diff --git a/actions/setup/js/generate_git_patch.cjs b/actions/setup/js/generate_git_patch.cjs
index 552e59311fd..63df67dcc93 100644
--- a/actions/setup/js/generate_git_patch.cjs
+++ b/actions/setup/js/generate_git_patch.cjs
@@ -3,17 +3,54 @@
 
 const fs = require("fs");
 const path = require("path");
-const { execSync } = require("child_process");
+const { promisify } = require("util");
+const { exec: execCallback } = require("child_process");
 
 const { getBaseBranch } = require("./get_base_branch.cjs");
 const { getErrorMessage } = require("./error_helpers.cjs");
 
+/**
+ * Execute a git command - works in both github-script and MCP server contexts
+ * @param {string} command - The git command to execute
+ * @param {Object} options - Options including cwd
+ * @returns {Promise<{stdout: string, stderr: string, exitCode: number}>} The result
+ */
+async function execGit(command, options = {}) {
+  const { cwd } = options;
+
+  // When running in github-script context, exec is available as a global
+  if (typeof exec !== "undefined" && exec.getExecOutput) {
+    const args = command.split(" ");
+    const cmd = args[0];
+    const cmdArgs = args.slice(1);
+    const result = await exec.getExecOutput(cmd, cmdArgs, { cwd, ignoreReturnCode: true });
+    if (result.exitCode !== 0) {
+      const error = new Error(`Command failed: ${command}`);
+      // @ts-ignore - Adding exitCode property to Error
+      error.exitCode = result.exitCode;
+      throw error;
+    }
+    return result;
+  }
+
+  // Fallback to promisified child_process.exec for MCP server context
+  const execAsync = promisify(execCallback);
+  try {
+    const result = await execAsync(command, { cwd });
+    return { stdout: result.stdout, stderr: result.stderr, exitCode: 0 };
+  } catch (error) {
+    // @ts-ignore - Adding exitCode property to Error
+    error.exitCode = error.code || 1;
+    throw error;
+  }
+}
+
 /**
  * Generates a git patch file for the current changes
  * @param {string} branchName - The branch name to generate patch for
- * @returns {Object} Object with patch info or error
+ * @returns {Promise<Object>} Object with patch info or error
  */
-function generateGitPatch(branchName) {
+async function generateGitPatch(branchName) {
   const patchPath = "/tmp/gh-aw/aw.patch";
   const cwd = process.env.GITHUB_WORKSPACE || process.cwd();
   const defaultBranch = process.env.DEFAULT_BRANCH || getBaseBranch();
@@ -33,29 +70,34 @@ function generateGitPatch(branchName) {
     if (branchName) {
       // Check if the branch exists locally
       try {
-        execSync(`git show-ref --verify --quiet refs/heads/${branchName}`, { cwd, encoding: "utf8" });
+        try {
+          await execGit(`git show-ref --verify --quiet refs/heads/${branchName}`, { cwd });
+        } catch (showRefError) {
+          // Branch doesn't exist, skip to strategy 2
+          throw showRefError;
+        }
 
         // Determine base ref for patch generation
         let baseRef;
         try {
           // Check if origin/branchName exists
-          execSync(`git show-ref --verify --quiet refs/remotes/origin/${branchName}`, { cwd, encoding: "utf8" });
+          await execGit(`git show-ref --verify --quiet refs/remotes/origin/${branchName}`, { cwd });
           baseRef = `origin/${branchName}`;
         } catch {
           // Use merge-base with default branch
-          execSync(`git fetch origin ${defaultBranch}`, { cwd, encoding: "utf8" });
-          baseRef = execSync(`git merge-base origin/${defaultBranch} ${branchName}`, { cwd, encoding: "utf8" }).trim();
+          await execGit(`git fetch origin ${defaultBranch}`, { cwd });
+          const mergeBaseResult = await execGit(`git merge-base origin/${defaultBranch} ${branchName}`, { cwd });
+          baseRef = mergeBaseResult.stdout.trim();
         }
 
         // Count commits to be included
-        const commitCount = parseInt(execSync(`git rev-list --count ${baseRef}..${branchName}`, { cwd, encoding: "utf8" }).trim(), 10);
+        const commitCountResult = await execGit(`git rev-list --count ${baseRef}..${branchName}`, { cwd });
+        const commitCount = parseInt(commitCountResult.stdout.trim(), 10);
 
         if (commitCount > 0) {
           // Generate patch from the determined base to the branch
-          const patchContent = execSync(`git format-patch ${baseRef}..${branchName} --stdout`, {
-            cwd,
-            encoding: "utf8",
-          });
+          const patchContentResult = await execGit(`git format-patch ${baseRef}..${branchName} --stdout`, { cwd });
+          const patchContent = patchContentResult.stdout;
 
           if (patchContent && patchContent.trim()) {
             fs.writeFileSync(patchPath, patchContent, "utf8");
@@ -69,7 +111,8 @@ function generateGitPatch(branchName) {
 
     // Strategy 2: Check if commits were made to current HEAD since checkout
     if (!patchGenerated) {
-      const currentHead = execSync("git rev-parse HEAD", { cwd, encoding: "utf8" }).trim();
+      const currentHeadResult = await execGit("git rev-parse HEAD", { cwd });
+      const currentHead = currentHeadResult.stdout.trim();
 
       if (!githubSha) {
         errorMessage = "GITHUB_SHA environment variable is not set";
@@ -78,17 +121,16 @@ function generateGitPatch(branchName) {
       } else {
         // Check if GITHUB_SHA is an ancestor of current HEAD
         try {
-          execSync(`git merge-base --is-ancestor ${githubSha} HEAD`, { cwd, encoding: "utf8" });
+          await execGit(`git merge-base --is-ancestor ${githubSha} HEAD`, { cwd });
 
           // Count commits between GITHUB_SHA and HEAD
-          const commitCount = parseInt(execSync(`git rev-list --count ${githubSha}..HEAD`, { cwd, encoding: "utf8" }).trim(), 10);
+          const commitCountResult = await execGit(`git rev-list --count ${githubSha}..HEAD`, { cwd });
+          const commitCount = parseInt(commitCountResult.stdout.trim(), 10);
 
           if (commitCount > 0) {
             // Generate patch from GITHUB_SHA to HEAD
-            const patchContent = execSync(`git format-patch ${githubSha}..HEAD --stdout`, {
-              cwd,
-              encoding: "utf8",
-            });
+            const patchContentResult = await execGit(`git format-patch ${githubSha}..HEAD --stdout`, { cwd });
+            const patchContent = patchContentResult.stdout;
 
             if (patchContent && patchContent.trim()) {
               fs.writeFileSync(patchPath, patchContent, "utf8");
diff --git a/actions/setup/js/generate_git_patch.test.cjs b/actions/setup/js/generate_git_patch.test.cjs
index 403838e4a80..3bcca457024 100644
--- a/actions/setup/js/generate_git_patch.test.cjs
+++ b/actions/setup/js/generate_git_patch.test.cjs
@@ -30,7 +30,7 @@ describe("generateGitPatch", () => {
 
     const { generateGitPatch } = await import("./generate_git_patch.cjs");
 
-    const result = generateGitPatch(null);
+    const result = await generateGitPatch(null);
 
     expect(result.success).toBe(false);
     expect(result).toHaveProperty("error");
@@ -43,7 +43,7 @@ describe("generateGitPatch", () => {
     process.env.GITHUB_WORKSPACE = "/tmp/nonexistent-repo";
     process.env.GITHUB_SHA = "abc123";
 
-    const result = generateGitPatch("nonexistent-branch");
+    const result = await generateGitPatch("nonexistent-branch");
 
     expect(result.success).toBe(false);
     expect(result).toHaveProperty("error");
@@ -57,7 +57,7 @@ describe("generateGitPatch", () => {
     process.env.GITHUB_SHA = "abc123";
 
     // Even if it fails, it should try to create the directory
-    const result = generateGitPatch("test-branch");
+    const result = await generateGitPatch("test-branch");
 
     expect(result).toHaveProperty("patchPath");
     expect(result.patchPath).toBe("/tmp/gh-aw/aw.patch");
@@ -69,7 +69,7 @@ describe("generateGitPatch", () => {
     process.env.GITHUB_WORKSPACE = "/tmp/nonexistent-repo";
     process.env.GITHUB_SHA = "abc123";
 
-    const result = generateGitPatch("test-branch");
+    const result = await generateGitPatch("test-branch");
 
     expect(result).toHaveProperty("success");
     expect(result).toHaveProperty("patchPath");
@@ -82,7 +82,7 @@ describe("generateGitPatch", () => {
     process.env.GITHUB_WORKSPACE = "/tmp/nonexistent-repo";
     process.env.GITHUB_SHA = "abc123";
 
-    const result = generateGitPatch(null);
+    const result = await generateGitPatch(null);
 
     expect(result).toHaveProperty("success");
     expect(result).toHaveProperty("patchPath");
@@ -94,7 +94,7 @@ describe("generateGitPatch", () => {
     process.env.GITHUB_WORKSPACE = "/tmp/nonexistent-repo";
     process.env.GITHUB_SHA = "abc123";
 
-    const result = generateGitPatch("");
+    const result = await generateGitPatch("");
 
     expect(result).toHaveProperty("success");
     expect(result).toHaveProperty("patchPath");
@@ -107,7 +107,7 @@ describe("generateGitPatch", () => {
     process.env.GITHUB_SHA = "abc123";
     process.env.DEFAULT_BRANCH = "develop";
 
-    const result = generateGitPatch("feature-branch");
+    const result = await generateGitPatch("feature-branch");
 
     expect(result).toHaveProperty("success");
     // Should attempt to use develop as default branch
@@ -121,7 +121,7 @@ describe("generateGitPatch", () => {
     delete process.env.DEFAULT_BRANCH;
     process.env.GH_AW_BASE_BRANCH = "master";
 
-    const result = generateGitPatch("feature-branch");
+    const result = await generateGitPatch("feature-branch");
 
     expect(result).toHaveProperty("success");
     // Should attempt to use master as base branch
diff --git a/actions/setup/js/safe_outputs_handlers.cjs b/actions/setup/js/safe_outputs_handlers.cjs
index 5e3425b9f4a..2d99dffb327 100644
--- a/actions/setup/js/safe_outputs_handlers.cjs
+++ b/actions/setup/js/safe_outputs_handlers.cjs
@@ -185,7 +185,7 @@ function createHandlers(server, appendSafeOutput, config = {}) {
    * Resolves the current branch if branch is not provided or is the base branch
    * Generates git patch for the changes (unless allow-empty is true)
    */
-  const createPullRequestHandler = args => {
+  const createPullRequestHandler = async args => {
     const entry = { ...args, type: "create_pull_request" };
     const baseBranch = getBaseBranch();
 
@@ -226,7 +226,7 @@ function createHandlers(server, appendSafeOutput, config = {}) {
 
     // Generate git patch
     server.debug(`Generating patch for create_pull_request with branch: ${entry.branch}`);
-    const patchResult = generateGitPatch(entry.branch);
+    const patchResult = await generateGitPatch(entry.branch);
 
     if (!patchResult.success) {
       // Patch generation failed or patch is empty
@@ -276,7 +276,7 @@ function createHandlers(server, appendSafeOutput, config = {}) {
    * Resolves the current branch if branch is not provided or is the base branch
    * Generates git patch for the changes
    */
-  const pushToPullRequestBranchHandler = args => {
+  const pushToPullRequestBranchHandler = async args => {
     const entry = { ...args, type: "push_to_pull_request_branch" };
     const baseBranch = getBaseBranch();
 
@@ -296,7 +296,7 @@ function createHandlers(server, appendSafeOutput, config = {}) {
 
     // Generate git patch
     server.debug(`Generating patch for push_to_pull_request_branch with branch: ${entry.branch}`);
-    const patchResult = generateGitPatch(entry.branch);
+    const patchResult = await generateGitPatch(entry.branch);
 
     if (!patchResult.success) {
       // Patch generation failed or patch is empty