Add Opencode support as a new backend (#20)

* Initial plan

* Add opencode support to ai-code-interface.el

Co-authored-by: tninja <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: tninja <[email protected]>

Author: Copilot

README.org

@@ -7,6 +7,7 @@ An Emacs interface for AI-assisted software development. *The purpose is to prov
   - [[https://github.com/google-gemini/gemini-cli][Gemini CLI]]
   - [[https://github.com/openai/codex][OpenAI Codex]]
   - [[https://docs.github.com/en/copilot/how-tos/use-copilot-agents/use-copilot-cli][GitHub Copilot CLI]]
+  - [[https://opencode.ai/][Opencode]]
 
 - I switch across different CLI based AI tool in emacs: Claude Code / Gemini CLI / Aider / OpenAI Codex. If you also use different AI tools inside emacs, but want to keep same user interface and experience, this package is for you.
 
@@ -64,6 +65,7 @@ An Emacs interface for AI-assisted software development. *The purpose is to prov
    - Gemini CLI (`[[https://github.com/linchen2chris/gemini-cli.el][gemini-cli.el]]`)
    - [[https://github.com/openai/codex][OpenAI codex CLI]] (`[[./ai-code-codex-cli.el][ai-code-codex-cli.el]]`)
    - [[https://docs.github.com/en/copilot/how-tos/use-copilot-agents/use-copilot-cli][GitHub Copilot CLI]] (`[[./ai-code-github-copilot-cli.el][ai-code-github-copilot-cli.el]]`)
+   - [[https://opencode.ai/][Opencode]] (`[[./ai-code-opencode.el][ai-code-opencode.el]]`)
 
    You can add other backends by customizing the `ai-code-backends` variable.
 

ai-code-backends.el

@@ -88,7 +88,17 @@ When called from Lisp code, sends CMD directly without prompting."
      :resume  codex-cli-resume
      :config  "~/.codex/config.toml"
      :upgrade "npm install -g @openai/codex@latest"
-     :cli     "codex"))
+     :cli     "codex")
+    (opencode
+     :label "ai-code-opencode.el"
+     :require ai-code-opencode
+     :start   opencode
+     :switch  opencode-switch-to-buffer
+     :send    opencode-send-command
+     :resume  opencode-resume
+     :config  "~/.opencode/config.json"
+     :upgrade nil
+     :cli     "opencode"))
   "Available AI backends and how to integrate with them.
 Each entry is (KEY :label STRING :require FEATURE :start FN :switch FN :send FN :resume FN-or-nil :upgrade STRING-or-nil :cli STRING).
 The :upgrade property can be either a string shell command or nil."

ai-code-interface.el

@@ -26,6 +26,7 @@
 (require 'ai-code-discussion)
 (require 'ai-code-codex-cli)
 (require 'ai-code-github-copilot-cli)
+(require 'ai-code-opencode)
 (require 'ai-code-file)
 (require 'ai-code-ai)
 

ai-code-opencode.el

@@ -0,0 +1,73 @@
+;;; ai-code-opencode.el --- Thin wrapper for Opencode  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;;
+;; Thin wrapper that reuses `claude-code' to run Opencode.
+;; Provides interactive commands and aliases for the AI Code suite.
+;;
+;; Opencode is an open-source alternative to Claude Code that provides
+;; HTTP server APIs and customization features (LSP, custom LLM providers, etc.)
+;; See: https://opencode.ai/
+;;
+;;; Code:
+
+(require 'claude-code)
+
+(declare-function claude-code--start "claude-code" (arg extra-switches &optional force-prompt force-switch-to-buffer))
+(declare-function claude-code--term-send-string "claude-code" (backend string))
+(defvar claude-code-terminal-backend)
+
+
+(defgroup ai-code-opencode nil
+  "Opencode integration via `claude-code'."
+  :group 'tools
+  :prefix "opencode-")
+
+(defcustom opencode-program "opencode"
+  "Path to the Opencode executable."
+  :type 'string
+  :group 'ai-code-opencode)
+
+;;;###autoload
+(defun opencode (&optional arg)
+  "Start Opencode (reuses `claude-code' startup logic)."
+  (interactive "P")
+  (let ((claude-code-program opencode-program) ; override dynamically
+        (claude-code-program-switches nil))    ; optional e.g.: '("exec" "--non-interactive")
+    (claude-code arg)))
+
+;;;###autoload
+(defun opencode-switch-to-buffer ()
+  (interactive)
+  (claude-code-switch-to-buffer))
+
+;;;###autoload
+(defun opencode-send-command (line)
+  (interactive "sOpencode> ")
+  (claude-code-send-command line))
+
+;;;###autoload
+(defun opencode-resume (&optional arg)
+  "Resume a previous Opencode session.
+
+This command starts Opencode with the --resume flag to resume
+a specific past session. The CLI will present an interactive list of past
+sessions to choose from.
+
+If current buffer belongs to a project, start in the project's root
+directory. Otherwise start in the directory of the current buffer file,
+or the current value of `default-directory' if no project and no buffer file.
+
+With double prefix ARG (\\[universal-argument] \\[universal-argument]),
+prompt for the project directory."
+  (interactive "P")
+  (let ((claude-code-program opencode-program)
+        (claude-code-program-switches nil))
+    (claude-code--start arg '("resume") nil t)
+    (claude-code--term-send-string claude-code-terminal-backend "")
+    (with-current-buffer claude-code-terminal-backend
+      (goto-char (point-min)))))
+
+(provide 'ai-code-opencode)
+
+;;; ai-code-opencode.el ends here