Add Letta agent

agent-shell-letta.el

@@ -0,0 +1,165 @@
+;;; agent-shell-letta.el --- Letta Code agent configuration -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026 Matias Forbord
+
+;; Author: Matias Forbord
+;; URL: https://github.com/xenodium/agent-shell
+
+;; This package is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; This package is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This file includes Letta Code-specific configurations.
+;;
+;; Letta agents are stateful: they keep long-term memory across
+;; sessions and conversations.  This integration drives Letta Code
+;; through the `letta-code-acp' adapter, which wraps
+;; `letta -p --output-format stream-json'.
+;;
+;; A Letta agent has a persistent "main chat" conversation plus any
+;; number of side conversations.  `agent-shell-letta-start-main-chat'
+;; attaches to the former; `agent-shell-letta-start-conversation'
+;; spawns a fresh one.
+;;
+;; The adapter is configured through environment variables set via
+;; `agent-shell-letta-environment', for example:
+;;
+;;   LETTA_API_KEY=...         Letta Cloud credentials.
+;;   LETTA_AGENT_ID=agent-...  Pin shells to a specific agent.
+;;   LETTA_MODEL=auto          Model handle.
+;;
+
+;;; Code:
+
+(eval-when-compile
+  (require 'cl-lib))
+(require 'shell-maker)
+(require 'acp)
+
+(declare-function agent-shell--indent-string "agent-shell")
+(declare-function agent-shell-make-agent-config "agent-shell")
+(autoload 'agent-shell-make-agent-config "agent-shell")
+(declare-function agent-shell--make-acp-client "agent-shell")
+(declare-function agent-shell--dwim "agent-shell")
+
+(defcustom agent-shell-letta-acp-command
+  '("letta-code-acp")
+  "Command and parameters for the Letta Code ACP adapter.
+
+The first element is the command name, and the rest are command parameters."
+  :type '(repeat string)
+  :group 'agent-shell)
+
+(defcustom agent-shell-letta-environment
+  nil
+  "Environment variables for the Letta Code ACP adapter.
+
+This should be a list of \"NAME=VALUE\" strings, typically built with
+`agent-shell-make-environment-variables'.  Use it to inject
+LETTA_API_KEY for Letta Cloud, LETTA_AGENT_ID to pin shells to a
+specific agent, or LETTA_MODEL to select a model."
+  :type '(repeat string)
+  :group 'agent-shell)
+
+(defvar agent-shell-letta--conversation-id nil
+  "Letta conversation the next shell session attaches to.
+
+\"default\" attaches to the agent's main chat.  nil spawns a fresh
+conversation.  Bound by the start commands; not user-facing.")
+
+(defun agent-shell-letta-make-agent-config ()
+  "Create a Letta Code agent configuration.
+
+Returns an agent configuration alist using `agent-shell-make-agent-config'."
+  (agent-shell-make-agent-config
+   :identifier 'letta
+   :mode-line-name "Letta"
+   :buffer-name "Letta"
+   :shell-prompt "Letta> "
+   :shell-prompt-regexp "Letta> "
+   :welcome-function #'agent-shell-letta--welcome-message
+   :client-maker (lambda (buffer)
+                   (agent-shell-letta-make-client :buffer buffer))
+   :install-instructions
+   "Install the adapter with 'npm install -g letta-code-acp', or
+customize `agent-shell-letta-acp-command' to point at a local build,
+e.g. '(\"node\" \"/path/to/letta-code-acp/dist/cli.js\")."))
+
+(defun agent-shell-letta-start-agent ()
+  "Start an interactive Letta Code agent shell."
+  (interactive)
+  (agent-shell--dwim :config (agent-shell-letta-make-agent-config)
+                     :new-shell t))
+
+(defun agent-shell-letta-start-main-chat ()
+  "Start a Letta Code agent shell attached to the agent's main chat.
+
+The main chat is the persistent top-level conversation of the Letta
+agent.  Shells opened with this command attach to the same
+conversation and share its memory."
+  (interactive)
+  (let ((agent-shell-letta--conversation-id "default"))
+    (agent-shell--dwim :config (agent-shell-letta-make-agent-config)
+                       :new-shell t)))
+
+(defun agent-shell-letta-start-conversation ()
+  "Start a Letta Code agent shell in a fresh conversation.
+
+Spawns a new conversation, separate from the agent's main chat and
+from any other shell."
+  (interactive)
+  (let ((agent-shell-letta--conversation-id nil))
+    (agent-shell--dwim :config (agent-shell-letta-make-agent-config)
+                       :new-shell t)))
+
+(cl-defun agent-shell-letta-make-client (&key buffer)
+  "Create a Letta Code ACP client with BUFFER as context."
+  (unless buffer
+    (error "Missing required argument: :buffer"))
+  (let ((environment (copy-sequence (or agent-shell-letta-environment (list)))))
+    (when agent-shell-letta--conversation-id
+      (push (format "LETTA_CONVERSATION_ID=%s" agent-shell-letta--conversation-id)
+            environment))
+    (agent-shell--make-acp-client :command (car agent-shell-letta-acp-command)
+                                  :command-params (cdr agent-shell-letta-acp-command)
+                                  :environment-variables environment
+                                  :context-buffer buffer)))
+
+(defun agent-shell-letta--welcome-message (config)
+  "Return Letta welcome message using `shell-maker' CONFIG."
+  (let ((art (agent-shell--indent-string 4 (agent-shell-letta--ascii-art)))
+        (message (string-trim-left (shell-maker-welcome-message config) "\n")))
+    (concat "\n\n"
+            art
+            "\n\n"
+            message)))
+
+(defun agent-shell-letta--ascii-art ()
+  "Letta ASCII art."
+  (let* ((is-dark (eq (frame-parameter nil 'background-mode) 'dark))
+         (text (string-trim "
+  ██╗     ███████╗████████╗████████╗ █████╗
+  ██║     ██╔════╝╚══██╔══╝╚══██╔══╝██╔══██╗
+  ██║     █████╗     ██║      ██║   ███████║
+  ██║     ██╔══╝     ██║      ██║   ██╔══██║
+  ███████╗███████╗   ██║      ██║   ██║  ██║
+  ╚══════╝╚══════╝   ╚═╝      ╚═╝   ╚═╝  ╚═╝
+" "\n")))
+    (propertize text 'font-lock-face (if is-dark
+                                         '(:foreground "#7fb3ff" :inherit fixed-pitch)
+                                       '(:foreground "#2a5db0" :inherit fixed-pitch)))))
+
+(provide 'agent-shell-letta)
+
+;;; agent-shell-letta.el ends here

agent-shell.el

@@ -71,6 +71,7 @@
 (require 'agent-shell-hermes)
 (require 'agent-shell-kimi)
 (require 'agent-shell-kiro)
+(require 'agent-shell-letta)
 (require 'agent-shell-mistral)
 (require 'agent-shell-openai)
 (require 'agent-shell-opencode)
@@ -577,6 +578,7 @@ Goose, Cursor, CodeBuddy, Auggie, and others."
         (agent-shell-goose-make-agent-config)
         (agent-shell-kimi-make-config)
         (agent-shell-kiro-make-config)
+        (agent-shell-letta-make-agent-config)
         (agent-shell-mistral-make-config)
         (agent-shell-opencode-make-agent-config)
         (agent-shell-pi-make-agent-config)
@@ -612,6 +614,7 @@ configuration alist for backwards compatibility."
                  (const :tag "Hermes" hermes)
                  (const :tag "Kimi" kimi)
                  (const :tag "Kiro" kiro)
+                 (const :tag "Letta Code" letta)
                  (const :tag "Mistral" le-chat)
                  (const :tag "OpenCode" opencode)
                  (const :tag "Pi" pi)