fix(channels): add optional defaultAccount routing

docs/channels/channel-routing.md

@@ -15,6 +15,8 @@ host configuration.
 
 - **Channel**: `whatsapp`, `telegram`, `discord`, `slack`, `signal`, `imessage`, `webchat`.
 - **AccountId**: per‑channel account instance (when supported).
+- Optional channel default account: `channels.<channel>.defaultAccount` chooses
+  which account is used when an outbound path does not specify `accountId`.
 - **AgentId**: an isolated workspace + session store (“brain”).
 - **SessionKey**: the bucket key used to store context and control concurrency.
 

docs/concepts/multi-agent.md

@@ -197,6 +197,16 @@ Channels that support **multiple accounts** (e.g. WhatsApp) use `accountId` to i
 each login. Each `accountId` can be routed to a different agent, so one server can host
 multiple phone numbers without mixing sessions.
 
+If you want a channel-wide default account when `accountId` is omitted, set
+`channels.<channel>.defaultAccount` (optional). When unset, OpenClaw falls back
+to `default` if present, otherwise the first configured account id (sorted).
+
+Common channels supporting this pattern include:
+
+- `whatsapp`, `telegram`, `discord`, `slack`, `signal`, `imessage`
+- `irc`, `line`, `googlechat`, `mattermost`, `matrix`, `nextcloud-talk`
+- `bluebubbles`, `zalo`, `zalouser`, `nostr`, `feishu`
+
 ## Concepts
 
 - `agentId`: one “brain” (workspace, per-agent auth, per-agent session store).

docs/gateway/configuration-reference.md

@@ -143,6 +143,7 @@ WhatsApp runs through the gateway's web channel (Baileys Web). It starts automat
 ```
 
 - Outbound commands default to account `default` if present; otherwise the first configured account id (sorted).
+- Optional `channels.whatsapp.defaultAccount` overrides that fallback default account selection when it matches a configured account id.
 - Legacy single-account Baileys auth dir is migrated by `openclaw doctor` into `whatsapp/default`.
 - Per-account overrides: `channels.whatsapp.accounts.<id>.sendReadReceipts`, `channels.whatsapp.accounts.<id>.dmPolicy`, `channels.whatsapp.accounts.<id>.allowFrom`.
 
@@ -203,6 +204,7 @@ WhatsApp runs through the gateway's web channel (Baileys Web). It starts automat
 ```
 
 - Bot token: `channels.telegram.botToken` or `channels.telegram.tokenFile`, with `TELEGRAM_BOT_TOKEN` as fallback for the default account.
+- Optional `channels.telegram.defaultAccount` overrides default account selection when it matches a configured account id.
 - `configWrites: false` blocks Telegram-initiated config writes (supergroup ID migrations, `/config set|unset`).
 - Telegram stream previews use `sendMessage` + `editMessageText` (works in direct and group chats).
 - Retry policy: see [Retry policy](/concepts/retry).
@@ -299,6 +301,7 @@ WhatsApp runs through the gateway's web channel (Baileys Web). It starts automat
 ```
 
 - Token: `channels.discord.token`, with `DISCORD_BOT_TOKEN` as fallback for the default account.
+- Optional `channels.discord.defaultAccount` overrides default account selection when it matches a configured account id.
 - Use `user:<id>` (DM) or `channel:<id>` (guild channel) for delivery targets; bare numeric IDs are rejected.
 - Guild slugs are lowercase with spaces replaced by `-`; channel keys use the slugged name (no `#`). Prefer guild IDs.
 - Bot-authored messages are ignored by default. `allowBots: true` enables them (own messages still filtered).
@@ -410,6 +413,7 @@ WhatsApp runs through the gateway's web channel (Baileys Web). It starts automat
 - **Socket mode** requires both `botToken` and `appToken` (`SLACK_BOT_TOKEN` + `SLACK_APP_TOKEN` for default account env fallback).
 - **HTTP mode** requires `botToken` plus `signingSecret` (at root or per-account).
 - `configWrites: false` blocks Slack-initiated config writes.
+- Optional `channels.slack.defaultAccount` overrides default account selection when it matches a configured account id.
 - `channels.slack.streaming` is the canonical stream mode key. Legacy `streamMode` and boolean `streaming` values are auto-migrated.
 - Use `user:<id>` (DM) or `channel:<id>` for delivery targets.
 
@@ -450,6 +454,7 @@ Chat modes: `oncall` (respond on @-mention, default), `onmessage` (every message
 
 - `channels.mattermost.configWrites`: allow or deny Mattermost-initiated config writes.
 - `channels.mattermost.requireMention`: require `@mention` before replying in channels.
+- Optional `channels.mattermost.defaultAccount` overrides default account selection when it matches a configured account id.
 
 ### Signal
 
@@ -474,6 +479,7 @@ Chat modes: `oncall` (respond on @-mention, default), `onmessage` (every message
 
 - `channels.signal.account`: pin channel startup to a specific Signal account identity.
 - `channels.signal.configWrites`: allow or deny Signal-initiated config writes.
+- Optional `channels.signal.defaultAccount` overrides default account selection when it matches a configured account id.
 
 ### BlueBubbles
 
@@ -493,6 +499,7 @@ BlueBubbles is the recommended iMessage path (plugin-backed, configured under `c
 ```
 
 - Core key paths covered here: `channels.bluebubbles`, `channels.bluebubbles.dmPolicy`.
+- Optional `channels.bluebubbles.defaultAccount` overrides default account selection when it matches a configured account id.
 - Full BlueBubbles channel configuration is documented in [BlueBubbles](/channels/bluebubbles).
 
 ### iMessage
@@ -521,6 +528,8 @@ OpenClaw spawns `imsg rpc` (JSON-RPC over stdio). No daemon or port required.
 }
 ```
 
+- Optional `channels.imessage.defaultAccount` overrides default account selection when it matches a configured account id.
+
 - Requires Full Disk Access to the Messages DB.
 - Prefer `chat_id:<id>` targets. Use `imsg chats --limit 20` to list chats.
 - `cliPath` can point to an SSH wrapper; set `remoteHost` (`host` or `user@host`) for SCP attachment fetching.
@@ -581,6 +590,7 @@ IRC is extension-backed and configured under `channels.irc`.
 ```
 
 - Core key paths covered here: `channels.irc`, `channels.irc.dmPolicy`, `channels.irc.configWrites`, `channels.irc.nickserv.*`.
+- Optional `channels.irc.defaultAccount` overrides default account selection when it matches a configured account id.
 - Full IRC channel configuration (host/port/TLS/channels/allowlists/mention gating) is documented in [IRC](/channels/irc).
 
 ### Multi-account (all channels)