fix CONTRIBUTING.md: branch naming should include issue number

Address han's review feedback:
- Changed feat/feature-name to feat/issue-N-feature-name
- Consistent with fix/issue-N-name format

.github/ISSUES/fix-queue-daemon-excess-agents.md

@@ -0,0 +1,67 @@
+# Fix: Queue daemon spawning excess agents due to race condition
+
+## Problem
+
+When enqueueing multiple tasks (e.g., 6 tasks), the queue daemon was spawning many more subagents than expected, eventually exhausting container memory.
+
+**Root Cause:** The combination of:
+1. `process_queue()` calling `opencode run` directly instead of `kugetsu start`, bypassing all concurrency logic
+2. `count_active_dev_sessions()` counting `pm-agent.json` toward `MAX_CONCURRENT_AGENTS`, reducing effective dev agent slots
+3. No atomic locking around session count check + session file creation (TOCTOU race condition)
+4. Background spawning of multiple concurrent processes in `process_queue()`
+
+**Expected behavior:** With `MAX_CONCURRENT_AGENTS=3` and 6 tasks:
+- Tasks should be processed sequentially via `kugetsu start`
+- Only 3 dev agents should run at a time
+- Tasks should queue and wait for slots to free up
+
+## Solution
+
+### 1. `count_active_dev_sessions()` - Exclude pm-agent
+Only count actual dev agent session files (exclude `pm-agent.json`).
+
+### 2. `process_queue()` - Call `kugetsu start` directly + retry logic
+- Call `kugetsu start` directly (foreground, sequential) instead of spawning `opencode run` background process
+- Dynamic batch size = available slots (removes need for `QUEUE_DAEMON_BATCH_SIZE`)
+- Retry logic (max 3 attempts) on failure
+- On failure: cleanup worktree/session and revert to `pending` state
+- Save `fork_pid` to queue item for timeout handling
+
+### 3. `cmd_start()` - Add flock
+- Add flock around critical section (count check + fork)
+- Track `fork_pid` for queue item timeout handling
+
+### 4. Notification System
+New notification types:
+| Event | Type |
+|-------|------|
+| Task enqueued | `task_queued` |
+| Task dequeued | `task_dequeued` |
+| Task started | `task_started` |
+| Task completed | `task_completed` |
+| Task error | `task_error` |
+
+### 5. Config
+- Remove `QUEUE_DAEMON_BATCH_SIZE` (no longer needed - batch size is now dynamic)
+
+## Notification Flow
+
+| Event | Location | Type |
+|-------|----------|------|
+| Task enqueued | `enqueue_task()` | `task_queued` |
+| Task dequeued | `process_queue()` after state change to `notified` | `task_dequeued` |
+| Task started | `cmd_start()` after session file created | `task_started` |
+| Task completed | `update_queue_item_state()` | `task_completed` |
+| Task error | `update_queue_item_state()` | `task_error` |
+
+## Out of Scope
+
+- Re-check loop in cmd_start (checking if session DB is reliable) - deferred to separate research issue
+- Buffer mechanism for excess forking (safety failsafe only)
+
+## Status
+
+- [x] Issue created
+- [x] Implementation
+- [x] PR created (#147)
+- [ ] Merged

CONTRIBUTING.md

@@ -2,10 +2,10 @@
 
 ## Workflow
 
-1. Create a branch for your work: `git checkout -b fix/issue-N-name` or `git checkout -b docs/topic-name`
+1. Create a branch for your work: `git checkout -b fix/issue-N-name` or `git checkout -b feat/issue-N-feature-name`
 2. Make changes and commit with clear messages
 3. Open a Pull Request for review
-4. Do not merge directly to `master` for reviewable changes
+4. Do not merge directly to `main` or `develop` for reviewable changes
 5. After approval, squash and merge
 
 ## Guidelines
@@ -14,10 +14,53 @@
 - Keep PRs focused and reasonably sized
 - Document any non-obvious decisions
 - Test changes before submitting
+- See [VERSIONING.md](VERSIONING.md) for backport compatibility rules
 
 ## Branches
 
-- `master` — stable, reviewed content only
+### Primary Branches
+
+- `main` — stable 0.1.x releases, production-ready code
+- `develop` — experimental 0.2.x work, next major version
+
+### Feature Branches
+
 - `fix/*` — bug fixes
+- `feat/*` — new features
 - `docs/*` — documentation updates
-- `research/*` — new research notes
+- `refactor/*` — code refactoring (no behavior change)
+
+## Branch Model
+
+```
+main (0.1.x stable)
+  └── v0.1.0, v0.1.1, v0.1.2, ...
+
+develop (0.2.x experimental)
+  └── (next major version work)
+```
+
+### Which Branch to Target?
+
+| Change Type | Target Branch | Backport? |
+|-------------|---------------|-----------|
+| Bug fix | `main` | N/A |
+| Documentation | `main` | N/A |
+| New feature (backport-compatible) | `main` | Can cherry-pick to `develop` |
+| Experimental feature | `develop` | No |
+| Breaking change | `develop` | No |
+
+## Backport Compatibility
+
+Before merging, consider if your change is backport-compatible:
+
+- **YES**: Bug fixes, docs, adding new optional inputs
+- **NO**: Changing behavior, changing defaults, removing features
+
+See [VERSIONING.md](VERSIONING.md) for full policy.
+
+## Release Process
+
+1. Bug fixes and docs → directly to `main`
+2. New features → `develop` or feature branches → `develop`
+3. When `develop` is stable enough → merge to `main` for release

VERSIONING.md

@@ -0,0 +1,71 @@
+# Versioning Policy
+
+## Branch Strategy
+
+Kugetsu uses a dual-branch model:
+
+| Branch | Purpose | Version | Stability |
+|--------|---------|---------|-----------|
+| `main` | Stable releases | 0.1.x | Production-ready |
+| `develop` | Experimental work | 0.2.x | Active development |
+
+### Branch Definitions
+
+- **`main`**: Contains the latest stable 0.1.x releases. All changes here should be production-ready and backport-compatible when possible.
+
+- **`develop`**: Contains work for the next major version (0.2.x). This branch may contain experimental features that could change or be removed.
+
+## Version Format
+
+Versions follow [Semantic Versioning](https://semver.org/):
+```
+MAJOR.MINOR.PATCH
+```
+
+- **MAJOR**: Incompatible API/behavior changes
+- **MINOR**: New functionality (backward-compatible)
+- **PATCH**: Bug fixes (backward-compatible)
+
+## Backport Compatibility
+
+### Backport-Compatible Changes (0.1.x)
+- Bug fixes
+- Documentation updates
+- Performance improvements
+- Adding new inputs/options (must have sensible defaults)
+- Changes that only affect 0.2.x-specific features
+
+### NOT Backport-Compatible
+- Removing or renaming existing options
+- Changing default values of existing options
+- Changing behavior of existing commands
+- Introducing breaking changes to the API/shell interface
+
+## Deprecation Policy
+
+When introducing breaking changes:
+
+1. **Deprecate in minor X**: Add warning messages, document the change
+2. **Remove in major X+1**: The breaking change is removed in the next major version
+
+Example:
+- Option `--old-flag` deprecated in v0.1.5
+- Option `--old-flag` removed in v1.0.0 (not v0.2.0)
+
+## What Constitutes a Version Bump
+
+| Change Type | Version Bump |
+|-------------|--------------|
+| Add new command/option | MINOR |
+| Bug fix | PATCH |
+| Change default value | MINOR (may warrant PATCH) |
+| Add new required input | MAJOR |
+| Remove deprecated feature | MAJOR |
+| Change behavior of existing command | MINOR (needs deprecation first) |
+
+## Release Process
+
+1. Changes are developed on feature branches
+2. PRs are opened against `main` for 0.1.x changes, or `develop` for 0.2.x
+3. After review and approval, changes are squash-merged
+4. Releases are tagged from `main` after significant changes

docs/CHANGELOG.md

@@ -0,0 +1,111 @@
+# Changelog
+
+All notable changes to kugetsu are documented here.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
+
+## [Unreleased]
+
+## [v0.2.1] - 2026-04-03
+
+### Fixed
+- Prevent excess agent spawning with flock + sequential processing
+
+## [v0.2.0] - 2026-03-30
+
+### Added
+- Queue system with background daemon
+- Agent timeout handling
+- Context dump/load for session isolation
+- PR tracking and safe destroy
+
+## [v0.1.13] - 2026-03-29
+
+### Fixed
+- Add missing closing parenthesis in process_queue Python extraction
+
+## [v0.1.12] - 2026-03-25
+
+### Added
+- Post-comment helper for PM agent
+
+## [v0.1.11] - 2026-03-20
+
+### Fixed
+- Wrap cmd_continue in subshell with cd for correct worktree dir
+
+## [v0.1.10] - 2026-03-15
+
+### Fixed
+- destroy --base now also deletes PM agent session
+
+## [v0.1.9] - 2026-03-10
+
+### Added
+- init creates base session in ~/.kugetsu-worktrees
+- Adds context to forked sessions
+- Clears logs on init
+
+## [v0.1.8] - 2026-03-05
+
+### Fixed
+- destroy --base and --pm-agent actually delete opencode sessions
+
+## [v0.1.7] - 2026-02-28
+
+### Fixed
+- Warn if init run from non-empty directory
+
+## [v0.1.6] - 2026-02-20
+
+### Fixed
+- Detect session via DB query instead of opencode session list
+
+## [v0.1.5] - 2026-02-15
+
+### Fixed
+- Update forked session permissions after detection
+
+## [v0.1.4] - 2026-02-10
+
+### Fixed
+- Call fix_session_permissions before forking
+
+## [v0.1.3] - 2026-02-05
+
+### Fixed
+- Session detection ordering bug and debugging
+
+## [v0.1.2] - 2026-01-28
+
+### Fixed
+- Improve session detection in cmd_start with retry logic and logging
+
+## [v0.1.1] - 2026-01-20
+
+### Fixed
+- Use cd + worktree inside parent dir instead of --dir flag
+
+## [v0.1.0] - 2026-01-15
+
+### Added
+- KUGETSU_VERBOSITY for PM agent output control
+- Initial documented release
+
+[Unreleased]: https://git.fbrns.co/shoko/kugetsu/compare/v0.2.1...HEAD
+[v0.2.1]: https://git.fbrns.co/shoko/kugetsu/compare/v0.2.0...v0.2.1
+[v0.2.0]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.13...v0.2.0
+[v0.1.13]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.12...v0.1.13
+[v0.1.12]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.11...v0.1.12
+[v0.1.11]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.10...v0.1.11
+[v0.1.10]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.9...v0.1.10
+[v0.1.9]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.8...v0.1.9
+[v0.1.8]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.7...v0.1.8
+[v0.1.7]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.6...v0.1.7
+[v0.1.6]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.5...v0.1.6
+[v0.1.5]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.4...v0.1.5
+[v0.1.4]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.3...v0.1.4
+[v0.1.3]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.2...v0.1.3
+[v0.1.2]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.1...v0.1.2
+[v0.1.1]: https://git.fbrns.co/shoko/kugetsu/compare/v0.1.0...v0.1.1
+[v0.1.0]: https://git.fbrns.co/shoko/kugetsu/releases/tag/v0.1.0

skills/kugetsu/SKILL.md

@@ -49,6 +49,8 @@ A default config file is created during `kugetsu init` with commented examples:
 | `MAX_CONCURRENT_AGENTS` | 3 | Maximum number of concurrent dev agents |
 | `KUGETSU_TEMP_DIR` | `~/.local/share/opencode/tool-output` | Temp directory for subagent tool output (useful in headless environments where /tmp is restricted) |
 | `KUGETSU_VERBOSITY` | `default` | PM agent verbosity level: `verbose`, `default`, or `quiet` |
+| `QUEUE_DAEMON_INTERVAL_MINUTES` | 5 | How often daemon polls queue (in minutes) |
+| `QUEUE_CLEANUP_AGE_DAYS` | 7 | Auto-cleanup completed/error items older than N days |
 
 ### Environment Variables for Agents
 
@@ -111,6 +113,10 @@ Each issue session gets its own git worktree to prevent conflicts:
 ├── worktrees/
 │   ├── github.com-shoko-kugetsu-14/     # Isolated workdir for issue #14
 │   └── github.com-shoko-kugetsu-15/     # Isolated workdir for issue #15
+├── queue/
+│   ├── items/                      # Queue item JSON files
+│   ├── daemon.pid                   # Daemon process ID
+│   └── daemon.log                  # Daemon log output
 └── index.json                       # Maps session IDs and issue refs to session files
 ```
 
@@ -258,16 +264,17 @@ kugetsu destroy --base -y
 
 ### kugetsu delegate `<message>`
 
-Send a message to the PM agent for task coordination (fire-and-forget):
+Send a message to the PM agent for task coordination via queue:
 ```bash
 kugetsu delegate "work on issue #14"
 kugetsu delegate "review PR #92"
 ```
 
-- Non-blocking: returns immediately, runs in background
-- PM agent processes the message asynchronously
-- Uses `KUGETSU_VERBOSITY` env var to control PM agent output verbosity
-- Log output stored in `~/.kugetsu/logs/delegate-<timestamp>.log`
+- **Always enqueues** (fire-and-forget): returns immediately
+- Queue daemon polls queue and invokes PM when slots available
+- Tasks are processed FIFO (first-in-first-out)
+- Use `kugetsu queue list` to see pending tasks
+- Use `kugetsu queue-daemon logs` to debug queue processing
 
 ### kugetsu logs [n]
 
@@ -328,35 +335,79 @@ kugetsu server default github   # Set default server
 kugetsu server get github       # Get server URL
 ```
 
-### kugetsu queue <list|enqueue|dequeue|clear>
+### kugetsu queue <list|stats|clear>
 
 Manage task queue for autonomous PM operation:
 ```bash
-kugetsu queue list              # Show queued tasks
-kugetsu queue enqueue "task"   # Add task to queue
-kugetsu queue dequeue          # Remove next task from queue
-kugetsu queue clear            # Clear all queued tasks
+kugetsu queue list              # Show queued tasks with status
+kugetsu queue stats            # Show queue statistics (total, pending, notified, completed, error)
+kugetsu queue clear            # Clean up old completed/error items
+kugetsu queue enqueue <issue-ref> <message>  # Manually enqueue a task
 ```
 
-- Queue stored in `~/.kugetsu/queue.json`
+**Queue Item States:**
+- `pending` - Waiting in queue, daemon can pick up
+- `notified` - PM agent has picked up the task
+- `completed` - Dev agent finished, PR created
+- `error` - Timeout or failure
+
+### kugetsu queue-daemon <start|stop|restart|status|logs>
+
+Manage the queue daemon background process:
+```bash
+kugetsu queue-daemon start     # Start daemon in background
+kugetsu queue-daemon stop      # Stop daemon
+kugetsu queue-daemon restart    # Restart daemon
+kugetsu queue-daemon status    # Check if daemon is running
+kugetsu queue-daemon logs       # Show recent daemon logs
+```
+
+**Daemon Behavior:**
+1. Runs at configurable interval (default: 5 minutes)
+2. Checks if active agents < MAX_CONCURRENT_AGENTS
+3. Picks 1-N pending items (configurable batch size)
+4. Forks PM session for each picked item
+5. PM decides whether to use `start` or `continue`
+
+**Queue Directory:**
+```
+~/.kugetsu/queue/
+├── items/                     # Queue item JSON files
+│   ├── q_1234567890.json    # One file per queued task
+│   └── q_1234567891.json
+├── daemon.pid                # Daemon process ID
+├── daemon.lock               # Daemon lock file
+└── daemon.log                # Daemon log output
+```
 
 ## Workflow Example
 
+### First-time Setup
 ```bash
-# First-time setup (requires TTY)
+# Initialize kugetsu (requires TTY)
 kugetsu init
-# Creates: base session + pm-agent session
 
-# Start work on issue
-kugetsu start github.com/shoko/kugetsu#14 "implement feature X"
-# Creates: worktree at ~/.kugetsu/worktrees/github.com-shoko-kugetsu-14/
+# Start the queue daemon (for autonomous operation)
+kugetsu queue-daemon start
+```
 
-# Continue later
+### Normal Workflow
+```bash
+# Enqueue tasks via delegate - agents will process them automatically
+kugetsu delegate "work on issue #14"
+kugetsu delegate "review PR #92"
+
+# Check queue status
+kugetsu queue list           # See pending tasks
+kugetsu queue stats         # See statistics
+
+# Debug queue daemon
+kugetsu queue-daemon status  # Is daemon running?
+kugetsu queue-daemon logs    # See daemon logs
+
+# Continue work on existing issue
 kugetsu continue github.com/shoko/kugetsu#14 "add tests"
 
-# Continue again
-kugetsu continue github.com/shoko/kugetsu#14 "fix failing test"
-
 # List all sessions
 kugetsu list
 
@@ -367,6 +418,21 @@ kugetsu prune --force
 kugetsu destroy github.com/shoko/kugetsu#14
 ```
 
+### Queue Daemon Management
+```bash
+# Check if daemon is running
+kugetsu queue-daemon status
+
+# View daemon logs for debugging
+kugetsu queue-daemon logs
+
+# Restart daemon if needed
+kugetsu queue-daemon restart
+
+# Stop daemon
+kugetsu queue-daemon stop
+```
+
 ## Headless Operation
 
 This design solves the headless CLI limitation discovered in Issue #14: