fix: guard provider-prefixed delivery targets

docs/.generated/plugin-sdk-api-baseline.sha256

@@ -1,2 +1,2 @@
-0f9284c6349bf03d3d89c1d25031031840dae4ade032622ca212240ed19829f6  plugin-sdk-api-baseline.json
-33706cf425386717973cc87357ae5e0df432dd5a519b4faea8b38e21d7daae78  plugin-sdk-api-baseline.jsonl
+1fbd0ea7f65901d96653458ba414f9ac69dc0142ff3772e48d63de8b9fa5567f  plugin-sdk-api-baseline.json
+2d29f4e632b05bd365f414096c87a2a3d9718f13fdbf9538824cb32db2902436  plugin-sdk-api-baseline.jsonl

docs/automation/cron-jobs.md

@@ -158,6 +158,8 @@ Before an isolated cron run enters the agent runner, OpenClaw checks reachable l
 
 Use `--announce --channel telegram --to "-1001234567890"` for channel delivery. For Telegram forum topics, use `-1001234567890:topic:123`; direct RPC/config callers may also pass `delivery.threadId` as a string or number. Slack/Discord/Mattermost targets should use explicit prefixes (`channel:<id>`, `user:<id>`). Matrix room IDs are case-sensitive; use the exact room ID or `room:!room:server` form from Matrix.
 
+When announce delivery uses `channel: "last"` or omits `channel`, a provider-prefixed target such as `telegram:123` can select the channel before cron falls back to session history or a single configured channel. Only prefixes advertised by the loaded plugin are provider selectors. If `delivery.channel` is explicit, the target prefix must name the same provider; for example, `channel: "whatsapp"` with `to: "telegram:123"` is rejected instead of letting WhatsApp interpret the Telegram ID as a phone number. Target-kind and service prefixes such as `channel:<id>`, `user:<id>`, `imessage:<handle>`, and `sms:<number>` remain channel-owned target syntax, not provider selectors.
+
 For isolated jobs, chat delivery is shared. If a chat route is available, the agent can use the `message` tool even when the job uses `--no-deliver`. If the agent sends to the configured/current target, OpenClaw skips the fallback announce. Otherwise `announce`, `webhook`, and `none` only control what the runner does with the final reply after the agent turn.
 
 When an agent creates an isolated reminder from an active chat, OpenClaw stores the preserved live delivery target for the fallback announce route. Internal session keys may be lowercase; provider delivery targets are not reconstructed from those keys when current chat context is available.

docs/channels/channel-routing.md

@@ -21,6 +21,12 @@ host configuration.
 - **AgentId**: an isolated workspace + session store (“brain”).
 - **SessionKey**: the bucket key used to store context and control concurrency.
 
+## Outbound target prefixes
+
+Explicit outbound targets may include a provider prefix, such as `telegram:123` or `tg:123`. Core treats that prefix as a channel-selection hint only when the selected channel is `last` or otherwise unresolved, and only when the loaded plugin advertises that prefix. If the caller already selected an explicit channel, the provider prefix must match that channel; cross-channel combinations such as WhatsApp delivery to `telegram:123` fail before plugin-specific target normalization.
+
+Target-kind and service prefixes such as `channel:<id>`, `user:<id>`, `room:<id>`, `thread:<id>`, `imessage:<handle>`, and `sms:<number>` stay inside the selected channel's grammar. They do not select the provider by themselves.
+
 ## Session key shapes (examples)
 
 Direct messages collapse to the agent’s **main** session by default:

docs/channels/synology-chat.md

@@ -110,6 +110,7 @@ Examples:
 ```bash
 openclaw message send --channel synology-chat --target 123456 --text "Hello from OpenClaw"
 openclaw message send --channel synology-chat --target synology-chat:123456 --text "Hello again"
+openclaw message send --channel synology-chat --target synology:123456 --text "Short prefix"
 ```
 
 Media sends are supported by URL-based file delivery.

docs/cli/cron.md

@@ -35,6 +35,8 @@ Run `openclaw cron --help` for the full command surface. See [Cron jobs](/automa
 
 `openclaw cron list` and `openclaw cron show <job-id>` preview the resolved delivery route. For `channel: "last"`, the preview shows whether the route resolved from the main or current session, or will fail closed.
 
+Provider-prefixed targets can disambiguate unresolved announce channels. For example, `to: "telegram:123"` selects Telegram when `delivery.channel` is omitted or `last`. Only prefixes advertised by the loaded plugin are provider selectors. If `delivery.channel` is explicit, the prefix must match that channel; `channel: "whatsapp"` with `to: "telegram:123"` is rejected. Service prefixes such as `imessage:` and `sms:` remain channel-owned target syntax.
+
 <Note>
 Isolated `cron add` jobs default to `--announce` delivery. Use `--no-deliver` to keep output internal. `--deliver` remains as a deprecated alias for `--announce`.
 </Note>