Heartbeat convention: simple liveness signal for agents

Lightweight liveness signal extracted from Deacon epic (gt-5af).

**Implementation**: Each agent writes a timestamp file on activity:
```bash
echo '{"ts":"'$(date -Iseconds)'"}' > ~/gt/<role>/heartbeat.json
```

**Integration points**:
- SessionStart hook writes heartbeat
- Periodic activity (mail check, work completion) refreshes it
- `gt status` shows staleness (e.g., 'mayor: 5m ago')

**Weight**: ~5 lines per agent
**Value**: Quick debugging - see which agents are active at a glance

No monitoring daemon needed - human checks `gt status` when curious.


Phase 2.2: gt prime shows ephemeral molecule context

Update gt prime to detect and display ephemeral molecule state.

## Detection

1. Check for active ephemeral molecule assigned to current identity
2. Parse molecule progress (current step, total steps)
3. Show in prime output

## Output

```
🔧 Polecat furiosa, checking in.

📦 Molecule: mol-polecat-work (eph-abc123)
   Step 3/8: do-work
   Source: gt-rixa
   Started: 10 minutes ago

Run 'bd mol status' for full molecule state.
```


Architecture: Decentralized rig structure with per-rig agents

## Decision

Adopt decentralized architecture where each rig contains all its agents (mayor/, witness/, refinery/, polecats/) rather than centralizing mayor clones at town level.

## Town Level Structure

```
~/ai/                              # Town root
├── config/                        # Town config (VISIBLE, not hidden)
│   ├── town.json                  # {"type": "town"}
│   ├── rigs.json                  # Registry of managed rigs
│   └── federation.json            # Wasteland config (future)
│
├── mayor/                         # Mayor's HOME at town level
│   ├── CLAUDE.md
│   ├── mail/inbox.jsonl
│   └── state.json
│
└── <rigs>/                        # Managed projects
```

## Rig Level Structure (e.g., wyvern)

```
wyvern/                            # Rig = clone of project repo
├── .git/info/exclude              # Gas Town adds: polecats/ refinery/ witness/ mayor/
├── .beads/                        # Beads (if project uses it)
├── [project files]                # Clean project code on main
│
├── polecats/                      # Worker clones
│   └── <name>/                    # Each is a git clone
│
├── refinery/
│   ├── rig/                       # Refinery's clone
│   ├── state.json
│   └── mail/inbox.jsonl
│
├── witness/                       # NEW: Per-rig pit boss
│   ├── rig/                       # Witness's clone
│   ├── state.json
│   └── mail/inbox.jsonl
│
└── mayor/
    ├── rig/                       # Mayor's clone for this rig
    └── state.json
```

## Key Decisions

1. **Visible config dir**: `config/` not `.gastown/` (models don't find hidden dirs)
2. **Witness per-rig**: Each rig has its own Witness (pit boss) with its own clone
3. **Mayor decentralized**: Mayor's clones live IN each rig at `<rig>/mayor/rig/`
4. **Minimal invasiveness**: Only `.git/info/exclude` modified, no commits to project
5. **Clone subdir name**: Keep `rig/` for consistency (refinery/rig/, witness/rig/, mayor/rig/)

## Role Detection

- Town root or mayor/ → Mayor (town level)
- Rig root → Mayor (canonical main)
- <rig>/mayor/rig/ → Mayor (rig-specific)
- <rig>/refinery/rig/ → Refinery
- <rig>/witness/rig/ → Witness
- <rig>/polecats/<name>/ → Polecat

## Migration from PGT

- `mayor/rigs/<rig>/` → `<rig>/mayor/rig/`
- `<rig>/town/` → eliminated (rig root IS the clone)
- Add `witness/` to each rig


inbox-check

Handle callbacks from agents. Check gt mail inbox, process lifecycle requests.


CLI: rig commands (add, list, show, remove)

GGT needs rig management commands.

Missing Commands:
- gt rig add <git-url> [--name NAME] - Add rig to workspace
- gt rig list - List all rigs with status
- gt rig show <rig> - Show detailed rig info
- gt rig remove <rig> - Remove a rig

PGT Reference: gastown-py/src/gastown/cli/rig_cmd.py

Current State:
- gt init creates rig structure but no ongoing management
- Rig discovery in internal/rig/manager.go but not exposed via CLI


Phase 3: Callbacks and plugins

Mail-based callback protocol and plugin surface.

## Callbacks
- Polecat → Witness: shutdown requests
- Witness → Deacon: escalations, status
- Crew → Deacon: recycle requests
- Deacon → Mayor: escalations

## Plugins
- .beads/plugins.yaml registry
- Cooldown tracking
- Plugin runner in deacon patrol

Depends: Phase 2


Update Refinery to use Beads merge queue

Replace branch discovery with Beads queue in the Refinery module:

Current (internal/refinery/manager.go):
- Scans for polecat/* branches
- Creates MR objects on-the-fly

New:
- Pull from Beads: bd ready --type=merge-request
- Process each MR
- Close with merge commit: bd close <id> --reason="Merged at <sha>"
- Handle failures: bd update <id> --status=blocked --reason="..."

The Engineer (agent) becomes Beads-native.
The Refinery (module) provides the infrastructure.


TIDY UP: Your previous work (gt-odvf: bd mol CLI docs) wa...

TIDY UP: Your previous work (gt-odvf: bd mol CLI docs) was already merged to main. Check your git status is clean, sync beads, and if nothing to do, just run 'gt done'.


Document harness concept in docs/harness.md

Create comprehensive harness documentation:
- What is a harness (installation directory)
- Recommended structure and naming
- .beads/redirect for default project
- config/ contents (rigs.json, town.json)
- Mayor home vs rig-level mayor/
- Example configurations
- Relationship to rigs


load-context

Run gt prime and bd prime. Verify issue assignment.
Check inbox for any relevant messages.

Read the assigned issue (gt-test123) and understand the requirements.
Identify any blockers or missing information.


Molecule composition: Includes directive

Add support for molecule composition via the Includes directive.

## Format
\`\`\`markdown
## Molecule: derived-name
Includes: mol-base-molecule

## Step: additional-step
Additional instructions here.
Needs: step-from-base
\`\`\`

## Implementation
1. Add \`Includes:\` parsing to ParseMoleculeSteps()
2. Resolve included molecule by ID
3. Merge steps from included molecule
4. Allow new steps to depend on included steps
5. Support multiple includes (polymers)

## Files to modify
- internal/beads/molecule.go
- internal/beads/molecule_test.go

## Acceptance
- [ ] Parse Includes directive
- [ ] Resolve and merge included steps
- [ ] Dependencies across molecules work
- [ ] Multiple includes supported
- [ ] Tests cover composition scenarios


request-shutdown

Send shutdown request to Witness.
Wait for termination.

The polecat is now ready to be cleaned up.
Do not exit directly - wait for Witness to kill the session.

Depends: generate-summary


gt session restart/status: Complete session management

Add missing session subcommands:

- gt session restart <rig> <polecat> - Restart a session (stop + start)
- gt session status <rig> <polecat> - Show session status details

status should show:
- Running state
- Uptime
- Current activity
- Last output timestamp


Git wrapper: shell out to git

Wrapper for git operations via subprocess.

## Interface

```go
type Git struct {
    workDir string
}

func NewGit(workDir string) *Git

// Core operations
func (g *Git) Clone(url, dest string) error
func (g *Git) Checkout(ref string) error
func (g *Git) Fetch(remote string) error
func (g *Git) Pull(remote, branch string) error
func (g *Git) Push(remote, branch string, force bool) error

// Commit operations
func (g *Git) Add(paths ...string) error
func (g *Git) Commit(message string) error
func (g *Git) CommitAll(message string) error

// Query operations
func (g *Git) Status() (*GitStatus, error)
func (g *Git) CurrentBranch() (string, error)
func (g *Git) HasUncommittedChanges() (bool, error)
func (g *Git) RemoteURL(remote string) (string, error)

// Merge operations
func (g *Git) Merge(branch string) error
func (g *Git) Rebase(onto string) error
func (g *Git) AbortMerge() error
func (g *Git) AbortRebase() error
```

## Implementation

Shell out to git binary via exec.Command. Parse output where needed (Status, CurrentBranch).

## Error Handling

- Wrap git stderr in error messages
- Detect specific failures (merge conflict, auth failure, not a repo)
- Return structured errors for callers to handle

## Testing

- Use temp directories with real git repos
- Test both success and failure paths


Merge: gt-g44u.3

branch: polecat/Ace
target: main
source_issue: gt-g44u.3
rig: gastown


Test molecule

Test


Merge: gt-5af.5

branch: polecat/Scabrous
target: main
source_issue: gt-5af.5
rig: gastown


Beads as Universal Data Plane

## Vision

Beads is the data plane for all Gas Town operations. Everything flows through beads:
- Work items (issues, tasks, epics)
- Mail (messages between agents)
- Merge requests (queue entries)
- Workflows (composable execution patterns)
- Resources (leases, locks, quotas)
- Schedules (timed activities)

## New Bead Categories

### Molecules (Composable Workflows)
Crystallized workflow patterns that can be attached to work items.

### Timed Beads (Scheduled Work)
Beads that wake up periodically via daemon.

### Pinned Beads (Ongoing Concerns)
Beads representing persistent concerns, not discrete tasks.

### Resource Beads (Leases/Locks)
Beads representing reserved resources.

## v1 Priority

- **P0**: Molecules (enables engineer-in-box)
- **P2**: Timed, Pinned, Resource beads (post-v1)