diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 9722d6d1..8e4d2ef4 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -42,6 +42,11 @@ jobs:
           npm install -g @devcontainers/cli
           devcontainer build --workspace-folder . --config devcontainer.json --image-name cs50/codespace:${{ github.sha }} --image-name cs50/codespace:latest
 
+      - name: Smoke-test (latest)
+        if: ${{ github.ref == 'refs/heads/main' }}
+        run: |
+          bash tests/smoke.sh cs50/codespace:latest
+
       - name: Push (latest) to GitHub Packages
         if: ${{ github.ref == 'refs/heads/main' }}
         run: |
@@ -72,6 +77,11 @@ jobs:
           npm install -g @devcontainers/cli
           devcontainer build --workspace-folder . --config devcontainer.json --image-name cs50/codespace:${{ github.sha }} --image-name cs50/codespace:${{ github.ref_name }}
 
+      - name: Smoke-test (${{ github.ref_name }})
+        if: ${{ github.ref != 'refs/heads/main' }}
+        run: |
+          bash tests/smoke.sh cs50/codespace:${{ github.ref_name }}
+
       - name: Squash (${{ github.ref_name }})
         if: ${{ github.ref != 'refs/heads/main' }}
         run: |
diff --git a/Dockerfile b/Dockerfile
index af014aa5..32a395ea 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -94,6 +94,13 @@ RUN npm install --global @vscode/vsce yarn && \
     mv design50-1.0.0.vsix /opt/cs50/extensions && \
     cd /tmp && \
     rm --force --recursive design50.vsix && \
+    git clone https://github.com/cs50/help50.vsix.git && \
+    cd help50.vsix && \
+    npm install && \
+    vsce package && \
+    mv help50-0.0.1.vsix /opt/cs50/extensions && \
+    cd /tmp && \
+    rm --force --recursive help50.vsix && \
     npm uninstall --global vsce yarn
 
 
diff --git a/devcontainer.json b/devcontainer.json
index 3ce0bc46..ba6d181c 100644
--- a/devcontainer.json
+++ b/devcontainer.json
@@ -14,6 +14,7 @@
                 "/opt/cs50/extensions/cs50-0.0.1.vsix",
                 "/opt/cs50/extensions/design50-1.0.0.vsix",
                 "/opt/cs50/extensions/ddb50-2.0.0.vsix",
+                "/opt/cs50/extensions/help50-0.0.1.vsix",
                 "/opt/cs50/extensions/phpliteadmin-0.0.1.vsix",
                 "/opt/cs50/extensions/style50-0.0.1.vsix",
                 "cs50.extension-uninstaller",
@@ -189,7 +190,11 @@
                 "terminal.integrated.defaultProfile.linux": "bash",
                 "terminal.integrated.gpuAcceleration": "off",
                 "terminal.integrated.profiles.linux": {
-                    "JavaScript Debug Terminal": null
+                    "JavaScript Debug Terminal": null,
+                    "Sysadmins": {
+                        "path": "sudo",
+                        "args": ["bash"]
+                    }
                 },
                 "terminal.integrated.persistentSessionReviveProcess": "never",
                 "terminal.integrated.sendKeybindingsToShell": true,
diff --git a/etc/profile.d/codespace.sh b/etc/profile.d/codespace.sh
index f49ed703..e55cc267 100644
--- a/etc/profile.d/codespace.sh
+++ b/etc/profile.d/codespace.sh
@@ -1,5 +1,10 @@
 # If not root
-if [ "$(whoami)" != "root" ]; then
+if [ `id -u` -ne 0 ]; then
+
+    # Library (from cs50/cli; absent in images built before help50 landed there)
+    if [ -f /opt/cs50/lib/cli ]; then
+        . /opt/cs50/lib/cli
+    fi
 
     # Check if running locally and set $RepositoryName if not already set
     if [[ "$CODESPACES" != "true" && -z "$RepositoryName" ]]; then
@@ -7,6 +12,9 @@ if [ "$(whoami)" != "root" ]; then
         export LOCAL_WORKSPACE_FOLDER="/workspaces/$RepositoryName"
     fi
 
+    # Where help50's helpers look for misplaced files (cs50/cli defaults this to $HOME)
+    export WORKDIR="/workspaces/$RepositoryName"
+
     # Rewrites URLs of the form http://HOST:PORT as https://$CODESPACE_NAME.app.github.dev:PORT
     _hostname() {
 
@@ -79,4 +87,53 @@ if [ "$(whoami)" != "root" ]; then
     http-server() {
         command http-server "$@" | _hostname | _version | uniq
     }
+
+    # help50 hooks, called by _help50 in /etc/profile.d/help50.sh after each command.
+    # When no local helper has advice, these relay the failed command's output to the
+    # help50 VS Code extension via command50, which shows a "help50" button in the
+    # terminal's title bar; clicking it asks the CS50 Duck to explain the error.
+    # command50 runs detached with output discarded so the prompt isn't delayed and a
+    # missing extension server degrades silently.
+    _help50_button() {
+        ( command50 help50.showButton "$1" "$2" > /dev/null 2>&1 & )
+        _HELP50_BUTTON=1
+    }
+    _help50_hide() {
+        if [[ -n "$_HELP50_BUTTON" ]]; then
+            ( command50 help50.hideButton > /dev/null 2>&1 & )
+            unset _HELP50_BUTTON
+        fi
+    }
+
+    # A helper had advice: show it here, as in cs50/cli. No button, since the advice is
+    # already on screen; a button still showing is about an earlier command.
+    _helpful() {
+        for name in n no y yes; do
+            alias $name=_rhetorical # Intercept answers to the rhetorical question
+        done
+        _alert "$(_ansi "$1")"
+        _help50_hide
+    }
+
+    # No helper matched: offer the duck the failed command's output to explain.
+    # If there's no output (e.g., grep with no match, or a program exiting 1), there's
+    # nothing to explain, and any button still showing is about an earlier command.
+    # $1 is the output, $2 the command line; the duck gets both, as a transcript.
+    _helpless() {
+        if [[ -z "${1//[[:space:]]/}" ]]; then
+            _help50_hide
+            return
+        fi
+        _alert "$(_ansi "🦆 Click \`help50\` above for help with that error.")"
+        if [[ -n "$2" ]]; then
+            _help50_button ask "$ $2"$'\n'"$1"
+        else
+            _help50_button ask "$1"
+        fi
+    }
+
+    # Command succeeded: hide the button, if showing
+    _helped() {
+        _help50_hide
+    }
 fi
diff --git a/tests/smoke.sh b/tests/smoke.sh
new file mode 100755
index 00000000..cafbb5fd
--- /dev/null
+++ b/tests/smoke.sh
@@ -0,0 +1,59 @@
+#!/bin/bash
+# Smoke-tests a built cs50/codespace image. Usage: tests/smoke.sh [IMAGE]
+# Each check has a timeout so that a regression that hangs the shell fails loudly.
+
+set -o errexit -o errtrace -o nounset -o pipefail
+step="startup"
+trap 'echo "FAILED: $step" >&2' ERR
+
+IMAGE="${1:-cs50/codespace}"
+run() { timeout 60 docker run --rm --env CODESPACES=true --env RepositoryName=smoke "$@"; }
+check() { step="$1"; echo "- $step"; }
+skip() { echo "- SKIPPED: $1"; }
+
+echo "Checking $IMAGE"
+
+check "login shells start without errors"
+test -z "$(run "$IMAGE" bash --login -c 'true' 2>&1)"
+
+check "non-interactive login shell exits (help50 must not start without a terminal)"
+run "$IMAGE" bash --login -c 'echo ok' | grep -qx ok
+echo true | run --interactive "$IMAGE" bash --login
+
+# The rest applies once the cs50/cli base image carries help50 (cs50/cli#210).
+# Branch builds use cs50/cli:amd64 (main), canary uses cs50/cli:canary.
+if run "$IMAGE" bash --login -c 'test -f /etc/profile.d/help50.sh -a -f /opt/cs50/lib/cli'; then
+
+    check "help50 is inherited from cs50/cli and its hooks are overridden by codespace.sh"
+    run "$IMAGE" bash --login -c '
+        test "$(type -P help50)" = /opt/cs50/bin/help50 &&
+        test "$WORKDIR" = /workspaces/smoke &&
+        for f in _helped _helpful _helpless _help50_button _alert _ansi; do declare -F "$f" > /dev/null || { echo "missing $f" >&2; exit 1; }; done &&
+        declare -f _help50_button | grep -q command50'
+
+    check "hooks behave: advice is printed, empty output is ignored (no extension server needed)"
+    run "$IMAGE" bash --login -c '
+        _helpful "Did you mean \`ls\`?" 2>&1 | grep -q "Did you mean" &&
+        test -z "$(_helpless "" 2>&1)" &&
+        test -z "$(_helpless "   " 2>&1)" &&
+        _helpless "cat: x: No such file" 2>&1 | grep -q help50'
+
+    # _help50_button discards command50's output, so stub it to see the payload
+    check "the duck gets the command line and output as a transcript (or output alone without a command)"
+    run "$IMAGE" bash --login -c '
+        _alert() { :; }
+        _help50_button() { printf "%s" "$2"; }
+        test "$(_helpless "cat: x: No such file" "cat x")" = "$(printf "%s\n%s" "$ cat x" "cat: x: No such file")" &&
+        test "$(_helpless "cat: x: No such file")" = "cat: x: No such file" &&
+        test -z "$(_helpless "   " "cat x")"'
+
+    check "root shells (Sysadmins profile) do not start help50"
+    run --user root "$IMAGE" bash --login -c 'test -z "${HELP50:-}" && ! declare -F _helpful > /dev/null'
+else
+    skip "help50 checks: base image has no help50 (cs50/cli without #210)"
+fi
+
+check "help50 extension is packaged for installation"
+run "$IMAGE" bash --login -c 'test -f /opt/cs50/extensions/help50-0.0.1.vsix && command -v command50 > /dev/null'
+
+echo "OK"