gg

gg

Use this skill to operate git-gud (gg) as a CLI tool for day-to-day stacked-diff workflows across GitHub and GitLab.

When to use

• You need multiple PRs/MRs that depend on each other
• You need to sync stack changes and keep review metadata updated (including GG-ID/GG-Parent normalization)
• You need machine-readable command output for automation (--json)

Prerequisites

• gg installed
• Provider CLI installed + authenticated:
  • GitHub: gh auth status
  • GitLab: glab auth status
• Git repo with gg initialized (gg setup)

Note: Network errors during auth check are non-fatal — gg prints a warning and continues. The operation may fail later if authentication is actually required.

Setup

Interactive wizard (recommended)

gg setup        # Quick mode: essential settings (provider, base, username)
gg setup --all  # Full mode: all settings organized by category

Quick mode prompts for: provider, base branch, username.

Full mode organizes all settings into groups: General, Sync, Land, Lint, Worktrees, and GitLab (if applicable). Includes sync_draft, sync_update_descriptions, and sync_update_title options.

Global config

Store shared defaults in ~/.config/gg/config.json that apply to all repos. Local config (gg setup) takes precedence.

Manual setup (.git/gg/config.json)

{
  "defaults": {
    "provider": "github",
    "base": "main",
    "branch_username": "your-github-user",
    "lint": ["cargo fmt --all --check", "cargo clippy -- -D warnings"],
    "auto_add_gg_ids": true,
    "sync_auto_rebase": false,
    "sync_behind_threshold": 1,
    "sync_auto_lint": false,
    "sync_draft": false,
    "sync_update_descriptions": true,
    "sync_update_title": false,
    "land_auto_clean": false,
    "land_wait_timeout_minutes": 30,
    "unstaged_action": "ask"
  }
}

{
  "defaults": {
    "provider": "gitlab",
    "base": "main",
    "branch_username": "your-gitlab-user",
    "lint": ["cargo fmt --all --check", "cargo clippy -- -D warnings"],
    "gitlab": {
      "auto_merge_on_land": false
    }
  }
}

auto_add_gg_ids is deprecated and kept only for compatibility with existing configs; runtime behavior always treats it as enabled.

Core workflow

1. Create/switch stack (prefer worktree):

gg co -w feature-auth

When splitting an existing stack into lower and upper stacks, prefer a managed worktree for the new upper stack:

gg unstack --target 3 --name feature-auth-followup --wt

2. Commit logical changes:

git add <files>
git commit -m "feat: add input validation"

3. Check stack state:

gg ls --json        # single-stack details + summary metrics
gg log --json       # smartlog-style view of the current stack
gg inbox --json     # cross-stack triage buckets for action needed

4. Publish/update PR/MR chain:

gg sync --json

If a mapped PR/MR still points at an old source branch after a stack split, gg sync recreates that PR/MR with the current entry branch, remaps config to the new number, comments on the old one, and closes it. JSON action is "recreated".

If gg sync --json returns a warning that the stack branch does not use the configured prefix, surface it to the user. The command may continue, but stack discovery/listing and saved PR/MR mappings can be inaccurate until the branch is renamed to match defaults.branch_username.

5. When approved + green CI, land only after user confirmation:

gg land -a -c --json

Agent operating rules (mandatory)

1. Never run gg land without explicit user confirmation.
2. Always use --json for gg ls, gg sync, gg land, gg clean -a, and gg lint.
3. Prefer worktrees for isolation (gg co -w <stack>).
4. Verify approved: true and ci_status success before landing. If the user requests --admin, skip the approval check (GitHub only — GitLab ignores the flag).
5. If sync warns stack is behind base, run gg rebase first.
6. Prefer gg absorb -s for multi-commit edits.
7. Never use git add -A blindly. Review git status first and only stage intended files. Use git add <specific-files> to avoid leaking secrets, env files, or unrelated changes.
8. Respect the immutability guard. Rewrite-style commands (gg sc, gg absorb, gg reorder/gg arrange, gg split, gg unstack, gg drop, gg rebase, gg restack) refuse to rewrite merged PRs/MRs or commits already on the base branch, except that gg rebase silently skips base-ancestor commits that naturally drop out when rebasing onto the refreshed base. If a command exits with ImmutableTargets, surface the listed commits and reasons to the user and get explicit confirmation before retrying with -f / --force (alias --ignore-immutable).

Common operations

• Navigate: gg mv, gg first, gg last, gg prev, gg next
• Amend current commit: gg sc / gg sc -a
• Auto-distribute staged hunks: gg absorb -s
• Split a commit into two: gg split — opens a two-panel TUI for hunk selection (files on the left, colored diff on the right), followed by inline commit message inputs for both the new and remainder commits. Use --no-tui to fall back to sequential git add -p style prompts. The -m flag bypasses the TUI message input for the new commit. The --no-edit flag skips the remainder message input. Pass FILES... to auto-select all hunks from those files (e.g., gg split -c 3 file1.rs file2.rs).
• Split a stack into two stacks: gg unstack — opens a picker by default. The selected entry and descendants become a new independent stack; lower entries remain in the original stack. Use --target <position|gg-id|sha> --no-tui for scripts, and --name <stack> to choose the new stack name.
• Drop commits from stack: gg drop <position|sha|gg-id>... -y (alias: gg abandon). Use -y / --yes to skip confirmation; add -f / --force only to bypass the immutability guard for merged/base-ancestor commits.
• Reorder/drop stack (TUI): gg reorder (or gg arrange) — opens interactive TUI for visual reordering and dropping commits. Press d to mark a commit for dropping. Use --no-tui to fall back to text editor (delete lines to drop).
• Reorder stack (direct): gg reorder -o "3,1,2"
• Sync subset: gg sync -u <position|gg-id|sha> --json
• Lint stack: gg lint --json
• Run a command across the stack: gg run -- <cmd...> (see below)
• Triage multiple stacks at once: gg inbox --json
• Repair ancestry drift: gg restack / gg restack --dry-run --json (see below)
• Clean merged stacks: gg clean -a --json
• Undo last local mutation: gg undo (see below)

Undoing local mutations (gg undo)

gg undo reverses the ref/HEAD effects of the most recent mutating gg command by replaying a snapshot from the per-repo operation log at <commondir>/gg/operations/*.json. It never touches the working tree, index, or untracked files — only refs move.

gg undo              # reverse the most recent local operation
gg undo --list       # see recent operations (newest-first)
gg undo <op_id>      # target a specific record from --list
gg undo; gg undo     # redo: a second undo reverses the first
gg undo --json       # machine-readable output

Every mutating command (sc, drop, split, unstack, rebase, reorder, absorb, reconcile, restack, checkout, nav, clean, sync, land, and run --amend) snapshots the refs it will touch before mutating and records the operation on success. The log keeps the last 100 records; interrupted/pending records are never pruned.

Refusal modes (exit 1, no refs touched, JSON includes refusal.reason):

• remote — target operation pushed/merged/closed/created a PR/MR. gg prints a provider-specific revert hint (gh pr close <n>, glab mr close <n>, git push --delete …). Agents must surface the hint to the user rather than attempt silent remote rollback.
• interrupted — operation crashed or was Ctrl-C'd mid-flight.
• stale — refs moved since the target operation finalised. The error names the ref, expected OID, and actual OID.
• unsupported_schema — record was written by a newer gg binary.

gg undo does not restore working-tree content (use git reflog or git stash), does not touch remotes, and does not support an --all / --range mode.

Repairing stack ancestry (gg restack)

gg restack detects and repairs ancestry drift — when a commit's GG-Parent trailer no longer matches its expected parent in the stack order. This happens after manual git rebase, git commit --amend, cherry-picks, or upstream rebases that rewrite commit SHAs without updating GG metadata.

gg restack --dry-run        # show plan without changes
gg restack --dry-run --json # machine-readable plan
gg restack                  # execute full ancestry repair
gg restack --from 3         # repair only from position 3 upward
gg restack --json           # execute with JSON output

Each step in the plan is one of:

• ok — parent already correct, no action needed
• reattach — parent differs, needs rebasing
• skip — below --from threshold, not checked

After a successful restack, run gg sync to push the repaired commits.

Running commands across the stack (gg run)

gg run walks every commit in the current stack (oldest → newest) and executes a command at each one. Use it for things that don't fit the lint config — ad-hoc verifications, formatters, single-shot scripts, etc.

• Read-only (default): gg run -- cargo test -p mycrate Each commit is checked out, the command runs, and the tree must stay clean. Any modification fails that commit (same contract as gg lint without --amend).
• Amend mode: gg run --amend -- cargo fmt Changes the command makes are folded into each commit via git commit --amend, then the rest of the stack is rebased on top. This is the same engine gg lint uses.
• Discard mode: gg run --discard -- ./mutating-check.sh Runs the command and throws away any changes (working tree + index + untracked). Useful when you only care about the exit code of a command that happens to mutate state.
• Stop on first failure (default) vs keep going: Add --keep-going / -k to continue through failing commits instead of aborting at the first one.
• Limit how far you go: --until <position|gg-id|sha> stops after the named commit. Everything above it is left untouched.
• Parallelize read-only runs: -j N / --jobs N spawns isolated worktrees per commit. Valid only with the default (read-only) mode. The dirty-tree check in each worker matches the sequential path (untracked files are ignored, tracked modifications fail).
• JSON output: gg run --json -- <cmd...> emits a single RunResponse document on stdout (see reference.md). Failures set run.all_passed = false; the process still exits non-zero, but only the run payload is printed — no trailing {"error":...} object.

Argument boundaries are preserved: gg run -- git commit -m "multi word" passes exactly those argv elements to git without shell splitting, so quoted args with spaces, globs, or shell metacharacters go through intact. Use -- before the command (as shown) so clap treats subsequent tokens as the command, not as gg run flags.

For repeatable linter runs with commands configured in .git/gg/config.json, prefer gg lint — it's gg run --amend with the command list coming from config.

Immutable commits

gg refuses by default to rewrite commits that look "already published":

• the tracked PR/MR is merged, or
• the commit is already reachable from origin/<base> (or the local base, as a fallback).

The guard protects gg sc, gg absorb, gg reorder / gg arrange, gg split, gg unstack, gg drop, gg rebase, and gg restack. gg rebase is a special case: merged commits (both base-ancestor commits and squash-merged PRs) are silently skipped because git rebase would drop them naturally via patch-id matching instead of rewriting them. For the remaining commands the command exits with an ImmutableTargets error listing every affected position, short SHA, title, and reason (e.g. merged as !123, already in origin/main).

To bypass it intentionally, pass -f / --force (long alias --ignore-immutable). Always surface the listed commits and reasons to the user first; the override still emits a warning and proceeds.

gg land's post-merge cleanup bypasses the guard by design, and gg absorb --dry-run skips it (no rewrite happens). See reference.md → "Immutable commits" for details.

PR/MR body ownership

gg sync uses managed markers to separate generated content from user edits:

(user content — preserved across syncs)

<!-- gg:managed:start -->
(generated by gg — regenerated on every sync)
<!-- gg:managed:end -->

(user content — preserved across syncs)

• New PRs/MRs: Body is wrapped in managed markers automatically.
• Re-sync with markers: Only the managed block is replaced; user content above/below is preserved.
• Legacy PRs (no markers): Body is left untouched with a warning — no risk of clobbering manual edits.
• Content inside the managed block is regenerated on each sync. Place persistent checklists and notes outside the markers.

Stack-navigation comments

If the repo's .git/gg/config.json has defaults.stack_nav_comments: true, gg sync posts and maintains a managed comment on each open PR/MR in the stack. The comment lists every entry (#N on GitHub, !N on GitLab) with a 👉 marker on the current one. The comment is identified by a hidden <!-- gg:stack-nav --> marker and managed entirely by git-gud — don't edit these comments manually, and don't be surprised when gg sync adds, updates, or removes them automatically.

Disable the feature by setting defaults.stack_nav_comments: false (the default). The next gg sync then cleans up any existing managed comments. Reconcile is skipped under --until to avoid partial-stack inconsistencies.

GitLab-specific

• gg land --auto-merge is GitLab-only and requests queueing/auto-merge.
• With merge trains enabled, landing may enqueue MRs instead of immediate merge.
• Track train state in gg ls --json with:
  • in_merge_train
  • merge_train_position
• Land action values on GitLab may include queued / already_queued (in addition to merged).
• When --wait detects CI failure, the error message includes the names and stages of failed pipeline jobs (fetched from the MR's head pipeline).
• After landing an MR, downstream MRs are automatically retargeted away from the merged branch — no manual retargeting in GitLab UI is needed. gg sync also handles this if an MR was merged directly in the UI.
• Use glab for auxiliary GitLab checks/actions.
• JSON fields always use pr_* naming, even for GitLab MRs (pr_number, pr_state).

Provider-neutral notes

• pr_state values: open, merged, closed, draft (same for both GitHub and GitLab).
• pr_url format varies by provider (/pull/N for GitHub, /-/merge_requests/N for GitLab).

See also

• Full command + schema reference: reference.md
• End-to-end walkthrough: examples/basic-flow.md
• Multi-commit editing: examples/multi-commit.md
• Merge trains (GitLab): examples/merge-train.md
• MCP server tools & schemas: reference.md → MCP Server section

MCP Server Usage for Agents

The gg-mcp binary exposes git-gud as an MCP server (stdio transport). Set GG_REPO_PATH to the target repo.

Read-only tools (safe, no side effects)

• stack_list / stack_log / stack_list_all / stack_status — inspect stacks (stack_log gives a smartlog-style view of the current stack; stack_list_all is cross-stack)
• pr_info — check PR state, CI, approval
• config_show — read repo configuration
• stack_undo_list — list recent operations from the per-repo operation log

Write tools (mutating, use with care)

• stack_checkout — create or switch stacks
• stack_sync — push and create/update PRs (use draft: true for safety)
• stack_land — merge approved PRs (always confirm with user first)
• stack_clean — remove merged stacks
• stack_rebase — rebase onto latest base
• stack_squash / stack_absorb — amend commits
• stack_reconcile — fix out-of-sync remote branches
• stack_drop — remove commits from the stack (always passes --yes; set force: true only to bypass the immutability guard for merged/base commits; agent confirms with user before any drop)
• stack_split — split a commit using interactive hunk selection (TUI opens by default; pass FILES... to auto-select all hunks for those files)
• stack_reorder — reorder commits with explicit order string (no TUI)
• stack_restack — repair stack ancestry drift (dry_run, from params)
• stack_undo — reverse the ref/HEAD effects of the most recent mutating gg command (refuses on remote-touching ops, returns provider-specific revert hints; agents must surface those hints rather than attempt silent remote rollback)

Navigation tools

• stack_move — jump to a commit by position, GG-ID, or SHA
• stack_navigate — move first/last/prev/next in the stack

Agent guidelines for MCP

• Prefer read-only tools to understand state before writing.
• Use stack_sync with draft: true for new PRs unless the user asks for non-draft. Note: draft: true only affects newly created PRs, not existing ones.
• Never call stack_land without explicit user approval.
• Parse JSON output from stack_sync, stack_land, stack_clean, and stack_lint.
• If stack_status shows behind_base > 0, run stack_rebase before syncing.
• Rewrite tools (stack_squash, stack_absorb, stack_reorder, stack_split, stack_drop, stack_rebase, plus CLI gg unstack) will fail with ImmutableTargets when a target commit is merged or already on the base branch. Each tool accepts a force: bool parameter that maps to --force / --ignore-immutable. Only set force: true after surfacing the affected commits to the user and getting explicit approval. stack_drop always passes --yes (MCP is non-interactive), but its force: bool param is separate from the confirmation-skip — leave it false unless the user has approved rewriting merged/base commits.