yup

src/commands/new.ts

@@ -97,8 +97,10 @@ export async function action(
   }
 
   const spin = spinner("Creating worktree", branch)
+  let branchCreated = false
   try {
-    await git.createWorktree(branch, worktreeAbs, root)
+    const wt = await git.createWorktree(branch, worktreeAbs, root)
+    branchCreated = wt.branchCreated
     const symlinkPath = join(root, '.sandlot', branch)
     await mkdir(dirname(symlinkPath), { recursive: true })
     await symlink(worktreeAbs, symlinkPath)
@@ -109,7 +111,7 @@ export async function action(
   } catch (err) {
     spin.fail(String((err as Error).message ?? err))
     await git.removeWorktree(worktreeAbs, root).catch(() => {})
-    await git.deleteLocalBranch(branch, root).catch(() => {})
+    if (branchCreated) await git.deleteLocalBranch(branch, root).catch(() => {})
     await unlinkSessionSymlink(root, branch)
     process.exit(1)
   }

src/commands/review.ts

@@ -11,13 +11,22 @@ export async function action(branch: string, extra: string | undefined, opts: {
   let prompt = `
 You're a grumpy old senior software engineer. You need to review some code my co-worker wrote.
 
-Launch three code review agents to review the changes between this branch and main with the following specializations:
+Launch four agents to review the changes between this branch and main with the following specializations:
 
 1. Checks CLAUDE.md compliance
 2. Looks specifically for bugs
-3. Looks for opportunities to simplify code
+3. Also looks specifically for bugs
+4. Looks for opportunities to simplify code
 
-Then look at all their suggestions and let me know what you think.
+Each one should deliver you a report in this format (the <tags> are just for you, not part of their output):
+
+<agentOutput>
+# Problem Identified
+
+Description of problem.
+</agentOutput>
+
+Once the agents are done, look at all their suggestions and let me know what you think.
 `
   if (extra) prompt += "\n\n" + extra
 

src/git.ts

@@ -36,7 +36,7 @@ export async function branchExists(branch: string, cwd?: string, opts?: { fetch?
 }
 
 /** Create a worktree for the given branch. */
-export async function createWorktree(branch: string, worktreePath: string, cwd: string): Promise<void> {
+export async function createWorktree(branch: string, worktreePath: string, cwd: string): Promise<{ branchCreated: boolean }> {
   // Clean up stale worktree path if it exists
   if (existsSync(worktreePath)) {
     await $`git worktree remove ${worktreePath} --force`.cwd(cwd).nothrow().quiet()
@@ -49,7 +49,20 @@ export async function createWorktree(branch: string, worktreePath: string, cwd:
   const exists = await branchExists(branch, cwd, { fetch: true })
 
   let result
+  let switchedFromBranch = false
   if (exists === "local") {
+    const main = await mainBranch(cwd)
+    if (branch === main) {
+      throw new Error(`Cannot create a worktree for the main branch "${main}".`)
+    }
+    // If the branch is checked out in the main worktree, switch it to main first
+    if (await currentBranch(cwd) === branch) {
+      if (await isDirty(cwd)) {
+        throw new Error(`Cannot move branch "${branch}" to a worktree: the main worktree has uncommitted changes. Commit or stash them first.`)
+      }
+      await checkout(main, cwd)
+      switchedFromBranch = true
+    }
     result = await $`git worktree add ${worktreePath} ${branch}`.cwd(cwd).nothrow().quiet()
   } else if (exists === "remote") {
     result = await $`git worktree add ${worktreePath} -b ${branch} origin/${branch}`.cwd(cwd).nothrow().quiet()
@@ -58,8 +71,10 @@ export async function createWorktree(branch: string, worktreePath: string, cwd:
     result = await $`git worktree add -b ${branch} ${worktreePath}`.cwd(cwd).nothrow().quiet()
   }
   if (result.exitCode !== 0) {
+    if (switchedFromBranch) await checkout(branch, cwd).catch(() => {})
     throw new Error(`Failed to create worktree for "${branch}": ${result.stderr.toString().trim()}`)
   }
+  return { branchCreated: exists !== "local" }
 }
 
 /** Remove a worktree. Silently succeeds if the worktree is already gone. */
@@ -228,6 +243,9 @@ export async function branchDiff(branch: string, main: string, cwd: string): Pro
 /** Detect the main branch name (main or master). */
 export async function mainBranch(cwd?: string): Promise<string> {
   const dir = cwd ?? "."
-  const result = await $`git -C ${dir} rev-parse --verify --quiet refs/heads/main`.nothrow().quiet()
-  return result.exitCode === 0 ? "main" : "master"
+  const main = await $`git -C ${dir} rev-parse --verify --quiet refs/heads/main`.nothrow().quiet()
+  if (main.exitCode === 0) return "main"
+  const master = await $`git -C ${dir} rev-parse --verify --quiet refs/heads/master`.nothrow().quiet()
+  if (master.exitCode === 0) return "master"
+  throw new Error("Could not detect main branch: neither \"main\" nor \"master\" exists.")
 }