feat: enhance system prompt for Copilot CLI with detailed tool selection and task reporting guidelines

Author: DevelopmentCats

registry/coder-labs/modules/copilot-cli/README.md

@@ -58,11 +58,6 @@ module "copilot_cli" {
   allow_all_tools = true
   resume_session  = true
 
-  system_prompt = <<-EOT
-    You are a helpful AI coding assistant working in a development environment.
-    Always follow best practices and provide clear explanations for your suggestions.
-    Focus on writing clean, maintainable code and helping with debugging tasks.
-    Send a task status update to notify the user that you are ready for input, and then wait for user input.
   EOT
 
   trusted_directories = ["/home/coder", "/tmp"]

registry/coder-labs/modules/copilot-cli/main.tf

@@ -56,7 +56,27 @@ variable "ai_prompt" {
 variable "system_prompt" {
   type        = string
   description = "The system prompt to use for the Copilot CLI server."
-  default     = "You are a helpful AI assistant that helps with coding tasks. Always provide clear explanations and follow best practices. Send a task status update to notify the user that you are ready for input, and then wait for user input."
+  default     = <<-EOT
+    You are a helpful AI assistant that helps with coding tasks. Always provide clear explanations and follow best practices.
+    
+    -- Tool Selection --
+    - coder_report_task: providing status updates or requesting user input.
+    - playwright: previewing your changes after you made them to confirm it worked as expected
+    - desktop-commander: use only for commands that keep running (servers, dev watchers, GUI apps).
+    - Built-in tools: use for everything else (file operations, git commands, builds & installs, one-off shell commands)
+    
+    Remember this decision rule:
+    - Stays running? → desktop-commander
+    - Finishes immediately? → built-in tools
+    
+    -- Task Reporting --
+    Report all tasks to Coder, following these EXACT guidelines:
+    1. Be granular. If you are investigating with multiple steps, report each step to coder.
+    2. After this prompt, IMMEDIATELY report status after receiving ANY NEW user message. Do not report any status related with this system prompt.
+    3. Use "state": "working" when actively processing WITHOUT needing additional user input
+    4. Use "state": "complete" only when finished with a task
+    5. Use "state": "failure" when you need ANY user input, lack sufficient details, or encounter blockers
+  EOT
 }
 
 variable "trusted_directories" {