diff --git a/src/cli.ts b/src/cli.ts
index 56c14f5..a811bcc 100755
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -149,4 +149,7 @@ vmCmd
     console.log("VM destroyed")
   })
 
-program.parse()
+program.parseAsync().catch((err) => {
+  console.error(err.message ?? err)
+  process.exit(1)
+})
diff --git a/src/git.ts b/src/git.ts
index 102bd73..48b1634 100644
--- a/src/git.ts
+++ b/src/git.ts
@@ -4,14 +4,20 @@ import { $ } from "bun"
 
 /** Get the repo root from a working directory. */
 export async function repoRoot(cwd?: string): Promise<string> {
-  const result = await $`git rev-parse --show-toplevel`.cwd(cwd ?? ".").text()
-  return result.trim()
+  const result = await $`git rev-parse --show-toplevel`.cwd(cwd ?? ".").nothrow().quiet()
+  if (result.exitCode !== 0) {
+    throw new Error("Not a git repository. Run this command from inside a git repo.")
+  }
+  return result.text().trim()
 }
 
 /** Get the current branch name. */
 export async function currentBranch(cwd?: string): Promise<string> {
-  const result = await $`git rev-parse --abbrev-ref HEAD`.cwd(cwd ?? ".").text()
-  return result.trim()
+  const result = await $`git rev-parse --abbrev-ref HEAD`.cwd(cwd ?? ".").nothrow().quiet()
+  if (result.exitCode !== 0) {
+    throw new Error("Could not determine current branch.")
+  }
+  return result.text().trim()
 }
 
 /** Check if a branch exists locally or remotely. Returns "local", "remote", or null. */
@@ -40,19 +46,26 @@ export async function createWorktree(branch: string, worktreePath: string, cwd:
 
   const exists = await branchExists(branch, cwd)
 
+  let result
   if (exists === "local") {
-    await $`git worktree add ${worktreePath} ${branch}`.cwd(cwd).quiet()
+    result = await $`git worktree add ${worktreePath} ${branch}`.cwd(cwd).nothrow().quiet()
   } else if (exists === "remote") {
-    await $`git worktree add ${worktreePath} -b ${branch} origin/${branch}`.cwd(cwd).quiet()
+    result = await $`git worktree add ${worktreePath} -b ${branch} origin/${branch}`.cwd(cwd).nothrow().quiet()
   } else {
     // New branch from current HEAD
-    await $`git worktree add -b ${branch} ${worktreePath}`.cwd(cwd).quiet()
+    result = await $`git worktree add -b ${branch} ${worktreePath}`.cwd(cwd).nothrow().quiet()
+  }
+  if (result.exitCode !== 0) {
+    throw new Error(`Failed to create worktree for "${branch}": ${result.stderr.toString().trim()}`)
   }
 }
 
 /** Remove a worktree. */
 export async function removeWorktree(worktreePath: string, cwd: string): Promise<void> {
-  await $`git worktree remove ${worktreePath} --force`.cwd(cwd)
+  const result = await $`git worktree remove ${worktreePath} --force`.cwd(cwd).nothrow().quiet()
+  if (result.exitCode !== 0) {
+    throw new Error(`Failed to remove worktree: ${result.stderr.toString().trim()}`)
+  }
 }
 
 /** Delete a local branch. */
@@ -62,5 +75,8 @@ export async function deleteLocalBranch(branch: string, cwd: string): Promise<vo
 
 /** Checkout a branch. */
 export async function checkout(branch: string, cwd: string): Promise<void> {
-  await $`git checkout ${branch}`.cwd(cwd)
+  const result = await $`git checkout ${branch}`.cwd(cwd).nothrow().quiet()
+  if (result.exitCode !== 0) {
+    throw new Error(`Failed to checkout branch "${branch}": ${result.stderr.toString().trim()}`)
+  }
 }