From 202ac26ccf2ff4845e4778283feb134f45b7e5b4 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 13:29:16 +0000
Subject: [PATCH 1/9] Initial plan


From cd9b898e4617ad08118027424dba3f523e2b3526 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 13:36:35 +0000
Subject: [PATCH 2/9] Add custom chat frontend with floating window UI

Co-authored-by: verlihirsh <6280012+verlihirsh@users.noreply.github.com>
---
 README.md                       |  31 +++
 ftplugin/opencode_chat.lua      |  31 +++
 lua/opencode.lua                |   2 +
 lua/opencode/ui/chat.lua        | 355 ++++++++++++++++++++++++++++++++
 lua/opencode/ui/chat_events.lua | 109 ++++++++++
 lua/opencode/ui/chat_init.lua   |  44 ++++
 6 files changed, 572 insertions(+)
 create mode 100644 ftplugin/opencode_chat.lua
 create mode 100644 lua/opencode/ui/chat.lua
 create mode 100644 lua/opencode/ui/chat_events.lua
 create mode 100644 lua/opencode/ui/chat_init.lua

diff --git a/README.md b/README.md
index 9abcf9b7..c13ce9bb 100644
--- a/README.md
+++ b/README.md
@@ -242,6 +242,37 @@ Please submit PRs adding new providers! 🙂
 
 ## 🚀 Usage
 
+### 💬 Chat — `require("opencode").chat()`
+
+Open a custom Neovim frontend for `opencode` with a floating window chat interface.
+
+- **Pure Neovim UI** — no terminal needed
+- **Real-time streaming** — see AI responses as they're generated
+- **Vim keybindings** — navigate with hjkl, yank messages, and more
+- **Session management** — create new sessions, interrupt responses
+- **Markdown rendering** — syntax highlighting for code blocks
+
+#### Keybindings
+
+| Key | Action |
+| --- | ------ |
+| `i` or `a` | Send a message |
+| `n` | Start a new session |
+| `q` or `<Esc>` | Close chat window |
+| `yy` | Yank current message to clipboard |
+| `<C-c>` | Interrupt current response |
+| `j`/`k` | Navigate up/down |
+| `gg`/`G` | Jump to top/bottom |
+
+#### Example Setup
+
+```lua
+-- Add to your keymaps
+vim.keymap.set('n', '<leader>oc', function()
+  require('opencode').chat()
+end, { desc = "Open OpenCode Chat" })
+```
+
 ### ✍️ Ask — `require("opencode").ask()`
 
 Input a prompt for `opencode`.
diff --git a/ftplugin/opencode_chat.lua b/ftplugin/opencode_chat.lua
new file mode 100644
index 00000000..f8e58aaa
--- /dev/null
+++ b/ftplugin/opencode_chat.lua
@@ -0,0 +1,31 @@
+-- Filetype plugin for opencode_chat buffers
+-- Provides syntax highlighting for chat messages
+
+-- Enable markdown-like syntax for code blocks
+vim.bo.commentstring = "<!-- %s -->"
+
+-- Set up basic syntax highlighting
+vim.cmd([[
+  syntax match OpencodeHeaderUser "^### You$"
+  syntax match OpencodeHeaderAssistant "^### Assistant$"
+  syntax match OpencodeSeparator "^─\+$"
+  syntax match OpencodeTypingIndicator "^▋$"
+
+  highlight default link OpencodeHeaderUser Title
+  highlight default link OpencodeHeaderAssistant Special
+  highlight default link OpencodeSeparator Comment
+  highlight default link OpencodeTypingIndicator WarningMsg
+]])
+
+-- Enable treesitter markdown highlighting if available
+local ok, ts_highlight = pcall(require, "vim.treesitter.highlighter")
+if ok then
+  local ok_ts = pcall(vim.treesitter.start, vim.api.nvim_get_current_buf(), "markdown")
+  if not ok_ts then
+    -- Fallback to basic markdown syntax
+    vim.cmd("runtime! syntax/markdown.vim")
+  end
+else
+  -- Fallback to basic markdown syntax
+  vim.cmd("runtime! syntax/markdown.vim")
+end
diff --git a/lua/opencode.lua b/lua/opencode.lua
index 1e6880b1..dc30da95 100644
--- a/lua/opencode.lua
+++ b/lua/opencode.lua
@@ -14,4 +14,6 @@ M.stop = require("opencode.provider").stop
 
 M.statusline = require("opencode.status").statusline
 
+M.chat = require("opencode.ui.chat_init").start_chat
+
 return M
diff --git a/lua/opencode/ui/chat.lua b/lua/opencode/ui/chat.lua
new file mode 100644
index 00000000..ec0948f1
--- /dev/null
+++ b/lua/opencode/ui/chat.lua
@@ -0,0 +1,355 @@
+---Custom chat frontend for opencode.nvim
+local M = {}
+
+---@class opencode.ui.chat.State
+---@field bufnr number
+---@field winid number
+---@field session_id string|nil
+---@field messages table[]
+---@field port number|nil
+---@field streaming_message_index number|nil
+
+---@type opencode.ui.chat.State|nil
+M.state = nil
+
+---Create a new chat window
+---@param opts? { width?: number, height?: number }
+---@return opencode.ui.chat.State
+function M.open(opts)
+  opts = opts or {}
+
+  -- Close existing chat window if open
+  if M.state then
+    M.close()
+  end
+
+  -- Create buffer
+  local bufnr = vim.api.nvim_create_buf(false, true)
+  vim.api.nvim_buf_set_option(bufnr, "filetype", "opencode_chat")
+  vim.api.nvim_buf_set_option(bufnr, "buftype", "nofile")
+  vim.api.nvim_buf_set_option(bufnr, "swapfile", false)
+  vim.api.nvim_buf_set_option(bufnr, "modifiable", false)
+  vim.api.nvim_buf_set_option(bufnr, "bufhidden", "wipe")
+
+  -- Create floating window
+  local width = opts.width or math.floor(vim.o.columns * 0.6)
+  local height = opts.height or math.floor(vim.o.lines * 0.7)
+
+  local winid = vim.api.nvim_open_win(bufnr, true, {
+    relative = "editor",
+    width = width,
+    height = height,
+    col = math.floor((vim.o.columns - width) / 2),
+    row = math.floor((vim.o.lines - height) / 2),
+    style = "minimal",
+    border = "rounded",
+    title = " OpenCode Chat ",
+    title_pos = "center",
+  })
+
+  -- Set window options
+  vim.api.nvim_win_set_option(winid, "wrap", true)
+  vim.api.nvim_win_set_option(winid, "linebreak", true)
+  vim.api.nvim_win_set_option(winid, "cursorline", true)
+
+  M.state = {
+    bufnr = bufnr,
+    winid = winid,
+    session_id = nil,
+    messages = {},
+    port = nil,
+    streaming_message_index = nil,
+  }
+
+  -- Setup keymaps
+  M.setup_keymaps(bufnr)
+
+  return M.state
+end
+
+---Setup buffer keymaps
+---@param bufnr number
+function M.setup_keymaps(bufnr)
+  local opts = { noremap = true, silent = true, buffer = bufnr }
+
+  -- Close window
+  vim.keymap.set("n", "q", function()
+    M.close()
+  end, vim.tbl_extend("force", opts, { desc = "Close chat" }))
+  vim.keymap.set("n", "<Esc>", function()
+    M.close()
+  end, vim.tbl_extend("force", opts, { desc = "Close chat" }))
+
+  -- Send prompt
+  vim.keymap.set("n", "i", function()
+    M.prompt_input()
+  end, vim.tbl_extend("force", opts, { desc = "Send message" }))
+  vim.keymap.set("n", "a", function()
+    M.prompt_input()
+  end, vim.tbl_extend("force", opts, { desc = "Send message" }))
+
+  -- Navigate messages
+  vim.keymap.set("n", "j", "j", opts)
+  vim.keymap.set("n", "k", "k", opts)
+  vim.keymap.set("n", "gg", "gg", opts)
+  vim.keymap.set("n", "G", "G", opts)
+
+  -- Copy message
+  vim.keymap.set("n", "yy", function()
+    M.yank_current_message()
+  end, vim.tbl_extend("force", opts, { desc = "Yank current message" }))
+
+  -- New session
+  vim.keymap.set("n", "n", function()
+    M.new_session()
+  end, vim.tbl_extend("force", opts, { desc = "New session" }))
+
+  -- Interrupt
+  vim.keymap.set("n", "<C-c>", function()
+    M.interrupt()
+  end, vim.tbl_extend("force", opts, { desc = "Interrupt" }))
+end
+
+---Close chat window
+function M.close()
+  if M.state then
+    if vim.api.nvim_win_is_valid(M.state.winid) then
+      vim.api.nvim_win_close(M.state.winid, true)
+    end
+    if vim.api.nvim_buf_is_valid(M.state.bufnr) then
+      vim.api.nvim_buf_delete(M.state.bufnr, { force = true })
+    end
+    M.state = nil
+  end
+end
+
+---Render messages to buffer
+function M.render()
+  if not M.state or not vim.api.nvim_buf_is_valid(M.state.bufnr) then
+    return
+  end
+
+  local lines = {}
+  local highlights = {}
+
+  for i, msg in ipairs(M.state.messages) do
+    -- Add separator
+    if i > 1 then
+      table.insert(lines, "")
+      table.insert(lines, string.rep("─", 80))
+      table.insert(lines, "")
+    end
+
+    -- Add role header
+    local role = msg.role == "user" and "You" or "Assistant"
+    local header = string.format("### %s", role)
+    local header_line = #lines
+    table.insert(lines, header)
+    table.insert(lines, "")
+
+    -- Add highlight for header
+    table.insert(highlights, {
+      line = header_line,
+      col_start = 0,
+      col_end = #header,
+      hl_group = msg.role == "user" and "Title" or "Special",
+    })
+
+    -- Add message content
+    if msg.text then
+      local content_lines = vim.split(msg.text, "\n")
+      for _, line in ipairs(content_lines) do
+        table.insert(lines, line)
+      end
+    end
+
+    -- Show typing indicator for streaming messages
+    if msg.streaming and not msg.complete then
+      table.insert(lines, "")
+      table.insert(lines, "▋") -- Typing indicator
+    end
+  end
+
+  -- Update buffer
+  vim.api.nvim_buf_set_option(M.state.bufnr, "modifiable", true)
+  vim.api.nvim_buf_set_lines(M.state.bufnr, 0, -1, false, lines)
+  vim.api.nvim_buf_set_option(M.state.bufnr, "modifiable", false)
+
+  -- Apply highlights
+  local ns_id = vim.api.nvim_create_namespace("opencode_chat")
+  vim.api.nvim_buf_clear_namespace(M.state.bufnr, ns_id, 0, -1)
+  for _, hl in ipairs(highlights) do
+    vim.api.nvim_buf_add_highlight(M.state.bufnr, ns_id, hl.hl_group, hl.line, hl.col_start, hl.col_end)
+  end
+
+  -- Scroll to bottom
+  if vim.api.nvim_win_is_valid(M.state.winid) then
+    vim.api.nvim_win_set_cursor(M.state.winid, { #lines, 0 })
+  end
+end
+
+---Prompt for user input
+function M.prompt_input()
+  if not M.state or not M.state.port or not M.state.session_id then
+    vim.notify("No active session", vim.log.levels.ERROR, { title = "opencode" })
+    return
+  end
+
+  vim.ui.input({ prompt = "Message: " }, function(input)
+    if input and input ~= "" then
+      M.send_message(input)
+    end
+  end)
+end
+
+---Send a message
+---@param text string
+function M.send_message(text)
+  if not M.state or not M.state.port or not M.state.session_id then
+    vim.notify("No active session", vim.log.levels.ERROR, { title = "opencode" })
+    return
+  end
+
+  -- Add user message to UI immediately
+  table.insert(M.state.messages, {
+    role = "user",
+    text = text,
+    timestamp = os.time(),
+  })
+  M.render()
+
+  -- Add placeholder for assistant response
+  table.insert(M.state.messages, {
+    role = "assistant",
+    text = "",
+    streaming = true,
+    complete = false,
+  })
+  M.state.streaming_message_index = #M.state.messages
+  M.render()
+
+  -- Send to backend
+  local client = require("opencode.cli.client")
+
+  -- TODO: Make provider and model configurable
+  client.send_message(text, M.state.session_id, M.state.port, "anthropic", "claude-3-5-sonnet-20241022", function()
+    -- Response will come via SSE events
+  end)
+end
+
+---Add or update a message
+---@param message table
+function M.add_message(message)
+  if not M.state then
+    return
+  end
+
+  -- Update last assistant message if streaming
+  if message.role == "assistant" and M.state.streaming_message_index then
+    local last = M.state.messages[M.state.streaming_message_index]
+    if last and last.role == "assistant" and last.streaming then
+      last.text = message.text or last.text or ""
+      if message.complete then
+        last.complete = true
+        last.streaming = false
+        M.state.streaming_message_index = nil
+      end
+      M.render()
+      return
+    end
+  end
+
+  -- Otherwise add new message
+  table.insert(M.state.messages, message)
+  M.render()
+end
+
+---Yank the current message under cursor
+function M.yank_current_message()
+  if not M.state then
+    return
+  end
+
+  -- Find which message the cursor is on
+  local cursor_line = vim.api.nvim_win_get_cursor(M.state.winid)[1]
+  local current_line = 0
+
+  for _, msg in ipairs(M.state.messages) do
+    -- Account for separator and header
+    if current_line > 0 then
+      current_line = current_line + 3 -- blank, separator, blank
+    end
+    current_line = current_line + 2 -- header + blank
+
+    local content_lines = vim.split(msg.text or "", "\n")
+    local msg_end = current_line + #content_lines
+
+    if cursor_line >= current_line and cursor_line <= msg_end then
+      -- Found the message, yank it
+      vim.fn.setreg('"', msg.text or "")
+      vim.notify("Message yanked to clipboard", vim.log.levels.INFO, { title = "opencode" })
+      return
+    end
+
+    current_line = msg_end
+  end
+end
+
+---Start a new session
+function M.new_session()
+  if not M.state or not M.state.port then
+    vim.notify("No connection to opencode", vim.log.levels.ERROR, { title = "opencode" })
+    return
+  end
+
+  -- Clear messages
+  M.state.messages = {}
+  M.state.session_id = nil
+  M.state.streaming_message_index = nil
+  M.render()
+
+  -- Create new session
+  local client = require("opencode.cli.client")
+  client.tui_execute_command("session.new", M.state.port, function()
+    -- Session ID will be set via SSE event
+    vim.notify("New session started", vim.log.levels.INFO, { title = "opencode" })
+  end)
+end
+
+---Interrupt the current session
+function M.interrupt()
+  if not M.state or not M.state.port then
+    vim.notify("No connection to opencode", vim.log.levels.ERROR, { title = "opencode" })
+    return
+  end
+
+  local client = require("opencode.cli.client")
+  client.tui_execute_command("session.interrupt", M.state.port, function()
+    if M.state and M.state.streaming_message_index then
+      local msg = M.state.messages[M.state.streaming_message_index]
+      if msg then
+        msg.complete = true
+        msg.streaming = false
+      end
+      M.state.streaming_message_index = nil
+      M.render()
+    end
+    vim.notify("Session interrupted", vim.log.levels.INFO, { title = "opencode" })
+  end)
+end
+
+---Set the session ID
+---@param session_id string
+function M.set_session_id(session_id)
+  if M.state then
+    M.state.session_id = session_id
+  end
+end
+
+---Get the current state
+---@return opencode.ui.chat.State|nil
+function M.get_state()
+  return M.state
+end
+
+return M
diff --git a/lua/opencode/ui/chat_events.lua b/lua/opencode/ui/chat_events.lua
new file mode 100644
index 00000000..a2a35fd4
--- /dev/null
+++ b/lua/opencode/ui/chat_events.lua
@@ -0,0 +1,109 @@
+---Event handler for custom chat frontend
+local M = {}
+
+---@type number|nil
+local sse_job_id = nil
+
+---Subscribe to opencode events and update chat UI
+---@param port number
+function M.subscribe(port)
+  local chat = require("opencode.ui.chat")
+
+  -- Unsubscribe from previous if any
+  M.unsubscribe()
+
+  -- Subscribe to SSE events
+  sse_job_id = require("opencode.cli.client").call(port, "/event", "GET", nil, function(event)
+    -- Only process events if chat window is still open
+    local state = chat.get_state()
+    if not state then
+      M.unsubscribe()
+      return
+    end
+
+    -- Handle different event types
+    if event.type == "message.delta" then
+      -- Streaming message chunk
+      local delta = event.properties and event.properties.delta or ""
+      local current_msg = state.messages[state.streaming_message_index]
+      if current_msg then
+        current_msg.text = (current_msg.text or "") .. delta
+        chat.render()
+      end
+    elseif event.type == "message.created" or event.type == "message.updated" then
+      -- Complete message
+      local msg = event.properties and event.properties.message
+      if msg and msg.role == "assistant" then
+        -- Check if we have a streaming message to update
+        if state.streaming_message_index then
+          local current_msg = state.messages[state.streaming_message_index]
+          if current_msg then
+            current_msg.text = msg.text or current_msg.text or ""
+            current_msg.complete = true
+            current_msg.streaming = false
+            state.streaming_message_index = nil
+            chat.render()
+          end
+        else
+          -- Add as new message
+          chat.add_message({
+            role = msg.role or "assistant",
+            text = msg.text or "",
+            streaming = false,
+            complete = true,
+          })
+        end
+      end
+    elseif event.type == "session.created" or event.type == "session.switched" then
+      -- New session started or switched
+      local session = event.properties and event.properties.session
+      if session and session.id then
+        chat.set_session_id(session.id)
+        -- Add a system message to indicate new session
+        chat.add_message({
+          role = "system",
+          text = "Session started: " .. session.id,
+          streaming = false,
+          complete = true,
+        })
+      end
+    elseif event.type == "session.idle" then
+      -- Session finished responding
+      if state.streaming_message_index then
+        local msg = state.messages[state.streaming_message_index]
+        if msg then
+          msg.complete = true
+          msg.streaming = false
+        end
+        state.streaming_message_index = nil
+        chat.render()
+      end
+    elseif event.type == "error" then
+      -- Handle errors
+      local error_msg = event.properties and event.properties.message or "Unknown error"
+      vim.notify("OpenCode error: " .. error_msg, vim.log.levels.ERROR, { title = "opencode" })
+
+      -- Mark streaming message as complete if error occurred
+      if state.streaming_message_index then
+        local msg = state.messages[state.streaming_message_index]
+        if msg then
+          msg.text = (msg.text or "") .. "\n\n[Error: " .. error_msg .. "]"
+          msg.complete = true
+          msg.streaming = false
+        end
+        state.streaming_message_index = nil
+        chat.render()
+      end
+    end
+  end)
+end
+
+---Unsubscribe from SSE events
+function M.unsubscribe()
+  if sse_job_id then
+    vim.fn.jobstop(sse_job_id)
+    sse_job_id = nil
+  end
+end
+
+return M
diff --git a/lua/opencode/ui/chat_init.lua b/lua/opencode/ui/chat_init.lua
new file mode 100644
index 00000000..860b5b71
--- /dev/null
+++ b/lua/opencode/ui/chat_init.lua
@@ -0,0 +1,44 @@
+---Main entry point for custom chat frontend
+local M = {}
+
+---Start a new chat session with custom UI
+---@param opts? { width?: number, height?: number }
+function M.start_chat(opts)
+  -- Get or start opencode server
+  require("opencode.cli.server")
+    .get_port(true)
+    :next(function(port)
+      -- Open chat window
+      local chat = require("opencode.ui.chat")
+      local state = chat.open(opts)
+
+      -- Store port
+      state.port = port
+
+      -- Subscribe to events first
+      require("opencode.ui.chat_events").subscribe(port)
+
+      -- Create new session via TUI command
+      local client = require("opencode.cli.client")
+      client.tui_execute_command("session.new", port, function()
+        -- Session will be set via SSE event
+      end)
+
+      -- Show welcome message
+      vim.schedule(function()
+        if chat.get_state() then
+          chat.add_message({
+            role = "assistant",
+            text = "Chat session starting... Type 'i' or 'a' to send a message.\n\nKeybindings:\n  i/a - Send message\n  n - New session\n  q/<Esc> - Close\n  yy - Yank message\n  <C-c> - Interrupt",
+            streaming = false,
+            complete = true,
+          })
+        end
+      end)
+    end)
+    :catch(function(err)
+      vim.notify("Failed to start opencode: " .. err, vim.log.levels.ERROR, { title = "opencode" })
+    end)
+end
+
+return M

From 5812b3c638540ae20b923d312b0a8d4a111433c1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 13:42:58 +0000
Subject: [PATCH 3/9] Fix deprecated APIs and add configurable provider/model
 settings

Co-authored-by: verlihirsh <6280012+verlihirsh@users.noreply.github.com>
---
 README.md                | 10 +++++++++
 lua/opencode/config.lua  | 15 +++++++++++++
 lua/opencode/ui/chat.lua | 47 +++++++++++++++++++++++++---------------
 3 files changed, 55 insertions(+), 17 deletions(-)

diff --git a/README.md b/README.md
index c13ce9bb..e0618567 100644
--- a/README.md
+++ b/README.md
@@ -267,6 +267,16 @@ Open a custom Neovim frontend for `opencode` with a floating window chat interfa
 #### Example Setup
 
 ```lua
+-- Configure chat options (optional)
+vim.g.opencode_opts = {
+  chat = {
+    provider_id = "anthropic",  -- AI provider (default: "anthropic")
+    model_id = "claude-3-5-sonnet-20241022",  -- AI model (default: "claude-3-5-sonnet-20241022")
+    width = 0.6,  -- Window width as fraction of editor width (default: 0.6)
+    height = 0.7,  -- Window height as fraction of editor height (default: 0.7)
+  }
+}
+
 -- Add to your keymaps
 vim.keymap.set('n', '<leader>oc', function()
   require('opencode').chat()
diff --git a/lua/opencode/config.lua b/lua/opencode/config.lua
index 259020b1..3c20aab4 100644
--- a/lua/opencode/config.lua
+++ b/lua/opencode/config.lua
@@ -32,12 +32,21 @@ vim.g.opencode_opts = vim.g.opencode_opts
 ---Supports [`snacks.picker`](https://github.com/folke/snacks.nvim/blob/main/docs/picker.md).
 ---@field select? opencode.select.Opts
 ---
+---Options for `chat()`.
+---@field chat? opencode.chat.Opts
+---
 ---Options for `opencode` event handling.
 ---@field events? opencode.events.Opts
 ---
 ---Provide an integrated `opencode` when one is not found.
 ---@field provider? opencode.Provider|opencode.provider.Opts
 
+---@class opencode.chat.Opts
+---@field provider_id? string AI provider to use (default: "anthropic")
+---@field model_id? string AI model to use (default: "claude-3-5-sonnet-20241022")
+---@field width? number Width of chat window as fraction of editor width (default: 0.6)
+---@field height? number Height of chat window as fraction of editor height (default: 0.7)
+
 ---@class opencode.Prompt : opencode.api.prompt.Opts
 ---@field prompt string The prompt to send to `opencode`.
 ---@field ask? boolean Call `ask(prompt)` instead of `prompt(prompt)`. Useful for prompts that expect additional user input.
@@ -105,6 +114,12 @@ local defaults = {
       },
     },
   },
+  chat = {
+    provider_id = "anthropic",
+    model_id = "claude-3-5-sonnet-20241022",
+    width = 0.6,
+    height = 0.7,
+  },
   events = {
     enabled = true,
     reload = true,
diff --git a/lua/opencode/ui/chat.lua b/lua/opencode/ui/chat.lua
index ec0948f1..b5785b4c 100644
--- a/lua/opencode/ui/chat.lua
+++ b/lua/opencode/ui/chat.lua
@@ -8,12 +8,14 @@ local M = {}
 ---@field messages table[]
 ---@field port number|nil
 ---@field streaming_message_index number|nil
+---@field provider_id string
+---@field model_id string
 
 ---@type opencode.ui.chat.State|nil
 M.state = nil
 
 ---Create a new chat window
----@param opts? { width?: number, height?: number }
+---@param opts? { width?: number, height?: number, provider_id?: string, model_id?: string }
 ---@return opencode.ui.chat.State
 function M.open(opts)
   opts = opts or {}
@@ -23,17 +25,20 @@ function M.open(opts)
     M.close()
   end
 
+  -- Get config
+  local config = require("opencode.config").opts.chat or {}
+
   -- Create buffer
   local bufnr = vim.api.nvim_create_buf(false, true)
-  vim.api.nvim_buf_set_option(bufnr, "filetype", "opencode_chat")
-  vim.api.nvim_buf_set_option(bufnr, "buftype", "nofile")
-  vim.api.nvim_buf_set_option(bufnr, "swapfile", false)
-  vim.api.nvim_buf_set_option(bufnr, "modifiable", false)
-  vim.api.nvim_buf_set_option(bufnr, "bufhidden", "wipe")
+  vim.api.nvim_set_option_value("filetype", "opencode_chat", { buf = bufnr })
+  vim.api.nvim_set_option_value("buftype", "nofile", { buf = bufnr })
+  vim.api.nvim_set_option_value("swapfile", false, { buf = bufnr })
+  vim.api.nvim_set_option_value("modifiable", false, { buf = bufnr })
+  vim.api.nvim_set_option_value("bufhidden", "wipe", { buf = bufnr })
 
   -- Create floating window
-  local width = opts.width or math.floor(vim.o.columns * 0.6)
-  local height = opts.height or math.floor(vim.o.lines * 0.7)
+  local width = opts.width or math.floor(vim.o.columns * (config.width or 0.6))
+  local height = opts.height or math.floor(vim.o.lines * (config.height or 0.7))
 
   local winid = vim.api.nvim_open_win(bufnr, true, {
     relative = "editor",
@@ -48,9 +53,9 @@ function M.open(opts)
   })
 
   -- Set window options
-  vim.api.nvim_win_set_option(winid, "wrap", true)
-  vim.api.nvim_win_set_option(winid, "linebreak", true)
-  vim.api.nvim_win_set_option(winid, "cursorline", true)
+  vim.api.nvim_set_option_value("wrap", true, { win = winid })
+  vim.api.nvim_set_option_value("linebreak", true, { win = winid })
+  vim.api.nvim_set_option_value("cursorline", true, { win = winid })
 
   M.state = {
     bufnr = bufnr,
@@ -59,6 +64,8 @@ function M.open(opts)
     messages = {},
     port = nil,
     streaming_message_index = nil,
+    provider_id = opts.provider_id or config.provider_id or "anthropic",
+    model_id = opts.model_id or config.model_id or "claude-3-5-sonnet-20241022",
   }
 
   -- Setup keymaps
@@ -171,9 +178,9 @@ function M.render()
   end
 
   -- Update buffer
-  vim.api.nvim_buf_set_option(M.state.bufnr, "modifiable", true)
+  vim.api.nvim_set_option_value("modifiable", true, { buf = M.state.bufnr })
   vim.api.nvim_buf_set_lines(M.state.bufnr, 0, -1, false, lines)
-  vim.api.nvim_buf_set_option(M.state.bufnr, "modifiable", false)
+  vim.api.nvim_set_option_value("modifiable", false, { buf = M.state.bufnr })
 
   -- Apply highlights
   local ns_id = vim.api.nvim_create_namespace("opencode_chat")
@@ -231,10 +238,16 @@ function M.send_message(text)
   -- Send to backend
   local client = require("opencode.cli.client")
 
-  -- TODO: Make provider and model configurable
-  client.send_message(text, M.state.session_id, M.state.port, "anthropic", "claude-3-5-sonnet-20241022", function()
-    -- Response will come via SSE events
-  end)
+  client.send_message(
+    text,
+    M.state.session_id,
+    M.state.port,
+    M.state.provider_id,
+    M.state.model_id,
+    function()
+      -- Response will come via SSE events
+    end
+  )
 end
 
 ---Add or update a message

From 93fbc7f500d575af3726195c22f449432f9e456e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 13:43:46 +0000
Subject: [PATCH 4/9] Fix code formatting with stylua

---
 lua/opencode/ui/chat.lua | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/lua/opencode/ui/chat.lua b/lua/opencode/ui/chat.lua
index b5785b4c..be648bc5 100644
--- a/lua/opencode/ui/chat.lua
+++ b/lua/opencode/ui/chat.lua
@@ -238,16 +238,9 @@ function M.send_message(text)
   -- Send to backend
   local client = require("opencode.cli.client")
 
-  client.send_message(
-    text,
-    M.state.session_id,
-    M.state.port,
-    M.state.provider_id,
-    M.state.model_id,
-    function()
-      -- Response will come via SSE events
-    end
-  )
+  client.send_message(text, M.state.session_id, M.state.port, M.state.provider_id, M.state.model_id, function()
+    -- Response will come via SSE events
+  end)
 end
 
 ---Add or update a message

From 01f709f71d5e090e14506882a29d17c7cc1f4130 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 13:46:28 +0000
Subject: [PATCH 5/9] Use existing SSE management infrastructure from client
 module

Co-authored-by: verlihirsh <6280012+verlihirsh@users.noreply.github.com>
---
 lua/opencode/ui/chat_events.lua | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/lua/opencode/ui/chat_events.lua b/lua/opencode/ui/chat_events.lua
index a2a35fd4..bb20e967 100644
--- a/lua/opencode/ui/chat_events.lua
+++ b/lua/opencode/ui/chat_events.lua
@@ -1,19 +1,13 @@
 ---Event handler for custom chat frontend
 local M = {}
 
----@type number|nil
-local sse_job_id = nil
-
 ---Subscribe to opencode events and update chat UI
 ---@param port number
 function M.subscribe(port)
   local chat = require("opencode.ui.chat")
 
-  -- Unsubscribe from previous if any
-  M.unsubscribe()
-
-  -- Subscribe to SSE events
-  sse_job_id = require("opencode.cli.client").call(port, "/event", "GET", nil, function(event)
+  -- Subscribe to SSE events using the client's built-in management
+  require("opencode.cli.client").sse_subscribe(port, function(event)
     -- Only process events if chat window is still open
     local state = chat.get_state()
     if not state then
@@ -100,10 +94,8 @@ end
 
 ---Unsubscribe from SSE events
 function M.unsubscribe()
-  if sse_job_id then
-    vim.fn.jobstop(sse_job_id)
-    sse_job_id = nil
-  end
+  -- Use the client's built-in SSE unsubscribe
+  require("opencode.cli.client").sse_unsubscribe()
 end
 
 return M

From 7f2dc0d60c3f6718e3bf180032d79c97da5816b9 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 14:00:31 +0000
Subject: [PATCH 6/9] Add frontend selection, default keymaps, and auto-setup
 in config

Co-authored-by: verlihirsh <6280012+verlihirsh@users.noreply.github.com>
---
 README.md                | 45 +++++++++++++++++++++++++++-------------
 lua/opencode/config.lua  | 19 +++++++++++++++++
 lua/opencode/ui/chat.lua | 37 +++++++++++++++++++--------------
 plugin/chat.lua          | 24 +++++++++++++++++++++
 4 files changed, 96 insertions(+), 29 deletions(-)
 create mode 100644 plugin/chat.lua

diff --git a/README.md b/README.md
index e0618567..6cadeaed 100644
--- a/README.md
+++ b/README.md
@@ -251,38 +251,55 @@ Open a custom Neovim frontend for `opencode` with a floating window chat interfa
 - **Vim keybindings** — navigate with hjkl, yank messages, and more
 - **Session management** — create new sessions, interrupt responses
 - **Markdown rendering** — syntax highlighting for code blocks
+- **Configurable** — customize keymaps, provider, model, and window size
 
-#### Keybindings
-
-| Key | Action |
-| --- | ------ |
-| `i` or `a` | Send a message |
-| `n` | Start a new session |
-| `q` or `<Esc>` | Close chat window |
-| `yy` | Yank current message to clipboard |
-| `<C-c>` | Interrupt current response |
-| `j`/`k` | Navigate up/down |
-| `gg`/`G` | Jump to top/bottom |
+#### Configuration
 
-#### Example Setup
+Enable the chat frontend and configure it in your `vim.g.opencode_opts`:
 
 ```lua
--- Configure chat options (optional)
 vim.g.opencode_opts = {
   chat = {
+    enabled = true,  -- Enable custom chat UI instead of terminal TUI (default: false)
     provider_id = "anthropic",  -- AI provider (default: "anthropic")
     model_id = "claude-3-5-sonnet-20241022",  -- AI model (default: "claude-3-5-sonnet-20241022")
     width = 0.6,  -- Window width as fraction of editor width (default: 0.6)
     height = 0.7,  -- Window height as fraction of editor height (default: 0.7)
+    keymaps = {
+      open = "<leader>oc",  -- Keymap to open chat (default: "<leader>oc")
+      send = { "i", "a" },  -- Keymaps to send message (default: {"i", "a"})
+      close = { "q", "<Esc>" },  -- Keymaps to close chat (default: {"q", "<Esc>"})
+      new_session = "n",  -- Keymap for new session (default: "n")
+      interrupt = "<C-c>",  -- Keymap to interrupt (default: "<C-c>")
+      yank = "yy",  -- Keymap to yank message (default: "yy")
+    }
   }
 }
+```
+
+When `enabled = true`, the global keymap will be automatically set up. You can also manually call the chat function:
 
--- Add to your keymaps
+```lua
 vim.keymap.set('n', '<leader>oc', function()
   require('opencode').chat()
 end, { desc = "Open OpenCode Chat" })
 ```
 
+#### Keybindings
+
+Default keybindings in the chat window (all configurable):
+
+| Key | Action |
+| --- | ------ |
+| `<leader>oc` | Open chat window (global) |
+| `i` or `a` | Send a message |
+| `n` | Start a new session |
+| `q` or `<Esc>` | Close chat window |
+| `yy` | Yank current message to clipboard |
+| `<C-c>` | Interrupt current response |
+| `j`/`k` | Navigate up/down |
+| `gg`/`G` | Jump to top/bottom |
+
 ### ✍️ Ask — `require("opencode").ask()`
 
 Input a prompt for `opencode`.
diff --git a/lua/opencode/config.lua b/lua/opencode/config.lua
index 3c20aab4..74669f77 100644
--- a/lua/opencode/config.lua
+++ b/lua/opencode/config.lua
@@ -42,10 +42,20 @@ vim.g.opencode_opts = vim.g.opencode_opts
 ---@field provider? opencode.Provider|opencode.provider.Opts
 
 ---@class opencode.chat.Opts
+---@field enabled? boolean Enable custom chat UI instead of terminal TUI (default: false)
 ---@field provider_id? string AI provider to use (default: "anthropic")
 ---@field model_id? string AI model to use (default: "claude-3-5-sonnet-20241022")
 ---@field width? number Width of chat window as fraction of editor width (default: 0.6)
 ---@field height? number Height of chat window as fraction of editor height (default: 0.7)
+---@field keymaps? opencode.chat.Keymaps Keymaps for chat window
+
+---@class opencode.chat.Keymaps
+---@field open? string|string[] Keymap(s) to open chat window (default: "<leader>oc")
+---@field send? string|string[] Keymap(s) to send message in chat (default: {"i", "a"})
+---@field close? string|string[] Keymap(s) to close chat window (default: {"q", "<Esc>"})
+---@field new_session? string Keymap to start new session (default: "n")
+---@field interrupt? string Keymap to interrupt response (default: "<C-c>")
+---@field yank? string Keymap to yank current message (default: "yy")
 
 ---@class opencode.Prompt : opencode.api.prompt.Opts
 ---@field prompt string The prompt to send to `opencode`.
@@ -115,10 +125,19 @@ local defaults = {
     },
   },
   chat = {
+    enabled = false,
     provider_id = "anthropic",
     model_id = "claude-3-5-sonnet-20241022",
     width = 0.6,
     height = 0.7,
+    keymaps = {
+      open = "<leader>oc",
+      send = { "i", "a" },
+      close = { "q", "<Esc>" },
+      new_session = "n",
+      interrupt = "<C-c>",
+      yank = "yy",
+    },
   },
   events = {
     enabled = true,
diff --git a/lua/opencode/ui/chat.lua b/lua/opencode/ui/chat.lua
index be648bc5..5c3bd625 100644
--- a/lua/opencode/ui/chat.lua
+++ b/lua/opencode/ui/chat.lua
@@ -77,23 +77,30 @@ end
 ---Setup buffer keymaps
 ---@param bufnr number
 function M.setup_keymaps(bufnr)
+  local config = require("opencode.config").opts.chat or {}
+  local keymaps = config.keymaps or {}
   local opts = { noremap = true, silent = true, buffer = bufnr }
 
+  -- Helper function to set keymaps that might be arrays
+  local function set_keymap(keys, callback, desc)
+    if type(keys) == "string" then
+      vim.keymap.set("n", keys, callback, vim.tbl_extend("force", opts, { desc = desc }))
+    elseif type(keys) == "table" then
+      for _, key in ipairs(keys) do
+        vim.keymap.set("n", key, callback, vim.tbl_extend("force", opts, { desc = desc }))
+      end
+    end
+  end
+
   -- Close window
-  vim.keymap.set("n", "q", function()
-    M.close()
-  end, vim.tbl_extend("force", opts, { desc = "Close chat" }))
-  vim.keymap.set("n", "<Esc>", function()
+  set_keymap(keymaps.close or { "q", "<Esc>" }, function()
     M.close()
-  end, vim.tbl_extend("force", opts, { desc = "Close chat" }))
+  end, "Close chat")
 
   -- Send prompt
-  vim.keymap.set("n", "i", function()
-    M.prompt_input()
-  end, vim.tbl_extend("force", opts, { desc = "Send message" }))
-  vim.keymap.set("n", "a", function()
+  set_keymap(keymaps.send or { "i", "a" }, function()
     M.prompt_input()
-  end, vim.tbl_extend("force", opts, { desc = "Send message" }))
+  end, "Send message")
 
   -- Navigate messages
   vim.keymap.set("n", "j", "j", opts)
@@ -102,17 +109,17 @@ function M.setup_keymaps(bufnr)
   vim.keymap.set("n", "G", "G", opts)
 
   -- Copy message
-  vim.keymap.set("n", "yy", function()
+  set_keymap(keymaps.yank or "yy", function()
     M.yank_current_message()
-  end, vim.tbl_extend("force", opts, { desc = "Yank current message" }))
+  end, "Yank current message")
 
   -- New session
-  vim.keymap.set("n", "n", function()
+  set_keymap(keymaps.new_session or "n", function()
     M.new_session()
-  end, vim.tbl_extend("force", opts, { desc = "New session" }))
+  end, "New session")
 
   -- Interrupt
-  vim.keymap.set("n", "<C-c>", function()
+  set_keymap(keymaps.interrupt or "<C-c>", function()
     M.interrupt()
   end, vim.tbl_extend("force", opts, { desc = "Interrupt" }))
 end
diff --git a/plugin/chat.lua b/plugin/chat.lua
new file mode 100644
index 00000000..c0ceb3b4
--- /dev/null
+++ b/plugin/chat.lua
@@ -0,0 +1,24 @@
+-- Setup global keymaps for chat functionality
+local config = require("opencode.config").opts.chat or {}
+
+-- Only setup global keymap if chat is enabled and keymap is configured
+if config.enabled and config.keymaps and config.keymaps.open then
+  local open_keys = config.keymaps.open
+
+  -- Helper function to set keymaps that might be arrays
+  local function set_keymap(keys)
+    if type(keys) == "string" then
+      vim.keymap.set("n", keys, function()
+        require("opencode").chat()
+      end, { desc = "Open OpenCode Chat", silent = true })
+    elseif type(keys) == "table" then
+      for _, key in ipairs(keys) do
+        vim.keymap.set("n", key, function()
+          require("opencode").chat()
+        end, { desc = "Open OpenCode Chat", silent = true })
+      end
+    end
+  end
+
+  set_keymap(open_keys)
+end

From ea848ff5962f1cb0df8f296d98a9ec62b73e95bc Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 14:19:16 +0000
Subject: [PATCH 7/9] Address code review feedback: add bounds checking, fix
 bugs, improve validation

Co-authored-by: verlihirsh <6280012+verlihirsh@users.noreply.github.com>
---
 ftplugin/opencode_chat.lua      |   6 +-
 lua/opencode/ui/chat.lua        | 100 +++++++++++++++++++++++---------
 lua/opencode/ui/chat_events.lua |  17 +++---
 lua/opencode/ui/chat_init.lua   |  29 ++++++++-
 4 files changed, 114 insertions(+), 38 deletions(-)

diff --git a/ftplugin/opencode_chat.lua b/ftplugin/opencode_chat.lua
index f8e58aaa..6016c585 100644
--- a/ftplugin/opencode_chat.lua
+++ b/ftplugin/opencode_chat.lua
@@ -8,11 +8,13 @@ vim.bo.commentstring = "<!-- %s -->"
 vim.cmd([[
   syntax match OpencodeHeaderUser "^### You$"
   syntax match OpencodeHeaderAssistant "^### Assistant$"
+  syntax match OpencodeHeaderSystem "^### System$"
   syntax match OpencodeSeparator "^─\+$"
   syntax match OpencodeTypingIndicator "^▋$"
 
   highlight default link OpencodeHeaderUser Title
   highlight default link OpencodeHeaderAssistant Special
+  highlight default link OpencodeHeaderSystem Comment
   highlight default link OpencodeSeparator Comment
   highlight default link OpencodeTypingIndicator WarningMsg
 ]])
@@ -20,8 +22,8 @@ vim.cmd([[
 -- Enable treesitter markdown highlighting if available
 local ok, ts_highlight = pcall(require, "vim.treesitter.highlighter")
 if ok then
-  local ok_ts = pcall(vim.treesitter.start, vim.api.nvim_get_current_buf(), "markdown")
-  if not ok_ts then
+  ok = pcall(vim.treesitter.start, vim.api.nvim_get_current_buf(), "markdown")
+  if not ok then
     -- Fallback to basic markdown syntax
     vim.cmd("runtime! syntax/markdown.vim")
   end
diff --git a/lua/opencode/ui/chat.lua b/lua/opencode/ui/chat.lua
index 5c3bd625..5ab2c843 100644
--- a/lua/opencode/ui/chat.lua
+++ b/lua/opencode/ui/chat.lua
@@ -37,8 +37,28 @@ function M.open(opts)
   vim.api.nvim_set_option_value("bufhidden", "wipe", { buf = bufnr })
 
   -- Create floating window
-  local width = opts.width or math.floor(vim.o.columns * (config.width or 0.6))
-  local height = opts.height or math.floor(vim.o.lines * (config.height or 0.7))
+  -- Support both fractional (0-1) and absolute pixel values
+  local width
+  if opts.width ~= nil then
+    if opts.width > 0 and opts.width < 1 then
+      width = math.floor(vim.o.columns * opts.width)
+    else
+      width = opts.width
+    end
+  else
+    width = math.floor(vim.o.columns * (config.width or 0.6))
+  end
+
+  local height
+  if opts.height ~= nil then
+    if opts.height > 0 and opts.height < 1 then
+      height = math.floor(vim.o.lines * opts.height)
+    else
+      height = opts.height
+    end
+  else
+    height = math.floor(vim.o.lines * (config.height or 0.7))
+  end
 
   local winid = vim.api.nvim_open_win(bufnr, true, {
     relative = "editor",
@@ -102,12 +122,6 @@ function M.setup_keymaps(bufnr)
     M.prompt_input()
   end, "Send message")
 
-  -- Navigate messages
-  vim.keymap.set("n", "j", "j", opts)
-  vim.keymap.set("n", "k", "k", opts)
-  vim.keymap.set("n", "gg", "gg", opts)
-  vim.keymap.set("n", "G", "G", opts)
-
   -- Copy message
   set_keymap(keymaps.yank or "yy", function()
     M.yank_current_message()
@@ -121,7 +135,7 @@ function M.setup_keymaps(bufnr)
   -- Interrupt
   set_keymap(keymaps.interrupt or "<C-c>", function()
     M.interrupt()
-  end, vim.tbl_extend("force", opts, { desc = "Interrupt" }))
+  end, "Interrupt")
 end
 
 ---Close chat window
@@ -146,27 +160,46 @@ function M.render()
   local lines = {}
   local highlights = {}
 
+  -- Get window width for dynamic separator
+  local win_width = vim.api.nvim_win_is_valid(M.state.winid) and vim.api.nvim_win_get_width(M.state.winid) or 80
+
   for i, msg in ipairs(M.state.messages) do
     -- Add separator
     if i > 1 then
       table.insert(lines, "")
-      table.insert(lines, string.rep("─", 80))
+      table.insert(lines, string.rep("─", win_width))
       table.insert(lines, "")
     end
 
-    -- Add role header
-    local role = msg.role == "user" and "You" or "Assistant"
-    local header = string.format("### %s", role)
+    -- Add role header with proper role handling
+    local role_label
+    if msg.role == "user" then
+      role_label = "You"
+    elseif msg.role == "system" then
+      role_label = "System"
+    else
+      -- Default to Assistant for assistant role or nil
+      role_label = "Assistant"
+    end
+    local header = string.format("### %s", role_label)
     local header_line = #lines
     table.insert(lines, header)
     table.insert(lines, "")
 
     -- Add highlight for header
+    local hl_group
+    if msg.role == "user" then
+      hl_group = "Title"
+    elseif msg.role == "system" then
+      hl_group = "Comment"
+    else
+      hl_group = "Special"
+    end
     table.insert(highlights, {
       line = header_line,
       col_start = 0,
       col_end = #header,
-      hl_group = msg.role == "user" and "Title" or "Special",
+      hl_group = hl_group,
     })
 
     -- Add message content
@@ -228,7 +261,6 @@ function M.send_message(text)
   table.insert(M.state.messages, {
     role = "user",
     text = text,
-    timestamp = os.time(),
   })
   M.render()
 
@@ -257,18 +289,27 @@ function M.add_message(message)
     return
   end
 
+  -- Validate message has required fields
+  if not message or not message.role then
+    vim.notify("Invalid message: missing role", vim.log.levels.WARN, { title = "opencode" })
+    return
+  end
+
   -- Update last assistant message if streaming
   if message.role == "assistant" and M.state.streaming_message_index then
-    local last = M.state.messages[M.state.streaming_message_index]
-    if last and last.role == "assistant" and last.streaming then
-      last.text = message.text or last.text or ""
-      if message.complete then
-        last.complete = true
-        last.streaming = false
-        M.state.streaming_message_index = nil
+    -- Verify index is within bounds
+    if M.state.streaming_message_index <= #M.state.messages then
+      local last = M.state.messages[M.state.streaming_message_index]
+      if last and last.role == "assistant" and last.streaming then
+        last.text = message.text or last.text or ""
+        if message.complete then
+          last.complete = true
+          last.streaming = false
+          M.state.streaming_message_index = nil
+        end
+        M.render()
+        return
       end
-      M.render()
-      return
     end
   end
 
@@ -339,10 +380,13 @@ function M.interrupt()
   local client = require("opencode.cli.client")
   client.tui_execute_command("session.interrupt", M.state.port, function()
     if M.state and M.state.streaming_message_index then
-      local msg = M.state.messages[M.state.streaming_message_index]
-      if msg then
-        msg.complete = true
-        msg.streaming = false
+      -- Verify index is within bounds
+      if M.state.streaming_message_index <= #M.state.messages then
+        local msg = M.state.messages[M.state.streaming_message_index]
+        if msg then
+          msg.complete = true
+          msg.streaming = false
+        end
       end
       M.state.streaming_message_index = nil
       M.render()
diff --git a/lua/opencode/ui/chat_events.lua b/lua/opencode/ui/chat_events.lua
index bb20e967..2f5fe8ae 100644
--- a/lua/opencode/ui/chat_events.lua
+++ b/lua/opencode/ui/chat_events.lua
@@ -19,17 +19,20 @@ function M.subscribe(port)
     if event.type == "message.delta" then
       -- Streaming message chunk
       local delta = event.properties and event.properties.delta or ""
-      local current_msg = state.messages[state.streaming_message_index]
-      if current_msg then
-        current_msg.text = (current_msg.text or "") .. delta
-        chat.render()
+      -- Verify index is within bounds
+      if state.streaming_message_index and state.streaming_message_index <= #state.messages then
+        local current_msg = state.messages[state.streaming_message_index]
+        if current_msg then
+          current_msg.text = (current_msg.text or "") .. delta
+          chat.render()
+        end
       end
     elseif event.type == "message.created" or event.type == "message.updated" then
       -- Complete message
       local msg = event.properties and event.properties.message
       if msg and msg.role == "assistant" then
         -- Check if we have a streaming message to update
-        if state.streaming_message_index then
+        if state.streaming_message_index and state.streaming_message_index <= #state.messages then
           local current_msg = state.messages[state.streaming_message_index]
           if current_msg then
             current_msg.text = msg.text or current_msg.text or ""
@@ -63,7 +66,7 @@ function M.subscribe(port)
       end
     elseif event.type == "session.idle" then
       -- Session finished responding
-      if state.streaming_message_index then
+      if state.streaming_message_index and state.streaming_message_index <= #state.messages then
         local msg = state.messages[state.streaming_message_index]
         if msg then
           msg.complete = true
@@ -78,7 +81,7 @@ function M.subscribe(port)
       vim.notify("OpenCode error: " .. error_msg, vim.log.levels.ERROR, { title = "opencode" })
 
       -- Mark streaming message as complete if error occurred
-      if state.streaming_message_index then
+      if state.streaming_message_index and state.streaming_message_index <= #state.messages then
         local msg = state.messages[state.streaming_message_index]
         if msg then
           msg.text = (msg.text or "") .. "\n\n[Error: " .. error_msg .. "]"
diff --git a/lua/opencode/ui/chat_init.lua b/lua/opencode/ui/chat_init.lua
index 860b5b71..23bb2790 100644
--- a/lua/opencode/ui/chat_init.lua
+++ b/lua/opencode/ui/chat_init.lua
@@ -27,9 +27,36 @@ function M.start_chat(opts)
       -- Show welcome message
       vim.schedule(function()
         if chat.get_state() then
+          local config = require("opencode.config").opts.chat or {}
+          local keymaps = config.keymaps or {}
+
+          -- Format keymaps for display
+          local function format_keys(keys)
+            if type(keys) == "string" then
+              return keys
+            elseif type(keys) == "table" then
+              return table.concat(keys, "/")
+            end
+            return "?"
+          end
+
+          local send_keys = format_keys(keymaps.send or { "i", "a" })
+          local new_session_key = format_keys(keymaps.new_session or "n")
+          local close_keys = format_keys(keymaps.close or { "q", "<Esc>" })
+          local yank_key = format_keys(keymaps.yank or "yy")
+          local interrupt_key = format_keys(keymaps.interrupt or "<C-c>")
+
           chat.add_message({
             role = "assistant",
-            text = "Chat session starting... Type 'i' or 'a' to send a message.\n\nKeybindings:\n  i/a - Send message\n  n - New session\n  q/<Esc> - Close\n  yy - Yank message\n  <C-c> - Interrupt",
+            text = string.format(
+              "Chat session starting... Type '%s' to send a message.\n\nKeybindings:\n  %s - Send message\n  %s - New session\n  %s - Close\n  %s - Yank message\n  %s - Interrupt",
+              send_keys,
+              send_keys,
+              new_session_key,
+              close_keys,
+              yank_key,
+              interrupt_key
+            ),
             streaming = false,
             complete = true,
           })

From 543a0afc6980eaa307092e162c663d1302cc000d Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 14:32:40 +0000
Subject: [PATCH 8/9] Initial plan


From 4b83a10d3c98590ef5adef2c0e77cb5312be62be Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 5 Jan 2026 14:36:10 +0000
Subject: [PATCH 9/9] Fix cursor position error when buffer is empty in
 new_session

Co-authored-by: verlihirsh <6280012+verlihirsh@users.noreply.github.com>
---
 lua/opencode/ui/chat.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lua/opencode/ui/chat.lua b/lua/opencode/ui/chat.lua
index 5ab2c843..4be0de03 100644
--- a/lua/opencode/ui/chat.lua
+++ b/lua/opencode/ui/chat.lua
@@ -230,7 +230,7 @@ function M.render()
   end
 
   -- Scroll to bottom
-  if vim.api.nvim_win_is_valid(M.state.winid) then
+  if vim.api.nvim_win_is_valid(M.state.winid) and #lines > 0 then
     vim.api.nvim_win_set_cursor(M.state.winid, { #lines, 0 })
   end
 end