diff --git a/src/app/app-shell.tsx b/src/app/app-shell.tsx
index 6c15e08..6c4dcb8 100644
--- a/src/app/app-shell.tsx
+++ b/src/app/app-shell.tsx
@@ -8,8 +8,6 @@ import {
   Moon,
   PanelLeftClose,
   PanelLeftOpen,
-  PanelRightClose,
-  PanelRightOpen,
   ReceiptText,
   Settings,
   Sun,
@@ -110,7 +108,6 @@ export function AppShell() {
   }, [])
 
   const sidebarToggleLabel = sidebarCollapsed ? "Expand navigation" : "Collapse navigation"
-  const assistantToggleLabel = assistantOpen ? "Close assistant" : "Open assistant"
 
   return (
     <AppLockGate>
@@ -124,20 +121,6 @@ export function AppShell() {
               <span>BudgetLens</span>
             </Link>
             <div className="flex items-center gap-1">
-              <Button
-                variant={assistantOpen ? "secondary" : "ghost"}
-                size="icon"
-                aria-label={assistantToggleLabel}
-                title={assistantToggleLabel}
-                aria-expanded={assistantOpen}
-                onClick={() => setAssistantOpen((open) => !open)}
-              >
-                {assistantOpen ? (
-                  <PanelRightClose className="size-5" aria-hidden="true" />
-                ) : (
-                  <PanelRightOpen className="size-5" aria-hidden="true" />
-                )}
-              </Button>
               <Button
                 variant="ghost"
                 size="icon"
diff --git a/src/features/assistant/model-select.tsx b/src/features/assistant/model-select.tsx
index e664b64..acb0cfc 100644
--- a/src/features/assistant/model-select.tsx
+++ b/src/features/assistant/model-select.tsx
@@ -1,8 +1,4 @@
-import { Brain, Check, ChevronDown, Eye, Search } from "lucide-react"
-import { useEffect, useMemo, useRef, useState } from "react"
-
-import { Input } from "@/components/ui/input"
-import { cn } from "@/lib/cn"
+import { useMemo, useState } from "react"
 
 export interface ModelSelectOption {
   id: string
@@ -36,34 +32,6 @@ function groupModels(
     .map(([provider, list]) => ({ provider, models: list }))
 }
 
-function matchesQuery(model: ModelSelectOption, query: string): boolean {
-  const haystack = `${model.name} ${model.id} ${model.provider}`.toLowerCase()
-  return query
-    .toLowerCase()
-    .split(/\s+/)
-    .filter(Boolean)
-    .every((token) => haystack.includes(token))
-}
-
-const PROVIDER_DOT_CLASSES = [
-  "bg-emerald-500",
-  "bg-sky-500",
-  "bg-violet-500",
-  "bg-amber-500",
-  "bg-rose-500",
-  "bg-cyan-500",
-  "bg-orange-500",
-  "bg-pink-500",
-] as const
-
-function providerDotClass(provider: string): string {
-  let hash = 0
-  for (let index = 0; index < provider.length; index += 1) {
-    hash = (hash * 31 + provider.charCodeAt(index)) >>> 0
-  }
-  return PROVIDER_DOT_CLASSES[hash % PROVIDER_DOT_CLASSES.length] ?? "bg-muted-foreground"
-}
-
 const RECENT_MODELS_STORAGE_KEY = "budgetlens.assistant.recent-models.v1"
 const MAX_RECENT_MODELS = 5
 
@@ -98,13 +66,27 @@ function formatContextTokens(tokens: number): string | null {
   return `${trimCompactNumber(tokens / 1000)}k`
 }
 
+function optionLabel(model: ModelSelectOption): string {
+  const flags: string[] = []
+  if (model.free) flags.push("free")
+  if (model.vision === true) flags.push("vision")
+  if (model.reasoning === true) flags.push("reasoning")
+  const contextLabel =
+    typeof model.contextTokens === "number" ? formatContextTokens(model.contextTokens) : null
+  if (contextLabel) flags.push(`${contextLabel} context`)
+  const suffix = flags.length > 0 ? ` (${flags.join(", ")})` : ""
+  return `${model.name} — ${model.provider}${suffix}`
+}
+
+/**
+ * Provider-grouped model picker built on a native select: the browser owns
+ * the expand/collapse, type-to-filter, and keyboard behavior, so there is no
+ * custom collapsed mode to maintain. Recent models lead as the first group;
+ * a stale selected id not present in the list stays visible so the current
+ * choice is never silently dropped.
+ */
 export function ModelSelect({ models, value, onChange, onCustom, disabled }: ModelSelectProps) {
-  const [open, setOpen] = useState(false)
-  const [query, setQuery] = useState("")
-  const [activeId, setActiveId] = useState<string | null>(null)
   const [recentIds, setRecentIds] = useState<string[]>(readRecentModelIds)
-  const searchRef = useRef<HTMLInputElement | null>(null)
-  const listRef = useRef<HTMLDivElement | null>(null)
 
   const selected = models.find((model) => model.id === value)
 
@@ -114,51 +96,20 @@ export function ModelSelect({ models, value, onChange, onCustom, disabled }: Mod
     const list: ModelSelectOption[] = []
     for (const id of recentIds) {
       const model = byId.get(id)
-      if (!model) continue
-      if (query.trim() && !matchesQuery(model, query)) continue
-      list.push(model)
+      if (model) list.push(model)
     }
     return list
-  }, [models, recentIds, query])
+  }, [models, recentIds])
 
-  const filtered = useMemo(() => {
-    const queryModels = query.trim() ? models.filter((model) => matchesQuery(model, query)) : models
+  const groups = useMemo(() => {
     const recentSet = new Set(recentModels.map((model) => model.id))
-    const rest = queryModels.filter((model) => !recentSet.has(model.id))
-    const groups = groupModels(rest).filter((group) => group.models.length > 0)
-    if (recentModels.length === 0) return groups
-    return [{ provider: "Recent", models: recentModels }, ...groups]
-  }, [models, query, recentModels])
-
-  const flatIds = useMemo(
-    () => filtered.flatMap((group) => group.models.map((model) => model.id)),
-    [filtered],
-  )
-
-  useEffect(() => {
-    if (open) {
-      setQuery("")
-      setActiveId(value)
-      searchRef.current?.focus()
-    }
-  }, [open, value])
-
-  useEffect(() => {
-    if (open && activeId) {
-      listRef.current
-        ?.querySelector(`[data-option-id="${CSS.escape(activeId)}"]`)
-        ?.scrollIntoView({ block: "nearest" })
-    }
-  }, [open, activeId])
-
-  function moveActive(direction: 1 | -1) {
-    if (flatIds.length === 0) return
-    const current = activeId ? flatIds.indexOf(activeId) : -1
-    const next = flatIds[(current + direction + flatIds.length) % flatIds.length]
-    if (next) setActiveId(next)
-  }
+    return groupModels(models.filter((model) => !recentSet.has(model.id))).filter(
+      (group) => group.models.length > 0,
+    )
+  }, [models, recentModels])
 
   function choose(id: string) {
+    if (!id) return
     setRecentIds((current) => {
       const next = [id, ...current.filter((entry) => entry !== id)].slice(0, MAX_RECENT_MODELS)
       try {
@@ -169,177 +120,45 @@ export function ModelSelect({ models, value, onChange, onCustom, disabled }: Mod
       return next
     })
     onChange(id)
-    setOpen(false)
   }
 
   return (
-    <div className="relative">
+    <div className="grid gap-1">
+      <select
+        aria-label="Select opencode model"
+        disabled={disabled}
+        value={selected ? value : ""}
+        onChange={(event) => choose(event.target.value)}
+        className="h-9 w-full rounded-xl border border-input bg-background px-2 text-xs outline-none focus-visible:ring-2 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50"
+      >
+        {selected ? null : <option value="">{value}</option>}
+        {recentModels.length > 0 ? (
+          <optgroup label="Recent">
+            {recentModels.map((model) => (
+              <option key={model.id} value={model.id}>
+                {optionLabel(model)}
+              </option>
+            ))}
+          </optgroup>
+        ) : null}
+        {groups.map((group) => (
+          <optgroup key={group.provider} label={group.provider}>
+            {group.models.map((model) => (
+              <option key={model.id} value={model.id}>
+                {optionLabel(model)}
+              </option>
+            ))}
+          </optgroup>
+        ))}
+      </select>
       <button
         type="button"
         disabled={disabled}
-        aria-haspopup="listbox"
-        aria-expanded={open}
-        aria-label="Select opencode model"
-        onClick={() => setOpen((isOpen) => !isOpen)}
-        className={cn(
-          "flex h-9 w-full items-center justify-between gap-2 rounded-xl border border-input bg-background px-2 text-left text-xs",
-          "outline-none focus-visible:ring-2 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50",
-        )}
+        onClick={onCustom}
+        className="w-fit rounded-lg px-2 py-1 text-left text-xs text-muted-foreground outline-none hover:bg-accent hover:text-accent-foreground focus-visible:ring-2 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50"
       >
-        <span className="min-w-0 truncate">
-          <span className="font-medium">{selected?.name ?? value}</span>
-          {selected && <span className="text-muted-foreground"> · {selected.provider}</span>}
-        </span>
-        <ChevronDown className="size-4 shrink-0 text-muted-foreground" aria-hidden="true" />
+        Custom model id…
       </button>
-
-      {open && (
-        <>
-          <button
-            type="button"
-            aria-label="Close model list"
-            tabIndex={-1}
-            className="fixed inset-0 z-40 cursor-default bg-transparent"
-            onClick={() => setOpen(false)}
-          />
-          <div className="absolute inset-x-0 top-full z-50 mt-1 overflow-hidden rounded-xl border bg-card text-card-foreground shadow-xl">
-            <div className="flex items-center gap-2 border-b px-2">
-              <Search className="size-4 shrink-0 text-muted-foreground" aria-hidden="true" />
-              <Input
-                ref={searchRef}
-                aria-label="Search models"
-                value={query}
-                onChange={(event) => {
-                  setQuery(event.target.value)
-                  setActiveId(null)
-                }}
-                onKeyDown={(event) => {
-                  if (event.key === "ArrowDown") {
-                    event.preventDefault()
-                    moveActive(1)
-                  } else if (event.key === "ArrowUp") {
-                    event.preventDefault()
-                    moveActive(-1)
-                  } else if (event.key === "Enter") {
-                    event.preventDefault()
-                    if (activeId) choose(activeId)
-                    else if (flatIds[0]) choose(flatIds[0])
-                  } else if (event.key === "Escape") {
-                    setOpen(false)
-                  }
-                }}
-                placeholder={
-                  models.length > 0 ? `Search ${models.length} models…` : "Search models…"
-                }
-                className="border-0 shadow-none focus-visible:ring-0"
-              />
-            </div>
-            <div ref={listRef} id="assistant-model-list" className="max-h-64 overflow-y-auto p-1">
-              {filtered.length === 0 && (
-                <p className="px-2 py-6 text-center text-xs text-muted-foreground">
-                  No models match “{query}”.
-                </p>
-              )}
-              {filtered.map((group) => (
-                <div key={group.provider}>
-                  <p className="px-2 pt-2 pb-1 text-[11px] font-semibold tracking-wide text-muted-foreground uppercase">
-                    {group.provider}
-                  </p>
-                  {group.models.map((model) => {
-                    const active = model.id === activeId
-                    const isSelected = model.id === value
-                    const contextLabel =
-                      typeof model.contextTokens === "number"
-                        ? formatContextTokens(model.contextTokens)
-                        : null
-                    return (
-                      <button
-                        key={model.id}
-                        type="button"
-                        data-option-id={model.id}
-                        onMouseEnter={() => setActiveId(model.id)}
-                        onClick={() => choose(model.id)}
-                        className={cn(
-                          "flex w-full items-center gap-2 rounded-lg px-2 py-1.5 text-left text-xs",
-                          active ? "bg-accent text-accent-foreground" : undefined,
-                        )}
-                      >
-                        <Check
-                          className={cn(
-                            "size-4 shrink-0",
-                            isSelected ? "opacity-100" : "opacity-0",
-                          )}
-                          aria-hidden="true"
-                        />
-                        <span className="min-w-0">
-                          <span className="flex items-center gap-1.5">
-                            <span
-                              aria-hidden="true"
-                              className={cn(
-                                "size-1.5 shrink-0 rounded-full",
-                                providerDotClass(model.provider),
-                              )}
-                            />
-                            <span className="truncate font-medium">{model.name}</span>
-                            {model.free && (
-                              <span className="shrink-0 rounded-full bg-emerald-500/15 px-1.5 py-px text-[10px] font-semibold text-emerald-600 dark:text-emerald-400">
-                                free
-                              </span>
-                            )}
-                            {model.vision === true && (
-                              <span
-                                title="Vision capable"
-                                className="inline-flex shrink-0 items-center rounded-full bg-muted px-1.5 py-px text-[10px] font-medium text-muted-foreground"
-                              >
-                                <Eye className="size-3" aria-hidden="true" />
-                                <span className="sr-only">Vision capable</span>
-                              </span>
-                            )}
-                            {model.reasoning === true && (
-                              <span
-                                title="Reasoning capable"
-                                className="inline-flex shrink-0 items-center rounded-full bg-muted px-1.5 py-px text-[10px] font-medium text-muted-foreground"
-                              >
-                                <Brain className="size-3" aria-hidden="true" />
-                                <span className="sr-only">Reasoning capable</span>
-                              </span>
-                            )}
-                            {contextLabel && (
-                              <span
-                                title={
-                                  typeof model.contextTokens === "number"
-                                    ? `${model.contextTokens} tokens context`
-                                    : "Large context window"
-                                }
-                                className="shrink-0 rounded-full bg-muted px-1.5 py-px text-[10px] font-medium text-muted-foreground"
-                              >
-                                {contextLabel}
-                              </span>
-                            )}
-                          </span>
-                          <span className="block truncate text-muted-foreground">{model.id}</span>
-                        </span>
-                      </button>
-                    )
-                  })}
-                </div>
-              ))}
-            </div>
-            <div className="border-t p-1">
-              <button
-                type="button"
-                onClick={() => {
-                  setOpen(false)
-                  onCustom()
-                }}
-                className="w-full rounded-lg px-2 py-1.5 text-left text-xs text-muted-foreground hover:bg-accent hover:text-accent-foreground"
-              >
-                Custom model id…
-              </button>
-            </div>
-          </div>
-        </>
-      )}
     </div>
   )
 }