SendMessage to a cloud session says "one-way for now … do not ask it to reply here", but the cloud session can reply via Remote send_message

Summary

When a local Claude Desktop (Code tab) session sends a message to a cloud session with the built-in SendMessage tool, the tool result says the route is one-way and tells the model not to ask for a reply:

… a Claude session running in the cloud; not confirmed read — that session may hold it (different permission mode: its user must approve first) or refuse it, and this route reports nothing back; one-way for now: a cloud session cannot message other sessions back yet — do not ask it to reply here; its response appears in its own transcript at claude.ai/code

In practice the cloud session can and does reply: it uses the Claude Code Remote MCP send_message tool, and the reply arrives in the local session as a normal user turn wrapped in <cross-session-message from-session="session_…">. So the instruction "do not ask it to reply" is misleading — models that follow it stop requesting replies that would in fact arrive, and they report the channel to the user as one-way.

Steps to reproduce

1. Have a local Claude Desktop Code session (Remote Control connected) and a cloud session (claude.ai/code) on the same account.
2. From the local session, call ListAgents, then SendMessage to the cloud session's name (listed with kind cloud).
3. Observe the tool result text quoted above.
4. In the cloud session, reply with the Claude Code Remote MCP send_message tool addressed to the local session.
5. The reply is delivered to the local session as a user turn (<cross-session-message from-session="session_…">).

Observed

• 2026-10-02 16:03 KST: local → cloud SendMessage returned the "one-way for now … do not ask it to reply here" text. At 16:04 the cloud session's reply arrived in the same local session as a user turn.
• Same round trip observed several times between 2026-10-01 and 2026-10-02 across four different local sessions (the reply woke idle local sessions as well).
• The wording caused repeated wrong conclusions: models wrote "cloud is one-way, do not attach reply requests" into shared instructions and reports, which then had to be corrected by hand.

Expected

The tool result should describe what is actually true, for example:

• "A reply cannot come back over this same route; the cloud session can reply through its own Remote tools, and that reply will arrive here as a cross-session message", or
• drop the "do not ask it to reply here" instruction when the target cloud session has the Remote send_message tool available.

Environment

• Claude Code 2.1.286 inside the Claude desktop app (Code tab), Windows 11
• Local session: Remote Control enabled; target: cloud session on the same account
• Tools involved: built-in ListAgents / SendMessage (local → cloud), Claude Code Remote MCP send_message (cloud → local)