenoteFile } from "./changelog/validate.mjs";
 
 const entryPoint = process.argv[1];
 if (entryPoint && import.meta.url === pathToFileURL(entryPoint).href) {
@@ -32,7 +34,7 @@ function main(): number {
 }
 
 function usage(): number {
-  console.log("Usage: changetool validate <path> [<path> ...]");
+  console.log(`Usage: validate-changelog.mts validate <path> [<path> ...]`);
   return 0;
 }
 
diff --git a/scripts/changetool/package.json b/scripts/changetool/package.json
deleted file mode 100644
index 7eb8ceb9be..0000000000
--- a/scripts/changetool/package.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "name": "changetool",
-  "version": "1.0.0",
-  "private": true,
-  "description": "Validates change-notes and merges them into CHANGELOG.md",
-  "license": "MIT",
-  "type": "module",
-  "scripts": {
-    "start": "tsx index.ts",
-    "test": "node --test --experimental-strip-types cli/*.test.ts"
-  },
-  "devDependencies": {
-    "@types/node": "^26.2.0",
-    "tsx": "^4.23.12",
-    "typescript": "^7.0.2"
-  },
-  "dependencies": {
-    "lite-matter": "^0.1.2",
-    "mdast-util-from-markdown": "^2.0.3"
-  }
-}
diff --git a/scripts/changetool/tsconfig.json b/scripts/changetool/tsconfig.json
deleted file mode 100644
index ee76bd1869..0000000000
--- a/scripts/changetool/tsconfig.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "extends": "../../tsconfig.json",
-  "compilerOptions": {
-    "module": "preserve",
-    "allowImportingTsExtensions": true,
-    "rootDir": ".",
-    "sourceMap": false
-  },
-  "include": ["./**/*.ts"],
-  "exclude": ["node_modules"]
-}
diff --git a/tsconfig.json b/tsconfig.json
index d2b39b5ef1..66545447c5 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -37,5 +37,5 @@
       "@octokit/core/dist-types/types": ["./node_modules/@octokit/core/dist-types/types.d.ts"]
     },
   },
-  "exclude": ["node_modules", "pr-checks", "scripts/changetool"]
+  "exclude": ["node_modules", "pr-checks"]
 }