Bug Description

sessions_send from one agent to another changes the target session's channel field in sessions.json from "telegram" to "webchat". This breaks Telegram message routing — the target agent stops receiving Telegram messages from the user.

Steps to Reproduce

1. Agent A (main) has a running session on Telegram
2. Agent B (builder) has a running session on Telegram (channel: "telegram" in sessions.json)
3. Agent A calls sessions_send(sessionKey="agent:builder:main", message="...")
4. Builder processes the message and responds
5. After this, builder's session in ~/.clawdbot/agents/builder/sessions/sessions.json shows "channel": "webchat" instead of "telegram"
6. User sends a message to the builder Telegram bot → no response (message not routed to the session)

Expected Behavior

sessions_send should not modify the target session's channel field. The delivery context should remain unchanged — the session should continue to be associated with its original channel (Telegram).

Actual Behavior

The channel field is overwritten to "webchat" because sessions_send injects the message via the gateway (webchat transport), and this overwrites the session's channel association.

Workaround

Manually edit sessions.json to restore "channel": "telegram" and restart the gateway. This is fragile and not suitable for automation.

Impact

This prevents using sessions_send for agent-to-agent communication when the target agent uses Telegram. It breaks a key use case: a watchdog/supervisor agent relaunching a worker agent.

Environment

• Clawdbot version: 2026.1.24-3
• OS: Linux (Ubuntu)
• Channel: Telegram
• Config: agentToAgent enabled, multiple agents with separate Telegram bot accounts