feat(plan): implement simple workflow for planning in main agent (#17326)

packages/core/src/tools/tool-names.ts

@@ -48,6 +48,19 @@ export const ALL_BUILTIN_TOOL_NAMES = [
   ASK_USER_TOOL_NAME,
 ] as const;
 
+/**
+ * Read-only tools available in Plan Mode.
+ * This list is used to dynamically generate the Plan Mode prompt,
+ * filtered by what tools are actually enabled in the current configuration.
+ */
+export const PLAN_MODE_TOOLS = [
+  GLOB_TOOL_NAME,
+  GREP_TOOL_NAME,
+  READ_FILE_TOOL_NAME,
+  LS_TOOL_NAME,
+  WEB_SEARCH_TOOL_NAME,
+] as const;
+
 /**
  * Validates if a tool name is syntactically valid.
  * Checks against built-in tools, discovered tools, and MCP naming conventions.