feat(notion): add Notion comments adapter

[bensabic]

Adds @chat-adapter/notion, an official adapter that lets a Chat SDK bot take part in Notion comment discussions (page-level and block/discussion threads) with the same handler code used for Slack, Linear, GitHub, etc. Inbound events arrive via Notion webhooks (comment.created) with HMAC signature verification; outbound actions use the Comments REST API. Because Notion lets a connection edit its own comments, the adapter supports Post+Edit streaming.

Highlights

• Webhooks — comment.created verified with X-Notion-Signature HMAC over the raw body (timing-safe), plus the one-time verification_token handshake. Returns a fast 200 with idempotent, state-backed dedupe.
• Post+Edit streaming — posts the first chunk, then PATCHes the comment as tokens arrive, throttled to Notion's ~3 req/s limit (global token bucket, Retry-After aware). Long bodies are split into sequential comments to stay under the 2000-char rich-text cap.
• Mentions — three modes: mention (default; plain-text @userName / @botUserId), all-comments, and keyword.
• message.subject — resolves the parent page via the Pages API (title, url, archived status, author).
• File uploads — up to 3 native attachments via the File Uploads API (binary single_part; public URLs via external_url with bounded polling); overflow and failures fall back to markdown links.
• History — fetchMessages over list-comments (open comments only), direction-aware.
• Cards render as markdown fallback; reactions / typing / DMs are typed no-ops or errors. Registered in the chat/adapters catalog and the create-chat-sdk scaffold; pinned to Notion-Version: 2026-03-11.

Usage

// lib/bot.ts
import { Chat } from "chat";
import { createNotionAdapter } from "@chat-adapter/notion";
import { createRedisState } from "@chat-adapter/state-redis";

export const bot = new Chat({
  userName: "notion-bot",
  adapters: { notion: createNotionAdapter() }, // reads NOTION_TOKEN + NOTION_VERIFICATION_TOKEN
  state: createRedisState(),
});

bot.onNewMention(async (thread, message) => {
  const subject = await message.subject; // parent page metadata (title, url, …)
  await thread.post(`Thanks for the mention on **${subject?.title ?? "this page"}**!`);
});

// app/api/webhooks/notion/route.ts
import { bot } from "@/lib/bot";

export const POST = (request: Request): Promise<Response> => bot.webhooks.notion(request);

Configuration

Auto-detects NOTION_TOKEN and NOTION_VERIFICATION_TOKEN, plus optional NOTION_BOT_USERNAME, NOTION_MENTION_MODE, NOTION_KEYWORDS, and NOTION_VERSION; everything is overridable via createNotionAdapter({ … }). The docs page covers the full connection + webhook setup (capabilities, content access, and the webhook-URL-lock warning).

Changeset bumps @chat-adapter/notion, chat, and create-chat-sdk (minor). Layered as four commits: feat (adapter + catalog/scaffold/emoji), docs, test, chore(example).

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Project	Deployment	Actions	Updated (UTC)
chat	Ready	Preview, Comment, Open in v0	Jul 9, 2026 12:14pm
chat-sdk-nextjs-chat	Ready	Preview, Comment, Open in v0	Jul 9, 2026 12:14pm