diff --git a/lua/avante/llm.lua b/lua/avante/llm.lua
index a0c5f0e..fb2ed72 100644
--- a/lua/avante/llm.lua
+++ b/lua/avante/llm.lua
@@ -139,6 +139,8 @@ M._stream = function(opts)
   ---@type AvanteCurlOutput
   local spec = Provider.parse_curl_args(Provider, code_opts)
 
+  local resp_ctx = {}
+
   ---@param line string
   local function parse_stream_data(line)
     local event = line:match("^event: (.+)$")
@@ -147,7 +149,7 @@ M._stream = function(opts)
       return
     end
     local data_match = line:match("^data: (.+)$")
-    if data_match then Provider.parse_response(data_match, current_event_state, handler_opts) end
+    if data_match then Provider.parse_response(resp_ctx, data_match, current_event_state, handler_opts) end
   end
 
   local function parse_response_without_stream(data)
diff --git a/lua/avante/providers/claude.lua b/lua/avante/providers/claude.lua
index 469c93b..a59bb6d 100644
--- a/lua/avante/providers/claude.lua
+++ b/lua/avante/providers/claude.lua
@@ -77,7 +77,7 @@ M.parse_messages = function(opts)
   return messages
 end
 
-M.parse_response = function(data_stream, event_state, opts)
+M.parse_response = function(ctx, data_stream, event_state, opts)
   if event_state == nil then
     if data_stream:match('"content_block_delta"') then
       event_state = "content_block_delta"
diff --git a/lua/avante/providers/gemini.lua b/lua/avante/providers/gemini.lua
index 11a1660..9e29e4e 100644
--- a/lua/avante/providers/gemini.lua
+++ b/lua/avante/providers/gemini.lua
@@ -64,7 +64,7 @@ M.parse_messages = function(opts)
   }
 end
 
-M.parse_response = function(data_stream, _, opts)
+M.parse_response = function(ctx, data_stream, _, opts)
   local ok, json = pcall(vim.json.decode, data_stream)
   if not ok then opts.on_complete(json) end
   if json.candidates then
diff --git a/lua/avante/providers/init.lua b/lua/avante/providers/init.lua
index 343437b..375c458 100644
--- a/lua/avante/providers/init.lua
+++ b/lua/avante/providers/init.lua
@@ -37,7 +37,7 @@ local DressingState = { winid = nil, input_winid = nil, input_bufnr = nil }
 ---@class ResponseParser
 ---@field on_chunk fun(chunk: string): any
 ---@field on_complete fun(err: string|nil): any
----@alias AvanteResponseParser fun(data_stream: string, event_state: string, opts: ResponseParser): nil
+---@alias AvanteResponseParser fun(ctx: any, data_stream: string, event_state: string, opts: ResponseParser): nil
 ---
 ---@class AvanteDefaultBaseProvider: table<string, any>
 ---@field endpoint? string
diff --git a/lua/avante/providers/openai.lua b/lua/avante/providers/openai.lua
index b5d57e4..fe3eddd 100644
--- a/lua/avante/providers/openai.lua
+++ b/lua/avante/providers/openai.lua
@@ -26,7 +26,8 @@ local P = require("avante.providers")
 ---
 ---@class OpenAIMessage
 ---@field role? "user" | "system" | "assistant"
----@field content string
+---@field content? string
+---@field reasoning_content? string
 ---
 ---@class AvanteProviderFunctor
 local M = {}
@@ -106,19 +107,30 @@ M.parse_messages = function(opts)
   return final_messages
 end
 
-M.parse_response = function(data_stream, _, opts)
+M.parse_response = function(ctx, data_stream, _, opts)
   if data_stream:match('"%[DONE%]":') then
     opts.on_complete(nil)
     return
   end
   if data_stream:match('"delta":') then
     ---@type OpenAIChatResponse
-    local json = vim.json.decode(data_stream)
-    if json.choices and json.choices[1] then
-      local choice = json.choices[1]
+    local jsn = vim.json.decode(data_stream)
+    Utils.debug("jsn", jsn)
+    if jsn.choices and jsn.choices[1] then
+      local choice = jsn.choices[1]
       if choice.finish_reason == "stop" or choice.finish_reason == "eos_token" then
         opts.on_complete(nil)
+      elseif choice.delta.reasoning_content and choice.delta.reasoning_content ~= vim.NIL then
+        if ctx.returned_think_start_tag == nil or not ctx.returned_think_start_tag then
+          ctx.returned_think_start_tag = true
+          opts.on_chunk("<think>\n")
+        end
+        opts.on_chunk(choice.delta.reasoning_content)
       elseif choice.delta.content then
+        if ctx.returned_think_end_tag == nil or not ctx.returned_think_end_tag then
+          ctx.returned_think_end_tag = true
+          opts.on_chunk("\n</think>\n\n")
+        end
         if choice.delta.content ~= vim.NIL then opts.on_chunk(choice.delta.content) end
       end
     end