`agent-shell-get-config` does not work in an `agent-shell-command-prefix` function

[lucius-martius]

Description

The code example in the readme describes the following to get a command-prefix specific for an agent type:

agent-shell/README.org

Lines 486 to 492 in 30fe4bd

	(setq agent-shell-command-prefix
	(lambda (buffer)
	(let ((config (agent-shell-get-config buffer)))
	(pcase (map-elt config :identifier)
	('claude-code '("docker" "exec" "claude-dev" "--"))
	('gemini-cli '("docker" "exec" "gemini-dev" "--"))
	(_ '("devcontainer" "exec" "."))))))

This currently does not work and (agent-shell-get-config buffer) always returns nil inside such a function.

(Correction: The function seems to get called twice, with (agent-shell-get-config buffer) returning nil the first time and the proper config the second time. This is still a valid issue however.)

The reason is likely that agent-shell--state is only filled after the client-maker has already been called, which in turn eventually calls the function in agent-shell-command-prefix with an empty agent-shell--state form:

agent-shell/agent-shell.el

Lines 2743 to 2750 in 30fe4bd

	(let ((command (map-elt (funcall (map-elt config :client-maker) (current-buffer)) :command)))
	(unless (executable-find command)
	(kill-buffer shell-buffer)
	(error "%s" (agent-shell--make-missing-executable-error
	:executable command
	:install-instructions (map-elt config :install-instructions)))))
	;; Initialize buffer-local state
	(setq-local agent-shell--state (agent-shell--make-state

So either the readme is wrong/outdated and we need to get the agent identifier in a different way (though I can't think of a non-hacky way off the top of my head), or this is a bug/regression.

Sidenote: A function that returns a command-prefix unconditionally works as expected.

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 version: 20260507.1212
  • acp.el version: 20260503.1815
  • ACP package (e.g. claude-agent-acp) version: any
  • Agent CLI (e.g. claude, gemini) version: any
• 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 reporting and providing details.

fbb6fd8 should fix it. Can you try and report back please?

[lucius-martius]

It works as expected now. It looks like the function is called three times (not just twice, like I wrote before) and getting the same plist value returned for config each time. Thanks for the quick fix.

[xenodium]

It works as expected now.

Glad to hear. Thaks for reporting back. If you're getting value out of agent-shell, consider sponsoring so I can make this project sustainable. I'm easing back into agent-shell since #500 and my available time is competing with other activities that help pay the bills.