session/load support is currently broken

[catern]

e2505ae (from #345 ) broke session/load support; the replayed agent messages from the ACP server are put in Messages instead of inserted into the agent-shell buffer.

Specifically all agent message are dropped because of this:

           ;; Notification is out of context (session/prompt finished).
           ;; Cannot derive where to display, so show in minibuffer.
           (if (not (shell-maker-busy))
               (message "%s %s (stale, consider reporting to ACP agent)"
                        (agent-shell--make-status-kind-label
                         :status (map-nested-elt acp-notification '(params update status))
                         :kind (map-nested-elt acp-notification '(params update kind)))
                        (propertize (or (map-nested-elt acp-notification '(params update title)) "")
                                    'face font-lock-doc-markup-face))

This happens for both claude-agent-acp and for my own ACP server.

Checklist

• I agree to communicate with the author myself (not AI-generated).
• I've read the README's Filing issues section.
• I'm running the latest versions (fill in below).
  • agent-shell:
  • acp.el:
  • ACP package (e.g. claude-code-acp):
  • Agent CLI (e.g. claude, gemini):
• For requesting new agent support, I'm including a link to the ACP-capable agent or related ACP package.
• For issues, I'm including ACP traffic (as per README).

[xenodium]

Thanks for filing. Could you share a traffic file reproducing the issue?

[xenodium]

Thanks for filing. Could you share a traffic file reproducing the issue?

Nevermind. Managed to reproduce.

[xenodium]

4ad3dc9 should fix it. Please give that a try.

[catern]

Yes, that seems to fix it for me. Thanks!

[catern]

Actually, while session/load is working, another closely related thing is still broken due to e2505ae : the agent emitting messages while the user hasn't submitted a prompt. In claude-agent-acp or in my agent, this happens when agent-shell is connected to a session which is prompted by some other connected client; then the messages from the agent are broadcast to agent-shell even though it didn't send a prompt. Before e2505ae this worked okay, though it had bugs; now it doesn't work at all.

[xenodium]

Been looking more into this space as agent bugs were resulting in unusable shell prompts (populated with our of turn data). The spec seems to be fairly explicit about keeping notification updates within prompt turns https://agentclientprotocol.com/protocol/prompt-turn

For example:

The Agent MAY send session/update notifications with content or tool call updates after receiving the session/cancel notification, but it MUST ensure that it does so before responding to the session/prompt request.

In claude-agent-acp or in my agent, this happens when agent-shell is connected to a session which is prompted by some other connected client

Wrt claude-agent-acp, out of turn updates look like a bug on their ACP implementation. There's a PR opened at agentclientprotocol/claude-agent-acp#353

I noticed these sorts of breaks before, but were later fixed by agents. Have you updated claude-agent-acp recently?

Wrt the other agent working before, this is starting to look like a happy accident since agent-shell was less strict about update notifications. At the moment, we're looking at a tradeoff between agent-shell resilience (when agents inadvertently send out-of-turn updates) and always inserting out of turn updates. Lemme have a further think about how we can potentially enable your use case. Maybe discuss in a separate issue or email. Are you ok to close this issue, as session loading is working again?

[catern]

Yes, let's close this, as you're right, session/load is working again now.