feat(claude-code): use tmux instead of screen (#432)

Author: bcpeinhardt

Diff for: claude-code/README.md

@@ -14,7 +14,7 @@ Run the [Claude Code](https://docs.anthropic.com/en/docs/agents-and-tools/claude
 ```tf
 module "claude-code" {
   source              = "registry.coder.com/modules/claude-code/coder"
-  version             = "1.0.31"
+  version             = "1.1.0"
   agent_id            = coder_agent.example.id
   folder              = "/home/coder"
   install_claude_code = true
@@ -25,7 +25,7 @@ module "claude-code" {
 ### Prerequisites
 
 - Node.js and npm must be installed in your workspace to install Claude Code
-- `screen` must be installed in your workspace to run Claude Code in the background
+- Either `screen` or `tmux` must be installed in your workspace to run Claude Code in the background
 - You must add the [Coder Login](https://registry.coder.com/modules/coder-login) module to your template
 
 The `codercom/oss-dogfood:latest` container image can be used for testing on container-based workspaces.
@@ -43,7 +43,7 @@ The `codercom/oss-dogfood:latest` container image can be used for testing on con
 > Join our [Discord channel](https://discord.gg/coder) or
 > [contact us](https://coder.com/contact) to get help or share feedback.
 
-Your workspace must have `screen` installed to use this.
+Your workspace must have either `screen` or `tmux` installed to use this.
 
 ```tf
 variable "anthropic_api_key" {
@@ -83,14 +83,14 @@ resource "coder_agent" "main" {
 module "claude-code" {
   count               = data.coder_workspace.me.start_count
   source              = "registry.coder.com/modules/claude-code/coder"
-  version             = "1.0.31"
+  version             = "1.1.0"
   agent_id            = coder_agent.example.id
   folder              = "/home/coder"
   install_claude_code = true
   claude_code_version = "0.2.57"
 
   # Enable experimental features
-  experiment_use_screen   = true
+  experiment_use_screen   = true # Or use experiment_use_tmux = true to use tmux instead
   experiment_report_tasks = true
 }
 ```
@@ -102,7 +102,7 @@ Run Claude Code as a standalone app in your workspace. This will install Claude
 ```tf
 module "claude-code" {
   source              = "registry.coder.com/modules/claude-code/coder"
-  version             = "1.0.31"
+  version             = "1.1.0"
   agent_id            = coder_agent.example.id
   folder              = "/home/coder"
   install_claude_code = true

Diff for: claude-code/main.tf

@@ -54,6 +54,12 @@ variable "experiment_use_screen" {
   default     = false
 }
 
+variable "experiment_use_tmux" {
+  type        = bool
+  description = "Whether to use tmux instead of screen for running Claude Code in the background."
+  default     = false
+}
+
 variable "experiment_report_tasks" {
   type        = bool
   description = "Whether to enable task reporting."
@@ -122,6 +128,39 @@ resource "coder_script" "claude_code" {
       coder exp mcp configure claude-code ${var.folder}
     fi
 
+    # Handle terminal multiplexer selection (tmux or screen)
+    if [ "${var.experiment_use_tmux}" = "true" ] && [ "${var.experiment_use_screen}" = "true" ]; then
+      echo "Error: Both experiment_use_tmux and experiment_use_screen cannot be true simultaneously."
+      echo "Please set only one of them to true."
+      exit 1
+    fi
+
+    # Run with tmux if enabled
+    if [ "${var.experiment_use_tmux}" = "true" ]; then
+      echo "Running Claude Code in the background with tmux..."
+      
+      # Check if tmux is installed
+      if ! command_exists tmux; then
+        echo "Error: tmux is not installed. Please install tmux manually."
+        exit 1
+      fi
+
+      touch "$HOME/.claude-code.log"
+      
+      export LANG=en_US.UTF-8
+      export LC_ALL=en_US.UTF-8
+      
+      # Create a new tmux session in detached mode
+      tmux new-session -d -s claude-code -c ${var.folder} "claude"
+      
+      # Send the prompt to the tmux session if needed
+      if [ -n "$CODER_MCP_CLAUDE_TASK_PROMPT" ]; then
+        tmux send-keys -t claude-code "$CODER_MCP_CLAUDE_TASK_PROMPT"
+        sleep 5
+        tmux send-keys -t claude-code Enter
+      fi
+    fi
+
     # Run with screen if enabled
     if [ "${var.experiment_use_screen}" = "true" ]; then
       echo "Running Claude Code in the background..."
@@ -182,20 +221,27 @@ resource "coder_app" "claude_code" {
     #!/bin/bash
     set -e
 
-    if [ "${var.experiment_use_screen}" = "true" ]; then
+    export LANG=en_US.UTF-8
+    export LC_ALL=en_US.UTF-8
+
+    if [ "${var.experiment_use_tmux}" = "true" ]; then
+      if tmux has-session -t claude-code 2>/dev/null; then
+        echo "Attaching to existing Claude Code tmux session." | tee -a "$HOME/.claude-code.log"
+        tmux attach-session -t claude-code
+      else
+        echo "Starting a new Claude Code tmux session." | tee -a "$HOME/.claude-code.log"
+        tmux new-session -s claude-code -c ${var.folder} "claude --dangerously-skip-permissions | tee -a \"$HOME/.claude-code.log\"; exec bash"
+      fi
+    elif [ "${var.experiment_use_screen}" = "true" ]; then
       if screen -list | grep -q "claude-code"; then
-        export LANG=en_US.UTF-8
-        export LC_ALL=en_US.UTF-8
-        echo "Attaching to existing Claude Code session." | tee -a "$HOME/.claude-code.log"
+        echo "Attaching to existing Claude Code screen session." | tee -a "$HOME/.claude-code.log"
         screen -xRR claude-code
       else
-        echo "Starting a new Claude Code session." | tee -a "$HOME/.claude-code.log"
-        screen -S claude-code bash -c 'export LANG=en_US.UTF-8; export LC_ALL=en_US.UTF-8; claude --dangerously-skip-permissions | tee -a "$HOME/.claude-code.log"; exec bash'
+        echo "Starting a new Claude Code screen session." | tee -a "$HOME/.claude-code.log"
+        screen -S claude-code bash -c 'claude --dangerously-skip-permissions | tee -a "$HOME/.claude-code.log"; exec bash'
       fi
     else
       cd ${var.folder}
-      export LANG=en_US.UTF-8
-      export LC_ALL=en_US.UTF-8
       claude
     fi
     EOT