diff --git a/lua/avante/selection.lua b/lua/avante/selection.lua
index 7130fd663..342235c74 100644
--- a/lua/avante/selection.lua
+++ b/lua/avante/selection.lua
@@ -201,7 +201,7 @@ function Selection:create_editing_input()
     input = mentions.new_content
     local project_context = mentions.enable_project_context and RepoMap.get_repo_map(file_ext) or nil
 
-    local diagnostics = Utils.get_current_selection_diagnostics()
+    local diagnostics = Utils.get_current_selection_diagnostics(code_bufnr, self.selection)
 
     Llm.stream({
       bufnr = code_bufnr,
diff --git a/lua/avante/sidebar.lua b/lua/avante/sidebar.lua
index 5ea5116e8..25c9c65ef 100644
--- a/lua/avante/sidebar.lua
+++ b/lua/avante/sidebar.lua
@@ -1542,8 +1542,8 @@ function Sidebar:create_input(opts)
 
     local diagnostics = nil
     if mentions.enable_diagnostics then
-      if self.selected_code ~= nil then
-        diagnostics = Utils.get_current_selection_diagnostics()
+      if self.code ~= nil and self.code.bufnr ~= nil and self.code.selection ~= nil then
+        diagnostics = Utils.get_current_selection_diagnostics(self.code.bufnr, self.code.selection)
       else
         diagnostics = Utils.get_diagnostics(self.code.bufnr)
       end
diff --git a/lua/avante/templates/_diagnostics.avanterules b/lua/avante/templates/_diagnostics.avanterules
index 095907774..23c3be344 100644
--- a/lua/avante/templates/_diagnostics.avanterules
+++ b/lua/avante/templates/_diagnostics.avanterules
@@ -1,11 +1,29 @@
 {%- if use_xml_format -%}
 {%- if diagnostics -%}
+<diagnostic_field_description>
+lnum: The starting line of the diagnostic (1-indexed)
+end_lnum: The final line of the diagnostic (1-indexed)
+col: The starting column of the diagnostic (1-indexed)
+end_col: The final column of the diagnostic (1-indexed)
+severity: The severity of the diagnostic
+message: The diagnostic text
+source: The source of the diagnostic
+</diagnostic_field_description>
 <diagnostics>
 {{diagnostics}}
 </diagnostics>
 {%- endif %}
 {%- else -%}
 {%- if diagnostics -%}
+DIAGNOSTIC_FIELD_DESCRIPTION:
+lnum: The starting line of the diagnostic (1-indexed)
+end_lnum: The final line of the diagnostic (1-indexed)
+col: The starting column of the diagnostic (1-indexed)
+end_col: The final column of the diagnostic (1-indexed)
+severity: The severity of the diagnostic
+message: The diagnostic text
+source: The source of the diagnostic
+
 DIAGNOSTICS:
 {{diagnostics}}
 {%- endif %}
diff --git a/lua/avante/utils/init.lua b/lua/avante/utils/init.lua
index 840ff850f..a84800123 100644
--- a/lua/avante/utils/init.lua
+++ b/lua/avante/utils/init.lua
@@ -772,18 +772,31 @@ function M.update_buffer_content(bufnr, new_lines)
   end
 end
 
+---@param bufnr integer
+---@return vim.Diagnostic[]
 function M.get_diagnostics(bufnr)
   if bufnr == nil then bufnr = api.nvim_get_current_buf() end
-  return vim.diagnostic.get(bufnr, { severity = { vim.diagnostic.severity.ERROR, vim.diagnostic.severity.WARN } })
+  local diagnositcs = ---@type vim.Diagnostic[]
+    vim.diagnostic.get(bufnr, { severity = { vim.diagnostic.severity.ERROR, vim.diagnostic.severity.WARN } })
+  return vim
+    .iter(diagnositcs)
+    :map(function(diagnostic)
+      diagnostic.lnum = diagnostic.lnum + 1
+      diagnostic.end_lnum = diagnostic.end_lnum + 1
+      diagnostic.col = diagnostic.col + 1
+      diagnostic.end_col = diagnostic.end_col + 1
+      return diagnostic
+    end)
+    :totable()
 end
 
-function M.get_current_selection_diagnostics()
-  local selection = M.get_visual_selection_and_range()
-  if not selection then return {} end
-  local diagnostics = M.get_diagnostics()
+---@param bufnr integer
+---@param selection avante.SelectionResult
+function M.get_current_selection_diagnostics(bufnr, selection)
+  local diagnostics = M.get_diagnostics(bufnr)
   local selection_diagnostics = {}
   for _, diagnostic in ipairs(diagnostics) do
-    if selection.range:contains(diagnostic.lnum, diagnostic.col) then
+    if selection.range.start.lnum <= diagnostic.lnum and selection.range.finish.lnum >= diagnostic.end_lnum then
       table.insert(selection_diagnostics, diagnostic)
     end
   end