diff --git a/action.yml b/action.yml
index 29369d9..0eb7870 100644
--- a/action.yml
+++ b/action.yml
@@ -43,17 +43,6 @@ runs:
       run: ${{ github.action_path }}/scripts/checkout.sh
       shell: bash
     - name: Run Ryu-Cho
-      env:
-        ACCESS_TOKEN: ${{ inputs.access-token }}
-        USER_NAME: ${{ inputs.username }}
-        EMAIL: ${{ inputs.email }}
-        UPSTREAM_REPO: ${{ inputs.upstream-repo }}
-        UPSTREAM_REPO_BRANCH: ${{ inputs.upstream-repo-branch }}
-        HEAD_REPO: ${{ inputs.head-repo }}
-        HEAD_REPO_BRANCH: ${{ inputs.head-repo-branch }}
-        TRACK_FROM: ${{ inputs.track-from }}
-        PATH_STARTS_WITH: ${{ inputs.path-starts-with }}
-        WORKFLOW_NAME: ${{ inputs.workflow-name }}
       run: |
         cd ryu-cho
         yarn install
diff --git a/package.json b/package.json
index e8884b3..3bccaef 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,7 @@
     "test:ui": "yarn lint && vitest --coverage --ui"
   },
   "dependencies": {
+    "@actions/core": "^1.9.0",
     "@octokit/rest": "^18.3.0",
     "@types/node": "^14.14.31",
     "@types/shelljs": "^0.8.8",
diff --git a/src/index.ts b/src/index.ts
index a9df293..83e8ec1 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,25 +1,21 @@
 import { assert } from './utils'
 import { createConfig } from './config'
 import { RyuCho } from './ryu-cho'
+import core from '@actions/core'
 
-assert(!!process.env.ACCESS_TOKEN, '`accessToken` is required.')
-assert(!!process.env.USER_NAME, '`userName` is required.')
-assert(!!process.env.EMAIL, '`email` is required.')
-assert(!!process.env.UPSTREAM_REPO, '`upstreamRepo` is required.')
-assert(!!process.env.HEAD_REPO, '`headRepo` is required.')
-assert(!!process.env.TRACK_FROM, '`trackFrom` is required.')
+assert(typeof core !== 'undefined', `core is undefined, which probably means you're not running in a GitHub Action`)
 
 const config = createConfig({
-  accessToken: process.env.ACCESS_TOKEN!,
-  userName: process.env.USER_NAME!,
-  email: process.env.EMAIL!,
-  upstreamRepo: process.env.UPSTREAM_REPO!,
-  upstreamRepoBranch: process.env.UPSTREAM_REPO_BRANCH,
-  headRepo: process.env.HEAD_REPO!,
-  headRepoBranch: process.env.HEAD_REPO_BRANCH,
-  workflowName: process.env.WORKFLOW_NAME,
-  trackFrom: process.env.TRACK_FROM!,
-  pathStartsWith: process.env.PATH_STARTS_WITH
+  accessToken: core.getInput('access-token', { required: true }),
+  userName: core.getInput('username', { required: true }),
+  email: core.getInput('email', { required: true }),
+  upstreamRepo: core.getInput('upstream-repo', { required: true }),
+  upstreamRepoBranch: core.getInput('upstream-repo-branch', { required: true }),
+  headRepo: core.getInput('head-repo', { required: true }),
+  headRepoBranch: core.getInput('head-repo-branch'),
+  workflowName: core.getInput('workflow-name'),
+  trackFrom: core.getInput('track-from', { required: true }),
+  pathStartsWith: core.getInput('path-starts-with'),
 })
 
 const ryuCho = new RyuCho(config)
diff --git a/yarn.lock b/yarn.lock
index 666252f..1fed00f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2,6 +2,21 @@
 # yarn lockfile v1
 
 
+"@actions/core@^1.9.0":
+  version "1.10.0"
+  resolved "https://registry.yarnpkg.com/@actions/core/-/core-1.10.0.tgz#44551c3c71163949a2f06e94d9ca2157a0cfac4f"
+  integrity sha512-2aZDDa3zrrZbP5ZYg159sNoLRb61nQ7awl5pSvIq5Qpj81vwDzdMRKzkWJGJuwVvWpvZKx7vspJALyvaaIQyug==
+  dependencies:
+    "@actions/http-client" "^2.0.1"
+    uuid "^8.3.2"
+
+"@actions/http-client@^2.0.1":
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/@actions/http-client/-/http-client-2.0.1.tgz#873f4ca98fe32f6839462a6f046332677322f99c"
+  integrity sha512-PIXiMVtz6VvyaRsGY268qvj57hXQEpsYogYOu2nrQhlf+XCGmZstmuZBbAybUl1nQGnvS1k1eEsQ69ZoD7xlSw==
+  dependencies:
+    tunnel "^0.0.6"
+
 "@esbuild/android-arm@0.15.13":
   version "0.15.13"
   resolved "https://registry.yarnpkg.com/@esbuild/android-arm/-/android-arm-0.15.13.tgz#ce11237a13ee76d5eae3908e47ba4ddd380af86a"
@@ -684,6 +699,11 @@ ts-node@^9.1.1:
     source-map-support "^0.5.17"
     yn "3.1.1"
 
+tunnel@^0.0.6:
+  version "0.0.6"
+  resolved "https://registry.yarnpkg.com/tunnel/-/tunnel-0.0.6.tgz#72f1314b34a5b192db012324df2cc587ca47f92c"
+  integrity sha512-1h/Lnq9yajKY2PEbBadPXj3VxsDDu844OnaAo52UVmIzIvwwtBPIuNvkjuzBlTWpfJyUbG3ez0KSBibQkj4ojg==
+
 type-detect@^4.0.0, type-detect@^4.0.5:
   version "4.0.8"
   resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"
@@ -699,6 +719,11 @@ universal-user-agent@^6.0.0:
   resolved "https://registry.yarnpkg.com/universal-user-agent/-/universal-user-agent-6.0.0.tgz#3381f8503b251c0d9cd21bc1de939ec9df5480ee"
   integrity sha512-isyNax3wXoKaulPDZWHQqbmIx1k2tb9fb3GGDBRxCscfYV2Ch7WxPArBsFEG8s/safwXTT7H4QGhaIkTp9447w==
 
+uuid@^8.3.2:
+  version "8.3.2"
+  resolved "https://registry.yarnpkg.com/uuid/-/uuid-8.3.2.tgz#80d5b5ced271bb9af6c445f21a1a04c606cefbe2"
+  integrity sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg==
+
 vite@^3.0.0:
   version "3.2.3"
   resolved "https://registry.yarnpkg.com/vite/-/vite-3.2.3.tgz#7a68d9ef73eff7ee6dc0718ad3507adfc86944a7"