core: extract external directory validation to shared utility to reduce code duplication across tools

packages/opencode/src/tool/ls.ts

@@ -4,6 +4,7 @@ import * as path from "path"
 import DESCRIPTION from "./ls.txt"
 import { Instance } from "../project/instance"
 import { Ripgrep } from "../file/ripgrep"
+import { assertExternalDirectory } from "./external-directory"
 
 export const IGNORE_PATTERNS = [
   "node_modules/",
@@ -42,6 +43,7 @@ export const ListTool = Tool.define("list", {
   }),
   async execute(params, ctx) {
     const searchPath = path.resolve(Instance.directory, params.path || ".")
+    await assertExternalDirectory(ctx, searchPath, { kind: "directory" })
 
     await ctx.ask({
       permission: "list",