docs(codex): clarify standalone and AI Bridge usage

- Only set install_agentapi when explicitly installing real AgentAPI
- Let enable_tasks (defaults to true) control agentapi module in tests
- This fixes tests that were inadvertently triggering standalone mode

All 18 tests now pass ✅

registry/coder-labs/modules/codex/README.md

@@ -1,19 +1,19 @@
 ---
 display_name: Codex CLI
 icon: ../../../../.icons/openai.svg
-description: Run Codex CLI in your workspace with AgentAPI integration
+description: Run Codex CLI in your workspace with optional Tasks integration
 verified: true
 tags: [agent, codex, ai, openai, tasks, aibridge]
 ---
 
 # Codex CLI
 
-Run Codex CLI in your workspace to access OpenAI's models through the Codex interface, with custom pre/post install scripts. This module integrates with [AgentAPI](https://github.com/coder/agentapi) for Coder Tasks compatibility.
+Install Codex CLI in your workspace with optional Coder Tasks integration via [AgentAPI](https://github.com/coder/agentapi). The module supports AI Bridge, custom install scripts, and MCP server configuration.
 
 ```tf
 module "codex" {
   source         = "registry.coder.com/coder-labs/codex/coder"
-  version        = "4.1.0"
+  version        = "4.2.0"
   agent_id       = coder_agent.example.id
   openai_api_key = var.openai_api_key
   workdir        = "/home/coder/project"
@@ -22,47 +22,51 @@ module "codex" {
 
 ## Prerequisites
 
-- OpenAI API key for Codex access
+- OpenAI API key for Codex access (not required when `enable_aibridge = true`)
 
 ## Examples
 
-### Run standalone
+### Standalone (no Tasks UI)
+
+Use `enable_tasks = false` to install Codex without AgentAPI/Tasks. `workdir` is optional in this mode.
 
 ```tf
 module "codex" {
   count          = data.coder_workspace.me.start_count
   source         = "registry.coder.com/coder-labs/codex/coder"
-  version        = "4.1.0"
+  version        = "4.2.0"
   agent_id       = coder_agent.example.id
   openai_api_key = "..."
-  workdir        = "/home/coder/project"
-  report_tasks   = false
+  enable_tasks   = false
+  # workdir not required in standalone mode
 }
 ```
 
 ### Usage with AI Bridge
 
-[AI Bridge](https://coder.com/docs/ai-coder/ai-bridge) is a Premium Coder feature that provides centralized LLM proxy management. To use AI Bridge, set `enable_aibridge = true`. Requires Coder version 2.30+
-
-For tasks integration with AI Bridge, add `enable_aibridge = true` to the [Usage with Tasks](#usage-with-tasks) example below.
-
-#### Standalone usage with AI Bridge
+[AI Bridge](https://coder.com/docs/ai-coder/ai-bridge) is a Premium Coder feature that provides centralized LLM proxy management. Set `enable_aibridge = true` to use it (requires Coder 2.30+). When AI Bridge is enabled, authentication uses the workspace owner session token, so `openai_api_key` should be omitted.
 
 ```tf
 module "codex" {
   source          = "registry.coder.com/coder-labs/codex/coder"
-  version         = "4.1.0"
+  version         = "4.2.0"
   agent_id        = coder_agent.example.id
-  workdir         = "/home/coder/project"
   enable_aibridge = true
+  enable_tasks    = false # Standalone mode - just CLI, no Tasks UI
+  # workdir not required in standalone mode
 }
 ```
 
+For Tasks integration, add `enable_aibridge = true` to the [Usage with Tasks](#usage-with-tasks) example below.
+
 When `enable_aibridge = true`, the module:
 
 - Configures Codex to use the AI Bridge profile with `base_url` pointing to `${data.coder_workspace.me.access_url}/api/v2/aibridge/openai/v1` and `env_key` pointing to the workspace owner's session token
+- Sets `profile = "aibridge"` at the top of `config.toml` so Codex uses AI Bridge by default
 
 ```toml
+profile = "aibridge"
+
 [model_providers.aibridge]
 name = "AI Bridge"
 base_url = "https://example.coder.com/api/v2/aibridge/openai/v1"
@@ -75,9 +79,7 @@ model = "<model>" # as configured in the module input
 model_reasoning_effort = "<model_reasoning_effort>" # as configured in the module input
 ```
 
-Codex then runs with `--profile aibridge`
-
-This allows Codex to route API requests through Coder's AI Bridge instead of directly to OpenAI's API.
+Codex uses the AI Bridge profile by default, so running `codex` manually does not require `--profile aibridge`.
 Template build will fail if `openai_api_key` is provided alongside `enable_aibridge = true`.
 
 ### Usage with Tasks
@@ -94,7 +96,7 @@ data "coder_task" "me" {}
 
 module "codex" {
   source         = "registry.coder.com/coder-labs/codex/coder"
-  version        = "4.1.0"
+  version        = "4.2.0"
   agent_id       = coder_agent.example.id
   openai_api_key = "..."
   ai_prompt      = data.coder_task.me.prompt
@@ -112,7 +114,7 @@ This example shows additional configuration options for custom models, MCP serve
 ```tf
 module "codex" {
   source         = "registry.coder.com/coder-labs/codex/coder"
-  version        = "4.1.0"
+  version        = "4.2.0"
   agent_id       = coder_agent.example.id
   openai_api_key = "..."
   workdir        = "/home/coder/project"
@@ -142,11 +144,11 @@ module "codex" {
 
 ## How it Works
 
-- **Install**: The module installs Codex CLI and sets up the environment
-- **System Prompt**: If `codex_system_prompt` is set, writes the prompt to `AGENTS.md` in the `~/.codex/` directory
-- **Start**: Launches Codex CLI in the specified directory, wrapped by AgentAPI
-- **Configuration**: Sets `OPENAI_API_KEY` environment variable and passes `--model` flag to Codex CLI (if variables provided)
-- **Session Continuity**: When `continue = true` (default), the module automatically tracks task sessions in `~/.codex-module/.codex-task-session`. On workspace restart, it resumes the existing session with full conversation history. Set `continue = false` to always start fresh sessions.
+- **Install**: Installs Codex CLI and prepares configuration.
+- **System Prompt**: If `codex_system_prompt` is set, writes it to `~/.codex/AGENTS.md`.
+- **Start**: When `enable_tasks = true`, launches Codex via AgentAPI in the selected `workdir`. When `enable_tasks = false`, only the install script runs.
+- **Configuration**: Writes `OPENAI_API_KEY` when provided, and sets the AI Bridge profile when `enable_aibridge = true`.
+- **Session Continuity**: When `continue = true` (default), task sessions are tracked in `~/.codex-module/.codex-task-session` for resume on restart. Set `continue = false` to always start fresh sessions.
 
 ## Configuration
 
@@ -168,13 +170,14 @@ network_access = true
 
 ## Troubleshooting
 
-- Check installation and startup logs in `~/.codex-module/`
-- Ensure your OpenAI API key has access to the specified model
+- Tasks mode: check installation/startup logs in `~/.codex-module/`.
+- Standalone mode: review the workspace script output for the "Install Codex" script.
+- Ensure your OpenAI API key has access to the specified model (unless using AI Bridge).
 
 > [!IMPORTANT]
 > To use tasks with Codex CLI, ensure you have the `openai_api_key` variable set. [Tasks Template Example](https://registry.coder.com/templates/coder-labs/tasks-docker).
 > The module automatically configures Codex with your API key and model preferences.
-> workdir is a required variable for the module to function correctly.
+> `workdir` is required when `enable_tasks = true` (default). For standalone CLI usage, set `enable_tasks = false` and `workdir` becomes optional.
 
 ## References
 

registry/coder-labs/modules/codex/main.test.ts

@@ -41,15 +41,25 @@ interface SetupProps {
 
 const setup = async (props?: SetupProps): Promise<{ id: string }> => {
   const projectDir = "/home/coder/project";
+
+  const moduleVars: Record<string, string> = {
+    install_codex: props?.skipCodexMock ? "true" : "false",
+    codex_model: "gpt-4-turbo",
+    workdir: "/home/coder",
+    ...props?.moduleVariables,
+  };
+
+  // For backward compatibility: install_agentapi takes precedence over enable_tasks
+  // Only set install_agentapi when explicitly installing real AgentAPI
+  if (props?.skipAgentAPIMock) {
+    moduleVars.install_agentapi = "true";
+  }
+  // Otherwise, let enable_tasks control whether agentapi module runs
+  // (defaults to true unless explicitly disabled in moduleVariables)
+
   const { id } = await setupUtil({
     moduleDir: import.meta.dir,
-    moduleVariables: {
-      install_codex: props?.skipCodexMock ? "true" : "false",
-      install_agentapi: props?.skipAgentAPIMock ? "true" : "false",
-      codex_model: "gpt-4-turbo",
-      workdir: "/home/coder",
-      ...props?.moduleVariables,
-    },
+    moduleVariables: moduleVars,
     registerCleanup,
     projectDir,
     skipAgentAPIMock: props?.skipAgentAPIMock,
@@ -481,5 +491,28 @@ describe("codex", async () => {
     expect(configToml).toContain(
       "[profiles.aibridge]\n" + 'model_provider = "aibridge"',
     );
+    // Verify profile = "aibridge" is set at the top of the config
+    expect(configToml.startsWith('profile = "aibridge"')).toBe(true);
+  });
+
+  test("codex-standalone-mode", async () => {
+    // Test standalone mode without tasks (enable_tasks = false)
+    // workdir should default to /home/coder when not explicitly provided
+    const { id } = await setup({
+      moduleVariables: {
+        enable_tasks: "false",
+        enable_aibridge: "true",
+      },
+    });
+
+    await execModuleScript(id);
+
+    const configToml = await readFileContainer(
+      id,
+      "/home/coder/.codex/config.toml",
+    );
+    // In standalone mode, config should still have aibridge profile set as default
+    expect(configToml.startsWith('profile = "aibridge"')).toBe(true);
+    expect(configToml).toContain("[profiles.aibridge]");
   });
 });

registry/coder-labs/modules/codex/main.tf

@@ -38,7 +38,19 @@ variable "icon" {
 
 variable "workdir" {
   type        = string
-  description = "The folder to run Codex in."
+  description = "The folder to run Codex in. Required when enable_tasks is true."
+  default     = null
+
+  validation {
+    condition     = var.workdir != null || !local.tasks_enabled
+    error_message = "workdir is required when enable_tasks is true. Set workdir or set enable_tasks = false for standalone CLI usage."
+  }
+}
+
+variable "enable_tasks" {
+  type        = bool
+  description = "Enable Tasks UI for Codex (requires workdir). When false, only installs Codex CLI with config for standalone usage."
+  default     = true
 }
 
 variable "report_tasks" {
@@ -122,10 +134,11 @@ variable "openai_api_key" {
   default     = ""
 }
 
+# TODO: Remove install_agentapi in next major version (5.0.0)
 variable "install_agentapi" {
   type        = bool
-  description = "Whether to install AgentAPI."
-  default     = true
+  description = "DEPRECATED: Use enable_tasks instead. Whether to install AgentAPI."
+  default     = null
 }
 
 variable "agentapi_version" {
@@ -184,7 +197,9 @@ resource "coder_env" "coder_aibridge_session_token" {
 }
 
 locals {
-  workdir         = trimsuffix(var.workdir, "/")
+  # Use enable_tasks, but fall back to install_agentapi if explicitly set (for backward compat)
+  tasks_enabled   = var.install_agentapi != null ? var.install_agentapi : var.enable_tasks
+  workdir         = var.workdir != null ? trimsuffix(var.workdir, "/") : "/home/coder"
   app_slug        = "codex"
   install_script  = file("${path.module}/scripts/install.sh")
   start_script    = file("${path.module}/scripts/start.sh")
@@ -204,6 +219,7 @@ locals {
 }
 
 module "agentapi" {
+  count   = local.tasks_enabled ? 1 : 0
   source  = "registry.coder.com/coder/agentapi/coder"
   version = "2.0.0"
 
@@ -218,7 +234,7 @@ module "agentapi" {
   cli_app_slug         = var.cli_app ? "${local.app_slug}-cli" : null
   cli_app_display_name = var.cli_app ? var.cli_app_display_name : null
   module_dir_name      = local.module_dir_name
-  install_agentapi     = var.install_agentapi
+  install_agentapi     = true
   agentapi_subdomain   = var.subdomain
   agentapi_version     = var.agentapi_version
   pre_install_script   = var.pre_install_script
@@ -262,6 +278,37 @@ module "agentapi" {
   EOT
 }
 
-output "task_app_id" {
-  value = module.agentapi.task_app_id
+
+# Standalone installation (when tasks are disabled)
+resource "coder_script" "standalone_install" {
+  count              = local.tasks_enabled ? 0 : 1
+  agent_id           = var.agent_id
+  display_name       = "Install Codex"
+  icon               = var.icon
+  run_on_start       = true
+  start_blocks_login = false
+  script             = <<-EOT
+    #!/bin/bash
+    set -o errexit
+    set -o pipefail
+
+    echo -n '${base64encode(local.install_script)}' | base64 -d > /tmp/install.sh
+    chmod +x /tmp/install.sh
+    ARG_OPENAI_API_KEY='${var.openai_api_key}' \
+    ARG_REPORT_TASKS='false' \
+    ARG_INSTALL='${var.install_codex}' \
+    ARG_CODEX_VERSION='${var.codex_version}' \
+    ARG_BASE_CONFIG_TOML='${base64encode(var.base_config_toml)}' \
+    ARG_ENABLE_AIBRIDGE='${var.enable_aibridge}' \
+    ARG_AIBRIDGE_CONFIG='${base64encode(var.enable_aibridge ? local.aibridge_config : "")}' \
+    ARG_ADDITIONAL_MCP_SERVERS='${base64encode(var.additional_mcp_servers)}' \
+    ARG_CODER_MCP_APP_STATUS_SLUG='' \
+    ARG_CODEX_START_DIRECTORY='${local.workdir}' \
+    ARG_CODEX_INSTRUCTION_PROMPT='${base64encode(var.codex_system_prompt)}' \
+    /tmp/install.sh
+  EOT
+}
+
+output "task_app_id" {
+  value = local.tasks_enabled ? module.agentapi[0].task_app_id : null
 }

registry/coder-labs/modules/codex/scripts/install.sh

@@ -151,6 +151,25 @@ function populate_config_toml() {
     write_minimal_default_config "$CONFIG_PATH"
   fi
 
+  # Set aibridge as default profile when AI Bridge is enabled
+  # This allows users to run `codex` without --profile flag
+  if [ "$ARG_ENABLE_AIBRIDGE" = "true" ]; then
+    printf "Setting aibridge as default profile\n"
+    # Remove any existing top-level profile line (before first section header)
+    # This only removes profile = ... at top level, not inside [profiles.*] sections
+    awk '
+      BEGIN { in_top_level = 1 }
+      /^\[/ { in_top_level = 0 }
+      in_top_level && /^profile[ \t]*=/ { next }
+      { print }
+    ' "$CONFIG_PATH" > "${CONFIG_PATH}.tmp"
+    mv "${CONFIG_PATH}.tmp" "$CONFIG_PATH"
+    # Prepend profile = "aibridge" to the config
+    local temp_config
+    temp_config=$(cat "$CONFIG_PATH")
+    echo -e "profile = \"aibridge\"\n\n$temp_config" > "$CONFIG_PATH"
+  fi
+
   append_mcp_servers_section "$CONFIG_PATH"
 
   if [ "$ARG_ENABLE_AIBRIDGE" = "true" ]; then