From 8e4d4fcc44afcc5ef410b50eedff52d8da244011 Mon Sep 17 00:00:00 2001
From: sam-shakeybridge-software <3429163+ssjoleary@users.noreply.github.com>
Date: Thu, 23 Apr 2026 17:50:26 +0100
Subject: [PATCH 1/2] fix: notify server when model is selected via
 EcaChatSelectModel

When a model was selected via EcaChatSelectModel, the local state was
updated but the server was never notified. This meant the server's
last-config-notified was out of sync with the client's selected model.

Send chat/selectedModelChanged to the server on model selection,
matching the approach used by eca-emacs. The local state update is
kept for immediate header refresh since the server's response to
chat/selectedModelChanged does not include selectModel.

Note: /model in chat does not update the header when the selected model
matches the server's last-config-notified value. This is a server-side
gap where chat-selected-model-changed should include select-model in its
notify-fields-changed-only! call to keep last-config-notified in sync.
---
 lua/eca/commands.lua | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lua/eca/commands.lua b/lua/eca/commands.lua
index 522c680..e687040 100644
--- a/lua/eca/commands.lua
+++ b/lua/eca/commands.lua
@@ -454,6 +454,7 @@ function M.setup()
     }, function(choice)
       if choice then
         chat.mediator:update_selected_model(choice)
+        chat.mediator:send("chat/selectedModelChanged", { model = choice, variant = nil }, nil)
       end
     end)
   end, {

From 78285a3dcf9dccf6dd10cd9f632eea73abc0560d Mon Sep 17 00:00:00 2001
From: sam-shakeybridge-software <3429163+ssjoleary@users.noreply.github.com>
Date: Thu, 23 Apr 2026 18:14:26 +0100
Subject: [PATCH 2/2] fix: use vim.NIL for variant and add server notification
 test

- Use vim.NIL instead of nil so variant is encoded as JSON null,
  matching eca-emacs behaviour
- Add test asserting chat/selectedModelChanged is sent to the server
  with the correct method and model param
---
 lua/eca/commands.lua           |  2 +-
 tests/test_select_commands.lua | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lua/eca/commands.lua b/lua/eca/commands.lua
index e687040..c6f4a31 100644
--- a/lua/eca/commands.lua
+++ b/lua/eca/commands.lua
@@ -454,7 +454,7 @@ function M.setup()
     }, function(choice)
       if choice then
         chat.mediator:update_selected_model(choice)
-        chat.mediator:send("chat/selectedModelChanged", { model = choice, variant = nil }, nil)
+        chat.mediator:send("chat/selectedModelChanged", { model = choice, variant = vim.NIL }, nil)
       end
     end)
   end, {
diff --git a/tests/test_select_commands.lua b/tests/test_select_commands.lua
index 8274422..c563fc8 100644
--- a/tests/test_select_commands.lua
+++ b/tests/test_select_commands.lua
@@ -82,6 +82,28 @@ T["EcaChatSelectModel"]["updates state when model selected"] = function()
   eq(child.lua_get("_G.State.config.models.selected"), "model2")
 end
 
+T["EcaChatSelectModel"]["notifies server of model change"] = function()
+  child.lua([[
+    _G.State.config.models.list = { "model1", "model2", "model3" }
+    _G.State.config.models.selected = "model1"
+
+    -- Capture outgoing notifications
+    _G.sent_notifications = {}
+    _G.Mediator.send = function(self, method, params, callback)
+      table.insert(_G.sent_notifications, { method = method, params = params })
+    end
+
+    _G.mock_select("model2")
+  ]])
+
+  child.cmd("EcaChatSelectModel")
+
+  local notifications = child.lua_get("_G.sent_notifications")
+  eq(#notifications, 1)
+  eq(notifications[1].method, "chat/selectedModelChanged")
+  eq(notifications[1].params.model, "model2")
+end
+
 T["EcaChatSelectModel"]["handles nil selection"] = function()
   -- Setup initial state
   child.lua([[