diff --git a/packages/core/src/ci-environment/services/github-actions.ts b/packages/core/src/ci-environment/services/github-actions.ts
index 9827514..d878417 100644
--- a/packages/core/src/ci-environment/services/github-actions.ts
+++ b/packages/core/src/ci-environment/services/github-actions.ts
@@ -1,50 +1,6 @@
-import { execSync } from "child_process";
+import { existsSync, readFileSync } from "node:fs";
 import type { Service, Context } from "../types";
 
-const getSha = ({ env }: Context) => {
-  const isPr =
-    env.GITHUB_EVENT_NAME === "pull_request" ||
-    env.GITHUB_EVENT_NAME === "pull_request_target";
-
-  if (isPr) {
-    const mergeCommitRegex = /^[a-z0-9]{40} [a-z0-9]{40}$/;
-    const mergeCommitMessage = execSync("git show --no-patch --format=%P")
-      .toString()
-      .trim();
-    // console.log(
-    //   `Handling PR with parent hash(es) '${mergeCommitMessage}' of current commit.`
-    // );
-    if (mergeCommitRegex.exec(mergeCommitMessage)) {
-      const mergeCommit = mergeCommitMessage.split(" ")[1];
-      // console.log(
-      //   `Fixing merge commit SHA ${process.env.GITHUB_SHA} -> ${mergeCommit}`
-      // );
-      return mergeCommit;
-    } else if (mergeCommitMessage === "") {
-      console.error(
-        `Error: automatic detection of commit SHA failed.
-
-Please run "actions/checkout" with "fetch-depth: 2". Example:
-
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 2
-
-`
-      );
-      process.exit(1);
-    } else {
-      console.error(
-        `Commit with SHA ${process.env.GITHUB_SHA} is not a valid commit`
-      );
-      process.exit(1);
-    }
-  }
-
-  return process.env.GITHUB_SHA ?? null;
-};
-
 const getBranch = ({ env }: Context) => {
   if (env.GITHUB_HEAD_REF) {
     return env.GITHUB_HEAD_REF;
@@ -64,28 +20,37 @@ const getRepository = ({ env }: Context) => {
   return env.GITHUB_REPOSITORY.split("/")[1];
 };
 
-const getPrNumber = ({ env }: Context) => {
-  const branchRegex = /refs\/pull\/(\d+)/;
-  const branchMatches = branchRegex.exec(env.GITHUB_REF || "");
-  if (branchMatches) {
-    return Number(branchMatches[1]);
-  }
-
-  return null;
+interface EventPayload {
+  pull_request?: {
+    head: {
+      sha: string;
+      ref: string;
+    };
+    number: number;
+  };
+}
+
+const readEventPayload = ({ env }: Context): EventPayload | null => {
+  if (!env.GITHUB_EVENT_PATH) return null;
+  if (!existsSync(env.GITHUB_EVENT_PATH)) return null;
+  return JSON.parse(readFileSync(env.GITHUB_EVENT_PATH, "utf-8"));
 };
 
 const service: Service = {
   name: "GitHub Actions",
   detect: ({ env }) => Boolean(env.GITHUB_ACTIONS),
-  config: ({ env }) => ({
-    commit: getSha({ env }),
-    branch: getBranch({ env }),
-    owner: env.GITHUB_REPOSITORY_OWNER || null,
-    repository: getRepository({ env }),
-    jobId: env.GITHUB_JOB || null,
-    runId: env.GITHUB_RUN_ID || null,
-    prNumber: getPrNumber({ env }),
-  }),
+  config: ({ env }) => {
+    const payload = readEventPayload({ env });
+    return {
+      commit: payload?.pull_request?.head.sha || process.env.GITHUB_SHA || null,
+      branch: payload?.pull_request?.head.ref || getBranch({ env }) || null,
+      owner: env.GITHUB_REPOSITORY_OWNER || null,
+      repository: getRepository({ env }),
+      jobId: env.GITHUB_JOB || null,
+      runId: env.GITHUB_RUN_ID || null,
+      prNumber: payload?.pull_request?.number || null,
+    };
+  },
 };
 
 export default service;