fix(auto-reply/chunk): honor webchat textChunkLimit/chunkMode config

luyao618 · luyao618 · commit 6778aad0004f · 2026-05-19T01:26:13.000+08:00
The webchat channel was explicitly bypassed in resolveTextChunkLimit and resolveChunkMode, hardcoding the 4000-char default and ignoring any channels.webchat.textChunkLimit override in user config. This made long WebChat assistant responses get cut at ~4000 chars with no escape hatch. Drop the INTERNAL_MESSAGE_CHANNEL special-case so webchat goes through the same provider config lookup as every other channel. The 4000-char fallback still applies when no override is configured, preserving existing behavior for users who do not set channels.webchat.textChunkLimit. Closes #83658
diff --git a/src/auto-reply/chunk.test.ts b/src/auto-reply/chunk.test.ts
@@ -330,6 +330,26 @@ describe("resolveTextChunkLimit", () => {
       options: undefined,
       expected: 4000,
     },
+    {
+      name: "honors webchat textChunkLimit override from config",
+      cfg: {
+        channels: {
+          webchat: { textChunkLimit: 16000 },
+        },
+      },
+      provider: "webchat" as const,
+      accountId: undefined,
+      options: undefined,
+      expected: 16000,
+    },
+    {
+      name: "falls back to default when webchat has no override",
+      cfg: { channels: {} },
+      provider: "webchat" as const,
+      accountId: undefined,
+      options: undefined,
+      expected: 4000,
+    },
   ] as const)("$name", ({ cfg, provider, accountId, options, expected }) => {
     expect(resolveTextChunkLimit(cfg as never, provider, accountId, options)).toBe(expected);
   });
@@ -584,6 +604,12 @@ describe("resolveChunkMode", () => {
     { cfg: providerCfg, provider: "discord", accountId: undefined, expected: "length" },
     { cfg: accountCfg, provider: "slack", accountId: "primary", expected: "newline" },
     { cfg: accountCfg, provider: "slack", accountId: "other", expected: "length" },
+    {
+      cfg: { channels: { webchat: { chunkMode: "newline" as const } } },
+      provider: "webchat",
+      accountId: undefined,
+      expected: "newline",
+    },
   ] as const)(
     "resolves default/provider/account/internal chunk mode for $provider $accountId",
     ({ cfg, provider, accountId, expected }) => {
diff --git a/src/auto-reply/chunk.ts b/src/auto-reply/chunk.ts
@@ -9,7 +9,6 @@ import { resolveChannelStreamingChunkMode } from "../plugin-sdk/channel-streamin
 import { resolveAccountEntry } from "../routing/account-lookup.js";
 import { normalizeAccountId } from "../routing/session-key.js";
 import { chunkTextByBreakResolver } from "../shared/text-chunking.js";
-import { INTERNAL_MESSAGE_CHANNEL } from "../utils/message-channel.js";
 
 export type TextChunkProvider = ChannelId;
 
@@ -64,7 +63,7 @@ export function resolveTextChunkLimit(
       ? opts.fallbackLimit
       : DEFAULT_CHUNK_LIMIT;
   const providerOverride = (() => {
-    if (!provider || provider === INTERNAL_MESSAGE_CHANNEL) {
+    if (!provider) {
       return undefined;
     }
     const channelsConfig = cfg?.channels as Record<string, unknown> | undefined;
@@ -102,7 +101,7 @@ export function resolveChunkMode(
   provider?: TextChunkProvider,
   accountId?: string | null,
 ): ChunkMode {
-  if (!provider || provider === INTERNAL_MESSAGE_CHANNEL) {
+  if (!provider) {
     return DEFAULT_CHUNK_MODE;
   }
   const channelsConfig = cfg?.channels as Record<string, unknown> | undefined;
