/parallel-assign

Parallel resolution of independent backlog issues via git worktrees.

CLI only (no direct viban.json access) | Opus sub-agents in isolated worktrees

viban is a zsh CLI tool. Always invoke as viban <command>, NEVER as python -m viban or python viban.

Input: $ARGUMENTS (optional: number of issues, default 3)

---

Output Rules

• Do NOT output any preamble. No "Your Task:", "I'll now...", "Let me...", or task summaries before starting work.
• NEVER delegate work back to the user. Each agent must complete its assigned issue fully — writing code, tests, and verifying. Phrases like "Your Task:", "TODO(human)", "Waiting for your implementation", "Take your time", or any message that asks the user to write code are strictly FORBIDDEN. If you encounter a TODO comment, implement it yourself.
• Start executing Phase 0 immediately and silently.

---

Phase 0: SETUP

0.1 Read Workflow

[ -f ".viban/workflow.md" ] && cat ".viban/workflow.md"

Fallback to CLAUDE.md, then default. Same as /viban:assign Phase 0.1.

0.2 Parse Arguments

Extract count from $ARGUMENTS:

• Number provided (e.g. /viban:parallel-assign 5) → use that number
• No number → default to 3
• Maximum: 5

0.3 Check Backlog & Git State

viban list

Count available backlog issues. Adjust N down if fewer available. If backlog is empty: notify user and exit.

[ -n "$(git status --porcelain)" ] && echo "Warning: Uncommitted changes"
git checkout main && git fetch origin main && git reset --hard origin/main

0.4 Assign Issues

Assign N issues, each with a unique session ID. Determine branch names per workflow convention:

ISSUES=()  # Array of "ID|BRANCH" pairs
for i in $(seq 1 $N); do
    SESSION=$(echo "${RANDOM}${i}" | md5 | head -c 8)
    ID=$(viban assign "$SESSION" 2>&1 | tail -1)
    [[ -z "$ID" || "$ID" == "No backlog" ]] && break

    BRANCH="issue-${ID}"

    ISSUES+=("${ID}|${BRANCH}")
done

If no issues were assigned: notify user and exit.

0.5 Create Worktrees

For each assigned issue, create an isolated git worktree:

mkdir -p "$PWD/.viban/worktrees"

for entry in "${ISSUES[@]}"; do
    ID="${entry%%|*}"
    BRANCH="${entry##*|}"
    # Use issue ID as worktree dir name (matches cmd_done cleanup at .viban/worktrees/{ID})
    WT_DIR="$PWD/.viban/worktrees/$ID"

    git worktree add -b "$BRANCH" "$WT_DIR" origin/main
done

0.6 Sync Status

viban sync --push-only

---

Phase 1: DISPATCH PARALLEL AGENTS

Spawn one opus agent per issue using Task tool. All agents launch in a single message with run_in_background: true.

Agent prompt template (per issue):

You are resolving viban issue #{ID} in an isolated git worktree.

## Environment
- Worktree path: {PROJECT_ROOT}/.viban/worktrees/{ID}
- Branch: {BRANCH}
- Main repo: {PROJECT_ROOT}
- ALL file operations must happen inside the worktree path

## Workflow (Analyze + Implement + Verify only)
{paste workflow.md Phase 1 (Analyze), Phase 2 (Implement), and Phase 3 (Verify) sections ONLY}
{DO NOT include: Pipeline summary, GitHub Sync, Phase 4 (Build and Test), Phase 5 (Ship), Issue Management, Post-merge, or Additional Rules}

## Issue Details
{paste viban get output}

## Plan (if available)
{paste .viban/plans/{ID}.md content, or "No plan available"}

## Instructions

You are one of {N} parallel agents working in isolated git worktrees.

1. Work ONLY inside your worktree: {PROJECT_ROOT}/.viban/worktrees/{ID}
   - cd to the worktree before any work
   - All reads, edits, and writes must target files under this path

2. Follow the project workflow phases:
   - Analyze: understand the issue, locate code, identify root cause
   - Implement: make focused changes following project conventions
   - Verify: manual verification of the fix

3. After implementation, commit on your branch:
   ```bash
   cd {PROJECT_ROOT}/.viban/worktrees/{ID}
   git add <specific files>
   git commit -m "type: description

   - Root cause: ...
   - Solution: ...

   Resolves: #{ID}"

4. That's it. Stop after committing.

ABSOLUTE RULES:

• NEVER delegate work back to the user. You must complete the entire issue yourself. Phrases like "Your Task:", "TODO(human)", "Waiting for your implementation" are FORBIDDEN. If you encounter a TODO comment, implement it yourself.
• Your job ends after committing. The coordinator handles push, PR creation, and issue status.
• FORBIDDEN: git push — the coordinator pushes from the main repo after verifying.
• FORBIDDEN: gh pr create — the coordinator creates PRs after transplanting branches.
• FORBIDDEN: viban done — this DELETES the card permanently.
• FORBIDDEN: viban review — the coordinator handles issue status.
• FORBIDDEN: reading or writing viban.json — use CLI commands only.
• Do NOT run the full test suite — the coordinator handles that.
• Do NOT remove the worktree — the coordinator handles cleanup.

### Dispatch Pattern

```text
# Pseudo-code for the dispatch
for each (ID, BRANCH) in ISSUES:
    Task(
        subagent_type="general-purpose",
        model="opus",
        run_in_background=True,
        prompt=filled_template(ID, BRANCH, workflow, issue_json, plan)
    )

---

Phase 2: MONITOR & COLLECT

1. Wait for all background agents to complete (poll via TaskOutput)
2. Collect results — note successes and failures

---

Phase 3: TRANSPLANT & CLEANUP

After all agents finish, the coordinator handles everything from the main project root ($PWD).

3.1 Verify Local Branches

Confirm each branch has commits from the agent:

for entry in "${ISSUES[@]}"; do
    BRANCH="${entry##*|}"
    git log --oneline -3 "$BRANCH"
done

If a branch has no new commits (agent failed), skip it and report.

3.2 Push Branches & Create PRs

For each branch with commits, push from the main repo and create a PR:

for entry in "${ISSUES[@]}"; do
    ID="${entry%%|*}"
    BRANCH="${entry##*|}"

    # Push the local branch to remote
    git push -u origin "$BRANCH"

    # Create PR
    gh pr create --head "$BRANCH" --base main \
        --title "type: title" \
        --body "Resolves: #${ID}"

    # Move issue to review
    viban review "$ID"
done

3.3 Verify PRs Exist

for entry in "${ISSUES[@]}"; do
    BRANCH="${entry##*|}"
    gh pr list --head "$BRANCH" --json number,title,url -q '.[0]'
done

---

Phase 4: TEST & REPORT

4.1 Run Tests

Run the full test suite once on main (not per-agent):

zsh tests/run_all.zsh

If tests fail: identify which agent's changes caused the failure and report.

4.2 Sync

viban sync --push-only

4.3 Report

Parallel Resolution Complete

| Issue | Title | Branch | PR | Status |
|-------|-------|--------|----|--------|
| #ID   | ...   | ...    | #N | review |

Total: N issues processed
  Succeeded: X
  Failed: Y

Local branches available:
  - {BRANCH_1}
  - {BRANCH_2}
  ...

Worktrees cleaned up. All PRs ready for human review.

---

Error Handling

• Agent fails mid-work: coordinator still attempts push + PR for any commits on the branch. If no commits, skip and call viban review {ID} to unblock the card.
• Worktree creation fails: skip that issue, log error, continue with others
• Push fails: report it; local branch still available for manual push
• PR creation fails: report it; branch is already pushed, user can create PR manually
• Test failures: report which branch likely caused the failure

---

CRITICAL RULES

1. NEVER read or write viban.json directly — always use viban CLI commands. Direct JSON access causes race conditions and data corruption.
2. NEVER exit with any issue still in in_progress. For every assigned issue, ensure viban review {ID} has been called.
3. Do NOT remove worktrees after PRs are created. Worktrees stay at .viban/worktrees/{ID} for the review flow (/viban:approve cleans up).

CLI Reference

Command	Description
viban list	Print board
viban assign [session]	Assign issue
viban get <id>	View issue
viban review <id>	Move to review
viban sync --push-only	Sync to GitHub