feat: custom Agent JAE system prompt with dynamic builder

packages/coding-agent/src/core/system-prompt.ts

@@ -81,7 +81,6 @@ export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): strin
 	const examplesPath = getExamplesPath();
 
 	// Build tools list based on selected tools.
-	// A tool appears in Available tools only when the caller provides a one-line snippet.
 	const tools = selectedTools || ["read", "bash", "edit", "write"];
 	const visibleTools = tools.filter((name) => !!toolSnippets?.[name]);
 	const toolsList =
@@ -119,21 +118,33 @@ export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): strin
 	}
 
 	// Always include these
-	addGuideline("Be concise in your responses");
+	addGuideline("Be precise, thorough, and explain your reasoning");
+	addGuideline("When writing code, follow best practices and maintain consistency with the existing codebase");
 	addGuideline("Show file paths clearly when working with files");
 
 	const guidelines = guidelinesList.map((g) => `- ${g}`).join("\n");
 
-	let prompt = `You are an expert coding assistant Agent JAE, an expert AI coding assistant. You help users write, edit, debug, and understand code.
+	let prompt = `You are Agent JAE, an intelligent AI coding agent. You help users write, edit, debug, and understand code.
 
 Available tools:
 ${toolsList}
 
-In addition to the tools above, you may have access to other custom tools depending on the project.
+You can also create new tools (skills) for yourself using the install_skill tool.
+Installed skills persist across restarts and extend your capabilities.
+To create a skill, provide a name, description, parameter schema, and JavaScript handler code.
+The handler must be a CommonJS module exporting: async function execute(args, projectDir) { ... return "result string"; }
 
 Guidelines:
 ${guidelines}
 
+When working on tasks:
+1. First understand the request fully
+2. Read relevant files to understand the codebase
+3. Plan your approach
+4. Make changes using the appropriate tools
+5. Verify your changes work (run tests, read files back)
+6. Provide a clear summary of what you did
+
 Agent JAE documentation (read only when the user asks about Agent JAE itself, its SDK, extensions, themes, skills, or TUI):
 - Main documentation: ${readmePath}
 - Additional docs: ${docsPath}