diff --git a/README.md b/README.md
index 9540b61..7b1d044 100644
--- a/README.md
+++ b/README.md
@@ -55,6 +55,8 @@ OLLIE_MODEL=qwen/qwen3-235b-a22b
 OLLIE_TOOLS_PATH=~/.config/ollie/tools    # directory for tool scripts ({tool} steps)
 OLLIE_MEMORY_PATH=~/.config/ollie/memory  # directory for memory files (ollie/m)
 OLLIE_ELEVATE_SOCKET=${XDG_RUNTIME_DIR}/ollie/elevate.sock  # socket path for x/elevate adapter (default: $XDG_RUNTIME_DIR/ollie/elevate.sock)
+OLLIE_COMPLETE_BACKEND=ollama             # backend for u/complete (required)
+OLLIE_COMPLETE_MODEL=qwen3:latest         # model for u/complete (required)
 ```
 
 Shell environment variables take precedence over the env file.
diff --git a/doc/env.sample b/doc/env.sample
index 8043c47..a325708 100644
--- a/doc/env.sample
+++ b/doc/env.sample
@@ -39,3 +39,7 @@
 
 # kiro / codewhisperer (bearer token or sqlite:// path)
 #OLLIE_KIRO_TOKEN=
+
+# u/complete: backend and model for acme code completion (required by u/complete)
+#OLLIE_COMPLETE_BACKEND=ollama
+#OLLIE_COMPLETE_MODEL=qwen3:latest
diff --git a/scripts/u/complete b/scripts/u/complete
index f772338..bb695c8 100644
--- a/scripts/u/complete
+++ b/scripts/u/complete
@@ -11,7 +11,36 @@ BFG="${0%/*}/../s/bfg"
 cmd=${0##*/}
 die() { printf '%s: %s\n' "$cmd" "$*" >&2; exit 1; }
 
-[ -z "${winid:-}" ] && die "must be run from an acme window (\$winid not set)"
+usage() {
+    cat <<EOF
+usage: $cmd [-model MODEL] [-backend BACKEND]
+
+Flags:
+  -model MODEL      model to use (default: \$OLLIE_COMPLETE_MODEL)
+  -backend BACKEND  backend to use (default: \$OLLIE_COMPLETE_BACKEND)
+  -help             show this help
+EOF
+    exit 0
+}
+
+model=${OLLIE_COMPLETE_MODEL:-}
+backend=${OLLIE_COMPLETE_BACKEND:-}
+
+while [ $# -gt 0 ]; do
+    case $1 in
+        -model)   model=$2;   shift ;;
+        -backend) backend=$2; shift ;;
+        -help)    usage ;;
+        -*) die "unknown flag: $1" ;;
+        *)  break ;;
+    esac
+    shift
+done
+
+[ -z "$model" ]   && die "model required: set OLLIE_COMPLETE_MODEL or pass -model"
+[ -z "$backend" ] && die "backend required: set OLLIE_COMPLETE_BACKEND or pass -backend"
+
+[ -z "${winid:-}" ] || [ "$winid" = "0" ] && die "must be run from an acme window"
 
 # Get filename for language context (last field of ctl line 1)
 filename=$(9p read acme/$winid/ctl | awk 'NR==1{print $NF}')
@@ -33,8 +62,8 @@ suffix=$(9p read acme/$winid/data)
 prefix="${prefix: -$PREFIX_MAX}"
 suffix="${suffix:0:$SUFFIX_MAX}"
 
-# Query model; -agent copilot strips tools and uses a minimal prompt
-result=$("$BFG" -agent copilot \
+# Query model
+result=$("$BFG" -agent copilot -model "$model" -backend "$backend" \
     "Complete the code at the cursor in ${filename}. Output ONLY the text to insert — no explanation, no markdown, no preamble.
 
 <prefix>