feat: per-channel responsePrefix override (#9001)

* feat: per-channel responsePrefix override

Add responsePrefix field to all channel config types and Zod schemas,
enabling per-channel and per-account outbound response prefix overrides.

Resolution cascade (most specific wins):
  L1: channels.<ch>.accounts.<id>.responsePrefix
  L2: channels.<ch>.responsePrefix
  L3: (reserved for channels.defaults)
  L4: messages.responsePrefix (existing global)

Semantics:
  - undefined -> inherit from parent level
  - empty string -> explicitly no prefix (stops cascade)
  - "auto" -> derive [identity.name] from routed agent

Changes:
  - Core logic: resolveResponsePrefix() in identity.ts accepts
    optional channel/accountId and walks the cascade
  - resolveEffectiveMessagesConfig() passes channel context through
  - Types: responsePrefix added to WhatsApp, Telegram, Discord, Slack,
    Signal, iMessage, Google Chat, MS Teams, Feishu, BlueBubbles configs
  - Zod schemas: responsePrefix added for config validation
  - All channel handlers wired: telegram, discord, slack, signal,
    imessage, line, heartbeat runner, route-reply, native commands
  - 23 new tests covering backward compat, channel/account levels,
    full cascade, auto keyword, empty string stops, unknown fallthrough

Fully backward compatible - no existing config is affected.
Fixes #8857

* fix: address CI lint + review feedback

- Replace Record<string, any> with proper typed helpers (no-explicit-any)
- Add curly braces to single-line if returns (eslint curly)
- Fix JSDoc: 'Per-channel' → 'channel/account' on shared config types
- Extract getChannelConfig() helper for type-safe dynamic key access

* fix: finish responsePrefix overrides (#9001) (thanks @mudrii)

* fix: normalize prefix wiring and types (#9001) (thanks @mudrii)

---------

Co-authored-by: Gustavo Madeira Santana <gumadeiras@gmail.com>

extensions/mattermost/src/channel.test.ts

@@ -1,3 +1,5 @@
+import type { OpenClawConfig } from "openclaw/plugin-sdk";
+import { createReplyPrefixOptions } from "openclaw/plugin-sdk";
 import { describe, expect, it } from "vitest";
 import { mattermostPlugin } from "./channel.js";
 
@@ -44,5 +46,27 @@ describe("mattermostPlugin", () => {
       });
       expect(formatted).toEqual(["@alice", "user123", "bot999"]);
     });
+
+    it("uses account responsePrefix overrides", () => {
+      const cfg: OpenClawConfig = {
+        channels: {
+          mattermost: {
+            responsePrefix: "[Channel]",
+            accounts: {
+              default: { responsePrefix: "[Account]" },
+            },
+          },
+        },
+      };
+
+      const prefixContext = createReplyPrefixOptions({
+        cfg,
+        agentId: "main",
+        channel: "mattermost",
+        accountId: "default",
+      });
+
+      expect(prefixContext.responsePrefix).toBe("[Account]");
+    });
   });
 });

extensions/mattermost/src/config-schema.ts

@@ -27,6 +27,7 @@ const MattermostAccountSchemaBase = z
     chunkMode: z.enum(["length", "newline"]).optional(),
     blockStreaming: z.boolean().optional(),
     blockStreamingCoalesce: BlockStreamingCoalesceSchema.optional(),
+    responsePrefix: z.string().optional(),
   })
   .strict();
 

extensions/mattermost/src/mattermost/monitor.ts

@@ -5,7 +5,7 @@ import type {
   RuntimeEnv,
 } from "openclaw/plugin-sdk";
 import {
-  createReplyPrefixContext,
+  createReplyPrefixOptions,
   createTypingCallbacks,
   logInboundDrop,
   logTypingFailure,
@@ -760,7 +760,12 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       accountId: account.accountId,
     });
 
-    const prefixContext = createReplyPrefixContext({ cfg, agentId: route.agentId });
+    const { onModelSelected, ...prefixOptions } = createReplyPrefixOptions({
+      cfg,
+      agentId: route.agentId,
+      channel: "mattermost",
+      accountId: account.accountId,
+    });
 
     const typingCallbacks = createTypingCallbacks({
       start: () => sendTypingIndicator(channelId, threadRootId),
@@ -775,8 +780,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
     });
     const { dispatcher, replyOptions, markDispatchIdle } =
       core.channel.reply.createReplyDispatcherWithTyping({
-        responsePrefix: prefixContext.responsePrefix,
-        responsePrefixContextProvider: prefixContext.responsePrefixContextProvider,
+        ...prefixOptions,
         humanDelay: core.channel.reply.resolveHumanDelayConfig(cfg, route.agentId),
         deliver: async (payload: ReplyPayload) => {
           const mediaUrls = payload.mediaUrls ?? (payload.mediaUrl ? [payload.mediaUrl] : []);
@@ -825,7 +829,7 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
         ...replyOptions,
         disableBlockStreaming:
           typeof account.blockStreaming === "boolean" ? !account.blockStreaming : undefined,
-        onModelSelected: prefixContext.onModelSelected,
+        onModelSelected,
       },
     });
     markDispatchIdle();

extensions/mattermost/src/types.ts

@@ -42,6 +42,8 @@ export type MattermostAccountConfig = {
   blockStreaming?: boolean;
   /** Merge streamed block replies before sending. */
   blockStreamingCoalesce?: BlockStreamingCoalesceConfig;
+  /** Outbound response prefix override for this channel/account. */
+  responsePrefix?: string;
 };
 
 export type MattermostConfig = {