support /fork command

Fixes #366

Author: ericdallo

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add `/fork` command to clone current chat into a new chat with the same history and settings, and `chat/opened` server notification.
+
 ## 0.118.1
 
 - Fix ECA stop timing out.

docs/protocol.md

@@ -1511,6 +1511,31 @@ interface ChatClearedParams {
 }
 ```
 
+### Chat opened (⬅️)
+
+A server notification indicating a new chat was created server-side (e.g. via `/fork`).
+Clients should create a new chat entry in the UI. The chat messages will follow as `chat/contentReceived` notifications.
+
+_Notification:_
+
+* method: `chat/opened`
+* params: `ChatOpenedParams` defined as follows:
+
+```typescript
+interface ChatOpenedParams {
+
+    /**
+     * The new chat session identifier.
+     */
+    chatId: string;
+
+    /**
+     * The title of the new chat.
+     */
+    title?: string;
+}
+```
+
 ### Chat delete (↩️)
 
 A client request to delete a existing chat, removing all previous messages and used tokens/costs from memory, good for reduce context or start a new clean chat.

integration-test/integration/chat/commands_test.clj

@@ -28,6 +28,7 @@
                        {:name "skill-create" :arguments [{:name "name"} {:name "prompt"}]}
                        {:name "costs" :arguments []}
                        {:name "compact" :arguments [{:name "additional-input"}]}
+                       {:name "fork" :arguments []}
                        {:name "resume" :arguments [{:name "chat-id"}]}
                        {:name "remote" :arguments []}
                        {:name "config" :arguments []}

src/eca/features/chat.clj

@@ -928,6 +928,10 @@
     (lifecycle/send-content! chat-ctx :user {:type :text
                                              :content-id (:user-content-id chat-ctx)
                                              :text (str message "\n")})
+    ;; Clear prompt-finished? so finish-chat-prompt! can properly terminate
+    ;; this prompt cycle. prompt-messages! already does this for regular
+    ;; prompts, but commands and mcp-prompts go through different paths.
+    (swap! db* update-in [:chats chat-id] dissoc :prompt-finished?)
     (case (:type decision)
       :mcp-prompt (send-mcp-prompt! decision chat-ctx)
       :eca-command (handle-command! decision chat-ctx)

src/eca/features/commands.clj

@@ -25,6 +25,12 @@
 
 (set! *warn-on-reflection* true)
 
+(defn ^:private fork-title [title]
+  (let [title (or title "Untitled")]
+    (if-let [[_ base n] (re-matches #"(.+?)\s*\((\d+)\)\s*$" title)]
+      (str base " (" (inc (parse-long n)) ")")
+      (str title " (2)"))))
+
 (defn ^:private normalize-command-name [f]
   (string/lower-case (fs/strip-ext (fs/file-name f))))
 
@@ -113,6 +119,10 @@
                        :type :native
                        :description "Summarize the chat so far cleaning previous chat history to reduce context."
                        :arguments [{:name "additional-input"}]}
+                      {:name "fork"
+                       :type :native
+                       :description "Fork current chat into a new chat with the same history and settings."
+                       :arguments []}
                       {:name "resume"
                        :type :native
                        :description "Resume the specified chat-id. Blank to list chats or 'latest'."
@@ -326,6 +336,28 @@
                                      metrics)
                 {:type :new-chat-status
                  :status :login})
+      "fork" (let [chat (get-in db [:chats chat-id])
+                    new-id (str (random-uuid))
+                    now (System/currentTimeMillis)
+                    new-title (fork-title (:title chat))
+                    new-chat {:id new-id
+                              :title new-title
+                              :status :idle
+                              :created-at now
+                              :updated-at now
+                              :model (:model chat)
+                              :last-api (:last-api chat)
+                              :messages (vec (:messages chat))
+                              :prompt-finished? true}]
+                (swap! db* assoc-in [:chats new-id] new-chat)
+                (db/update-workspaces-cache! @db* metrics)
+                (messenger/chat-opened messenger {:chat-id new-id :title new-title})
+                {:type :chat-messages
+                 :chats {new-id {:messages (:messages chat)
+                                 :title new-title}
+                         chat-id {:messages [{:role "system"
+                                              :content [{:type :text
+                                                         :text (str "Chat forked to: " new-title)}]}]}}})
       "resume" (let [chats (into {}
                                  (filter #(and (not= chat-id (first %))
                                                (not (:subagent (second %)))))

src/eca/messenger.clj

@@ -9,6 +9,7 @@
   (chat-cleared [this params])
   (chat-status-changed [this params])
   (chat-deleted [this params])
+  (chat-opened [this params])
   (rewrite-content-received [this data])
   (tool-server-updated [this params])
   (config-updated [this params])

src/eca/remote/messenger.clj

@@ -30,6 +30,10 @@
     (messenger/chat-deleted inner params)
     (sse/broadcast! sse-connections* "chat:deleted" (->camel params)))
 
+  (chat-opened [_this params]
+    (messenger/chat-opened inner params)
+    (sse/broadcast! sse-connections* "chat:opened" (->camel params)))
+
   (rewrite-content-received [_this data]
     (messenger/rewrite-content-received inner data))
 

src/eca/server.clj

@@ -153,6 +153,9 @@
   (chat-deleted [_this params]
     (jsonrpc.server/discarding-stdout
      (jsonrpc.server/send-notification server "chat/deleted" params)))
+  (chat-opened [_this params]
+    (jsonrpc.server/discarding-stdout
+     (jsonrpc.server/send-notification server "chat/opened" params)))
   (rewrite-content-received [_this content]
     (jsonrpc.server/discarding-stdout
      (jsonrpc.server/send-notification server "rewrite/contentReceived" content)))

test/eca/test_helper.clj

@@ -32,6 +32,7 @@
   (chat-cleared [_ params] (swap! messages* update :chat-clear (fnil conj []) params))
   (chat-status-changed [_ params] (swap! messages* update :chat-status-changed (fnil conj []) params))
   (chat-deleted [_ params] (swap! messages* update :chat-deleted (fnil conj []) params))
+  (chat-opened [_ params] (swap! messages* update :chat-opened (fnil conj []) params))
   (rewrite-content-received [_ data] (swap! messages* update :rewrite-content-received (fnil conj []) data))
   (config-updated [_ data] (swap! messages* update :config-updated (fnil conj []) data))
   (tool-server-updated [_ data] (swap! messages* update :tool-server-update (fnil conj []) data))