gh-stack

gh-stack

gh stack is a GitHub CLI extension for managing stacked branches and pull requests. A stack is an ordered list of branches where each branch builds on the one below it, rooted on a trunk branch (typically the repo's default branch). Each branch maps to one PR whose base is the branch below it, so reviewers see only the diff for that layer.

main (trunk)
 └── feat/auth-layer     → PR #1 (base: main)               - bottom (closest to trunk)
  └── feat/api-endpoints → PR #2 (base: feat/auth-layer)
   └── feat/frontend     → PR #3 (base: feat/api-endpoints) - top (furthest from trunk)

The bottom of the stack is the branch closest to the trunk, and the top is the branch furthest from the trunk. Each branch inherits from the one below it. Navigation commands (up, down, top, bottom) follow this model: up moves away from trunk, down moves toward it.

When to use this skill

Use this skill when the user wants to:

• Break a large change into a chain of small, reviewable PRs
• Create, rebase, push, or sync a stack of dependent branches
• Navigate between layers of a branch stack
• View the status of stacked PRs
• Tear down and rebuild a stack to remove, reorder, or rename branches

Prerequisites

The GitHub CLI (gh) v2.0+ must be installed and authenticated. Install the extension with:

gh extension install github/gh-stack

Before using gh stack, configure git to prevent interactive prompts:

git config rerere.enabled true           # remember conflict resolutions (skips prompt on init)
git config remote.pushDefault origin     # if multiple remotes exist (skips remote picker)

Agent rules

All gh stack commands must be run non-interactively. Every command invocation must include the flags and positional arguments needed to avoid prompts, TUIs, and interactive menus. If a command would prompt for input, it will hang indefinitely.

1. Always supply branch names as positional arguments to init, add, and checkout. Running these commands without arguments triggers interactive prompts.
2. When a prefix is set, pass only the suffix to add. gh stack add auth with prefix feat → feat/auth. Passing feat/auth creates feat/feat/auth.
3. Always use --auto with gh stack submit to auto-generate PR titles. Without --auto, submit prompts for a title for each new PR.
4. Always use --json with gh stack view. Without --json, the command launches an interactive TUI that cannot be operated by agents. There is no other appropriate flag — always pass --json.
5. Use --remote <name> when multiple remotes are configured, or pre-configure git config remote.pushDefault origin. Without this, push, submit, sync, link, and checkout trigger an interactive remote picker.
6. Avoid branches shared across multiple stacks. If a branch belongs to multiple stacks, commands exit with code 6. Check out a non-shared branch first.
7. Plan your stack layers by dependency order before writing code. Foundational changes (models, APIs, shared utilities) go in lower branches; dependent changes (UI, consumers) go in higher branches. Think through the dependency chain before running gh stack init.
8. Use standard git add and git commit for staging and committing. This gives you full control over which changes go into each branch. The -Am shortcut is available but should not be the default approach—stacked PRs are most effective when each branch contains a deliberate, logical set of changes.
9. Navigate down the stack when you need to change a lower layer. If you're working on a frontend branch and realize you need API changes, don't hack around it at the current layer. Navigate to the appropriate branch (gh stack down, gh stack checkout, or gh stack bottom), make and commit the changes there, run gh stack rebase --upstack, then navigate back up to continue.
10. Use gh stack link for external tool workflows. When branches are managed by an external tool (jj, Sapling, etc.), use gh stack link branch-a branch-b. link does not rely on local tracking state and is intended for API-driven PR and stack management. Always provide at least 2 branch names or PR numbers.

Never do any of the following — each triggers an interactive prompt or TUI that will hang:

• ❌ gh stack view or gh stack view --short — always use gh stack view --json
• ❌ gh stack submit without --auto — always use gh stack submit --auto
• ❌ gh stack init without branch arguments — always provide branch names
• ❌ gh stack add without a branch name — always provide a branch name
• ❌ gh stack checkout without an argument — always provide a PR number or branch name
• ❌ gh stack checkout <pr-number> when a different local stack already exists on those branches — this triggers an unbypassable conflict resolution prompt; use gh stack unstack first to remove the local stack, then retry the checkout

Thinking about stack structure

Each branch in a stack should represent a discrete, logical unit of work that can be reviewed independently. The changes within a branch should be cohesive—they belong together and make sense as a single PR.

Dependency chain

Stacked branches form a dependency chain: each branch builds on the one below it. This means foundational changes must go in lower (earlier) branches, and code that depends on them goes in higher (later) branches.

Plan your layers before writing code. For example, a full-stack feature might be structured like this (use branch names relevant to your actual task, not these generic ones):

This is illustrative — choose branch names and layer boundaries that reflect the specific work you're doing. The key principle is: if code in one layer depends on code in another, the dependency must be in the same branch or a lower one.

Branch naming

Prefer initializing stacks with a prefix (-p). Prefixes group branches under a namespace (e.g., feat/auth, feat/api) and keep branch names clean and consistent. When a prefix is set, pass only the suffix to subsequent add calls — the prefix is applied automatically. Without a prefix, you'll need to pass the full branch name each time.

Staging changes deliberately

The main reason to use git add and git commit directly is to control which changes go into which branch. When you have multiple files in your working tree, you can stage a subset for the current branch, commit them, then create a new branch and stage the rest there:

This keeps each branch focused on one concern. Multiple commits per branch are fine — the key is that all commits in a branch relate to the same logical concern, and changes that belong to a different concern go in a different branch.

When to create a new branch

Create a new branch (gh stack add) when you're starting a different concern that depends on what you've built so far. Signs it's time for a new branch:

• You're switching from backend to frontend work
• You're moving from core logic to tests or documentation
• The next set of changes has a different reviewer audience
• The current branch's PR is already large enough to review

One stack, one story

Think of a stack from the reviewer's perspective: the stack of PRs should tell a cohesive story about a feature or project. A reviewer should be able to read the PRs in sequence and understand the progression of changes, with each PR being a small, logical piece of the whole.

When to use a single stack: All the branches are part of the same feature, project, or closely related effort. Even if the work spans multiple concerns (models, API, frontend), they're all building toward the same goal.

When to create a separate stack: The work is unrelated to your current stack — a different feature, a bug fix in an unrelated area, or an independent refactor. Don't mix unrelated work into a single stack just because you happen to be working on both. Start a new stack with gh stack init or switch to an existing stack with gh stack checkout for each distinct effort.

Small, incidental fixes (e.g., fixing a typo you noticed) can go in the current stack if they're trivial. But if a change grows into its own project, it deserves its own stack.

Quick reference

Workflows

End-to-end: create a stack from scratch

Shortcut: If you prefer a faster flow, gh stack add -Am "message" branch-name combines staging, committing, and branch creation into one command. This is useful for single-commit layers but bypasses deliberate staging.

Making mid-stack changes

This is a critical workflow for agents. When you're working on a higher layer and realize you need to change something in a lower layer (e.g., you're building frontend components but need to add an API endpoint), navigate down to the correct branch, make the change there, and rebase.

Why this matters: If you make API changes on the frontend branch, those changes will end up in the wrong PR. The API PR won't include them, and the frontend PR will have unrelated API diffs mixed in. Always put changes in the branch where they logically belong.

Modify a mid-stack branch and sync

When you need to revisit a branch after the initial creation (e.g., responding to review feedback):

Routine sync after merges

Note for agents: In non-interactive environments, the prune prompt is not shown. Use --prune explicitly to delete local branches for merged PRs.

Squash-merge recovery

When a PR is squash-merged on GitHub, the original branch's commits no longer exist in the trunk history. gh stack detects this automatically and uses git rebase --onto to correctly replay remaining commits.

If sync hits a conflict during this process, it restores all branches to their pre-rebase state and exits with code 3. See Handle rebase conflicts for the resolution workflow.

Handle rebase conflicts (agent workflow)

Parsing --json output

Restructure a stack (remove a branch, reorder, or rename)

Use unstack to tear down the stack, make structural changes, then re-init:

Commands

Initialize a stack — gh stack init

Creates a new stack. Always provide at least one branch name as a positional argument — running without branch arguments triggers interactive prompts that agents cannot use.

Behavior:

• Using -p is recommended — it simplifies branch naming for subsequent add calls
• Creates any branches that don't already exist (branching from the trunk branch)
• Existing branches are adopted automatically; missing branches are created from the trunk
• Checks out the last branch in the list
• Enables git rerere so conflict resolutions are remembered across rebases. On first run in a repo, this may trigger a confirmation prompt — pre-configure with git config rerere.enabled true to avoid it

Add a branch — gh stack add

Add a new branch on top of the current stack. Must be run while on the topmost branch (or the trunk if the stack has no branches yet). Always provide a branch name — running without one triggers an interactive prompt.

Recommended workflow — create the branch, then use standard git:

Shortcut — stage, commit, and branch in one command:

Behavior notes:

• -A and -u are mutually exclusive.
• When the current branch has no commits (e.g., right after init), add -Am commits directly on the current branch instead of creating a new one.
• Prefix handling: Only pass the suffix when a prefix is set. gh stack add api with prefix todo → todo/api. Passing todo/api creates todo/todo/api. Without a prefix, pass the full branch name.
• If called from a branch that is not the topmost in the stack, exits with code 5: "can only add branches on top of the stack". Use gh stack top to switch first.
• Uncommitted changes: When using gh stack add branch-name without -Am, any uncommitted changes (staged or unstaged) in your working tree carry over to the new branch. This is standard git behavior — the working tree is not touched. Commit or stash changes on the current branch before running add if you want a clean starting point on the new branch.

Push branches to remote — gh stack push

Push all stack branches to the remote.

Behavior:

• Pushes all active (non-merged) branches atomically (--force-with-lease --atomic)
• Does not create or update pull requests — use gh stack submit for that

Output (stderr):

• Pushed N branches summary

Submit branches and create PRs — gh stack submit

Push all stack branches and create PRs on GitHub. Always pass --auto — without it, submit prompts for a PR title for each new branch.

Behavior:

• Pushes all active (non-merged) branches atomically (--force-with-lease --atomic)
• Creates a new PR for each branch that doesn't have one (base set to the first non-merged ancestor branch)
• After creating PRs, links them together as a Stack on GitHub (requires the repository to have stacks enabled)
• If every PR in the stack has already been merged, the stack is complete and can't be extended. submit automatically forks your unmerged branches into a new stack rooted at the trunk and creates it on GitHub, leaving the merged stack untouched.
• If stacks are not available (exit code 9), the repository does not have stacked PRs enabled. In interactive mode, submit offers to create regular (unstacked) PRs instead. In non-interactive mode, it exits with code 9.
• Syncs PR metadata for branches that already have PRs

PR title auto-generation (--auto):

• Single commit on branch → uses the commit subject as the PR title, commit body as PR body
• Multiple commits on branch → humanizes the branch name (hyphens/underscores → spaces) as the title

Output (stderr):

• Created PR #N for <branch> for each newly created PR
• PR #N for <branch> is up to date for existing PRs
• Pushed and synced N branches summary

Link branches as a stack (no local tracking) — gh stack link

Link PRs into a stack on GitHub without creating any local tracking state. This is the recommended approach if you are managing stacked branches with other tools (jj, Sapling, git-town) and want to simply create GitHub Stacked PRs via an API.

Behavior:

• Arguments are provided in stack order (bottom to top)
• Each argument can be a branch name or a PR number. Numeric arguments are tried as PR numbers first; if no PR with that number exists, the argument is treated as a branch name
• Branch arguments are pushed to the remote automatically (non-force, atomic)
• For branches without open PRs, new PRs are created with auto-generated titles and the correct base branch chaining (first branch uses --base, subsequent branches use the previous branch)
• Existing PRs whose base branch doesn't match the expected chain are corrected automatically
• If the PRs are not yet in a stack, a new stack is created. If some PRs are already in a stack, the stack is updated (additive only — existing PRs are never removed)
• Does not create or modify any local state

Output (stderr):

• Pushing N branches to <remote>...
• Found PR #N for branch <name> for branches with existing PRs
• Created PR #N for <branch> (base: <base>) for newly created PRs
• Updated base branch for PR #N to <base> when base branches are corrected
• Created stack with N PRs or Updated stack to N PRs

Sync the stack — gh stack sync

Fetch, rebase, push, and sync PR state in a single command. This is the recommended command for routine synchronization.

What it does (in order):

1. Fetch latest changes from the remote
2. Fast-forward trunk to match remote (skips if already up to date, warns if diverged)
3. Cascade rebase all stack branches onto their updated parents (only if trunk moved). Handles merged PRs automatically. If a conflict is detected, all branches are restored to their pre-rebase state and the command exits with code 3 — see Handle rebase conflicts for the resolution workflow
4. Push all active branches atomically
5. Sync PR state from GitHub and report the status of each PR
6. Sync the stack object — link the open PRs into a stack on GitHub. If the PRs are not yet in a stack, a new stack is created; if some PRs are already in a stack, it is updated (additive only). This only happens when two or more PRs exist. Sync never opens PRs — use gh stack submit for that
7. Prune — in interactive terminals, prompts to delete local branches for merged PRs. Use --prune to skip the prompt. In non-interactive environments, pruning only happens when --prune is passed explicitly

Output (stderr):

• ✓ Fetched latest changes from origin
• ✓ Trunk main fast-forwarded to <sha> or ✓ Trunk main is already up to date
• ✓ Rebased <branch> onto <base> per branch (if base moved)
• ✓ Pushed N branches
• ✓ PR #N (<branch>) — Open per branch
• Merged: #N, #M for merged branches
• ✓ Stack created on GitHub with N PRs / ✓ Stack updated on GitHub with N PRs / ✓ Linked to the existing stack on GitHub (when two or more PRs exist)
• ✓ Pruned <branch> (merged) per pruned branch (when pruning)
• ✓ Stack synced when the stack object on GitHub was created/updated to match local, or ✓ Branches synced when only the branches were synced (fewer than two PRs, stacked PRs unavailable, or a divergence)

Rebase the stack — gh stack rebase

Pull from remote and cascade-rebase stack branches. Use this when sync reports a conflict or when you need finer control (e.g., rebase only part of the stack).

Conflict handling: See Handle rebase conflicts in the Workflows section for the full resolution workflow.

Merged PR detection: If a branch's PR was merged on GitHub, the rebase automatically handles this using --onto mode and correctly replays commits on top of the merge target.

Rerere (conflict memory): git rerere is enabled by init so previously resolved conflicts are auto-resolved in future rebases.

No-trunk mode: Use --no-trunk to skip fetching from the remote and rebasing with the trunk branch. Only inter-branch rebases are performed (branch 2 onto branch 1, branch 3 onto branch 2, etc.). Useful when you only need to align stack branches with each other without pulling upstream changes.

View the stack — gh stack view

Display the current stack's branches, PR status, and recent commits. Always pass --json — without it, this command launches an interactive TUI that agents cannot operate.

--json output format:

Fields per branch:

• name — branch name
• head — current HEAD SHA
• base — parent branch's HEAD SHA at last sync
• isCurrent — whether this is the checked-out branch
• isMerged — whether the PR has been merged
• needsRebase — whether the base branch is not an ancestor (non-linear history)
• pr — PR metadata (omitted if no PR exists). state is "OPEN" or "MERGED".

Navigate the stack

Move between branches without remembering branch names. These commands are fully non-interactive.

Navigation clamps to stack bounds. Merged branches are skipped when navigating from active branches.

Check out a stack — gh stack checkout

Check out a stack from a pull request number or branch name. Always provide an argument — running gh stack checkout without arguments triggers an interactive selection menu.

When a PR number is provided (e.g. 123), the command fetches the stack on GitHub, pulls the branches, and sets up the stack locally. If the stack already exists locally and matches, it switches to the branch.

⚠️ Agent warning: If the local and remote stacks have different branch compositions, this command triggers an interactive conflict-resolution prompt that cannot be bypassed with a flag. To avoid this: run gh stack unstack first to remove the conflicting local stack, then retry gh stack checkout <pr-number>.

When a branch name is provided, the command resolves it against locally tracked stacks only. This is always safe for non-interactive use.

Remove a stack — gh stack unstack

Tear down a stack so you can restructure it — remove a branch, reorder branches, rename branches, or make other large changes. After unstacking, use gh stack init to re-create the stack with the desired structure.

You must have a branch from the stack checked out locally. The command targets the active stack — the one that contains the currently checked out branch.

Output conventions

• Status messages go to stderr with emoji prefixes: ✓ (success), ✗ (error), ⚠ (warning), ℹ (info).
• Data output (e.g., view --json) goes to stdout.
• When piping output, use 2>/dev/null to suppress status messages if only data output is needed.

Exit codes and error recovery

Known limitations

1. Stacks are strictly linear. Branching stacks (multiple children on a single parent) are not supported. Each branch has exactly one parent and at most one child. If you need parallel workstreams, use separate stacks.
2. Stack disambiguation cannot be bypassed. If the current branch is the trunk of multiple stacks, commands error with code 6. Check out a non-shared branch first.
3. Multiple remotes require --remote or config. If more than one remote is configured, pass --remote <name> or set remote.pushDefault in git config before running push, sync, or rebase.
4. Merging PRs: Merging Stacked PRs from the CLI is not supported yet. Direct users to open the PR URL in a browser to merge PRs.
5. Remote stack checkout requires a PR number. checkout with a branch name only works with locally tracked stacks. Use a PR number (e.g. gh stack checkout 123) to pull stacks from GitHub.
6. PR title and body are auto-generated. There is no flag to set a custom PR title or body during submit. The title and body are generated from commit messages plus a footer. Use gh pr edit to modify PR title and body after creation.