diff --git a/install.sh b/install.sh
index 84c5be9742..dface28918 100755
--- a/install.sh
+++ b/install.sh
@@ -625,6 +625,36 @@ _is_pkg_installed() {
     esac
 }
 
+# ── Helper: human-readable apt distro label for the sudo package prompt (#6207) ──
+# Reads /etc/os-release so the Accept? prompt can say which distro we detected and
+# that packages come from that distro's official apt repos (not a tarball).
+_apt_distro_description() {
+    # Plain ( ... ) subshell — not $() — so case/;; stays bash-3.2-safe on macOS.
+    # Bash 3.2 misparses case arms inside command substitution and errors on `;;`.
+    (
+        if [ ! -r /etc/os-release ]; then
+            printf 'a debian-like system'
+            exit 0
+        fi
+        # shellcheck disable=SC1091
+        . /etc/os-release 2>/dev/null || true
+        if [ -n "${NAME:-}" ] && [ -n "${VERSION_ID:-}" ]; then
+            _ad_label="$NAME $VERSION_ID"
+        elif [ -n "${PRETTY_NAME:-}" ]; then
+            _ad_label="$PRETTY_NAME"
+        elif [ -n "${NAME:-}" ]; then
+            _ad_label="$NAME"
+        else
+            printf 'a debian-like system'
+            exit 0
+        fi
+        case " ${ID:-} ${ID_LIKE:-} " in
+            *" debian "*|*" ubuntu "*) _ad_label="${_ad_label} (debian-like)" ;;
+        esac
+        printf '%s' "$_ad_label"
+    )
+}
+
 # ── Helper: install packages via apt, escalating to sudo only if needed ──
 # Usage: _smart_apt_install pkg1 pkg2 pkg3 ...
 _smart_apt_install() {
@@ -655,11 +685,14 @@ _smart_apt_install() {
 
     # Step 3: Escalate -- need elevated permissions for remaining packages
     if command -v sudo >/dev/null 2>&1; then
+        _ad_desc="$(_apt_distro_description)"
         echo ""
         echo "    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
         echo "    WARNING: We require sudo elevated permissions to install:"
         echo "    $_STILL_MISSING"
-        echo "    If you accept, we'll run sudo now, and it'll prompt your password."
+        echo "    Detected ${_ad_desc}."
+        echo "    If you accept, we'll run sudo apt-get to install these packages"
+        echo "    from your distro's official repositories (not a third-party tarball)."
         echo "    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
         echo ""
         printf "    Accept? [Y/n] "
diff --git a/tests/sh/test_apt_distro_prompt.sh b/tests/sh/test_apt_distro_prompt.sh
new file mode 100755
index 0000000000..19601b0065
--- /dev/null
+++ b/tests/sh/test_apt_distro_prompt.sh
@@ -0,0 +1,94 @@
+#!/bin/bash
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
+# Unit tests for install.sh's _apt_distro_description helper (#6207).
+# The sudo Accept? prompt should name the detected distro and say packages come
+# from official apt repos. Hermetic: extract the helper and rewrite
+# /etc/os-release to per-test fixtures (same pattern as test_strixhalo_wsl_reroute.sh).
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+INSTALL_SH="$SCRIPT_DIR/../../install.sh"
+PASS=0
+FAIL=0
+
+_TMP_ROOT=$(mktemp -d)
+trap 'rm -rf "$_TMP_ROOT"' EXIT
+
+assert_eq() {
+    _label="$1"; _expected="$2"; _actual="$3"
+    if [ "$_actual" = "$_expected" ]; then
+        echo "  PASS: $_label"; PASS=$((PASS + 1))
+    else
+        echo "  FAIL: $_label (expected '$_expected', got '$_actual')"; FAIL=$((FAIL + 1))
+    fi
+}
+
+assert_contains() {
+    _label="$1"; _hay="$2"; _needle="$3"
+    case "$_hay" in
+        *"$_needle"*) echo "  PASS: $_label"; PASS=$((PASS + 1)) ;;
+        *) echo "  FAIL: $_label (missing '$_needle' in: $_hay)"; FAIL=$((FAIL + 1)) ;;
+    esac
+}
+
+# Extract helper with /etc/os-release rewritten to $1.
+build_func() {
+    _fix="$1"
+    _f=$(mktemp -p "$_TMP_ROOT")
+    sed -n '/^_apt_distro_description()/,/^}/p' "$INSTALL_SH" \
+        | sed -e "s#/etc/os-release#$_fix/os-release#g" \
+        > "$_f"
+    echo "$_f"
+}
+
+run_desc() {
+    _os="$1"
+    _d=$(mktemp -d -p "$_TMP_ROOT")
+    printf '%s\n' "$_os" > "$_d/os-release"
+    _f=$(build_func "$_d")
+    # shellcheck disable=SC1090
+    . "$_f"
+    _apt_distro_description
+}
+
+echo "=== _apt_distro_description ==="
+
+assert_eq "ubuntu name+version debian-like" \
+    "Ubuntu 24.04 (debian-like)" \
+    "$(run_desc "$(printf 'NAME=\"Ubuntu\"\nVERSION_ID=\"24.04\"\nID=ubuntu\nID_LIKE=debian\n')")"
+
+assert_eq "debian name+version debian-like" \
+    "Debian GNU/Linux 12 (debian-like)" \
+    "$(run_desc "$(printf 'NAME=\"Debian GNU/Linux\"\nVERSION_ID=\"12\"\nID=debian\n')")"
+
+assert_eq "pretty_name fallback when name/version missing" \
+    "Linux Mint 22 (debian-like)" \
+    "$(run_desc "$(printf 'PRETTY_NAME=\"Linux Mint 22\"\nID=linuxmint\nID_LIKE=\"ubuntu debian\"\n')")"
+
+# NAME alone (no VERSION_ID) — still prefer NAME over PRETTY_NAME.
+assert_eq "name only" \
+    "Pop!_OS (debian-like)" \
+    "$(run_desc "$(printf 'NAME=\"Pop!_OS\"\nID=pop\nID_LIKE=\"ubuntu debian\"\n')")"
+
+assert_eq "missing os-release file" \
+    "a debian-like system" \
+    "$(
+        _d=$(mktemp -d -p "$_TMP_ROOT")
+        _f=$(build_func "$_d")
+        # shellcheck disable=SC1090
+        . "$_f"
+        _apt_distro_description
+    )"
+
+echo "=== _smart_apt_install prompt contract ==="
+_smart=$(sed -n '/^_smart_apt_install()/,/^}/p' "$INSTALL_SH")
+assert_contains "calls distro helper" "$_smart" '_apt_distro_description'
+assert_contains "names detected distro" "$_smart" 'Detected ${_ad_desc}'
+assert_contains "mentions apt-get" "$_smart" 'sudo apt-get'
+assert_contains "mentions official repos" "$_smart" "official repositories"
+assert_contains "rejects tarball worry" "$_smart" "not a third-party tarball"
+
+echo ""
+echo "Results: $PASS passed, $FAIL failed"
+[ "$FAIL" -eq 0 ]