feat(adapters): add support for Gemini 3 in Copilot (#2419)

Closes #2413

Author: olimorris

lua/codecompanion/adapters/http/copilot/init.lua

@@ -164,11 +164,99 @@ return {
         self.headers["X-Initiator"] = "agent"
       end
 
-      return handlers(self).form_messages(self, messages)
+      local result = handlers(self).form_messages(self, messages)
+
+      -- Transform reasoning data and merge consecutive LLM messages for Copilot API
+      if result.messages then
+        local merged = {}
+        local i = 1
+        while i <= #result.messages do
+          local current = result.messages[i]
+
+          -- Transform reasoning data
+          if current.reasoning then
+            if current.reasoning.content then
+              current.reasoning_text = current.reasoning.content
+            end
+            if current.reasoning.opaque then
+              current.reasoning_opaque = current.reasoning.opaque
+            end
+            current.reasoning = nil
+          end
+
+          -- Check if next message is also from LLM and has tool_calls but no content
+          -- This indicates tool calls that should be merged with the previous message
+          if
+            i < #result.messages
+            and result.messages[i + 1].role == current.role
+            and result.messages[i + 1].tool_calls
+            and not result.messages[i + 1].content
+          then
+            -- Merge tool_calls from next message into current
+            current.tool_calls = result.messages[i + 1].tool_calls
+            i = i + 1 -- Skip the next message since we merged it
+          end
+
+          table.insert(merged, current)
+          i = i + 1
+        end
+        result.messages = merged
+      end
+
+      return result
     end,
     form_tools = function(self, tools)
       return handlers(self).form_tools(self, tools)
     end,
+    form_reasoning = function(self, data)
+      local content = vim
+        .iter(data)
+        :map(function(item)
+          return item.content
+        end)
+        :filter(function(content)
+          return content ~= nil
+        end)
+        :join("")
+
+      local opaque
+      for _, item in ipairs(data) do
+        if item.opaque then
+          opaque = item.opaque
+          break
+        end
+      end
+
+      return {
+        content = content,
+        opaque = opaque,
+      }
+    end,
+    ---Copilot with Gemini 3 provides reasoning data that must be sent back in responses
+    ---@param self CodeCompanion.HTTPAdapter
+    ---@param data table
+    ---@return table
+    parse_message_meta = function(self, data)
+      local extra = data.extra
+      if not extra then
+        return data
+      end
+
+      if extra.reasoning_text then
+        data.output.reasoning = data.output.reasoning or {}
+        data.output.reasoning.content = extra.reasoning_text
+      end
+      if extra.reasoning_opaque then
+        data.output.reasoning = data.output.reasoning or {}
+        data.output.reasoning.opaque = extra.reasoning_opaque
+      end
+
+      if data.output.content == "" then
+        data.output.content = nil
+      end
+
+      return data
+    end,
     tokens = function(self, data)
       if data and data ~= "" then
         local data_mod = adapter_utils.clean_streamed_data(data)

lua/codecompanion/adapters/http/openai.lua

@@ -148,12 +148,19 @@ return {
             end
           end
 
-          return {
+          local result = {
             role = m.role,
             content = m.content,
             tool_calls = tool_calls,
             tool_call_id = m.tools and m.tools.call_id or nil,
           }
+
+          -- Adapter's like Copilot have reasoning fields that must be preserved
+          if m.reasoning then
+            result.reasoning = m.reasoning
+          end
+
+          return result
         end)
         :totable()
 
@@ -302,12 +309,12 @@ return {
       end
 
       return {
-        extra = find_extra_fields(delta),
+        status = "success",
         output = {
           role = delta.role,
           content = delta.content,
         },
-        status = "success",
+        extra = find_extra_fields(delta),
       }
     end,
 

lua/codecompanion/strategies/chat/init.lua

@@ -1014,7 +1014,7 @@ function Chat:_submit_http(payload)
     end
 
     local result = adapters.call_handler(adapter, "parse_chat", data, tools)
-
+    -- TODO: Rename this to be `parse_extra` for clarity
     local parse_meta = adapters.get_handler(adapter, "parse_meta")
     if result and result.extra and type(parse_meta) == "function" then
       result = parse_meta(adapter, result)
@@ -1029,7 +1029,7 @@ function Chat:_submit_http(payload)
         end
         if result.output.reasoning then
           table.insert(reasoning, result.output.reasoning)
-          if config.display.chat.show_reasoning then
+          if config.display.chat.show_reasoning and result.output.reasoning.content then
             self:add_buf_message({
               role = config.constants.LLM_ROLE,
               content = result.output.reasoning.content,
@@ -1218,10 +1218,8 @@ function Chat:done(output, reasoning, tools, meta, opts)
     if vim.iter(reasoning):any(function(item)
       return item and type(item) ~= "string"
     end) then
-      -- `reasoning` contains non-trivial data structure (table, etc.). Invoke the corresponding handler.
       reasoning_content = adapters.call_handler(self.adapter, "build_reasoning", reasoning)
     else
-      -- reasoning is all string. Simply concat them.
       reasoning_content = table.concat(reasoning, "")
     end
   end

…ters/http/stubs/copilot_no_streaming.txt …p/copilot/stubs/copilot_no_streaming.txttests/adapters/http/stubs/copilot_no_streaming.txt renamed to tests/adapters/http/copilot/stubs/copilot_no_streaming.txt tests/adapters/http/stubs/copilot_no_streaming.txt renamed to tests/adapters/http/copilot/stubs/copilot_no_streaming.txt

@@ -0,0 +1,4 @@
+data: {"choices":[{"index":0,"delta":{"content":null,"role":"assistant","reasoning_text":"**Discovering Update Scope**\n\nI'm currently trying to ascertain the extent of the requested update. I need to locate `quotes.lua` within the repository and understand its structure before implementing any modifications. The user's vague instructions necessitate a deeper dive into the file's content to determine the precise nature of the update.\n\n\n"}}],"created":1763682744,"id":"takfaZb8F-DrlOoPh4G-2AU","usage":{"completion_tokens":0,"prompt_tokens":0,"prompt_tokens_details":{"cached_tokens":0},"total_tokens":0,"reasoning_tokens":0},"model":"gemini-3-pro-preview"}
+data: {"choices":[{"index":0,"delta":{"content":null,"role":"assistant","reasoning_text":"**Commencing File Search**\n\nI've initiated the file search. My current focus is solely on locating `quotes.lua` within the repository. Once found, I'll analyze its structure and content. This initial step is critical to comprehend the file's current state and inform my subsequent actions.\n\n\n"}}],"created":1763682744,"id":"takfaZb8F-DrlOoPh4G-2AU","usage":{"completion_tokens":0,"prompt_tokens":0,"prompt_tokens_details":{"cached_tokens":0},"total_tokens":0,"reasoning_tokens":0},"model":"gemini-3-pro-preview"}
+data: {"choices":[{"index":0,"delta":{"content":"I will search for the `quotes.lua` file to locate it within the repository.\n","role":"assistant"}}],"created":1763682744,"id":"takfaZb8F-DrlOoPh4G-2AU","usage":{"completion_tokens":0,"prompt_tokens":0,"prompt_tokens_details":{"cached_tokens":0},"total_tokens":0,"reasoning_tokens":0},"model":"gemini-3-pro-preview"}
+data: {"choices":[{"finish_reason":"tool_calls","index":0,"delta":{"content":null,"role":"assistant","tool_calls":[{"function":{"arguments":"{\"query\":\"**/quotes.lua\"}","name":"file_search"},"id":"call_MHxoeW9qWnVicVd6R0FkMFZ3UWw","index":0,"type":"function"}],"reasoning_opaque":"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"}}],"created":1763682744,"id":"takfaZb8F-DrlOoPh4G-2AU","usage":{"completion_tokens":31,"prompt_tokens":6009,"prompt_tokens_details":{"cached_tokens":0},"total_tokens":6132,"reasoning_tokens":92},"model":"gemini-3-pro-preview"}

…dapters/http/stubs/copilot_streaming.txt …http/copilot/stubs/copilot_streaming.txttests/adapters/http/stubs/copilot_streaming.txt renamed to tests/adapters/http/copilot/stubs/copilot_streaming.txt tests/adapters/http/stubs/copilot_streaming.txt renamed to tests/adapters/http/copilot/stubs/copilot_streaming.txt

@@ -210,11 +210,33 @@ T["Copilot adapter"]["it can form tools to be sent to the API"] = function()
   h.eq({ tools = { weather } }, adapter.handlers.form_tools(adapter, tools))
 end
 
+T["Copilot adapter"]["forms reasoning output"] = function()
+  local messages = {
+    {
+      content = "Content 1\n",
+    },
+    {
+      content = "Content 2\n",
+    },
+    {
+      content = "Content 3\n",
+    },
+    {
+      opaque = "gj5HGhYVIOT",
+    },
+  }
+
+  local form_reasoning = adapter.handlers.form_reasoning(adapter, messages)
+
+  h.eq("Content 1\nContent 2\nContent 3\n", form_reasoning.content)
+  h.eq("gj5HGhYVIOT", form_reasoning.opaque)
+end
+
 T["Copilot adapter"]["Streaming"] = new_set()
 
 T["Copilot adapter"]["Streaming"]["can output streamed data into the chat buffer"] = function()
   local output = ""
-  local lines = vim.fn.readfile("tests/adapters/http/stubs/copilot_streaming.txt")
+  local lines = vim.fn.readfile("tests/adapters/http/copilot/stubs/copilot_streaming.txt")
   for _, line in ipairs(lines) do
     local chat_output = adapter.handlers.chat_output(adapter, line)
     if chat_output and chat_output.output.content then
@@ -227,7 +249,7 @@ end
 
 T["Copilot adapter"]["Streaming"]["can process tools"] = function()
   local tools = {}
-  local lines = vim.fn.readfile("tests/adapters/http/stubs/copilot_tools_streaming.txt")
+  local lines = vim.fn.readfile("tests/adapters/http/copilot/stubs/copilot_tools_streaming.txt")
   for _, line in ipairs(lines) do
     adapter.handlers.chat_output(adapter, line, tools)
   end
@@ -247,6 +269,80 @@ T["Copilot adapter"]["Streaming"]["can process tools"] = function()
   h.eq(tool_output, tools)
 end
 
+T["Copilot adapter"]["Streaming"]["stores reasoning_opaque in extra"] = function()
+  local lines = vim.fn.readfile("tests/adapters/http/copilot/stubs/copilot_tools_streaming_reasoning.txt")
+
+  local output = {}
+  for _, line in ipairs(lines) do
+    local chat_output = adapter.handlers.chat_output(adapter, line)
+    if chat_output then
+      table.insert(output, adapter.handlers.parse_message_meta(adapter, chat_output))
+    end
+  end
+
+  h.expect_starts_with("lgxMQq0m/J6cVjsaH8bbfhxHtAvK4Y", output[#output].output.reasoning.opaque)
+end
+
+T["Copilot adapter"]["Streaming"]["can send reasoning opaque back in messages"] = function()
+  local input = {
+    {
+      content = "Search for quotes.lua",
+      role = "user",
+    },
+    {
+      content = "LLM's response here",
+      reasoning = {
+        content = "Some reasoning here",
+        opaque = "SzZZSfDxyWB",
+      },
+      role = "llm",
+    },
+    {
+      role = "llm",
+      tools = {
+        calls = {
+          {
+            _index = 0,
+            ["function"] = {
+              arguments = '{"dryRun":false,"edits":[{"newText":"    \\"The only limit to our realization of tomorrow will be our doubts of today. - Franklin D. Roosevelt\\",\\n    \\"Talk is cheap. Show me the code. - Linus Torvalds\\",\\n  }","oldText":"    \\"The only limit to our realization of tomorrow will be our doubts of today. - Franklin D. Roosevelt\\",\\n  }","replaceAll":false}],"explanation":"Adding a new quote by Linus Torvalds to the end of the list in quotes.lua.","filepath":"quotes.lua","mode":"append"}',
+              name = "insert_edit_into_file",
+            },
+            id = "call_MHxYMWV1QmRVTng0Znd2b0tyM0Y",
+            type = "function",
+          },
+        },
+      },
+    },
+  }
+
+  local expected = {
+    {
+      content = "Search for quotes.lua",
+      role = "user",
+    },
+    {
+      content = "LLM's response here",
+      role = "llm",
+      reasoning_opaque = "SzZZSfDxyWB",
+      reasoning_text = "Some reasoning here",
+      tool_calls = {
+        {
+          ["function"] = {
+            arguments = '{"dryRun":false,"edits":[{"newText":"    \\"The only limit to our realization of tomorrow will be our doubts of today. - Franklin D. Roosevelt\\",\\n    \\"Talk is cheap. Show me the code. - Linus Torvalds\\",\\n  }","oldText":"    \\"The only limit to our realization of tomorrow will be our doubts of today. - Franklin D. Roosevelt\\",\\n  }","replaceAll":false}],"explanation":"Adding a new quote by Linus Torvalds to the end of the list in quotes.lua.","filepath":"quotes.lua","mode":"append"}',
+            name = "insert_edit_into_file",
+          },
+          id = "call_MHxYMWV1QmRVTng0Znd2b0tyM0Y",
+          type = "function",
+        },
+      },
+    },
+  }
+
+  local output = adapter.handlers.form_messages(adapter, input)
+
+  h.eq({ messages = expected }, output)
+end
+
 T["Copilot adapter"]["No Streaming"] = new_set({
   hooks = {
     pre_case = function()
@@ -260,7 +356,7 @@ T["Copilot adapter"]["No Streaming"] = new_set({
 })
 
 T["Copilot adapter"]["No Streaming"]["can output for the chat buffer"] = function()
-  local data = vim.fn.readfile("tests/adapters/http/stubs/copilot_no_streaming.txt")
+  local data = vim.fn.readfile("tests/adapters/http/copilot/stubs/copilot_no_streaming.txt")
   data = table.concat(data, "\n")
 
   -- Match the format of the actual request
@@ -273,7 +369,7 @@ T["Copilot adapter"]["No Streaming"]["can output for the chat buffer"] = functio
 end
 
 T["Copilot adapter"]["No Streaming"]["can process tools"] = function()
-  local data = vim.fn.readfile("tests/adapters/http/stubs/copilot_tools_no_streaming.txt")
+  local data = vim.fn.readfile("tests/adapters/http/copilot/stubs/copilot_tools_no_streaming.txt")
   data = table.concat(data, "\n")
 
   local tools = {}
@@ -297,7 +393,7 @@ T["Copilot adapter"]["No Streaming"]["can process tools"] = function()
 end
 
 T["Copilot adapter"]["No Streaming"]["can output for the inline assistant"] = function()
-  local data = vim.fn.readfile("tests/adapters/http/stubs/copilot_no_streaming.txt")
+  local data = vim.fn.readfile("tests/adapters/http/copilot/stubs/copilot_no_streaming.txt")
   data = table.concat(data, "\n")
 
   -- Match the format of the actual request