Support queued pending messages while a session is still running

[webwww123]

Summary

Please support a pending / queued send workflow similar to Codex / Claude Code:

• if I send a new message while the agent is still working on the previous turn,
• the new message should be queued and automatically sent after the current turn completes.

Actual behavior

The web UI currently blocks extra sends while a send is already pending / resolving.

Expected behavior

• Allow multiple user messages to be queued in order.
• Show that they are queued / pending.
• Automatically flush the queue when the previous turn is done.

Why this matters

This is very useful when supervising long-running coding sessions. I often know the next instruction before the current response finishes.

[github-actions]

I checked the current implementation, and this feature is not in the web UI yet.

Right now the web client explicitly blocks a second send while the first send is still in flight. useSendMessage() returns early with onBlocked('pending') when a message mutation or session-resume is already pending, and the chat composer/runtime are disabled from the same isSending state. I also did not find any outbound message queue in web/src, so there is currently no queued/pending-send workflow in the PWA.

On the backend side, I did not find the same restriction. The message route accepts a POST, forwards it to engine.sendMessage(...), and MessageService stores and broadcasts the user message. On the CLI side, incoming user messages are already fed into agent message queues for Codex/Claude. Based on the current code, this looks like a real web UX gap rather than a hub/CLI protocol limitation.

Relevant code:

• web/src/hooks/mutations/useSendMessage.ts:104 - blocks a second send when a send or session-resolution is already pending
• web/src/components/SessionChat.tsx:314 - disables the composer while isSending is true
• web/src/lib/assistant-runtime.ts:200 - disables the assistant runtime while isSending is true
• hub/src/web/routes/messages.ts:40 - message endpoint validates input and forwards to engine.sendMessage(...)
• hub/src/sync/messageService.ts:66 - stores and broadcasts each submitted user message
• cli/src/codex/runCodex.ts:74 - Codex path pushes received user messages into its message queue
• cli/src/claude/runClaude.ts:162 - Claude path receives user messages and routes them into its queue

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HAPI Bot