diff --git a/docs/SPEC.md b/docs/SPEC.md
index b6cfa09..6c08df9 100644
--- a/docs/SPEC.md
+++ b/docs/SPEC.md
@@ -409,7 +409,25 @@ Open questions on the schema:
   earlier run. No reject/dismiss command yet — see Status below.)*
 - **Scheduling**: systemd `.service` (oneshot) + `.timer` running it
   periodically, matching the pattern already used for other periodic tasks
-  on this box. *(Not implemented — still a single one-shot `cargo run`.)*
+  on this box. *(Implemented — user-level units under `systemd/`, run 10s
+  after login and then hourly, non-persistent. Install from the main
+  checkout:*
+
+  ```sh
+  cargo build --release && mkdir -p ~/.config/systemd/user &&
+    cp systemd/* ~/.config/systemd/user/ && systemctl --user daemon-reload &&
+    systemctl --user enable --now pkgwatch.timer
+  ```
+
+  *`pkgwatch.service` sets `WorkingDirectory` to `~/dev/pkgwatch` because
+  `packages.d/`, `state/` and `work/` resolve relative to cwd.)*
+- **Notifications**: `notifier.rs` sends a desktop notification
+  (`notify-send`) when a tier 4-6 release is newly queued for review or a
+  tier 1-3 release is published; both are best-effort and never fail a
+  run. A non-zero exit (verification/build/network failure) triggers
+  `pkgwatch-failure.service` via `OnFailure=`. Approving via
+  `pkgwatch review --approve` doesn't notify — the operator is already at
+  the terminal.
 
 ## Prior art / reference points
 
@@ -473,7 +491,8 @@ Open questions on the schema:
       ever actually fails on it.
 - [ ] Not yet implemented: `pkgwatch review <name> --reject` (a pending
       review can only be approved or left pending, not dismissed),
-      scheduling/`check_interval`, non-GitHub sources, `minisign`/tier-1
+      per-package `check_interval` (the timer is a fixed hourly tick),
+      non-GitHub sources, `minisign`/tier-1
       method, retention/pruning of old versions in the local repo (see
       Scaling > Local repo retention), staggering/auth for GitHub API
       rate limits at higher package counts.
diff --git a/src/main.rs b/src/main.rs
index 300ac6b..9f992b6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,6 +8,7 @@ mod config;
 mod fetcher;
 mod github;
 mod hash;
+mod notifier;
 mod pipeline;
 mod publisher;
 mod sanity;
diff --git a/src/notifier.rs b/src/notifier.rs
new file mode 100644
index 0000000..a7a3bab
--- /dev/null
+++ b/src/notifier.rs
@@ -0,0 +1,111 @@
+//! Tells the operator, via a desktop notification, that a package needs
+//! attention (a tier 4-6 release awaiting review) or just landed in the
+//! local repo. Best-effort: a missing `notify-send` or session bus must
+//! never fail a run, since the pipeline's real outcome is already in
+//! state and stdout.
+
+use std::path::Path;
+use std::process::Command;
+
+/// What happened to a package that the operator should hear about.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Event<'a> {
+    /// Tier 4-6: verified, waiting on `pkgwatch review <name> --approve`.
+    NeedsReview { name: &'a str, version: &'a str },
+    /// Tier 1-3: built and added to the local repo, waiting on `pacman -Syu`.
+    Published { name: &'a str, version: &'a str },
+}
+
+/// (summary, body) for `event` — pure, so the wording is unit-testable
+/// without a notification daemon.
+fn message(event: Event<'_>) -> (String, String) {
+    match event {
+        Event::NeedsReview { name, version } => (
+            format!("{name} {version} needs review"),
+            format!("Run `pkgwatch review {name} --approve`, then `sudo pacman -Syu`."),
+        ),
+        Event::Published { name, version } => (
+            format!("{name} {version} published"),
+            "Run `sudo pacman -Syu` to install it.".to_string(),
+        ),
+    }
+}
+
+/// Best-effort desktop notification via the real `notify-send`; never
+/// fails the caller.
+pub fn notify(event: Event<'_>) {
+    notify_with(Path::new("notify-send"), event);
+}
+
+/// `notify_send_bin` is injectable for the same reason as
+/// `publisher::publish_with`'s `repo_add_bin`.
+fn notify_with(notify_send_bin: &Path, event: Event<'_>) {
+    let (summary, body) = message(event);
+    let result = Command::new(notify_send_bin)
+        .args(["--app-name=pkgwatch", "--", &summary, &body])
+        .status();
+    match result {
+        Ok(status) if status.success() => {}
+        Ok(status) => eprintln!("  warning: notify-send exited with {status}"),
+        Err(err) => eprintln!("  warning: could not run notify-send: {err}"),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_support::write_executable_script;
+
+    #[test]
+    fn message_for_review_names_the_approve_command() {
+        let (summary, body) = message(Event::NeedsReview {
+            name: "claude-code",
+            version: "v2.1.278",
+        });
+        assert_eq!(summary, "claude-code v2.1.278 needs review");
+        assert!(body.contains("pkgwatch review claude-code --approve"));
+    }
+
+    #[test]
+    fn message_for_publish_points_at_pacman() {
+        let (summary, body) = message(Event::Published {
+            name: "uv",
+            version: "0.12.17",
+        });
+        assert_eq!(summary, "uv 0.12.17 published");
+        assert!(body.contains("pacman -Syu"));
+    }
+
+    #[test]
+    fn notify_invokes_binary_with_summary_and_body() {
+        let stub_dir = tempfile::tempdir().unwrap();
+        let log_path = stub_dir.path().join("invoked_with.txt");
+        let stub = write_executable_script(
+            stub_dir.path(),
+            "fake-notify-send",
+            &format!("printf '%s\\n' \"$@\" > {}", log_path.display()),
+        );
+
+        notify_with(
+            &stub,
+            Event::Published {
+                name: "uv",
+                version: "0.12.17",
+            },
+        );
+
+        let invoked_with = std::fs::read_to_string(&log_path).unwrap();
+        assert!(invoked_with.contains("uv 0.12.17 published"));
+    }
+
+    #[test]
+    fn notify_survives_missing_binary() {
+        notify_with(
+            Path::new("/nonexistent/notify-send"),
+            Event::NeedsReview {
+                name: "x",
+                version: "1",
+            },
+        );
+    }
+}
diff --git a/src/pipeline.rs b/src/pipeline.rs
index 8d0b037..5b8d5bc 100644
--- a/src/pipeline.rs
+++ b/src/pipeline.rs
@@ -10,6 +10,7 @@ use crate::checker;
 use crate::config::{self, Package};
 use crate::fetcher::{self, DownloadedAsset};
 use crate::github::GithubEndpoints;
+use crate::notifier::{self, Event};
 use crate::publisher;
 use crate::sanity;
 use crate::state;
@@ -151,6 +152,10 @@ fn process_package(
             state::save_last_version(state_dir, name, &latest)?;
             state::clear_pending_version(state_dir, name)?;
             println!("  published {name} {latest}");
+            notifier::notify(Event::Published {
+                name,
+                version: &latest,
+            });
         }
         TierAction::StillPending => {
             println!("  tier 4-6 pass: still pending review (`pkgwatch review` to see it)");
@@ -165,6 +170,10 @@ fn process_package(
                     "  tier 4-6 pass: flagged for human review (`pkgwatch review` to approve)"
                 ),
             }
+            notifier::notify(Event::NeedsReview {
+                name,
+                version: &latest,
+            });
         }
     }
     Ok(())
diff --git a/src/test_support.rs b/src/test_support.rs
index 49b701a..d53c80b 100644
--- a/src/test_support.rs
+++ b/src/test_support.rs
@@ -1,21 +1,54 @@
 //! Test-only fixture helpers shared across modules' `#[cfg(test)]` code
-//! (`publisher`, `sanity`) — not production code, and not built outside
+//! (`publisher`, `sanity`, `notifier`) — not production code, and not built outside
 //! `cargo test`. See docs/ARCHITECTURE.md > "organize by pipeline stage, not
 //! by layer": this exists to remove one specific piece of duplication
 //! (two near-identical copies of "write an executable shell script"), not
 //! as a general test-utils dump.
 
 use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::time::{Duration, Instant};
+
+/// Set by `wait_until_executable`'s probe so the script exits before
+/// running its real body.
+const PROBE_ENV: &str = "PKGWATCH_TEST_SCRIPT_PROBE";
+/// `ETXTBSY`: exec of a file some process still has open for writing.
+const TEXT_FILE_BUSY: i32 = 26;
 
 /// Writes an executable `#!/bin/sh` script named `name` into `dir`,
 /// running `body` as its contents. Used to stand in for a real binary
 /// (`repo-add`, a package's own `--version` command) in tests, without
 /// needing the real tool installed or a mutated global `PATH`.
+///
+/// Doesn't return until the script can actually be exec'd. `cargo test`
+/// runs tests on parallel threads, and a `fork` on another thread between
+/// this function's write-open and close leaves the child holding a copy of
+/// the write fd until it execs, so an immediate exec of the new script can
+/// fail with `Text file busy`. Once no holder is left none can appear (our
+/// fd is closed), so a probe exec that succeeds proves later ones will.
 pub(crate) fn write_executable_script(dir: &Path, name: &str, body: &str) -> PathBuf {
     let path = dir.join(name);
-    std::fs::write(&path, format!("#!/bin/sh\n{body}\n")).unwrap();
+    std::fs::write(
+        &path,
+        format!("#!/bin/sh\n[ -z \"${PROBE_ENV}\" ] || exit 0\n{body}\n"),
+    )
+    .unwrap();
     let mut perms = std::fs::metadata(&path).unwrap().permissions();
     std::os::unix::fs::PermissionsExt::set_mode(&mut perms, 0o755);
     std::fs::set_permissions(&path, perms).unwrap();
+    wait_until_executable(&path);
     path
 }
+
+fn wait_until_executable(path: &Path) {
+    let deadline = Instant::now() + Duration::from_secs(5);
+    loop {
+        match Command::new(path).env(PROBE_ENV, "1").status() {
+            Ok(_) => return,
+            Err(err) if err.raw_os_error() == Some(TEXT_FILE_BUSY) && Instant::now() < deadline => {
+                std::thread::sleep(Duration::from_millis(5));
+            }
+            Err(err) => panic!("probe-exec of {} failed: {err}", path.display()),
+        }
+    }
+}
diff --git a/systemd/pkgwatch-failure.service b/systemd/pkgwatch-failure.service
new file mode 100644
index 0000000..35e2aaf
--- /dev/null
+++ b/systemd/pkgwatch-failure.service
@@ -0,0 +1,11 @@
+# Triggered by pkgwatch.service's OnFailure=. Covers what the in-process
+# notifier can't: a verification failure, build failure, or network error
+# exits non-zero, and that would otherwise only show up in the journal.
+[Unit]
+Description=Notify that a pkgwatch run failed
+
+[Service]
+Type=oneshot
+# Absolute path: systemd requires one, unlike the in-process notifier,
+# which resolves notify-send from PATH.
+ExecStart=/usr/bin/notify-send --app-name=pkgwatch --urgency=critical "pkgwatch run failed" "See: journalctl --user -u pkgwatch.service"
diff --git a/systemd/pkgwatch.service b/systemd/pkgwatch.service
new file mode 100644
index 0000000..232a5d4
--- /dev/null
+++ b/systemd/pkgwatch.service
@@ -0,0 +1,17 @@
+# User-level oneshot: one check -> fetch -> verify -> build -> publish pass.
+# Install: see docs/SPEC.md > Scheduling.
+#
+# WorkingDirectory matters: packages.d/, state/ and work/ are all resolved
+# relative to the cwd, so this must be the main checkout, not a worktree.
+# The binary is the release build in that same checkout (`cargo build
+# --release`), so a rebuild is what picks up code changes.
+[Unit]
+Description=pkgwatch: check tracked packages for new upstream releases
+OnFailure=pkgwatch-failure.service
+
+[Service]
+Type=oneshot
+WorkingDirectory=%h/dev/pkgwatch
+ExecStart=%h/dev/pkgwatch/target/release/pkgwatch
+# Builds (makepkg, large Go/Rust binaries) can legitimately take a while.
+TimeoutStartSec=30min
diff --git a/systemd/pkgwatch.timer b/systemd/pkgwatch.timer
new file mode 100644
index 0000000..409c0a1
--- /dev/null
+++ b/systemd/pkgwatch.timer
@@ -0,0 +1,18 @@
+# Periodic, not persistent (see docs/SPEC.md > Vision): no catch-up burst
+# for missed ticks. The laptop is only on while logged in, so the user
+# manager starting (= login) is what matters: OnStartupSec runs a check
+# right after login (10s, so the session bus and network are up) instead
+# of waiting up to an hour for the next tick.
+#
+# No RandomizedDelaySec: it applies to every trigger, including the
+# startup one, and a single machine has no herd to spread out anyway.
+[Unit]
+Description=Run pkgwatch at login and hourly
+
+[Timer]
+OnStartupSec=10s
+OnCalendar=hourly
+Persistent=false
+
+[Install]
+WantedBy=timers.target