Drop usage of execSync, switch to $ util

mcp/files.ts

@@ -1,5 +1,5 @@
-import { execSync } from "node:child_process";
 import { type } from "arktype";
+import { $ } from "../utils/shell.ts";
 import { contextualize, tool } from "./shared.ts";
 
 export const ListFiles = type({
@@ -17,14 +17,19 @@ export const ListFilesTool = tool({
     try {
       // Use git ls-files to list tracked files
       // This respects .gitignore and gives a clean list of source files
-      const command = path === "." ? "git ls-files" : `git ls-files ${path}`;
+      const pathStr = path ?? ".";
-      const output = execSync(command, { encoding: "utf-8" });
+      const output = $("git", pathStr === "." ? ["ls-files"] : ["ls-files", pathStr], {
+        log: false,
+      });
       const files = output.split("\n").filter((f) => f.trim() !== "");
 
       if (files.length === 0) {
         // Fallback for non-git environments or untracked files
-        const findCmd = `find ${path} -maxdepth 3 -not -path '*/.*' -type f`;
+        const findOutput = $(
-        const findOutput = execSync(findCmd, { encoding: "utf-8" });
+          "find",
+          [pathStr, "-maxdepth", "3", "-not", "-path", "*/.*", "-type", "f"],
+          { log: false }
+        );
         return {
           files: findOutput.split("\n").filter((f) => f.trim() !== ""),
           method: "find",

mcp/pr.ts

@@ -1,6 +1,6 @@
-import { execSync } from "node:child_process";
 import { type } from "arktype";
 import { log } from "../utils/cli.ts";
+import { $ } from "../utils/shell.ts";
 import { contextualize, tool } from "./shared.ts";
 
 export const PullRequest = type({
@@ -15,9 +15,7 @@ export const PullRequestTool = tool({
   parameters: PullRequest,
   execute: contextualize(async ({ title, body, base }, ctx) => {
     // Get the current branch name
-    const currentBranch = execSync("git rev-parse --abbrev-ref HEAD", {
+    const currentBranch = $("git", ["rev-parse", "--abbrev-ref", "HEAD"], { log: false });
-      encoding: "utf8",
-    }).trim();
 
     log.info(`Current branch: ${currentBranch}`);
 

mcp/prInfo.ts

@@ -1,6 +1,6 @@
-import { execSync } from "node:child_process";
 import { type } from "arktype";
 import { log } from "../utils/cli.ts";
+import { $ } from "../utils/shell.ts";
 import { contextualize, tool } from "./shared.ts";
 
 export const PullRequestInfo = type({
@@ -30,14 +30,14 @@ export const PullRequestInfoTool = tool({
 
     // Automatically fetch and checkout branches for review
     log.info(`Fetching base branch: origin/${baseBranch}`);
-    execSync(`git fetch origin ${baseBranch} --depth=20`, { stdio: "inherit" });
+    $("git", ["fetch", "origin", baseBranch, "--depth=20"]);
 
     log.info(`Fetching PR branch: origin/${headBranch}`);
-    execSync(`git fetch origin ${headBranch}`, { stdio: "inherit" });
+    $("git", ["fetch", "origin", headBranch]);
 
     log.info(`Checking out PR branch: origin/${headBranch}`);
     // check out a local branch tracking the remote branch so we can push changes
-    execSync(`git checkout -B ${headBranch} origin/${headBranch}`, { stdio: "inherit" });
+    $("git", ["checkout", "-B", headBranch, `origin/${headBranch}`]);
 
     return {
       number: data.number,

scratch.ts

@@ -2,7 +2,6 @@ import { spawnSync } from "child_process";
 import { existsSync } from "fs";
 
 function findCliPath(name: string): string | null {
-    
   const result = spawnSync("which", [name], { encoding: "utf-8" });
   if (result.status === 0 && result.stdout) {
     const cliPath = result.stdout.trim();
@@ -11,6 +10,6 @@ function findCliPath(name: string): string | null {
     }
   }
   return null;
-  }
+}
 
 console.log(findCliPath("codei"));

todo.md

@@ -8,6 +8,11 @@
 [] add footer to the working comment ("executed by {agent}", link to pullfrog (homepage) w/ small logo?, feedback (create github issue), link to workflow run)- see https://github.com/colinhacks/zod/issues/5459#issuecomment-3548382991
 [] avoid passing all of process.env into agents: minimum # of vars
 [] toon encode in prompt
+[] branching: use pullfrog/ prefix
+[] test modifications to existing PRs (proper branching)
+[] web access settings
+[] implement Learnings
+[] implement Billing
 
 ## MAYBE
 

utils/setup.ts

@@ -2,6 +2,7 @@ import { execSync } from "node:child_process";
 import { existsSync, rmSync } from "node:fs";
 import { log } from "./cli.ts";
 import type { RepoContext } from "./github.ts";
+import { $ } from "./shell.ts";
 
 export interface SetupOptions {
   tempDir: string;
@@ -25,7 +26,7 @@ export function setupTestRepo(options: SetupOptions): void {
       rmSync(tempDir, { recursive: true, force: true });
 
       log.info("📦 Cloning pullfrogai/scratch into .temp...");
-      execSync(`git clone ${repoUrl} ${tempDir}`, { stdio: "inherit" });
+      $("git", ["clone", repoUrl, tempDir]);
     } else {
       log.info("📦 Resetting existing .temp repository...");
       execSync("git reset --hard HEAD && git clean -fd", {
@@ -35,7 +36,7 @@ export function setupTestRepo(options: SetupOptions): void {
     }
   } else {
     log.info("📦 Cloning pullfrogai/scratch into .temp...");
-    execSync(`git clone ${repoUrl} ${tempDir}`, { stdio: "inherit" });
+    $("git", ["clone", repoUrl, tempDir]);
   }
 }
 
@@ -87,6 +88,6 @@ export function setupGitAuth(githubToken: string, repoContext: RepoContext): voi
 
   // Update remote URL to embed the token
   const remoteUrl = `https://x-access-token:${githubToken}@github.com/${repoContext.owner}/${repoContext.name}.git`;
-  execSync(`git remote set-url origin "${remoteUrl}"`, { stdio: "inherit" });
+  $("git", ["remote", "set-url", "origin", remoteUrl]);
   log.info("✓ Updated remote URL with authentication token");
 }

utils/shell.ts

@@ -0,0 +1,71 @@
+import { spawnSync } from "node:child_process";
+
+interface ShellOptions {
+  cwd?: string;
+  encoding?:
+    | "utf-8"
+    | "utf8"
+    | "ascii"
+    | "base64"
+    | "base64url"
+    | "hex"
+    | "latin1"
+    | "ucs-2"
+    | "ucs2"
+    | "utf16le";
+  log?: boolean;
+  onError?: (result: { status: number; stdout: string; stderr: string }) => void;
+}
+
+/**
+ * Execute a shell command safely using spawnSync with argument arrays.
+ * Prevents shell injection by avoiding string interpolation in shell commands.
+ *
+ * @param cmd - The command to execute
+ * @param args - Array of arguments to pass to the command
+ * @param options - Optional configuration (cwd, encoding, onError)
+ * @returns The trimmed stdout output
+ * @throws Error if command fails and no onError handler is provided
+ */
+export function $(cmd: string, args: string[], options?: ShellOptions): string {
+  const encoding = options?.encoding ?? "utf-8";
+  const result = spawnSync(cmd, args, {
+    stdio: ["inherit", "pipe", "pipe"],
+    encoding,
+    cwd: options?.cwd,
+  });
+
+  const stdout = result.stdout ?? "";
+  const stderr = result.stderr ?? "";
+
+  // Write output to process streams so it behaves like stdio: "inherit"
+  // Only log if log option is not explicitly set to false
+  if (options?.log !== false) {
+    if (stdout) {
+      process.stdout.write(stdout);
+    }
+    if (stderr) {
+      process.stderr.write(stderr);
+    }
+  }
+
+  // Handle errors
+  if (result.status !== 0) {
+    const errorResult = {
+      status: result.status ?? -1,
+      stdout,
+      stderr,
+    };
+
+    if (options?.onError) {
+      options.onError(errorResult);
+      return stdout.trim();
+    }
+
+    throw new Error(
+      `Command failed with exit code ${errorResult.status}: ${stderr || "Unknown error"}`
+    );
+  }
+
+  return stdout.trim();
+}