diff --git a/lua/gemini/completion.lua b/lua/gemini/completion.lua
index 000536d..73f6456 100644
--- a/lua/gemini/completion.lua
+++ b/lua/gemini/completion.lua
@@ -58,37 +58,32 @@ local function show_suggestion(suggestion, start_col)
     local line = vim.api.nvim_win_get_cursor(0)[1] - 1
     local line_text = vim.api.nvim_buf_get_lines(0, line, line + 1, true)[1]
     
-    -- Get text before cursor on current line
-    local prefix = string.sub(line_text, 1, start_col)
-    
-    -- Process first line of suggestion
+    -- Get text after cursor on current line
+    local input_after_cursor = string.sub(line_text, start_col + 1)
     local first_line = suggestion_lines[1]
     
-    -- Find the longest common prefix between the input and suggestion
+    -- Find the longest common prefix between the existing text and suggestion
     local common_length = 0
-    local input_after_cursor = string.sub(line_text, start_col + 1)
-    local suggestion_text = first_line
-    
-    while common_length < #input_after_cursor and common_length < #suggestion_text do
+    while common_length < #input_after_cursor and common_length < #first_line do
         if string.sub(input_after_cursor, common_length + 1, common_length + 1) ==
-           string.sub(suggestion_text, common_length + 1, common_length + 1) then
+           string.sub(first_line, common_length + 1, common_length + 1) then
             common_length = common_length + 1
         else
             break
         end
     end
     
-    -- Only show the part of suggestion that doesn't overlap with existing text
-    first_line = string.sub(suggestion_text, common_length + 1)
+    -- Only show the part of suggestion that doesn't overlap
+    first_line = string.sub(first_line, common_length + 1)
     
     if first_line == "" and #suggestion_lines == 1 then return end
     
     current_suggestion.text = suggestion
     current_suggestion.start_col = start_col
     
-    -- Show first line as virtual text only if there's non-overlapping content
+    -- Show first line as virtual text
     if first_line ~= "" then
-        vim.api.nvim_buf_set_extmark(0, current_suggestion.namespace_id, line, start_col + common_length, {
+        vim.api.nvim_buf_set_extmark(0, current_suggestion.namespace_id, line, start_col, {
             virt_text = {{first_line, 'GeminiSuggestion'}},
             virt_text_pos = 'inline',
             virt_text_hide = true,
@@ -102,13 +97,13 @@ local function show_suggestion(suggestion, start_col)
             table.insert(virt_lines, {{suggestion_lines[i], 'GeminiSuggestion'}})
         end
         
-        vim.api.nvim_buf_set_extmark(0, current_suggestion.namespace_id, line, start_col + common_length, {
+        vim.api.nvim_buf_set_extmark(0, current_suggestion.namespace_id, line, start_col, {
             virt_lines = virt_lines,
             virt_lines_above = false,
         })
     end
     
-    debug_print("Showing suggestion (%d lines, common prefix length: %d)", #suggestion_lines, common_length)
+    debug_print("Showing suggestion: '%s' (common length: %d)", first_line, common_length)
 end
 
 function M.accept_suggestion()
@@ -119,7 +114,7 @@ function M.accept_suggestion()
     local line = vim.api.nvim_win_get_cursor(0)[1] - 1
     local col = vim.api.nvim_win_get_cursor(0)[2]
     
-    -- Only accept if we're still at or before the suggestion start
+    -- Only accept if we're still at or after the suggestion start
     if col < current_suggestion.start_col then
         return false
     end
@@ -132,7 +127,7 @@ function M.accept_suggestion()
     local suggestion_lines = vim.split(current_suggestion.text, "\n")
     if #suggestion_lines == 0 then return false end
     
-    -- For the first line, only insert the part that doesn't overlap with existing text
+    -- For the first line, only insert the part that doesn't overlap
     local first_line = suggestion_lines[1]
     local common_length = 0
     while common_length < #text_after_cursor and common_length < #first_line do