diff --git a/keyserver/src/responders/farcaster-webhook-responders.js b/keyserver/src/responders/farcaster-webhook-responders.js
--- a/keyserver/src/responders/farcaster-webhook-responders.js
+++ b/keyserver/src/responders/farcaster-webhook-responders.js
@@ -3,16 +3,108 @@
 import { createHmac } from 'crypto';
 import type { $Request } from 'express';
 
+import bots from 'lib/facts/bots.js';
+import { extractKeyserverIDFromID } from 'lib/keyserver-conn/keyserver-call-utils.js';
 import { type NeynarWebhookCastCreatedEvent } from 'lib/types/farcaster-types.js';
+import { threadTypes } from 'lib/types/thread-types-enum.js';
+import { type NewThreadResponse } from 'lib/types/thread-types.js';
 import { neynarWebhookCastCreatedEventValidator } from 'lib/types/validators/farcaster-webhook-validators.js';
 import { ServerError } from 'lib/utils/errors.js';
 import { assertWithValidator } from 'lib/utils/validation-utils.js';
 
+import {
+  getFarcasterChannelTagBlob,
+  createOrUpdateFarcasterChannelTag,
+  farcasterChannelTagBlobValidator,
+} from '../creators/farcaster-channel-tag-creator.js';
+import { createThread } from '../creators/thread-creator.js';
+import { fetchServerThreadInfos } from '../fetchers/thread-fetchers.js';
+import { createBotViewer } from '../session/bots.js';
+import { updateRole } from '../updaters/thread-updaters.js';
+import { thisKeyserverAdmin, thisKeyserverID } from '../user/identity.js';
+import { getFarcasterBotConfig } from '../utils/farcaster-bot.js';
+import { getVerifiedUserIDForFID } from '../utils/farcaster-utils.js';
+import { neynarClient } from '../utils/fc-cache.js';
 import { getNeynarConfig } from '../utils/neynar-utils.js';
 
 const taggedCommFarcasterInputValidator =
   neynarWebhookCastCreatedEventValidator;
 
+const noChannelCommunityID = '80887273';
+const { commbot } = bots;
+const commbotViewer = createBotViewer(commbot.userID);
+
+async function createTaggedFarcasterCommunity(
+  channelID: string,
+  taggerUserID: ?string,
+): Promise<NewThreadResponse> {
+  const keyserverAdminPromise = thisKeyserverAdmin();
+
+  const neynarChannel =
+    await neynarClient?.fetchFarcasterChannelByID(channelID);
+  if (!neynarChannel) {
+    throw new ServerError('channel_not_found');
+  }
+
+  const leadFID = neynarChannel.lead.fid.toString();
+  const [leadUserID, keyserverAdmin] = await Promise.all([
+    getVerifiedUserIDForFID(leadFID),
+    keyserverAdminPromise,
+  ]);
+
+  const communityAdminID = leadUserID
+    ? leadUserID
+    : taggerUserID || keyserverAdmin.id;
+
+  const initialMemberIDs = [
+    ...new Set([leadUserID, taggerUserID, communityAdminID].filter(Boolean)),
+  ];
+
+  const newThreadResponse = await createThread(
+    commbotViewer,
+    {
+      type: threadTypes.COMMUNITY_ROOT,
+      name: neynarChannel.name,
+      initialMemberIDs,
+    },
+    {
+      forceAddMembers: true,
+      addViewerAsGhost: true,
+    },
+  );
+
+  const { newThreadID } = newThreadResponse;
+  const fetchThreadResult = await fetchServerThreadInfos({
+    threadID: newThreadResponse.newThreadID,
+  });
+  const threadInfo = fetchThreadResult.threadInfos[newThreadID];
+
+  if (!threadInfo) {
+    throw new ServerError('fetch_failed');
+  }
+
+  const adminRoleID = Object.keys(threadInfo.roles).find(
+    roleID => threadInfo.roles[roleID].name === 'Admins',
+  );
+
+  if (!adminRoleID) {
+    throw new ServerError('community_missing_admin');
+  }
+
+  await updateRole(commbotViewer, {
+    threadID: newThreadID,
+    memberIDs: [communityAdminID],
+    role: adminRoleID,
+  });
+
+  await createOrUpdateFarcasterChannelTag(commbotViewer, {
+    commCommunityID: newThreadResponse.newThreadID,
+    farcasterChannelID: channelID,
+  });
+
+  return newThreadResponse;
+}
+
 async function verifyNeynarWebhookSignature(
   signature: string,
   event: NeynarWebhookCastCreatedEvent,
@@ -32,16 +124,70 @@
   const { body } = req;
 
   const event = assertWithValidator(body, taggedCommFarcasterInputValidator);
+  const eventTaggerFID = event.data.author.fid;
+
+  const taggerUserIDPromise = getVerifiedUserIDForFID(
+    eventTaggerFID.toString(),
+  );
 
   const signature = req.header('X-Neynar-Signature');
   if (!signature) {
     throw new ServerError('missing_neynar_signature');
   }
 
-  const isValidSignature = await verifyNeynarWebhookSignature(signature, event);
+  const [isValidSignature, farcasterBotConfig] = await Promise.all([
+    verifyNeynarWebhookSignature(signature, event),
+    getFarcasterBotConfig(),
+  ]);
+
   if (!isValidSignature) {
     throw new ServerError('invalid_webhook_signature');
   }
+
+  const eventChannelID = event.data.channel?.id;
+  const isAuthoritativeFarcasterBot =
+    farcasterBotConfig.authoritativeFarcasterBot;
+
+  if (!eventChannelID && !isAuthoritativeFarcasterBot) {
+    return;
+  }
+
+  let channelCommunityID = noChannelCommunityID;
+  if (eventChannelID) {
+    const blobDownload = await getFarcasterChannelTagBlob(eventChannelID);
+    if (blobDownload.found) {
+      const blobText = await blobDownload.blob.text();
+      const blobObject = JSON.parse(blobText);
+      const farcasterChannelTagBlob = assertWithValidator(
+        blobObject,
+        farcasterChannelTagBlobValidator,
+      );
+
+      const { commCommunityID } = farcasterChannelTagBlob;
+      const commCommunityKeyserverID =
+        extractKeyserverIDFromID(commCommunityID);
+      const keyserverID = await thisKeyserverID();
+
+      if (keyserverID !== commCommunityKeyserverID) {
+        return;
+      }
+      channelCommunityID = commCommunityID.split('|')[1];
+    } else if (!blobDownload.found && blobDownload.status === 404) {
+      if (!isAuthoritativeFarcasterBot) {
+        return;
+      }
+
+      const taggerUserID = await taggerUserIDPromise;
+      const newThreadResponse = await createTaggedFarcasterCommunity(
+        eventChannelID,
+        taggerUserID,
+      );
+      channelCommunityID = newThreadResponse.newThreadID;
+    } else {
+      throw new ServerError('blob_fetch_failed');
+    }
+  }
+  console.log(channelCommunityID);
 }
 
 export { taggedCommFarcasterResponder, taggedCommFarcasterInputValidator };