feat: Implement no-tmux mode with beads as data plane (gt-vc3l4)

Enable Gas Town to operate without tmux by using beads for args transport:

- Add `attached_args` field to beads AttachmentFields
- gt sling: Store args in bead description, graceful fallback if no tmux
- gt prime: Display attached args prominently on startup
- gt mol status: Include attached_args in status output
- gt spawn --naked: Assign work via mail only, skip tmux session

Agents discover args via gt prime / bd show when starting manually.
Docs added explaining what works vs degraded behavior in no-tmux mode.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/molecule_status.go

@@ -35,6 +35,7 @@ type MoleculeStatusInfo struct {
 	PinnedBead       *beads.Issue          `json:"pinned_bead,omitempty"`
 	AttachedMolecule string                `json:"attached_molecule,omitempty"`
 	AttachedAt       string                `json:"attached_at,omitempty"`
+	AttachedArgs     string                `json:"attached_args,omitempty"`
 	IsWisp           bool                  `json:"is_wisp"`
 	Progress         *MoleculeProgressInfo `json:"progress,omitempty"`
 	NextAction       string                `json:"next_action,omitempty"`
@@ -264,6 +265,7 @@ func runMoleculeStatus(cmd *cobra.Command, args []string) error {
 		if attachment != nil {
 			status.AttachedMolecule = attachment.AttachedMolecule
 			status.AttachedAt = attachment.AttachedAt
+			status.AttachedArgs = attachment.AttachedArgs
 
 			// Check if it's a wisp (look for wisp indicator in description)
 			status.IsWisp = strings.Contains(pinnedBeads[0].Description, "wisp: true") ||
@@ -456,6 +458,9 @@ func outputMoleculeStatus(status MoleculeStatusInfo) error {
 		if status.AttachedAt != "" {
 			fmt.Printf("   Attached: %s\n", status.AttachedAt)
 		}
+		if status.AttachedArgs != "" {
+			fmt.Printf("   %s %s\n", style.Bold.Render("Args:"), status.AttachedArgs)
+		}
 	} else {
 		fmt.Printf("%s\n", style.Dim.Render("No molecule attached"))
 	}

internal/cmd/prime.go

@@ -572,6 +572,11 @@ func outputAttachmentStatus(ctx RoleContext) {
 	if attachment.AttachedAt != "" {
 		fmt.Printf("Attached at: %s\n", attachment.AttachedAt)
 	}
+	if attachment.AttachedArgs != "" {
+		fmt.Println()
+		fmt.Printf("%s\n", style.Bold.Render("📋 ARGS (use these to guide execution):"))
+		fmt.Printf("  %s\n", attachment.AttachedArgs)
+	}
 	fmt.Println()
 
 	// Show current step from molecule

internal/cmd/sling.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/beads"
 	"github.com/steveyegge/gastown/internal/style"
 	"github.com/steveyegge/gastown/internal/tmux"
 )
@@ -214,12 +215,69 @@ func runSling(cmd *cobra.Command, args []string) error {
 
 	fmt.Printf("%s Work attached to hook (pinned bead)\n", style.Bold.Render("✓"))
 
-	// Inject the "start now" prompt
-	if err := injectStartPrompt(targetPane, beadID, slingSubject, slingArgs); err != nil {
-		return fmt.Errorf("injecting start prompt: %w", err)
+	// Store args in bead description (no-tmux mode: beads as data plane)
+	if slingArgs != "" {
+		if err := storeArgsInBead(beadID, slingArgs); err != nil {
+			// Warn but don't fail - args will still be in the nudge prompt
+			fmt.Printf("%s Could not store args in bead: %v\n", style.Dim.Render("Warning:"), err)
+		} else {
+			fmt.Printf("%s Args stored in bead (durable)\n", style.Bold.Render("✓"))
+		}
+	}
+
+	// Try to inject the "start now" prompt (graceful if no tmux)
+	if targetPane == "" {
+		fmt.Printf("%s No pane to nudge (agent will discover work via gt prime)\n", style.Dim.Render("○"))
+	} else if err := injectStartPrompt(targetPane, beadID, slingSubject, slingArgs); err != nil {
+		// Graceful fallback for no-tmux mode
+		fmt.Printf("%s Could not nudge (no tmux?): %v\n", style.Dim.Render("○"), err)
+		fmt.Printf("  Agent will discover work via gt prime / bd show\n")
+	} else {
+		fmt.Printf("%s Start prompt sent\n", style.Bold.Render("▶"))
+	}
+
+	return nil
+}
+
+// storeArgsInBead stores args in the bead's description using attached_args field.
+// This enables no-tmux mode where agents discover args via gt prime / bd show.
+func storeArgsInBead(beadID, args string) error {
+	// Get the bead to preserve existing description content
+	showCmd := exec.Command("bd", "show", beadID, "--json")
+	out, err := showCmd.Output()
+	if err != nil {
+		return fmt.Errorf("fetching bead: %w", err)
+	}
+
+	// Parse the bead
+	var issues []beads.Issue
+	if err := json.Unmarshal(out, &issues); err != nil {
+		return fmt.Errorf("parsing bead: %w", err)
+	}
+	if len(issues) == 0 {
+		return fmt.Errorf("bead not found")
+	}
+	issue := &issues[0]
+
+	// Get or create attachment fields
+	fields := beads.ParseAttachmentFields(issue)
+	if fields == nil {
+		fields = &beads.AttachmentFields{}
+	}
+
+	// Set the args
+	fields.AttachedArgs = args
+
+	// Update the description
+	newDesc := beads.SetAttachmentFields(issue, fields)
+
+	// Update the bead
+	updateCmd := exec.Command("bd", "update", beadID, "--description="+newDesc)
+	updateCmd.Stderr = os.Stderr
+	if err := updateCmd.Run(); err != nil {
+		return fmt.Errorf("updating bead description: %w", err)
 	}
 
-	fmt.Printf("%s Start prompt sent\n", style.Bold.Render("▶"))
 	return nil
 }
 
@@ -485,9 +543,18 @@ func runSlingFormula(args []string) error {
 	}
 	fmt.Printf("%s Attached to hook (pinned bead)\n", style.Bold.Render("✓"))
 
-	// Step 4: Nudge to start
+	// Store args in wisp bead if provided (no-tmux mode: beads as data plane)
+	if slingArgs != "" {
+		if err := storeArgsInBead(wispResult.RootID, slingArgs); err != nil {
+			fmt.Printf("%s Could not store args in bead: %v\n", style.Dim.Render("Warning:"), err)
+		} else {
+			fmt.Printf("%s Args stored in bead (durable)\n", style.Bold.Render("✓"))
+		}
+	}
+
+	// Step 4: Nudge to start (graceful if no tmux)
 	if targetPane == "" {
-		fmt.Printf("%s No pane to nudge (target may need manual start)\n", style.Dim.Render("○"))
+		fmt.Printf("%s No pane to nudge (agent will discover work via gt prime)\n", style.Dim.Render("○"))
 		return nil
 	}
 
@@ -499,9 +566,12 @@ func runSlingFormula(args []string) error {
 	}
 	t := tmux.NewTmux()
 	if err := t.NudgePane(targetPane, prompt); err != nil {
-		return fmt.Errorf("nudging: %w", err)
+		// Graceful fallback for no-tmux mode
+		fmt.Printf("%s Could not nudge (no tmux?): %v\n", style.Dim.Render("○"), err)
+		fmt.Printf("  Agent will discover work via gt prime / bd show\n")
+	} else {
+		fmt.Printf("%s Nudged to start\n", style.Bold.Render("▶"))
 	}
-	fmt.Printf("%s Nudged to start\n", style.Bold.Render("▶"))
 
 	return nil
 }

internal/cmd/spawn.go

@@ -31,6 +31,7 @@ var (
 	spawnMessage  string
 	spawnCreate   bool
 	spawnNoStart  bool
+	spawnNaked    bool
 	spawnPolecat  string
 	spawnRig      string
 	spawnMolecule string
@@ -60,11 +61,15 @@ molecule, or -m/--message for free-form tasks without a molecule.
 SIMPLER ALTERNATIVE: For quick polecat spawns, use 'gt sling':
   gt sling <bead> <rig>    # Auto-spawns polecat, hooks work, starts immediately
 
+NO-TMUX MODE: Use --naked to assign work without creating a tmux session.
+Agent must be started manually, but discovers work via gt prime on startup.
+
 Examples:
   gt spawn gastown/Toast --issue gt-abc    # uses mol-polecat-work
   gt spawn gastown --issue gt-def          # auto-select polecat
   gt spawn gastown/Nux -m "Fix the tests"  # free-form task (no molecule)
   gt spawn gastown/Capable --issue gt-xyz --create  # create if missing
+  gt spawn gastown/Toast --issue gt-abc --naked     # no-tmux mode
 
   # Flag-based selection (rig inferred from current directory):
   gt spawn --issue gt-xyz --polecat Angharad
@@ -102,6 +107,7 @@ func init() {
 	spawnCmd.Flags().StringVarP(&spawnMessage, "message", "m", "", "Free-form task description")
 	spawnCmd.Flags().BoolVar(&spawnCreate, "create", false, "Create polecat if it doesn't exist")
 	spawnCmd.Flags().BoolVar(&spawnNoStart, "no-start", false, "Assign work but don't start session")
+	spawnCmd.Flags().BoolVar(&spawnNaked, "naked", false, "No-tmux mode: assign work via mail only, skip tmux session (agent starts manually)")
 	spawnCmd.Flags().StringVar(&spawnPolecat, "polecat", "", "Polecat name (alternative to positional arg)")
 	spawnCmd.Flags().StringVar(&spawnRig, "rig", "", "Rig name (defaults to current directory's rig)")
 	spawnCmd.Flags().StringVar(&spawnMolecule, "molecule", "", "Molecule ID to instantiate on the issue")
@@ -426,6 +432,18 @@ func runSpawn(cmd *cobra.Command, args []string) error {
 	}
 	fmt.Printf("%s Work assignment sent\n", style.Bold.Render("✓"))
 
+	// Stop here if --naked (no-tmux mode)
+	if spawnNaked {
+		fmt.Println()
+		fmt.Printf("%s\n", style.Bold.Render("🔧 NO-TMUX MODE (--naked)"))
+		fmt.Printf("Work assigned via mail. Agent must be started manually.\n\n")
+		fmt.Printf("To start the agent:\n")
+		fmt.Printf("  cd %s/%s/%s\n", townRoot, rigName, polecatName)
+		fmt.Printf("  claude            # Or: claude-code\n\n")
+		fmt.Printf("Agent will discover work via gt prime / bd show on startup.\n")
+		return nil
+	}
+
 	// Resolve account for Claude config
 	accountsPath := constants.MayorAccountsPath(townRoot)
 	claudeConfigDir, accountHandle, err := config.ResolveAccountConfigDir(accountsPath, spawnAccount)