diff --git a/extensions/mattermost/package.json b/extensions/mattermost/package.json
index 8ba462f45..f98f3c446 100644
--- a/extensions/mattermost/package.json
+++ b/extensions/mattermost/package.json
@@ -6,6 +6,20 @@
   "clawdbot": {
     "extensions": [
       "./index.ts"
-    ]
+    ],
+    "channel": {
+      "id": "mattermost",
+      "label": "Mattermost",
+      "selectionLabel": "Mattermost (plugin)",
+      "docsPath": "/channels/mattermost",
+      "docsLabel": "mattermost",
+      "blurb": "self-hosted Slack-style chat; install the plugin to enable.",
+      "order": 65
+    },
+    "install": {
+      "npmSpec": "@clawdbot/mattermost",
+      "localPath": "extensions/mattermost",
+      "defaultChoice": "npm"
+    }
   }
 }
diff --git a/extensions/mattermost/src/channel.ts b/extensions/mattermost/src/channel.ts
index 840772a17..b365fc61e 100644
--- a/extensions/mattermost/src/channel.ts
+++ b/extensions/mattermost/src/channel.ts
@@ -3,26 +3,42 @@ import {
   buildChannelConfigSchema,
   DEFAULT_ACCOUNT_ID,
   deleteAccountFromConfigSection,
-  getChatChannelMeta,
-  listMattermostAccountIds,
-  looksLikeMattermostTargetId,
   migrateBaseNameToDefaultAccount,
   normalizeAccountId,
-  normalizeMattermostBaseUrl,
-  normalizeMattermostMessagingTarget,
-  resolveDefaultMattermostAccountId,
-  resolveMattermostAccount,
-  resolveMattermostGroupRequireMention,
   setAccountEnabledInConfigSection,
-  mattermostOnboardingAdapter,
-  MattermostConfigSchema,
   type ChannelPlugin,
-  type ResolvedMattermostAccount,
 } from "clawdbot/plugin-sdk";
 
+import { MattermostConfigSchema } from "./config-schema.js";
+import { resolveMattermostGroupRequireMention } from "./group-mentions.js";
+import {
+  looksLikeMattermostTargetId,
+  normalizeMattermostMessagingTarget,
+} from "./normalize.js";
+import { mattermostOnboardingAdapter } from "./onboarding.js";
+import {
+  listMattermostAccountIds,
+  resolveDefaultMattermostAccountId,
+  resolveMattermostAccount,
+  type ResolvedMattermostAccount,
+} from "./mattermost/accounts.js";
+import { normalizeMattermostBaseUrl } from "./mattermost/client.js";
+import { monitorMattermostProvider } from "./mattermost/monitor.js";
+import { probeMattermost } from "./mattermost/probe.js";
+import { sendMessageMattermost } from "./mattermost/send.js";
 import { getMattermostRuntime } from "./runtime.js";
 
-const meta = getChatChannelMeta("mattermost");
+const meta = {
+  id: "mattermost",
+  label: "Mattermost",
+  selectionLabel: "Mattermost (plugin)",
+  detailLabel: "Mattermost Bot",
+  docsPath: "/channels/mattermost",
+  docsLabel: "mattermost",
+  blurb: "self-hosted Slack-style chat; install the plugin to enable.",
+  systemImage: "bubble.left.and.bubble.right",
+  order: 65,
+} as const;
 
 export const mattermostPlugin: ChannelPlugin<ResolvedMattermostAccount> = {
   id: "mattermost",
@@ -96,8 +112,7 @@ export const mattermostPlugin: ChannelPlugin<ResolvedMattermostAccount> = {
       return { ok: true, to: trimmed };
     },
     sendText: async ({ to, text, accountId, deps, replyToId }) => {
-      const send =
-        deps?.sendMattermost ?? getMattermostRuntime().channel.mattermost.sendMessageMattermost;
+      const send = deps?.sendMattermost ?? sendMessageMattermost;
       const result = await send(to, text, {
         accountId: accountId ?? undefined,
         replyToId: replyToId ?? undefined,
@@ -105,8 +120,7 @@ export const mattermostPlugin: ChannelPlugin<ResolvedMattermostAccount> = {
       return { channel: "mattermost", ...result };
     },
     sendMedia: async ({ to, text, mediaUrl, accountId, deps, replyToId }) => {
-      const send =
-        deps?.sendMattermost ?? getMattermostRuntime().channel.mattermost.sendMessageMattermost;
+      const send = deps?.sendMattermost ?? sendMessageMattermost;
       const result = await send(to, text, {
         accountId: accountId ?? undefined,
         mediaUrl,
@@ -144,11 +158,7 @@ export const mattermostPlugin: ChannelPlugin<ResolvedMattermostAccount> = {
       if (!token || !baseUrl) {
         return { ok: false, error: "bot token or baseUrl missing" };
       }
-      return await getMattermostRuntime().channel.mattermost.probeMattermost(
-        baseUrl,
-        token,
-        timeoutMs,
-      );
+      return await probeMattermost(baseUrl, token, timeoutMs);
     },
     buildAccountSnapshot: ({ account, runtime, probe }) => ({
       accountId: account.accountId,
@@ -256,7 +266,7 @@ export const mattermostPlugin: ChannelPlugin<ResolvedMattermostAccount> = {
         botTokenSource: account.botTokenSource,
       });
       ctx.log?.info(`[${account.accountId}] starting channel`);
-      return getMattermostRuntime().channel.mattermost.monitorMattermostProvider({
+      return monitorMattermostProvider({
         botToken: account.botToken ?? undefined,
         baseUrl: account.baseUrl ?? undefined,
         accountId: account.accountId,
diff --git a/extensions/mattermost/src/config-schema.ts b/extensions/mattermost/src/config-schema.ts
new file mode 100644
index 000000000..3cbecaf34
--- /dev/null
+++ b/extensions/mattermost/src/config-schema.ts
@@ -0,0 +1,24 @@
+import { z } from "zod";
+
+import { BlockStreamingCoalesceSchema } from "clawdbot/plugin-sdk";
+
+const MattermostAccountSchema = z
+  .object({
+    name: z.string().optional(),
+    capabilities: z.array(z.string()).optional(),
+    enabled: z.boolean().optional(),
+    configWrites: z.boolean().optional(),
+    botToken: z.string().optional(),
+    baseUrl: z.string().optional(),
+    chatmode: z.enum(["oncall", "onmessage", "onchar"]).optional(),
+    oncharPrefixes: z.array(z.string()).optional(),
+    requireMention: z.boolean().optional(),
+    textChunkLimit: z.number().int().positive().optional(),
+    blockStreaming: z.boolean().optional(),
+    blockStreamingCoalesce: BlockStreamingCoalesceSchema.optional(),
+  })
+  .strict();
+
+export const MattermostConfigSchema = MattermostAccountSchema.extend({
+  accounts: z.record(z.string(), MattermostAccountSchema.optional()).optional(),
+});
diff --git a/extensions/mattermost/src/group-mentions.ts b/extensions/mattermost/src/group-mentions.ts
new file mode 100644
index 000000000..773e655ff
--- /dev/null
+++ b/extensions/mattermost/src/group-mentions.ts
@@ -0,0 +1,14 @@
+import type { ChannelGroupContext } from "clawdbot/plugin-sdk";
+
+import { resolveMattermostAccount } from "./mattermost/accounts.js";
+
+export function resolveMattermostGroupRequireMention(
+  params: ChannelGroupContext,
+): boolean | undefined {
+  const account = resolveMattermostAccount({
+    cfg: params.cfg,
+    accountId: params.accountId,
+  });
+  if (typeof account.requireMention === "boolean") return account.requireMention;
+  return true;
+}
diff --git a/src/mattermost/accounts.ts b/extensions/mattermost/src/mattermost/accounts.ts
similarity index 96%
rename from src/mattermost/accounts.ts
rename to extensions/mattermost/src/mattermost/accounts.ts
index 08ffa2f94..e75f34593 100644
--- a/src/mattermost/accounts.ts
+++ b/extensions/mattermost/src/mattermost/accounts.ts
@@ -1,6 +1,7 @@
-import type { ClawdbotConfig } from "../config/config.js";
-import type { MattermostAccountConfig, MattermostChatMode } from "../config/types.js";
-import { DEFAULT_ACCOUNT_ID, normalizeAccountId } from "../routing/session-key.js";
+import type { ClawdbotConfig } from "clawdbot/plugin-sdk";
+import { DEFAULT_ACCOUNT_ID, normalizeAccountId } from "clawdbot/plugin-sdk";
+
+import type { MattermostAccountConfig, MattermostChatMode } from "../types.js";
 import { normalizeMattermostBaseUrl } from "./client.js";
 
 export type MattermostTokenSource = "env" | "config" | "none";
diff --git a/src/mattermost/client.ts b/extensions/mattermost/src/mattermost/client.ts
similarity index 100%
rename from src/mattermost/client.ts
rename to extensions/mattermost/src/mattermost/client.ts
diff --git a/src/mattermost/index.ts b/extensions/mattermost/src/mattermost/index.ts
similarity index 100%
rename from src/mattermost/index.ts
rename to extensions/mattermost/src/mattermost/index.ts
diff --git a/extensions/mattermost/src/mattermost/monitor-helpers.ts b/extensions/mattermost/src/mattermost/monitor-helpers.ts
new file mode 100644
index 000000000..8c68a4f25
--- /dev/null
+++ b/extensions/mattermost/src/mattermost/monitor-helpers.ts
@@ -0,0 +1,150 @@
+import { Buffer } from "node:buffer";
+
+import type WebSocket from "ws";
+
+import type { ClawdbotConfig } from "clawdbot/plugin-sdk";
+
+export type ResponsePrefixContext = {
+  model?: string;
+  modelFull?: string;
+  provider?: string;
+  thinkingLevel?: string;
+  identityName?: string;
+};
+
+export function extractShortModelName(fullModel: string): string {
+  const slash = fullModel.lastIndexOf("/");
+  const modelPart = slash >= 0 ? fullModel.slice(slash + 1) : fullModel;
+  return modelPart.replace(/-\d{8}$/, "").replace(/-latest$/, "");
+}
+
+export function formatInboundFromLabel(params: {
+  isGroup: boolean;
+  groupLabel?: string;
+  groupId?: string;
+  directLabel: string;
+  directId?: string;
+  groupFallback?: string;
+}): string {
+  if (params.isGroup) {
+    const label = params.groupLabel?.trim() || params.groupFallback || "Group";
+    const id = params.groupId?.trim();
+    return id ? `${label} id:${id}` : label;
+  }
+
+  const directLabel = params.directLabel.trim();
+  const directId = params.directId?.trim();
+  if (!directId || directId === directLabel) return directLabel;
+  return `${directLabel} id:${directId}`;
+}
+
+type DedupeCache = {
+  check: (key: string | undefined | null, now?: number) => boolean;
+};
+
+export function createDedupeCache(options: { ttlMs: number; maxSize: number }): DedupeCache {
+  const ttlMs = Math.max(0, options.ttlMs);
+  const maxSize = Math.max(0, Math.floor(options.maxSize));
+  const cache = new Map<string, number>();
+
+  const touch = (key: string, now: number) => {
+    cache.delete(key);
+    cache.set(key, now);
+  };
+
+  const prune = (now: number) => {
+    const cutoff = ttlMs > 0 ? now - ttlMs : undefined;
+    if (cutoff !== undefined) {
+      for (const [entryKey, entryTs] of cache) {
+        if (entryTs < cutoff) {
+          cache.delete(entryKey);
+        }
+      }
+    }
+    if (maxSize <= 0) {
+      cache.clear();
+      return;
+    }
+    while (cache.size > maxSize) {
+      const oldestKey = cache.keys().next().value as string | undefined;
+      if (!oldestKey) break;
+      cache.delete(oldestKey);
+    }
+  };
+
+  return {
+    check: (key, now = Date.now()) => {
+      if (!key) return false;
+      const existing = cache.get(key);
+      if (existing !== undefined && (ttlMs <= 0 || now - existing < ttlMs)) {
+        touch(key, now);
+        return true;
+      }
+      touch(key, now);
+      prune(now);
+      return false;
+    },
+  };
+}
+
+export function rawDataToString(
+  data: WebSocket.RawData,
+  encoding: BufferEncoding = "utf8",
+): string {
+  if (typeof data === "string") return data;
+  if (Buffer.isBuffer(data)) return data.toString(encoding);
+  if (Array.isArray(data)) return Buffer.concat(data).toString(encoding);
+  if (data instanceof ArrayBuffer) {
+    return Buffer.from(data).toString(encoding);
+  }
+  return Buffer.from(String(data)).toString(encoding);
+}
+
+function normalizeAgentId(value: string | undefined | null): string {
+  const trimmed = (value ?? "").trim();
+  if (!trimmed) return "main";
+  if (/^[a-z0-9][a-z0-9_-]{0,63}$/i.test(trimmed)) return trimmed;
+  return (
+    trimmed
+      .toLowerCase()
+      .replace(/[^a-z0-9_-]+/g, "-")
+      .replace(/^-+/, "")
+      .replace(/-+$/, "")
+      .slice(0, 64) || "main"
+  );
+}
+
+type AgentEntry = NonNullable<NonNullable<ClawdbotConfig["agents"]>["list"]>[number];
+
+function listAgents(cfg: ClawdbotConfig): AgentEntry[] {
+  const list = cfg.agents?.list;
+  if (!Array.isArray(list)) return [];
+  return list.filter((entry): entry is AgentEntry => Boolean(entry && typeof entry === "object"));
+}
+
+function resolveAgentEntry(cfg: ClawdbotConfig, agentId: string): AgentEntry | undefined {
+  const id = normalizeAgentId(agentId);
+  return listAgents(cfg).find((entry) => normalizeAgentId(entry.id) === id);
+}
+
+export function resolveIdentityName(cfg: ClawdbotConfig, agentId: string): string | undefined {
+  const entry = resolveAgentEntry(cfg, agentId);
+  return entry?.identity?.name?.trim() || undefined;
+}
+
+export function resolveThreadSessionKeys(params: {
+  baseSessionKey: string;
+  threadId?: string | null;
+  parentSessionKey?: string;
+  useSuffix?: boolean;
+}): { sessionKey: string; parentSessionKey?: string } {
+  const threadId = (params.threadId ?? "").trim();
+  if (!threadId) {
+    return { sessionKey: params.baseSessionKey, parentSessionKey: undefined };
+  }
+  const useSuffix = params.useSuffix ?? true;
+  const sessionKey = useSuffix
+    ? `${params.baseSessionKey}:thread:${threadId}`
+    : params.baseSessionKey;
+  return { sessionKey, parentSessionKey: params.parentSessionKey };
+}
diff --git a/src/mattermost/monitor.ts b/extensions/mattermost/src/mattermost/monitor.ts
similarity index 80%
rename from src/mattermost/monitor.ts
rename to extensions/mattermost/src/mattermost/monitor.ts
index fb8bd00db..7c0d98fca 100644
--- a/src/mattermost/monitor.ts
+++ b/extensions/mattermost/src/mattermost/monitor.ts
@@ -1,52 +1,21 @@
 import WebSocket from "ws";
 
-import {
-  resolveEffectiveMessagesConfig,
-  resolveHumanDelayConfig,
-  resolveIdentityName,
-} from "../agents/identity.js";
-import { chunkMarkdownText, resolveTextChunkLimit } from "../auto-reply/chunk.js";
-import { hasControlCommand } from "../auto-reply/command-detection.js";
-import { shouldHandleTextCommands } from "../auto-reply/commands-registry.js";
-import { formatInboundEnvelope, formatInboundFromLabel } from "../auto-reply/envelope.js";
-import {
-  createInboundDebouncer,
-  resolveInboundDebounceMs,
-} from "../auto-reply/inbound-debounce.js";
-import { dispatchReplyFromConfig } from "../auto-reply/reply/dispatch-from-config.js";
-import { finalizeInboundContext } from "../auto-reply/reply/inbound-context.js";
+import type {
+  ChannelAccountSnapshot,
+  ClawdbotConfig,
+  ReplyPayload,
+  RuntimeEnv,
+} from "clawdbot/plugin-sdk";
 import {
   buildPendingHistoryContextFromMap,
   clearHistoryEntries,
   DEFAULT_GROUP_HISTORY_LIMIT,
   recordPendingHistoryEntry,
+  resolveChannelMediaMaxBytes,
   type HistoryEntry,
-} from "../auto-reply/reply/history.js";
-import { createReplyDispatcherWithTyping } from "../auto-reply/reply/reply-dispatcher.js";
-import {
-  extractShortModelName,
-  type ResponsePrefixContext,
-} from "../auto-reply/reply/response-prefix-template.js";
-import { buildMentionRegexes, matchesMentionPatterns } from "../auto-reply/reply/mentions.js";
-import type { ReplyPayload } from "../auto-reply/types.js";
-import type { ClawdbotConfig } from "../config/config.js";
-import { loadConfig } from "../config/config.js";
-import { resolveStorePath, updateLastRoute } from "../config/sessions.js";
-import { danger, logVerbose, shouldLogVerbose } from "../globals.js";
-import { createDedupeCache } from "../infra/dedupe.js";
-import { rawDataToString } from "../infra/ws.js";
-import { recordChannelActivity } from "../infra/channel-activity.js";
-import { enqueueSystemEvent } from "../infra/system-events.js";
-import { getChildLogger } from "../logging.js";
-import { mediaKindFromMime, type MediaKind } from "../media/constants.js";
-import { fetchRemoteMedia, type FetchLike } from "../media/fetch.js";
-import { saveMediaBuffer } from "../media/store.js";
-import { resolveAgentRoute } from "../routing/resolve-route.js";
-import { resolveThreadSessionKeys } from "../routing/session-key.js";
-import type { RuntimeEnv } from "../runtime.js";
-import type { ChannelAccountSnapshot } from "../channels/plugins/types.js";
-import { resolveChannelMediaMaxBytes } from "../channels/plugins/media-limits.js";
-import { resolveCommandAuthorizedFromAuthorizers } from "../channels/command-gating.js";
+} from "clawdbot/plugin-sdk";
+
+import { getMattermostRuntime } from "../runtime.js";
 import { resolveMattermostAccount } from "./accounts.js";
 import {
   createMattermostClient,
@@ -59,6 +28,15 @@ import {
   type MattermostPost,
   type MattermostUser,
 } from "./client.js";
+import {
+  createDedupeCache,
+  extractShortModelName,
+  formatInboundFromLabel,
+  rawDataToString,
+  resolveIdentityName,
+  resolveThreadSessionKeys,
+  type ResponsePrefixContext,
+} from "./monitor-helpers.js";
 import { sendMessageMattermost } from "./send.js";
 
 export type MonitorMattermostOpts = {
@@ -71,6 +49,9 @@ export type MonitorMattermostOpts = {
   statusSink?: (patch: Partial<ChannelAccountSnapshot>) => void;
 };
 
+type FetchLike = typeof fetch;
+type MediaKind = "image" | "audio" | "video" | "document" | "unknown";
+
 type MattermostEventPayload = {
   event?: string;
   data?: {
@@ -208,8 +189,9 @@ function buildMattermostWsUrl(baseUrl: string): string {
 }
 
 export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}): Promise<void> {
+  const core = getMattermostRuntime();
   const runtime = resolveRuntime(opts);
-  const cfg = opts.config ?? loadConfig();
+  const cfg = opts.config ?? core.config.loadConfig();
   const account = resolveMattermostAccount({
     cfg,
     accountId: opts.accountId,
@@ -235,7 +217,11 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
 
   const channelCache = new Map<string, { value: MattermostChannel | null; expiresAt: number }>();
   const userCache = new Map<string, { value: MattermostUser | null; expiresAt: number }>();
-  const logger = getChildLogger({ module: "mattermost" });
+  const logger = core.logging.getChildLogger({ module: "mattermost" });
+  const logVerboseMessage = (message: string) => {
+    if (!core.logging.shouldLogVerbose()) return;
+    logger.debug?.(message);
+  };
   const mediaMaxBytes =
     resolveChannelMediaMaxBytes({
       cfg,
@@ -262,13 +248,13 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
     const out: MattermostMediaInfo[] = [];
     for (const fileId of ids) {
       try {
-        const fetched = await fetchRemoteMedia({
+        const fetched = await core.channel.media.fetchRemoteMedia({
           url: `${client.apiBaseUrl}/files/${fileId}`,
           fetchImpl: fetchWithAuth,
           filePathHint: fileId,
           maxBytes: mediaMaxBytes,
         });
-        const saved = await saveMediaBuffer(
+        const saved = await core.channel.media.saveMediaBuffer(
           fetched.buffer,
           fetched.contentType ?? undefined,
           "inbound",
@@ -278,7 +264,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
         out.push({
           path: saved.path,
           contentType,
-          kind: mediaKindFromMime(contentType),
+          kind: core.media.mediaKindFromMime(contentType),
         });
       } catch (err) {
         logger.debug?.(`mattermost: failed to download file ${fileId}: ${String(err)}`);
@@ -366,7 +352,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       payload.data?.channel_display_name ?? channelInfo?.display_name ?? channelName;
     const roomLabel = channelName ? `#${channelName}` : channelDisplay || `#${channelId}`;
 
-    const route = resolveAgentRoute({
+    const route = core.channel.routing.resolveAgentRoute({
       cfg,
       channel: "mattermost",
       accountId: account.accountId,
@@ -387,12 +373,12 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
     const sessionKey = threadKeys.sessionKey;
     const historyKey = kind === "dm" ? null : sessionKey;
 
-    const mentionRegexes = buildMentionRegexes(cfg, route.agentId);
+    const mentionRegexes = core.channel.mentions.buildMentionRegexes(cfg, route.agentId);
     const rawText = post.message?.trim() || "";
     const wasMentioned =
       kind !== "dm" &&
       ((botUsername ? rawText.toLowerCase().includes(`@${botUsername.toLowerCase()}`) : false) ||
-        matchesMentionPatterns(rawText, mentionRegexes));
+        core.channel.mentions.matchesMentionPatterns(rawText, mentionRegexes));
     const pendingBody =
       rawText ||
       (post.file_ids?.length
@@ -416,11 +402,11 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       });
     };
 
-    const allowTextCommands = shouldHandleTextCommands({
+    const allowTextCommands = core.channel.commands.shouldHandleTextCommands({
       cfg,
       surface: "mattermost",
     });
-    const isControlCommand = allowTextCommands && hasControlCommand(rawText, cfg);
+    const isControlCommand = allowTextCommands && core.channel.text.hasControlCommand(rawText, cfg);
     const oncharEnabled = account.chatmode === "onchar" && kind !== "dm";
     const oncharPrefixes = oncharEnabled ? resolveOncharPrefixes(account.oncharPrefixes) : [];
     const oncharResult = oncharEnabled
@@ -456,7 +442,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
     const bodyText = normalizeMention(baseText, botUsername);
     if (!bodyText) return;
 
-    recordChannelActivity({
+    core.channel.activity.record({
       channel: "mattermost",
       accountId: account.accountId,
       direction: "inbound",
@@ -476,13 +462,13 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       kind === "dm"
         ? `Mattermost DM from ${senderName}`
         : `Mattermost message in ${roomLabel} from ${senderName}`;
-    enqueueSystemEvent(`${inboundLabel}: ${preview}`, {
+    core.system.enqueueSystemEvent(`${inboundLabel}: ${preview}`, {
       sessionKey,
       contextKey: `mattermost:message:${channelId}:${post.id ?? "unknown"}`,
     });
 
     const textWithId = `${bodyText}\n[mattermost message id: ${post.id ?? "unknown"} channel: ${channelId}]`;
-    const body = formatInboundEnvelope({
+    const body = core.channel.reply.formatInboundEnvelope({
       channel: "Mattermost",
       from: fromLabel,
       timestamp: typeof post.create_at === "number" ? post.create_at : undefined,
@@ -498,7 +484,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
         limit: historyLimit,
         currentMessage: combinedBody,
         formatEntry: (entry) =>
-          formatInboundEnvelope({
+          core.channel.reply.formatInboundEnvelope({
             channel: "Mattermost",
             from: fromLabel,
             timestamp: entry.timestamp,
@@ -513,11 +499,11 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
 
     const to = kind === "dm" ? `user:${senderId}` : `channel:${channelId}`;
     const mediaPayload = buildMattermostMediaPayload(mediaList);
-    const commandAuthorized = resolveCommandAuthorizedFromAuthorizers({
+    const commandAuthorized = core.channel.commands.resolveCommandAuthorizedFromAuthorizers({
       useAccessGroups: cfg.commands?.useAccessGroups ?? false,
       authorizers: [],
     });
-    const ctxPayload = finalizeInboundContext({
+    const ctxPayload = core.channel.reply.finalizeInboundContext({
       Body: combinedBody,
       RawBody: bodyText,
       CommandBody: bodyText,
@@ -557,10 +543,10 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
 
     if (kind === "dm") {
       const sessionCfg = cfg.session;
-      const storePath = resolveStorePath(sessionCfg?.store, {
+      const storePath = core.channel.session.resolveStorePath(sessionCfg?.store, {
         agentId: route.agentId,
       });
-      await updateLastRoute({
+      await core.channel.session.updateLastRoute({
         storePath,
         sessionKey: route.mainSessionKey,
         deliveryContext: {
@@ -571,14 +557,12 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       });
     }
 
-    if (shouldLogVerbose()) {
-      const previewLine = bodyText.slice(0, 200).replace(/\n/g, "\\n");
-      logVerbose(
-        `mattermost inbound: from=${ctxPayload.From} len=${bodyText.length} preview="${previewLine}"`,
-      );
-    }
+    const previewLine = bodyText.slice(0, 200).replace(/\n/g, "\\n");
+    logVerboseMessage(
+      `mattermost inbound: from=${ctxPayload.From} len=${bodyText.length} preview="${previewLine}"`,
+    );
 
-    const textLimit = resolveTextChunkLimit(cfg, "mattermost", account.accountId, {
+    const textLimit = core.channel.text.resolveTextChunkLimit(cfg, "mattermost", account.accountId, {
       fallbackLimit: account.textChunkLimit ?? 4000,
     });
 
@@ -586,43 +570,45 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       identityName: resolveIdentityName(cfg, route.agentId),
     };
 
-    const { dispatcher, replyOptions, markDispatchIdle } = createReplyDispatcherWithTyping({
-      responsePrefix: resolveEffectiveMessagesConfig(cfg, route.agentId).responsePrefix,
-      responsePrefixContextProvider: () => prefixContext,
-      humanDelay: resolveHumanDelayConfig(cfg, route.agentId),
-      deliver: async (payload: ReplyPayload) => {
-        const mediaUrls = payload.mediaUrls ?? (payload.mediaUrl ? [payload.mediaUrl] : []);
-        const text = payload.text ?? "";
-        if (mediaUrls.length === 0) {
-          const chunks = chunkMarkdownText(text, textLimit);
-          for (const chunk of chunks.length > 0 ? chunks : [text]) {
-            if (!chunk) continue;
-            await sendMessageMattermost(to, chunk, {
-              accountId: account.accountId,
-              replyToId: threadRootId,
-            });
+    const { dispatcher, replyOptions, markDispatchIdle } =
+      core.channel.reply.createReplyDispatcherWithTyping({
+        responsePrefix: core.channel.reply.resolveEffectiveMessagesConfig(cfg, route.agentId)
+          .responsePrefix,
+        responsePrefixContextProvider: () => prefixContext,
+        humanDelay: core.channel.reply.resolveHumanDelayConfig(cfg, route.agentId),
+        deliver: async (payload: ReplyPayload) => {
+          const mediaUrls = payload.mediaUrls ?? (payload.mediaUrl ? [payload.mediaUrl] : []);
+          const text = payload.text ?? "";
+          if (mediaUrls.length === 0) {
+            const chunks = core.channel.text.chunkMarkdownText(text, textLimit);
+            for (const chunk of chunks.length > 0 ? chunks : [text]) {
+              if (!chunk) continue;
+              await sendMessageMattermost(to, chunk, {
+                accountId: account.accountId,
+                replyToId: threadRootId,
+              });
+            }
+          } else {
+            let first = true;
+            for (const mediaUrl of mediaUrls) {
+              const caption = first ? text : "";
+              first = false;
+              await sendMessageMattermost(to, caption, {
+                accountId: account.accountId,
+                mediaUrl,
+                replyToId: threadRootId,
+              });
+            }
           }
-        } else {
-          let first = true;
-          for (const mediaUrl of mediaUrls) {
-            const caption = first ? text : "";
-            first = false;
-            await sendMessageMattermost(to, caption, {
-              accountId: account.accountId,
-              mediaUrl,
-              replyToId: threadRootId,
-            });
-          }
-        }
-        runtime.log?.(`delivered reply to ${to}`);
-      },
-      onError: (err, info) => {
-        runtime.error?.(danger(`mattermost ${info.kind} reply failed: ${String(err)}`));
-      },
-      onReplyStart: () => sendTypingIndicator(channelId, threadRootId),
-    });
+          runtime.log?.(`delivered reply to ${to}`);
+        },
+        onError: (err, info) => {
+          runtime.error?.(`mattermost ${info.kind} reply failed: ${String(err)}`);
+        },
+        onReplyStart: () => sendTypingIndicator(channelId, threadRootId),
+      });
 
-    await dispatchReplyFromConfig({
+    await core.channel.reply.dispatchReplyFromConfig({
       ctx: ctxPayload,
       cfg,
       dispatcher,
@@ -644,8 +630,11 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
     }
   };
 
-  const inboundDebounceMs = resolveInboundDebounceMs({ cfg, channel: "mattermost" });
-  const debouncer = createInboundDebouncer<{
+  const inboundDebounceMs = core.channel.debounce.resolveInboundDebounceMs({
+    cfg,
+    channel: "mattermost",
+  });
+  const debouncer = core.channel.debounce.createInboundDebouncer<{
     post: MattermostPost;
     payload: MattermostEventPayload;
   }>({
@@ -664,7 +653,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       if (entry.post.file_ids && entry.post.file_ids.length > 0) return false;
       const text = entry.post.message?.trim() ?? "";
       if (!text) return false;
-      return !hasControlCommand(text, cfg);
+      return !core.channel.text.hasControlCommand(text, cfg);
     },
     onFlush: async (entries) => {
       const last = entries.at(-1);
@@ -686,7 +675,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       await handlePost(mergedPost, last.payload, ids.length > 0 ? ids : undefined);
     },
     onError: (err) => {
-      runtime.error?.(danger(`mattermost debounce flush failed: ${String(err)}`));
+      runtime.error?.(`mattermost debounce flush failed: ${String(err)}`);
     },
   });
 
@@ -739,7 +728,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
         try {
           await debouncer.enqueue({ post, payload });
         } catch (err) {
-          runtime.error?.(danger(`mattermost handler failed: ${String(err)}`));
+          runtime.error?.(`mattermost handler failed: ${String(err)}`);
         }
       });
 
@@ -758,7 +747,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       });
 
       ws.on("error", (err) => {
-        runtime.error?.(danger(`mattermost websocket error: ${String(err)}`));
+        runtime.error?.(`mattermost websocket error: ${String(err)}`);
         opts.statusSink?.({
           lastError: String(err),
         });
diff --git a/src/mattermost/probe.ts b/extensions/mattermost/src/mattermost/probe.ts
similarity index 100%
rename from src/mattermost/probe.ts
rename to extensions/mattermost/src/mattermost/probe.ts
diff --git a/src/mattermost/send.ts b/extensions/mattermost/src/mattermost/send.ts
similarity index 93%
rename from src/mattermost/send.ts
rename to extensions/mattermost/src/mattermost/send.ts
index 40f038cc0..f5b22c768 100644
--- a/src/mattermost/send.ts
+++ b/extensions/mattermost/src/mattermost/send.ts
@@ -1,7 +1,4 @@
-import { loadConfig } from "../config/config.js";
-import { logVerbose, shouldLogVerbose } from "../globals.js";
-import { recordChannelActivity } from "../infra/channel-activity.js";
-import { loadWebMedia } from "../web/media.js";
+import { getMattermostRuntime } from "../runtime.js";
 import { resolveMattermostAccount } from "./accounts.js";
 import {
   createMattermostClient,
@@ -34,6 +31,8 @@ type MattermostTarget =
 const botUserCache = new Map<string, MattermostUser>();
 const userByNameCache = new Map<string, MattermostUser>();
 
+const getCore = () => getMattermostRuntime();
+
 function cacheKey(baseUrl: string, token: string): string {
   return `${baseUrl}::${token}`;
 }
@@ -129,7 +128,9 @@ export async function sendMessageMattermost(
   text: string,
   opts: MattermostSendOpts = {},
 ): Promise<MattermostSendResult> {
-  const cfg = loadConfig();
+  const core = getCore();
+  const logger = core.logging.getChildLogger({ module: "mattermost" });
+  const cfg = core.config.loadConfig();
   const account = resolveMattermostAccount({
     cfg,
     accountId: opts.accountId,
@@ -161,7 +162,7 @@ export async function sendMessageMattermost(
   const mediaUrl = opts.mediaUrl?.trim();
   if (mediaUrl) {
     try {
-      const media = await loadWebMedia(mediaUrl);
+      const media = await core.media.loadWebMedia(mediaUrl);
       const fileInfo = await uploadMattermostFile(client, {
         channelId,
         buffer: media.buffer,
@@ -171,8 +172,8 @@ export async function sendMessageMattermost(
       fileIds = [fileInfo.id];
     } catch (err) {
       uploadError = err instanceof Error ? err : new Error(String(err));
-      if (shouldLogVerbose()) {
-        logVerbose(
+      if (core.logging.shouldLogVerbose()) {
+        logger.debug?.(
           `mattermost send: media upload failed, falling back to URL text: ${String(err)}`,
         );
       }
@@ -194,7 +195,7 @@ export async function sendMessageMattermost(
     fileIds,
   });
 
-  recordChannelActivity({
+  core.channel.activity.record({
     channel: "mattermost",
     accountId: account.accountId,
     direction: "outbound",
diff --git a/src/channels/plugins/normalize/mattermost.ts b/extensions/mattermost/src/normalize.ts
similarity index 100%
rename from src/channels/plugins/normalize/mattermost.ts
rename to extensions/mattermost/src/normalize.ts
diff --git a/extensions/mattermost/src/onboarding-helpers.ts b/extensions/mattermost/src/onboarding-helpers.ts
new file mode 100644
index 000000000..8a5d1f585
--- /dev/null
+++ b/extensions/mattermost/src/onboarding-helpers.ts
@@ -0,0 +1,42 @@
+import type { ClawdbotConfig, WizardPrompter } from "clawdbot/plugin-sdk";
+import { DEFAULT_ACCOUNT_ID, normalizeAccountId } from "clawdbot/plugin-sdk";
+
+type PromptAccountIdParams = {
+  cfg: ClawdbotConfig;
+  prompter: WizardPrompter;
+  label: string;
+  currentId?: string;
+  listAccountIds: (cfg: ClawdbotConfig) => string[];
+  defaultAccountId: string;
+};
+
+export async function promptAccountId(params: PromptAccountIdParams): Promise<string> {
+  const existingIds = params.listAccountIds(params.cfg);
+  const initial = params.currentId?.trim() || params.defaultAccountId || DEFAULT_ACCOUNT_ID;
+  const choice = (await params.prompter.select({
+    message: `${params.label} account`,
+    options: [
+      ...existingIds.map((id) => ({
+        value: id,
+        label: id === DEFAULT_ACCOUNT_ID ? "default (primary)" : id,
+      })),
+      { value: "__new__", label: "Add a new account" },
+    ],
+    initialValue: initial,
+  })) as string;
+
+  if (choice !== "__new__") return normalizeAccountId(choice);
+
+  const entered = await params.prompter.text({
+    message: `New ${params.label} account id`,
+    validate: (value) => (value?.trim() ? undefined : "Required"),
+  });
+  const normalized = normalizeAccountId(String(entered));
+  if (String(entered).trim() !== normalized) {
+    await params.prompter.note(
+      `Normalized account id to "${normalized}".`,
+      `${params.label} account`,
+    );
+  }
+  return normalized;
+}
diff --git a/src/channels/plugins/onboarding/mattermost.ts b/extensions/mattermost/src/onboarding.ts
similarity index 91%
rename from src/channels/plugins/onboarding/mattermost.ts
rename to extensions/mattermost/src/onboarding.ts
index 3c7ffe2db..431c648ae 100644
--- a/src/channels/plugins/onboarding/mattermost.ts
+++ b/extensions/mattermost/src/onboarding.ts
@@ -1,14 +1,12 @@
-import type { ClawdbotConfig } from "../../../config/config.js";
+import type { ChannelOnboardingAdapter, ClawdbotConfig, WizardPrompter } from "clawdbot/plugin-sdk";
+import { DEFAULT_ACCOUNT_ID, normalizeAccountId } from "clawdbot/plugin-sdk";
+
 import {
   listMattermostAccountIds,
   resolveDefaultMattermostAccountId,
   resolveMattermostAccount,
-} from "../../../mattermost/accounts.js";
-import { DEFAULT_ACCOUNT_ID, normalizeAccountId } from "../../../routing/session-key.js";
-import { formatDocsLink } from "../../../terminal/links.js";
-import type { WizardPrompter } from "../../../wizard/prompts.js";
-import type { ChannelOnboardingAdapter } from "../onboarding-types.js";
-import { promptAccountId } from "./helpers.js";
+} from "./mattermost/accounts.js";
+import { promptAccountId } from "./onboarding-helpers.js";
 
 const channel = "mattermost" as const;
 
@@ -19,7 +17,7 @@ async function noteMattermostSetup(prompter: WizardPrompter): Promise<void> {
       "2) Create a bot + copy its token",
       "3) Use your server base URL (e.g., https://chat.example.com)",
       "Tip: the bot must be a member of any channel you want it to monitor.",
-      `Docs: ${formatDocsLink("/channels/mattermost", "mattermost")}`,
+      "Docs: https://docs.clawd.bot/channels/mattermost",
     ].join("\n"),
     "Mattermost bot token",
   );
diff --git a/extensions/mattermost/src/types.ts b/extensions/mattermost/src/types.ts
new file mode 100644
index 000000000..43e509763
--- /dev/null
+++ b/extensions/mattermost/src/types.ts
@@ -0,0 +1,40 @@
+import type { BlockStreamingCoalesceConfig } from "clawdbot/plugin-sdk";
+
+export type MattermostChatMode = "oncall" | "onmessage" | "onchar";
+
+export type MattermostAccountConfig = {
+  /** Optional display name for this account (used in CLI/UI lists). */
+  name?: string;
+  /** Optional provider capability tags used for agent/runtime guidance. */
+  capabilities?: string[];
+  /** Allow channel-initiated config writes (default: true). */
+  configWrites?: boolean;
+  /** If false, do not start this Mattermost account. Default: true. */
+  enabled?: boolean;
+  /** Bot token for Mattermost. */
+  botToken?: string;
+  /** Base URL for the Mattermost server (e.g., https://chat.example.com). */
+  baseUrl?: string;
+  /**
+   * Controls when channel messages trigger replies.
+   * - "oncall": only respond when mentioned
+   * - "onmessage": respond to every channel message
+   * - "onchar": respond when a trigger character prefixes the message
+   */
+  chatmode?: MattermostChatMode;
+  /** Prefix characters that trigger onchar mode (default: [">", "!"]). */
+  oncharPrefixes?: string[];
+  /** Require @mention to respond in channels. Default: true. */
+  requireMention?: boolean;
+  /** Outbound text chunk size (chars). Default: 4000. */
+  textChunkLimit?: number;
+  /** Disable block streaming for this account. */
+  blockStreaming?: boolean;
+  /** Merge streamed block replies before sending. */
+  blockStreamingCoalesce?: BlockStreamingCoalesceConfig;
+};
+
+export type MattermostConfig = {
+  /** Optional per-account Mattermost configuration (multi-account). */
+  accounts?: Record<string, MattermostAccountConfig>;
+} & MattermostAccountConfig;
diff --git a/src/auto-reply/reply/get-reply-run.ts b/src/auto-reply/reply/get-reply-run.ts
index a2adbf312..524b6ddaf 100644
--- a/src/auto-reply/reply/get-reply-run.ts
+++ b/src/auto-reply/reply/get-reply-run.ts
@@ -159,8 +159,7 @@ export async function runPreparedReply(
   const isGroupChat = sessionCtx.ChatType === "group";
   const originatingChannel =
     (ctx.OriginatingChannel ?? ctx.Surface ?? ctx.Provider)?.toString().toLowerCase() ?? "";
-  const wasMentioned =
-    ctx.WasMentioned === true || (originatingChannel === "mattermost" && isGroupChat);
+  const wasMentioned = ctx.WasMentioned === true;
   const isHeartbeat = opts?.isHeartbeat === true;
   const typingMode = resolveTypingMode({
     configured: sessionCfg?.typingMode ?? agentCfg?.typingMode,
diff --git a/src/channels/dock.ts b/src/channels/dock.ts
index 469880482..81b07c36a 100644
--- a/src/channels/dock.ts
+++ b/src/channels/dock.ts
@@ -12,7 +12,6 @@ import { requireActivePluginRegistry } from "../plugins/runtime.js";
 import {
   resolveDiscordGroupRequireMention,
   resolveIMessageGroupRequireMention,
-  resolveMattermostGroupRequireMention,
   resolveSlackGroupRequireMention,
   resolveTelegramGroupRequireMention,
   resolveWhatsAppGroupRequireMention,
@@ -231,30 +230,6 @@ const DOCKS: Record<ChatChannelId, ChannelDock> = {
       buildToolContext: (params) => buildSlackThreadingToolContext(params),
     },
   },
-  mattermost: {
-    id: "mattermost",
-    capabilities: {
-      chatTypes: ["direct", "channel", "group", "thread"],
-      media: true,
-      threads: true,
-    },
-    outbound: { textChunkLimit: 4000 },
-    streaming: {
-      blockStreamingCoalesceDefaults: { minChars: 1500, idleMs: 1000 },
-    },
-    groups: {
-      resolveRequireMention: resolveMattermostGroupRequireMention,
-    },
-    threading: {
-      buildToolContext: ({ context, hasRepliedRef }) => ({
-        currentChannelId: context.To?.startsWith("channel:")
-          ? context.To.slice("channel:".length)
-          : undefined,
-        currentThreadTs: context.ReplyToId,
-        hasRepliedRef,
-      }),
-    },
-  },
   signal: {
     id: "signal",
     capabilities: {
diff --git a/src/channels/plugins/group-mentions.ts b/src/channels/plugins/group-mentions.ts
index bb7a111e8..79dfa0320 100644
--- a/src/channels/plugins/group-mentions.ts
+++ b/src/channels/plugins/group-mentions.ts
@@ -1,7 +1,6 @@
 import type { ClawdbotConfig } from "../../config/config.js";
 import { resolveChannelGroupRequireMention } from "../../config/group-policy.js";
 import type { DiscordConfig } from "../../config/types.js";
-import { resolveMattermostAccount } from "../../mattermost/accounts.js";
 import { resolveSlackAccount } from "../../slack/accounts.js";
 
 type GroupMentionParams = {
@@ -185,15 +184,6 @@ export function resolveSlackGroupRequireMention(params: GroupMentionParams): boo
   return true;
 }
 
-export function resolveMattermostGroupRequireMention(params: GroupMentionParams): boolean {
-  const account = resolveMattermostAccount({
-    cfg: params.cfg,
-    accountId: params.accountId,
-  });
-  if (typeof account.requireMention === "boolean") return account.requireMention;
-  return true;
-}
-
 export function resolveBlueBubblesGroupRequireMention(params: GroupMentionParams): boolean {
   return resolveChannelGroupRequireMention({
     cfg: params.cfg,
diff --git a/src/channels/registry.ts b/src/channels/registry.ts
index 25fb13502..52e7a5f01 100644
--- a/src/channels/registry.ts
+++ b/src/channels/registry.ts
@@ -9,7 +9,6 @@ export const CHAT_CHANNEL_ORDER = [
   "whatsapp",
   "discord",
   "slack",
-  "mattermost",
   "signal",
   "imessage",
 ] as const;
@@ -68,16 +67,6 @@ const CHAT_CHANNEL_META: Record<ChatChannelId, ChannelMeta> = {
     blurb: "supported (Socket Mode).",
     systemImage: "number",
   },
-  mattermost: {
-    id: "mattermost",
-    label: "Mattermost",
-    selectionLabel: "Mattermost (Bot Token)",
-    detailLabel: "Mattermost Bot",
-    docsPath: "/channels/mattermost",
-    docsLabel: "mattermost",
-    blurb: "self-hosted Slack-style chat (bot token + URL).",
-    systemImage: "bubble.left.and.bubble.right",
-  },
   signal: {
     id: "signal",
     label: "Signal",
diff --git a/src/infra/outbound/deliver.ts b/src/infra/outbound/deliver.ts
index 74caa18c6..2d874d7e9 100644
--- a/src/infra/outbound/deliver.ts
+++ b/src/infra/outbound/deliver.ts
@@ -6,7 +6,6 @@ import type { ChannelOutboundAdapter } from "../../channels/plugins/types.js";
 import type { ClawdbotConfig } from "../../config/config.js";
 import type { sendMessageDiscord } from "../../discord/send.js";
 import type { sendMessageIMessage } from "../../imessage/send.js";
-import type { sendMessageMattermost } from "../../mattermost/send.js";
 import { markdownToSignalTextChunks, type SignalTextStyleRange } from "../../signal/format.js";
 import { sendMessageSignal } from "../../signal/send.js";
 import type { sendMessageSlack } from "../../slack/send.js";
@@ -29,12 +28,18 @@ type SendMatrixMessage = (
   opts?: { mediaUrl?: string; replyToId?: string; threadId?: string; timeoutMs?: number },
 ) => Promise<{ messageId: string; roomId: string }>;
 
+type SendMattermostMessage = (
+  to: string,
+  text: string,
+  opts?: { accountId?: string; mediaUrl?: string; replyToId?: string },
+) => Promise<{ messageId: string; channelId: string }>;
+
 export type OutboundSendDeps = {
   sendWhatsApp?: typeof sendMessageWhatsApp;
   sendTelegram?: typeof sendMessageTelegram;
   sendDiscord?: typeof sendMessageDiscord;
   sendSlack?: typeof sendMessageSlack;
-  sendMattermost?: typeof sendMessageMattermost;
+  sendMattermost?: SendMattermostMessage;
   sendSignal?: typeof sendMessageSignal;
   sendIMessage?: typeof sendMessageIMessage;
   sendMatrix?: SendMatrixMessage;
diff --git a/src/plugin-sdk/index.ts b/src/plugin-sdk/index.ts
index ef8f22d55..1da3650fe 100644
--- a/src/plugin-sdk/index.ts
+++ b/src/plugin-sdk/index.ts
@@ -81,7 +81,6 @@ export type {
 export {
   DiscordConfigSchema,
   IMessageConfigSchema,
-  MattermostConfigSchema,
   MSTeamsConfigSchema,
   SignalConfigSchema,
   SlackConfigSchema,
@@ -121,7 +120,6 @@ export {
   resolveBlueBubblesGroupRequireMention,
   resolveDiscordGroupRequireMention,
   resolveIMessageGroupRequireMention,
-  resolveMattermostGroupRequireMention,
   resolveSlackGroupRequireMention,
   resolveTelegramGroupRequireMention,
   resolveWhatsAppGroupRequireMention,
@@ -241,21 +239,6 @@ export {
 } from "../channels/plugins/normalize/slack.js";
 export { buildSlackThreadingToolContext } from "../slack/threading-tool-context.js";
 
-// Channel: Mattermost
-export {
-  listEnabledMattermostAccounts,
-  listMattermostAccountIds,
-  resolveDefaultMattermostAccountId,
-  resolveMattermostAccount,
-  type ResolvedMattermostAccount,
-} from "../mattermost/accounts.js";
-export { normalizeMattermostBaseUrl } from "../mattermost/client.js";
-export { mattermostOnboardingAdapter } from "../channels/plugins/onboarding/mattermost.js";
-export {
-  looksLikeMattermostTargetId,
-  normalizeMattermostMessagingTarget,
-} from "../channels/plugins/normalize/mattermost.js";
-
 // Channel: Telegram
 export {
   listTelegramAccountIds,
diff --git a/src/plugins/runtime/index.ts b/src/plugins/runtime/index.ts
index e564ad2f8..4765c71c7 100644
--- a/src/plugins/runtime/index.ts
+++ b/src/plugins/runtime/index.ts
@@ -57,9 +57,6 @@ import { enqueueSystemEvent } from "../../infra/system-events.js";
 import { monitorIMessageProvider } from "../../imessage/monitor.js";
 import { probeIMessage } from "../../imessage/probe.js";
 import { sendMessageIMessage } from "../../imessage/send.js";
-import { monitorMattermostProvider } from "../../mattermost/monitor.js";
-import { probeMattermost } from "../../mattermost/probe.js";
-import { sendMessageMattermost } from "../../mattermost/send.js";
 import { shouldLogVerbose } from "../../globals.js";
 import { getChildLogger } from "../../logging.js";
 import { normalizeLogLevel } from "../../logging/levels.js";
@@ -233,11 +230,6 @@ export function createPluginRuntime(): PluginRuntime {
         monitorSlackProvider,
         handleSlackAction,
       },
-      mattermost: {
-        probeMattermost,
-        sendMessageMattermost,
-        monitorMattermostProvider,
-      },
       telegram: {
         auditGroupMembership: auditTelegramGroupMembership,
         collectUnmentionedGroupIds: collectTelegramUnmentionedGroupIds,
diff --git a/src/plugins/runtime/types.ts b/src/plugins/runtime/types.ts
index 31350693c..089e20c37 100644
--- a/src/plugins/runtime/types.ts
+++ b/src/plugins/runtime/types.ts
@@ -98,10 +98,6 @@ type ResolveSlackUserAllowlist =
 type SendMessageSlack = typeof import("../../slack/send.js").sendMessageSlack;
 type MonitorSlackProvider = typeof import("../../slack/index.js").monitorSlackProvider;
 type HandleSlackAction = typeof import("../../agents/tools/slack-actions.js").handleSlackAction;
-type ProbeMattermost = typeof import("../../mattermost/probe.js").probeMattermost;
-type SendMessageMattermost = typeof import("../../mattermost/send.js").sendMessageMattermost;
-type MonitorMattermostProvider =
-  typeof import("../../mattermost/monitor.js").monitorMattermostProvider;
 type AuditTelegramGroupMembership =
   typeof import("../../telegram/audit.js").auditTelegramGroupMembership;
 type CollectTelegramUnmentionedGroupIds =
@@ -246,11 +242,6 @@ export type PluginRuntime = {
       monitorSlackProvider: MonitorSlackProvider;
       handleSlackAction: HandleSlackAction;
     };
-    mattermost: {
-      probeMattermost: ProbeMattermost;
-      sendMessageMattermost: SendMessageMattermost;
-      monitorMattermostProvider: MonitorMattermostProvider;
-    };
     telegram: {
       auditGroupMembership: AuditTelegramGroupMembership;
       collectUnmentionedGroupIds: CollectTelegramUnmentionedGroupIds;
diff --git a/ui/src/ui/views/channels.ts b/ui/src/ui/views/channels.ts
index 96a6b8556..d9f148764 100644
--- a/ui/src/ui/views/channels.ts
+++ b/ui/src/ui/views/channels.ts
@@ -101,7 +101,7 @@ function resolveChannelOrder(snapshot: ChannelsStatusSnapshot | null): ChannelKe
   if (snapshot?.channelOrder?.length) {
     return snapshot.channelOrder;
   }
-  return ["whatsapp", "telegram", "discord", "slack", "mattermost", "signal", "imessage", "nostr"];
+  return ["whatsapp", "telegram", "discord", "slack", "signal", "imessage", "nostr"];
 }
 
 function renderChannel(