Skill: Branch Context Check (Branch / Worktree Intent Guard)

Type: Execution

Purpose

Prevent accidental commits on the wrong branch or into a dirty working tree owned by another session.

This skill verifies:

• Current branch intent matches the current task
• Recent commits on the branch are related to the current work
• Dirty files are attributable to the current session or intentionally carried forward
• The safest next step is clear before staging, committing, pushing, or continuing work
• Post-publish branch/worktree cleanup is explicitly chosen after push, PR creation, or PR merge

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When to Use

• Before committing or pushing changes
• Before running a finalize-and-commit workflow
• When continuing work after time has passed or after switching sessions
• When the current branch name looks tied to another task, issue, PR, or agent session
• When the working tree is dirty and file ownership is unclear
• When deciding whether to create a new branch or separate worktree
• After pushing a branch, opening a PR, or merging a PR when deciding whether to switch back to base, delete local/remote branches, or remove worktrees

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When NOT to Use

• Non-Git directories
• Read-only repository inspection with no intent to edit, stage, commit, or push
• Trivial commands that do not depend on branch state
• Repositories where the user explicitly confirms the current branch is correct for this exact task

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Inputs Required

Do not run this skill without:

• A Git repository
• Current task intent, summarized from the user's request or conversation
• Access to Git status, branch, diff, and recent commit history

Optional but recommended:

• Target base branch (e.g., main, develop, release branch)
• Intended branch name, ticket ID, PR title, or issue reference
• List of files modified by the current session
• Known previous-session work that should remain untouched
• PR URL/number and merge state when deciding post-publish cleanup

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Output Format

1. Branch Context Snapshot
2. Intent Match Verdict (match, ambiguous, mismatch, or blocked)
3. Dirty Worktree Ownership
4. Recommended Action
5. User Confirmation Required
6. Post-Publish Cleanup Decision, if applicable

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Procedure

Gate 0 – Task Intent Capture

Summarize the current task in one sentence before inspecting Git.

Extract these intent signals when available:

• Feature, bug, documentation, or refactor scope
• Ticket/issue/PR ID
• Expected files, packages, or modules
• User-stated branch or worktree preference
• Whether the work is new, a continuation, or finalization of existing work

If intent cannot be summarized, ask the user for a short task description before recommending any Git action.

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Gate 1 – Git Context Snapshot

Collect evidence with non-destructive commands:

• git status --short --branch
• git branch --show-current
• git diff --name-only
• git diff --cached --name-only
• git log --oneline --decorate -5

When useful and available, also check:

• git rev-parse --abbrev-ref --symbolic-full-name @{u} for upstream branch
• git status --porcelain=v1 for machine-readable dirty files
• git merge-base --fork-point <base> HEAD or git merge-base <base> HEAD when evaluating whether branch commits are tied to the expected base

Do not run commands that alter the index, working tree, branch, or stash.

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Gate 2 – Branch Intent Inference

Infer the current branch's likely purpose from:

• Branch name tokens (feature/foo, ticket IDs, user names, session IDs)
• Recent commit messages and touched areas
• Upstream branch name and ahead/behind status
• Whether the branch is a protected/shared branch such as main, master, develop, release/*, or hotfix/*
• Whether the branch is clean or already contains task-specific commits

Compare that inferred purpose against the current task intent from Gate 0.

Classify the result:

• match: Branch name, recent commits, and file scope clearly align with the current task.
• ambiguous: Evidence is weak or generic; current branch may be correct but needs user confirmation.
• mismatch: Branch appears tied to a different task, issue, PR, or previous session.
• blocked: Dirty state or branch history makes safe continuation impossible without a user decision.

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Gate 3 – Dirty Worktree Ownership

Separate files into:

• Current-session changes: Files edited in the current conversation or explicitly requested by the user.
• Carried-forward changes: Dirty files that existed before the current task or are not attributable to this session.
• Staged changes: Files already staged before this skill runs.
• Unknown ownership: Files whose origin cannot be determined.

Then check overlap:

• Same file touched by current-session and carried-forward changes
• Same module or feature area touched by unrelated tasks
• Staged changes that do not belong to the current task

If overlap exists, classify the verdict as blocked unless the user explicitly confirms the combined scope.

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Gate 4 – Decision Matrix

Use this matrix to recommend the next action:

Condition	Verdict	Recommended Action
Branch matches current task and dirty files are in-scope	match	Continue finalize, stage only confirmed files
Branch is generic or evidence is weak, but no conflicting dirty files exist	ambiguous	Ask user to confirm branch before commit
Clean branch clearly belongs to another task	mismatch	Create/switch to a task-appropriate branch or worktree before editing/committing
Dirty branch contains previous-session work unrelated to current task	blocked	Do not commit; ask whether to finish previous work, split via worktree, or isolate current-session patch
Current branch is protected/shared and task is non-trivial	blocked	Create a feature/fix branch before committing
Staged files include unknown or unrelated changes	blocked	Unstage only with explicit user approval; otherwise stop before commit
Branch is ahead of upstream with unrelated commits	mismatch	Do not add new task commits; create a separate branch from the correct base or ask user to confirm stacking

When recommending a new branch, propose a concrete name derived from the task, for example fix/login-timeout or docs/branch-guard.

When recommending a worktree, include the base branch assumption and state that only user-confirmed changes should be moved or recreated there.

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Gate 5 – Handoff

Before any staging or commit:

• Present the verdict and evidence.
• State exactly which files are safe to commit now.
• State which files must be left untouched.
• Ask for user confirmation when verdict is ambiguous, mismatch, or blocked.

If used inside finalize-and-commit or docs-finalize-and-commit, this gate must complete before their Working Set Validation gate proceeds.

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Gate 6 – Post-Publish Cleanup Decision

Run this gate after any commit/push/PR operation before ending the workflow. The agent must either perform an approved cleanup or explicitly state why no cleanup was performed.

Step 6-1: Capture publish state

Inspect:

• git status --short --branch
• git branch --show-current
• git worktree list
• git branch --format='%(refname:short) %(upstream:short)'
• Remote branch existence for the current task branch
• PR state (OPEN, MERGED, CLOSED) and merge commit when a PR exists

Use gh pr view or equivalent repository tooling when available. If GitHub metadata is unavailable, do not infer that a branch is merged from Git alone when squash merge may have been used.

Step 6-2: Present cleanup choices

Offer the applicable choices instead of silently ending:

• Keep branch/worktree: keep the current branch for follow-up commits or an open PR.
• Return to base: switch to the base branch and fast-forward pull.
• Delete local branch: delete the task branch after it is no longer needed.
• Delete remote branch: delete the remote task branch after the PR is merged or closed intentionally.
• Remove worktree: remove a separate task worktree after confirming it is clean and no longer needed.
• Prune metadata: run remote/worktree prune after branch or worktree cleanup.

If the user explicitly requested cleanup, execute every eligible cleanup step after the safety checks below pass. If the user did not request cleanup, stop and ask which option to apply.

Step 6-3: Safety checks before deletion

Deletion is eligible only when all relevant checks pass:

• Working tree is clean in the branch/worktree being cleaned.
• The PR for the task branch is MERGED, or the user explicitly confirms that the branch is obsolete.
• No open PR depends on the branch.
• No stacked branch or follow-up branch uses the branch as its base, unless the user confirms that dependency is gone.
• The branch is not the current checkout when deleting it locally.
• A worktree is not removed unless git status inside that worktree is clean.
• Remote deletion targets only the task branch, never a base/protected branch.

Prefer git branch -d. If squash merge makes git branch -d reject a branch whose PR is confirmed MERGED, use git branch -D only after stating that reason and only for the task branch.

Step 6-4: Verification after cleanup

After cleanup, verify and report:

• Current branch
• git status --short --branch
• Remaining local branches relevant to the task
• Remaining remote branches relevant to the task
• git worktree list

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Guardrails

• Do not treat the current branch as valid just because it is already checked out.
• Do not assume a new session can be reliably detected; infer risk from branch, commits, dirty files, and task intent.
• Do not run destructive Git commands (reset, checkout --, restore, clean, stash, rebase, branch deletion) without explicit user approval.
• Do not use git add ., git add -A, or git add --all.
• Do not commit staged changes until staged ownership is confirmed.
• Do not move dirty changes across branches or worktrees automatically.
• Do not mix unrelated tasks in one commit just because they are already dirty.
• Explicitly state assumptions about base branch and branch naming.
• Do not end a commit/push/PR workflow without a cleanup decision or a clear statement that cleanup is not applicable yet.
• Do not delete local branches, remote branches, or worktrees unless the safety checks in Gate 6 pass.
• Do not delete a branch just because it was pushed; open PR branches normally stay until merge or an explicit user decision.
• Do not remove the current worktree. Switch away first or remove only a separate clean worktree path.

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Failure Patterns

Common bad outputs:

• Saying "working tree clean" but ignoring that the branch itself belongs to a previous task
• Continuing on a feature branch whose recent commits are unrelated to the current request
• Treating dirty files as current-session changes without evidence
• Recommending git stash as a default solution, hiding ownership instead of clarifying it
• Creating a new branch from the wrong feature branch when the correct base should be main or develop
• Staging all files after warning that some files are out of scope
• Asking for generic confirmation without listing the exact branch, commits, and files that caused the risk
• Ending after push or merge while leaving stale branches/worktrees without mentioning cleanup choices
• Deleting a branch for an open PR or an unverified squash merge
• Removing a worktree without checking that worktree's own status

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Example 1 (Clean Wrong Branch)

Input:

Current task: add billing export tests. git status --short --branch shows a clean working tree on feature/oauth-login. Recent commits mention OAuth callback handling.

Output:

1. Branch Context Snapshot: branch feature/oauth-login, clean tree, recent commits are OAuth-related.
2. Intent Match Verdict: mismatch — current task is billing export tests, but branch intent is OAuth login.
3. Dirty Worktree Ownership: no dirty files.
4. Recommended Action: create a new branch from the correct base, for example test/billing-export, before making or committing billing changes.
5. User Confirmation Required: yes — confirm base branch (main assumed) and new branch/worktree preference.

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Example 2 (Dirty Previous Session)

Input:

Current task: update dashboard copy. Current branch is agent/aaa-refactor. Working tree has modified src/auth/session.ts and src/dashboard/Home.tsx. Conversation history only touched src/dashboard/Home.tsx. Recent commits on the branch mention auth session refactoring.

Output:

1. Branch Context Snapshot: branch agent/aaa-refactor, dirty files in auth and dashboard, recent commits are auth-related.
2. Intent Match Verdict: blocked — branch and one dirty file appear to belong to a previous auth refactor session.
3. Dirty Worktree Ownership: src/dashboard/Home.tsx is current-session; src/auth/session.ts is carried-forward/unknown.
4. Recommended Action: do not commit from this state. Ask whether to finish the auth refactor first, create a separate worktree for dashboard copy, or commit only the confirmed dashboard file after explicit approval.
5. User Confirmation Required: yes — exact commit scope must be confirmed before staging.

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Notes

This skill is intentionally conservative. Its goal is not to automate branch management; it is to prevent accidental task mixing at the commit boundary.