Deprecating `dir` leaves no way to configure where helper apps open

[bpmct]

Problem

dir on coder_agent was deprecated in #507 (to avoid breaking Coder Desktop file sync). But dir was also how templates controlled where the helper apps open:

• the built-in vscode display app opens the folder from dir
• the web terminal starts sessions in dir

With dir deprecated, there's no first-class replacement for either. A community member flagged this — most of their users only ever interact with the directory their code is cloned into.

Workarounds today

VS Code Desktop: hide vscode in display_apps and use the vscode-desktop module with folder:

resource "coder_agent" "main" {
  os   = "linux"
  arch = "amd64"

  display_apps {
    vscode = false
  }
}

module "vscode" {
  count    = data.coder_workspace.me.start_count
  source   = "registry.coder.com/coder/vscode-desktop/coder"
  version  = "1.2.1"
  agent_id = coder_agent.main.id
  folder   = "/home/coder/project"
}

⚠️ This only works via the dashboard button. If users open the workspace directly from the VS Code extension sidebar (which is how the community member expects it to work, and how many of our own engineers connect), the extension reads the agent's expanded directory — i.e. dir — so there's no workaround at all for that path.

Web terminal: hide web_terminal in display_apps and add a coder_app with a command that cd's first:

resource "coder_agent" "main" {
  os   = "linux"
  arch = "amd64"

  display_apps {
    vscode       = false
    web_terminal = false
  }
}

resource "coder_app" "terminal" {
  agent_id     = coder_agent.main.id
  slug         = "terminal"
  display_name = "Terminal"
  icon         = "/icon/terminal.svg"
  command      = "cd /home/coder/project && exec $SHELL"
}

Neither is obvious, and neither is documented as the migration path.

Suggestion

1. Document this better — e.g. discourage use of the helper apps and point to coder_app / registry modules with explicit folder/command properties. Not ideal on its own though: people connecting directly from the VS Code extension never touch the dashboard buttons, so better docs don't help them at all.
2. Add a proper way for helper apps (and the VS Code extension) to open in a directory, without the file sync breakage that dir caused.
3. Other ideas welcome!

cc @matifali @mafredri — related to the migration-guidance discussion on #507

Generated by Coder Agents

[linear-code]

ENG-3004

[mafredri]

Add a proper way for helper apps (and the VS Code extension) to open in a directory, without the file sync breakage that dir caused.

I think the deprecation of dir is an opportune moment for us to re-consider how folder selection happens. Here at coder/coder we basically have one template, but we work on multiple projects. Having this folder be defined at the template level makes sense for some apps, but not for others. Take the VS Code Desktop button, for example, as a user I'd love to choose which folder is actually opened up.

Some kind of file explorer is one option, another would be automatic project discovery (e.g. find all .git repos in home).

For the VS Code extension, and when connecting through it, we could also utilize the automatic project discovery there to give options when connecting to a workspace.