agents >=0.22.0 changed the default of `throttle`. useAgentChat now coalesces updates every 50ms; pass throttle: false to render every chunk as it arrives, or a number to change the interval. 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";
const pkg = JSON.parse(fs.readFileSync(path.join(root, "package.json"), "utf8"));
const entry = pkg.exports["./chat/react"];
const src = fs.readFileSync(path.join(root, entry.import), "utf8");
const resolveSrc = /function resolveChatThrottleMs\(options\) \{[\s\S]*?\n\}/.exec(src);
const optionsSrc = /function chatThrottleOptions\(options\) \{[\s\S]*?\n\}/.exec(src);
if (!resolveSrc || !optionsSrc || !src.includes("...chatThrottleOptions(")) {
  if (src.includes("useChat(") && !/throttle/.test(src)) {
    console.error("FAIL: agents " + pkg.version + " useAgentChat has no default throttle (agents/chat/react passes no throttle to useChat)");
    process.exit(1);
  }
  console.error("ERROR: agents/chat/react has an unexpected shape");
  process.exit(2);
}
const fns = new Function(resolveSrc[0] + "\n" + optionsSrc[0] + "\nreturn { resolveChatThrottleMs, chatThrottleOptions };")();
const got = {
  byDefault: fns.resolveChatThrottleMs({}),
  off: String(fns.resolveChatThrottleMs({ throttle: false })),
  custom: fns.resolveChatThrottleMs({ throttle: 120 }),
  passed: fns.chatThrottleOptions({})
};
const types = fs.readFileSync(path.join(root, entry.types), "utf8");
if (got.byDefault !== 50 || got.off !== "undefined" || got.custom !== 120 || got.passed.throttle !== 50 || !/throttle\?: number \| false/.test(types)) {
  console.error("ERROR: unexpected throttle values " + JSON.stringify(got));
  process.exit(2);
}
console.log("OK: agents " + pkg.version + " useAgentChat throttle defaults to 50 ms; false turns it off: " + JSON.stringify(got));

const fs = require("fs");
const path = require("path");
const root = "/w/node_modules/agents";
const pkg = JSON.parse(fs.readFileSync(path.join(root, "package.json"), "utf8"));
const entry = pkg.exports["./chat/react"];
const src = fs.readFileSync(path.join(root, entry.import), "utf8");
const resolveSrc = /function resolveChatThrottleMs\(options\) \{[\s\S]*?\n\}/.exec(src);
const optionsSrc = /function chatThrottleOptions\(options\) \{[\s\S]*?\n\}/.exec(src);
if (!resolveSrc || !optionsSrc || !src.includes("...chatThrottleOptions(")) {
  if (src.includes("useChat(") && !/throttle/.test(src)) {
    console.error("FAIL: agents " + pkg.version + " useAgentChat has no default throttle (agents/chat/react passes no throttle to useChat)");
    process.exit(1);
  }
  console.error("ERROR: agents/chat/react has an unexpected shape");
  process.exit(2);
}
const fns = new Function(resolveSrc[0] + "\n" + optionsSrc[0] + "\nreturn { resolveChatThrottleMs, chatThrottleOptions };")();
const got = {
  byDefault: fns.resolveChatThrottleMs({}),
  off: String(fns.resolveChatThrottleMs({ throttle: false })),
  custom: fns.resolveChatThrottleMs({ throttle: 120 }),
  passed: fns.chatThrottleOptions({})
};
const types = fs.readFileSync(path.join(root, entry.types), "utf8");
if (got.byDefault !== 50 || got.off !== "undefined" || got.custom !== 120 || got.passed.throttle !== 50 || !/throttle\?: number \| false/.test(types)) {
  console.error("ERROR: unexpected throttle values " + JSON.stringify(got));
  process.exit(2);
}
console.log("OK: agents " + pkg.version + " useAgentChat throttle defaults to 50 ms; false turns it off: " + JSON.stringify(got));