diff --git a/lua/core/options.lua b/lua/core/options.lua
index fda04ca..e4d7a6d 100644
--- a/lua/core/options.lua
+++ b/lua/core/options.lua
@@ -31,7 +31,6 @@ vim.opt.completeopt = {
     "menuone",
     "noinsert",
     "noselect",
-    "fuzzy",
 }
 vim.opt.complete = { "o" }
 -- set nowrap
diff --git a/lua/lsp/completion/init.lua b/lua/lsp/completion/init.lua
index dc3d05d..75a063c 100644
--- a/lua/lsp/completion/init.lua
+++ b/lua/lsp/completion/init.lua
@@ -17,8 +17,6 @@ local function on_attach(client, buf)
         return
     end
 
-    vim.bo[buf].omnifunc = "v:lua.ow_lsp_completion.omnifunc"
-
     vim.api.nvim_clear_autocmds({ group = GROUP, buffer = buf })
     vim.api.nvim_create_autocmd("InsertCharPre", {
         buffer = buf,
@@ -208,12 +206,7 @@ function M.setup()
         return "<CR>"
     end, { expr = true, replace_keycodes = true })
 
-    vim.keymap.set(
-        "i",
-        "<C-x><C-o>",
-        session.trigger_manual,
-        { expr = true, remap = false }
-    )
+    vim.keymap.set("i", "<C-x><C-o>", session.trigger)
 end
 
 return M
diff --git a/lua/lsp/completion/session.lua b/lua/lsp/completion/session.lua
index 170ab2d..4979eef 100644
--- a/lua/lsp/completion/session.lua
+++ b/lua/lsp/completion/session.lua
@@ -28,15 +28,15 @@ local function item_range(item)
 end
 
 ---@param response ow.lsp.CompletionResponse
----@return integer? character 0-indexed UTF-16 character where edit starts
-local function response_edit_start(response)
+---@return lsp.Position?
+local function edit_start(response)
     if not response.result or response.err then
         return nil
     end
     local result = response.result
     local defaults = default_range(result.items and result.itemDefaults)
     if defaults then
-        return defaults.start.character
+        return defaults.start
     end
     local items = result.items or result
     if type(items) ~= "table" then
@@ -45,7 +45,7 @@ local function response_edit_start(response)
     for _, item in ipairs(items) do
         local range = item_range(item)
         if range then
-            return range.start.character
+            return range.start
         end
     end
     return nil
@@ -75,54 +75,48 @@ local function apply_defaults(items, defaults)
 end
 
 ---@param responses table<integer, ow.lsp.CompletionResponse>
----@param base string
+---@param base string  text between start col and cursor, used for fuzzy match
 ---@return vim.v.completed_item[]
 local function build_items(responses, base)
-    local entries = {}
+    ---@type vim.v.completed_item[]
+    local items = {}
     for client_id, response in pairs(responses) do
         if response.result and not response.err then
-            local raw = response.result.items or response.result
-            if type(raw) == "table" then
-                apply_defaults(raw, response.result.itemDefaults)
-                for _, item in ipairs(raw) do
-                    entries[#entries + 1] =
-                        { item = item, client_id = client_id }
+            local raw_items = response.result.items or response.result
+            if type(raw_items) == "table" then
+                apply_defaults(raw_items, response.result.itemDefaults)
+                for _, raw in ipairs(raw_items) do
+                    local item = Item.from_lsp(raw, client_id)
+                    local kind_icon, kind_hl = kind.get(raw.kind)
+                    items[#items + 1] = {
+                        word = item.word,
+                        abbr = item.abbr,
+                        kind = kind_icon,
+                        kind_hlgroup = kind_hl,
+                        icase = 1,
+                        dup = 1,
+                        empty = 1,
+                        user_data = {
+                            ow = {
+                                item = item,
+                            },
+                        },
+                        filter = raw.filterText or raw.label,
+                    }
                 end
             end
         end
     end
-
     if base ~= "" then
-        entries = vim.tbl_filter(function(entry)
-            local key = entry.item.filterText or entry.item.label
-            return vim.startswith(key, base)
-        end, entries)
+        if vim.o.completeopt:find("fuzzy", 1, true) then
+            items = vim.fn.matchfuzzy(items, base, { key = "filter" })
+        else
+            items = vim.tbl_filter(function(item)
+                return vim.startswith(item.filter, base)
+            end, items)
+        end
     end
-
-    -- for _, entry in ipairs(entries) do
-    --     entry.sort_key = entry.item.sortText or entry.item.label
-    -- end
-    -- table.sort(entries, function(a, b)
-    --     return a.sort_key < b.sort_key
-    -- end)
-
-    ---@type vim.v.completed_item[]
-    local result = {}
-    for _, entry in ipairs(entries) do
-        local item = Item.from_lsp(entry.item, entry.client_id)
-        local kind_icon, kind_hl = kind.get(entry.item.kind)
-        result[#result + 1] = {
-            word = item.word,
-            abbr = item.abbr,
-            kind = kind_icon,
-            kind_hlgroup = kind_hl,
-            icase = 1,
-            dup = 1,
-            empty = 1,
-            user_data = { ow = { item = item } },
-        }
-    end
-    return result
+    return items
 end
 
 local function buffer_has_completion_client()
@@ -161,19 +155,12 @@ local function is_trigger_char(char)
     return false
 end
 
-local function feed_omnifunc()
-    if vim.fn.mode() ~= "i" or vim.fn.pumvisible() ~= 0 then
-        return
-    end
-    vim.api.nvim_feedkeys(vim.keycode("<C-x><C-o>"), "n", false)
-end
-
 ---@class ow.lsp.completion.Session
----@field private generation integer
----@field private phase ('awaiting' | 'ready' | 'done')?
----@field private result table<integer, ow.lsp.CompletionResponse>?
+---@field private generation integer  monotonic counter for discarding stale async callbacks
 ---@field private cancel function?
----@field trigger_char string?
+---@field private trigger_char string?
+---@field private manual boolean
+---@field is_incomplete boolean  server flagged last response as truncated
 local Session = {}
 Session.__index = Session
 
@@ -181,39 +168,28 @@ Session.__index = Session
 function Session.new()
     return setmetatable({
         generation = 0,
-        phase = nil,
-        result = nil,
         cancel = nil,
         trigger_char = nil,
+        manual = false,
+        is_incomplete = false,
     }, Session)
 end
 
----@return boolean
-function Session:is_awaiting()
-    return self.phase == "awaiting"
-end
-
----@return boolean
-function Session:is_ready()
-    return self.phase == "ready"
-end
-
 function Session:discard()
     if self.cancel then
         pcall(self.cancel)
     end
     self.generation = self.generation + 1
-    self.phase = nil
-    self.result = nil
     self.cancel = nil
 end
 
 ---@param trigger_kind integer
 ---@param trigger_char? string
-function Session:dispatch(trigger_kind, trigger_char)
+---@param manual? boolean  true when invoked by the user (via M.trigger)
+function Session:dispatch(trigger_kind, trigger_char, manual)
     self:discard()
-    self.phase = "awaiting"
     self.trigger_char = trigger_char
+    self.manual = manual or false
     local gen = self.generation
     local buf = vim.api.nvim_get_current_buf()
     local params = vim.lsp.util.make_position_params(0, "utf-16")
@@ -227,60 +203,63 @@ function Session:dispatch(trigger_kind, trigger_char)
         vim.lsp.protocol.Methods.textDocument_completion,
         params,
         function(result)
-            if self.generation ~= gen or self.phase ~= "awaiting" then
+            if self.generation ~= gen then
                 return
             end
-            self.phase = "ready"
-            self.result = result
-            feed_omnifunc()
+            vim.schedule(function()
+                -- Re-check: another dispatch may have fired between response
+                -- and the scheduled callback running.
+                if self.generation ~= gen then
+                    return
+                end
+                if vim.fn.mode() ~= "i" then
+                    return
+                end
+                local word_start, cursor = word_bounds()
+                if
+                    not self.manual
+                    and not self.trigger_char
+                    and word_start == cursor
+                then
+                    return
+                end
+                self.is_incomplete = false
+                for _, response in pairs(result) do
+                    local r = response.result
+                    if type(r) == "table" and r.isIncomplete then
+                        self.is_incomplete = true
+                        break
+                    end
+                end
+                local start = word_start
+                for _, response in pairs(result) do
+                    local pos = edit_start(response)
+                    if pos then
+                        start = pos.character
+                        break
+                    end
+                end
+                local base =
+                    vim.api.nvim_get_current_line():sub(start + 1, cursor)
+                vim.fn.complete(start + 1, build_items(result, base))
+            end)
         end
     )
 end
 
----@return integer
-function Session:start_col()
-    for _, response in pairs(self.result or {}) do
-        local col = response_edit_start(response)
-        if col then
-            return col
-        end
-    end
-    local start = word_bounds()
-    return start
-end
-
----@param base string
----@return vim.v.completed_item[]
-function Session:finalize(base)
-    local items = build_items(self.result or {}, base)
-    self.phase = "done"
-    return items
-end
-
----@type ow.lsp.completion.Session?
-local session = nil
+local session = Session.new()
 
 local dispatcher = util.debounce(function(_, trigger_kind, char)
     if vim.fn.mode() ~= "i" then
         return
     end
-    if not session then
-        session = Session.new()
-    end
     session:dispatch(trigger_kind, char)
 end, REQUEST_DEBOUNCE_MS)
 
--- Set by `trigger_manual` when the user explicitly invokes completion via
--- <C-x><C-o>. Survives the dispatch+response round-trip so the omnifunc knows
--- to skip the "no word before cursor" guard. Reset on the next auto trigger.
-local manual_pending = false
-
 local M = {}
 
----Expose for the <C-x><C-o> keymap wrapper.
-function M.trigger_manual()
-    manual_pending = true
-    return vim.keycode("<C-x><C-o>")
+function M.trigger()
+    session:dispatch(vim.lsp.protocol.CompletionTriggerKind.Invoked, nil, true)
 end
 
 function M.on_insert_char_pre()
@@ -288,61 +267,24 @@ function M.on_insert_char_pre()
     if char == "" then
         return
     end
-    manual_pending = false
+    if not buffer_has_completion_client() then
+        return
+    end
     local is_word = char:match("[%w_]") ~= nil
     local is_trigger = not is_word and is_trigger_char(char)
     if not (is_word or is_trigger) then
         return
     end
-    -- For word chars, let Vim's native in-place filtering handle things while
-    -- the pum is already showing. Trigger chars always schedule a request
-    -- because they change the completion context (e.g. member access).
-    if is_word and vim.fn.pumvisible() ~= 0 then
+    -- Word chars: let Vim's native in-place filtering narrow the already-
+    -- visible pum. Re-dispatch only if the server flagged the last response
+    -- as incomplete (meaning it expects to be re-queried on more input).
+    if is_word and vim.fn.pumvisible() ~= 0 and not session.is_incomplete then
         return
     end
-
     local kind_num = is_trigger
             and vim.lsp.protocol.CompletionTriggerKind.TriggerCharacter
         or vim.lsp.protocol.CompletionTriggerKind.Invoked
     dispatcher:call(nil, kind_num, is_trigger and char or nil)
 end
 
--- Global entry point for Vim's 'omnifunc' option. Referenced via
--- `v:lua.ow_lsp_completion.omnifunc` from on_attach's `vim.bo.omnifunc`.
-_G.ow_lsp_completion = _G.ow_lsp_completion or {}
-
----@param findstart 0 | 1
----@param base string
----@return integer | vim.v.completed_item[]
-function _G.ow_lsp_completion.omnifunc(findstart, base)
-    if not session then
-        session = Session.new()
-    end
-    if not buffer_has_completion_client() or session:is_awaiting() then
-        return findstart == 1 and -3 or {}
-    end
-    if
-        findstart == 1
-        and session:is_ready()
-        and not manual_pending
-        and not session.trigger_char
-    then
-        local start, cursor = word_bounds()
-        if start == cursor then
-            return -3
-        end
-    end
-    if not session:is_ready() then
-        session:dispatch(vim.lsp.protocol.CompletionTriggerKind.Invoked)
-        return findstart == 1 and -3 or {}
-    end
-    if findstart == 1 then
-        return session:start_col()
-    end
-    local items = session:finalize(base)
-    session = nil
-    manual_pending = false
-    return items
-end
-
 return M