agents >=0.27.0 changed what `browserTool` does. browserTool now has its own tool description instead of codemode's generic one. Silent: code written for older versions still runs, without an error.

const fs = require("fs");
const path = require("path");
const root = "/w/node_modules/agents";
let pkg, entry, core;
try {
  pkg = JSON.parse(fs.readFileSync(path.join(root, "package.json"), "utf8"));
  const exp = pkg.exports["./browser/ai-sdk"];
  const entryFile = path.join(root, exp.import || exp.default);
  entry = fs.readFileSync(entryFile, "utf8");
  const m = entry.match(/createBrowserToolCore[^}]*\} from "(\.\.?\/[^"]+)"/);
  if (!/function browserTool\(/.test(entry) || !m) throw new Error("browserTool or its core import not found");
  core = fs.readFileSync(path.join(path.dirname(entryFile), m[1]), "utf8");
} catch (e) {
  console.error("ERROR: cannot load agents/browser/ai-sdk: " + e.message);
  process.exit(2);
}
const start = core.indexOf("function createBrowserToolCore(");
if (start < 0) {
  console.error("ERROR: createBrowserToolCore not found");
  process.exit(2);
}
const body = core.slice(start, start + 6000);
const ownIntro = body.includes("Run JavaScript that drives a persistent Chrome browser over the Chrome DevTools Protocol (CDP).");
const timeoutRule = body.includes("Each run times out after");
const ownDescription = /\.tool\(\{\s*description\s*\}\)/.test(body);
const genericWithHints = /\.tool\(\{\s*connectorHints:/.test(body);
if (ownIntro && timeoutRule && ownDescription && !genericWithHints) {
  console.log("OK: agents " + pkg.version + " browserTool passes its own description (cdp API, run time limit) to codemode");
  process.exit(0);
}
if (genericWithHints && !ownIntro && !ownDescription) {
  console.error("FAIL: agents " + pkg.version + " browserTool uses codemode's generic description with only a cdp connector hint");
  process.exit(1);
}
console.error("ERROR: unexpected browserTool core " + JSON.stringify({ ownIntro, timeoutRule, ownDescription, genericWithHints }));
process.exit(2);

const fs = require("fs");
const path = require("path");
const root = "/w/node_modules/agents";
let pkg, entry, core;
try {
  pkg = JSON.parse(fs.readFileSync(path.join(root, "package.json"), "utf8"));
  const exp = pkg.exports["./browser/ai-sdk"];
  const entryFile = path.join(root, exp.import || exp.default);
  entry = fs.readFileSync(entryFile, "utf8");
  const m = entry.match(/createBrowserToolCore[^}]*\} from "(\.\.?\/[^"]+)"/);
  if (!/function browserTool\(/.test(entry) || !m) throw new Error("browserTool or its core import not found");
  core = fs.readFileSync(path.join(path.dirname(entryFile), m[1]), "utf8");
} catch (e) {
  console.error("ERROR: cannot load agents/browser/ai-sdk: " + e.message);
  process.exit(2);
}
const start = core.indexOf("function createBrowserToolCore(");
if (start < 0) {
  console.error("ERROR: createBrowserToolCore not found");
  process.exit(2);
}
const body = core.slice(start, start + 6000);
const ownIntro = body.includes("Run JavaScript that drives a persistent Chrome browser over the Chrome DevTools Protocol (CDP).");
const timeoutRule = body.includes("Each run times out after");
const ownDescription = /\.tool\(\{\s*description\s*\}\)/.test(body);
const genericWithHints = /\.tool\(\{\s*connectorHints:/.test(body);
if (ownIntro && timeoutRule && ownDescription && !genericWithHints) {
  console.log("OK: agents " + pkg.version + " browserTool passes its own description (cdp API, run time limit) to codemode");
  process.exit(0);
}
if (genericWithHints && !ownIntro && !ownDescription) {
  console.error("FAIL: agents " + pkg.version + " browserTool uses codemode's generic description with only a cdp connector hint");
  process.exit(1);
}
console.error("ERROR: unexpected browserTool core " + JSON.stringify({ ownIntro, timeoutRule, ownDescription, genericWithHints }));
process.exit(2);