fix(ci): pin deb builds to ubuntu-22.04 and enforce the fleet glibc floor (#41)

* fix(ci): pin deb builds to ubuntu-22.04 and enforce the fleet glibc floor

The v1.60.0 debs failed to install on Raspberry Pi OS bookworm:

  socktop : Depends: libc6 (>= 2.39) but 2.36-9+rpt2+deb12u14 is to be installed

Cross-compiled binaries link against the RUNNER's (multiarch) glibc, so
the runner picks the minimum glibc the packages demand. ubuntu-latest
migrated from 22.04 (glibc 2.35) to 24.04 (glibc 2.39) between the
1.50.x releases and now, silently raising the requirement past the
Debian-12 fleet.

Pin the build job to ubuntu-22.04 (2.35 — satisfied by bookworm's 2.36)
and add a post-build gate that reads each .deb's computed libc6
requirement and fails the run if it exceeds the fleet floor, so the next
runner migration turns into a red build instead of a fleet-wide apt
error.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(ci): extract the libc6 version, not the 6 in 'libc6'

The floor gate's second grep matched the trailing digit of the package
name before the version ('libc6 (>= 2.34)' -> '6'), failing every
target. sed capture group instead; verified against realistic Depends
strings.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* chore: bump all crates to 1.60.1

The 1.60.0 debs were built against glibc 2.39 and never installed on the
bookworm fleet; rather than force-moving the tag, the rebuilt release
ships as 1.60.1. Nothing was published to crates.io at 1.60.0.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/build-deb.yml

@@ -18,7 +18,15 @@ env:
 jobs:
   build-deb:
     name: Build .deb for ${{ matrix.target }}
-    runs-on: ubuntu-latest
+    # PINNED, not ubuntu-latest: the binaries link against this runner's
+    # (multiarch) glibc, so the runner sets the MINIMUM glibc the .debs demand
+    # at install time. ubuntu-latest moved to 24.04/glibc 2.39 and the packages
+    # stopped installing on Debian 12/RPi OS bookworm (glibc 2.36). 22.04 links
+    # 2.35, which bookworm satisfies. The "enforce glibc floor" step below
+    # turns any future violation into a red build instead of a fleet-wide apt
+    # failure — if this pin ever has to move past bookworm's glibc, that step
+    # is the contract to renegotiate first.
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
         include:
@@ -159,6 +167,22 @@ jobs:
           mkdir -p debs
           cp target/${{ matrix.target }}/debian/*.deb debs/
 
+      - name: Enforce glibc floor (Debian 12 / RPi OS bookworm fleet)
+        run: |
+          # The fleet's oldest supported glibc. A .deb that demands newer libc6
+          # than this will not install on the Pis — fail HERE, not at apt time.
+          FLOOR="2.36"
+          fail=0
+          for deb in debs/*.deb; do
+            req=$(dpkg-deb -f "$deb" Depends | sed -n 's/.*libc6 (>= \([0-9.]*\)).*/\1/p' | head -1)
+            echo "$deb -> libc6 >= ${req:-none}"
+            if [ -n "$req" ] && [ "$(printf '%s\n' "$req" "$FLOOR" | sort -V | tail -1)" != "$FLOOR" ]; then
+              echo "::error::$deb requires libc6 >= $req, exceeding the fleet floor $FLOOR (bookworm). The build runner's glibc is too new — see the runs-on pin comment."
+              fail=1
+            fi
+          done
+          exit $fail
+
       - name: List generated packages
         run: ls -lh debs/
 

CHANGELOG.md

@@ -1,8 +1,14 @@
 # Changelog
 
-## 1.60.0 — unreleased
+## 1.60.1 — unreleased
 
-Everything since `v1.50.0`. Applies to all three crates (`socktop`, `socktop_agent`, `socktop_connector`), which move to 1.60.0 together.
+Identical to 1.60.0 plus rebuilt Debian packages: the 1.60.0 debs were linked
+against glibc 2.39 (a GitHub runner migration) and would not install on
+Debian 12 / Raspberry Pi OS bookworm. CI now pins the build environment and
+gates every package against the fleet's glibc floor. 1.60.0 was never
+published to crates.io.
+
+Everything since `v1.50.0`. Applies to all three crates (`socktop`, `socktop_agent`, `socktop_connector`), which move to 1.60.1 together.
 
 ### Security
 
@@ -51,6 +57,13 @@ Everything since `v1.50.0`. Applies to all three crates (`socktop`, `socktop_age
 - `socktop` consumes `socktop_connector` via a path+version dep — connector changes are testable in-repo before publishing.
 - wasm examples build against the in-repo connector; note `zellij_socktop_plugin` has pre-existing compile errors and needs its own rework.
 
+### Process kill (PR #40)
+
+- **Kill a local process from the TUI** (`t` on a selected process, or inside Process Details): btop-style Terminate/Force-kill confirmation. Local agents only — the signal is sent by socktop itself with its own privileges, never over the wire; remote agents never show the option. PID-reuse guarded (the confirmed name must still own the PID at signal time).
+- **Agent no longer reports dead processes**: a long-lived sysinfo `System` accumulated every process ever seen (21k+ entries on a 289-process host), inflating memory, per-poll work, and the process count — and keeping killed processes on screen forever. Update agent and client together on machines where the kill feature will be used.
+- Killed rows leave the list when the process actually exits and cannot be resurrected by cached agent snapshots; details views for dead processes close themselves, including through parent-navigation chains.
+- Selection hint no longer vanishes for long process names; confirmation/info dialogs size to their content.
+
 ### Upgrade notes
 
 - **Release/publish order**: `socktop_connector` → `socktop` → agent packages.

Cargo.lock

@@ -2412,7 +2412,7 @@ dependencies = [
 
 [[package]]
 name = "socktop"
-version = "1.60.0"
+version = "1.60.1"
 dependencies = [
  "anyhow",
  "assert_cmd",
@@ -2423,6 +2423,7 @@ dependencies = [
  "serde",
  "serde_json",
  "socktop_connector",
+ "sysinfo",
  "tempfile",
  "tokio",
  "unicode-width",
@@ -2431,7 +2432,7 @@ dependencies = [
 
 [[package]]
 name = "socktop_agent"
-version = "1.60.0"
+version = "1.60.1"
 dependencies = [
  "anyhow",
  "assert_cmd",
@@ -2463,7 +2464,7 @@ dependencies = [
 
 [[package]]
 name = "socktop_connector"
-version = "1.60.0"
+version = "1.60.1"
 dependencies = [
  "flate2",
  "futures-util",

socktop/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "socktop"
-version = "1.60.0"
+version = "1.60.1"
 authors = ["Jason Witty <jasonpwitty+socktop@proton.me>"]
 description = "Remote system monitor over WebSocket, TUI like top"
 edition = "2024"
@@ -11,7 +11,7 @@ repository = "https://github.com/jasonwitty/socktop"
 
 [dependencies]
 # socktop connector for agent communication
-socktop_connector = { version = "1.60.0", path = "../socktop_connector" }
+socktop_connector = { version = "1.60.1", path = "../socktop_connector" }
 
 tokio = { workspace = true }
 futures-util = { workspace = true }
@@ -22,6 +22,9 @@ ratatui = { workspace = true }
 crossterm = { workspace = true }
 unicode-width = { workspace = true }
 anyhow = { workspace = true }
+# Local process signalling only (src/proc_kill.rs). The TUI never gathers its
+# own metrics — everything on screen comes from the agent over the connector.
+sysinfo = { workspace = true }
 dirs-next = { workspace = true }
 
 [dev-dependencies]

socktop/src/app.rs

@@ -20,6 +20,7 @@ use ratatui::{
 use tokio::time::{sleep, timeout};
 
 use crate::history::{PerCoreHistory, push_capped};
+use crate::proc_kill::{KillSignal, kill_local_process};
 use crate::retry::{RetryTiming, compute_retry_timing};
 use crate::types::Metrics;
 use crate::ui::cpu::{
@@ -51,6 +52,21 @@ use socktop_connector::{
 const MIN_METRICS_INTERVAL_MS: u64 = 100;
 const MIN_PROCESSES_INTERVAL_MS: u64 = 200;
 
+/// Floor for the post-kill forced refresh delay: just past the agent's
+/// DEFAULT `Processes` cache TTL of 1500ms, so the answer reflects the kill
+/// instead of the cached snapshot taken before it. The effective delay scales
+/// with the user's processes interval — see [`App::proc_refresh_settle`].
+const PROC_CACHE_SETTLE_FLOOR: Duration = Duration::from_millis(1_600);
+
+/// Margin a tombstone outlives the settle window by. With default intervals
+/// this reproduces the original fixed 5s tombstone (1.6s + 3.4s).
+const TOMBSTONE_MARGIN: Duration = Duration::from_millis(3_400);
+
+/// How long to keep re-checking a signalled process for its exit. Long enough
+/// to cover a slow shutdown, short enough that a process which plainly ignored
+/// the signal keeps its row.
+const KILL_WATCH_FOR: Duration = Duration::from_secs(5);
+
 /// Budget for one request/response round trip. Replies are matched to
 /// requests by order, so a request that never answers would otherwise hang
 /// `ws.next()` forever and freeze the TUI (raw mode even eats Ctrl+C).
@@ -136,6 +152,15 @@ pub struct App {
     procs_row_peak_cpu: f32,
 
     last_procs_poll: Instant,
+    /// When set, the next metrics tick polls processes regardless of the
+    /// regular cadence. Used after a kill — see refresh_after_kill.
+    procs_refresh_due_at: Option<Instant>,
+    /// PIDs we have signalled, with the instant we stop watching for their
+    /// exit. Re-checked each metrics tick — see poll_kill_watch.
+    kill_watch: Vec<(u32, Instant)>,
+    /// PIDs confirmed gone after a signal, kept briefly so the agent's cached
+    /// process list cannot put them back on screen.
+    killed_gone: Vec<(u32, Instant)>,
     last_disks_poll: Instant,
     procs_interval: Duration,
     disks_interval: Duration,
@@ -153,6 +178,10 @@ pub struct App {
     last_io_write_bytes: Option<u64>,            // Previous write bytes for delta calculation
     pub max_process_mem_bytes: u64, // Maximum memory usage observed for current process
     pub process_details_unsupported: bool, // Track if agent doesn't support process details
+    /// The agent has successfully answered at least one details request this
+    /// session. Distinguishes "this agent is too old" from "that process is
+    /// gone", which arrive over the wire as the same error.
+    process_details_answered: bool,
     last_process_details_poll: Instant,
     last_journal_poll: Instant,
     process_details_interval: Duration,
@@ -165,6 +194,13 @@ pub struct App {
     // Security / status flags
     pub is_tls: bool,
     pub has_token: bool,
+    // Whether the connected agent is on this machine. Gates the local
+    // process-kill feature (t = SIGTERM, k = SIGKILL).
+    pub is_local: bool,
+    // Pending kill awaiting confirmation: (pid, process name). Which signal is
+    // sent depends on the button chosen in the confirmation modal, so it isn't
+    // decided until then.
+    pending_kill: Option<(u32, String)>,
 
     // --compact: pin the compact layout regardless of window size. Without it the
     // layout switches on its own once the window is too short for the Disks pane.
@@ -222,6 +258,9 @@ impl App {
             procs_filter_dirty: true,
             procs_row_cache: Vec::new(),
             procs_row_peak_cpu: 0.0,
+            procs_refresh_due_at: None,
+            kill_watch: Vec::new(),
+            killed_gone: Vec::new(),
             last_procs_poll: Instant::now()
                 .checked_sub(Duration::from_secs(2))
                 .unwrap_or_else(Instant::now), // trigger immediately on first loop
@@ -242,6 +281,7 @@ impl App {
             last_io_write_bytes: None,
             max_process_mem_bytes: 0,
             process_details_unsupported: false,
+            process_details_answered: false,
             last_process_details_poll: Instant::now()
                 .checked_sub(Duration::from_secs(10))
                 .unwrap_or_else(Instant::now),
@@ -255,6 +295,8 @@ impl App {
             verify_hostname: false,
             is_tls: false,
             has_token: false,
+            is_local: false,
+            pending_kill: None,
             force_compact: false,
             header_title: String::new(),
             header_intervals_text: String::new(),
@@ -306,6 +348,232 @@ impl App {
         self
     }
 
+    /// Enable the local process-kill feature. Only set true when the agent has
+    /// been verified to be on this machine (see [`crate::local`]).
+    pub fn with_local(mut self, is_local: bool) -> Self {
+        self.is_local = is_local;
+        self
+    }
+
+    /// Look up the display name of a process by PID. Prefers the details
+    /// payload, which is the only source that has a name for a process not in
+    /// the top-N list — e.g. after walking up to a parent from the details
+    /// modal.
+    fn process_name_for_pid(&self, pid: u32) -> Option<String> {
+        if let Some(details) = self
+            .process_details
+            .as_ref()
+            .filter(|d| d.process.pid == pid)
+        {
+            return Some(details.process.name.clone());
+        }
+        self.last_metrics
+            .as_ref()?
+            .top_processes
+            .iter()
+            .find(|p| p.pid == pid)
+            .map(|p| p.name.clone())
+    }
+
+    /// Raise the kill confirmation for `pid`. No-op unless the agent is on this
+    /// machine — the same gate the keybinding uses, repeated here because this
+    /// is also reachable from the details modal.
+    fn prompt_kill(&mut self, pid: u32) {
+        if !self.is_local {
+            return;
+        }
+        let name = self
+            .process_name_for_pid(pid)
+            .unwrap_or_else(|| "process".to_string());
+        self.modal_manager.push_modal(ModalType::Confirmation {
+            title: "Confirm signal".to_string(),
+            message: format!("Send a signal to {name} (PID {pid})?"),
+            confirm_text: "Terminate".to_string(),
+            cancel_text: "Cancel".to_string(),
+        });
+        self.pending_kill = Some((pid, name));
+    }
+
+    /// Signal the process the confirmation was raised for, then report the
+    /// outcome. Pops the confirmation first so the result lands on top of
+    /// whatever was underneath it (the process list, or the details modal).
+    fn run_pending_kill(&mut self, signal: KillSignal) {
+        let Some((pid, name)) = self.pending_kill.take() else {
+            return;
+        };
+        self.modal_manager.pop_modal();
+        // The name shown in the confirmation doubles as the reuse guard: if
+        // the PID has been recycled since, the kill is refused. The "process"
+        // fallback from prompt_kill means "name unknown" — no guard possible.
+        let expected = (name != "process").then_some(name.as_str());
+        let (title, message) = match kill_local_process(pid, expected, signal) {
+            Ok(()) => {
+                self.refresh_after_kill(pid);
+                (
+                    "Signal sent".to_string(),
+                    format!("Sent {} to {name} (PID {pid}).", signal.label()),
+                )
+            }
+            Err(e) => ("Signal failed".to_string(), e),
+        };
+        self.modal_manager
+            .push_modal(ModalType::Info { title, message });
+    }
+
+    /// Bring the process list back in step with reality after a signal.
+    ///
+    /// A single check at signal time is not enough, which is what the first
+    /// version got wrong: SIGTERM is a *request*, so the process is usually
+    /// still alive for the few hundred milliseconds it takes to wind down. The
+    /// row therefore stayed put, and the list looked like the kill had done
+    /// nothing.
+    ///
+    /// So the PID goes on a watch list, re-checked every metrics tick until it
+    /// exits (or the watch expires). Confirmed-gone PIDs are also remembered
+    /// briefly — see `killed_gone` — because the agent serves `Processes` from
+    /// a 1500ms cache and would otherwise hand back a snapshot taken before
+    /// the kill and put the row straight back.
+    fn refresh_after_kill(&mut self, pid: u32) {
+        self.kill_watch.retain(|(p, _)| *p != pid);
+        self.kill_watch.push((pid, Instant::now() + KILL_WATCH_FOR));
+        // Check once right now: SIGKILL, and anything already exiting, is gone
+        // by the time the confirmation is dismissed.
+        self.poll_kill_watch();
+        self.procs_refresh_due_at = Some(Instant::now() + self.proc_refresh_settle());
+    }
+
+    /// How long the post-kill forced refresh waits, and the base of the
+    /// tombstone lifetime. Scales with the user's processes interval: someone
+    /// who raised the agent's Processes TTL will have raised their client
+    /// interval to match (there is no point polling faster than the cache),
+    /// so the interval is the best client-side signal for how stale an agent
+    /// snapshot can be. Never below the default-TTL floor.
+    fn proc_refresh_settle(&self) -> Duration {
+        PROC_CACHE_SETTLE_FLOOR.max(self.procs_interval)
+    }
+
+    /// How long a confirmed-dead PID is remembered, so a cached agent snapshot
+    /// taken before the kill cannot resurrect its row. Must outlive the settle
+    /// window plus one round trip, hence settle + margin.
+    fn kill_tombstone_for(&self) -> Duration {
+        self.proc_refresh_settle() + TOMBSTONE_MARGIN
+    }
+
+    /// Re-check the processes we have signalled and retire the rows of any that
+    /// have since exited. Cheap: one `/proc` lookup per watched PID, and the
+    /// list is almost always empty.
+    fn poll_kill_watch(&mut self) {
+        if self.kill_watch.is_empty() {
+            return;
+        }
+        let now = Instant::now();
+        let mut gone = Vec::new();
+        self.kill_watch.retain(|(pid, deadline)| {
+            if !crate::proc_kill::process_exists(*pid) {
+                gone.push(*pid);
+                return false;
+            }
+            // Still alive. Keep watching until the deadline — a process that
+            // ignores the signal outright should keep its row.
+            now < *deadline
+        });
+        for pid in gone {
+            self.forget_process_row(pid);
+            // Nothing left to show details for. Also matters mechanically: the
+            // details poll keys off the selection, which forget_process_row
+            // just cleared, so leaving the modal open would freeze it on the
+            // dead process's last sample.
+            self.close_details_for_gone_process(pid);
+            self.killed_gone.push((pid, now));
+        }
+        let tombstone_for = self.kill_tombstone_for();
+        self.killed_gone
+            .retain(|(_, at)| now.duration_since(*at) < tombstone_for);
+    }
+
+    /// Drop rows for processes we have confirmed dead. Applied to every process
+    /// list the agent sends, because its cached snapshot can predate the kill.
+    fn drop_tombstoned_rows(&mut self) {
+        if self.killed_gone.is_empty() {
+            return;
+        }
+        let now = Instant::now();
+        let tombstone_for = self.kill_tombstone_for();
+        self.killed_gone
+            .retain(|(_, at)| now.duration_since(*at) < tombstone_for);
+        let pids: Vec<u32> = self.killed_gone.iter().map(|(p, _)| *p).collect();
+        for pid in pids {
+            self.forget_process_row(pid);
+        }
+    }
+
+    /// Give up a selection whose process is no longer in the list. `Processes`
+    /// carries every process, not a top-N window, so a PID that is absent has
+    /// genuinely gone — and a selection pointing at it means the hint offers to
+    /// kill a corpse and `t` reports "no longer exists".
+    fn drop_vanished_selection(&mut self) {
+        let Some(pid) = self.selected_process_pid else {
+            return;
+        };
+        let present = self
+            .last_metrics
+            .as_ref()
+            .is_some_and(|m| m.top_processes.iter().any(|p| p.pid == pid));
+        if !present {
+            self.selected_process_pid = None;
+            self.selected_process_index = None;
+        }
+    }
+
+    /// Close the details view for a process that no longer exists, and drop the
+    /// data collected for it.
+    ///
+    /// A parent-navigation chain can leave another details view underneath
+    /// (child → P → parent killed): the resurfacing view must resume polling,
+    /// so retarget the selection to it — the same thing SwitchToParentProcess
+    /// does on the way down. Without this the child view came back with no
+    /// selection (forget_process_row had just cleared it) and wiped data, and
+    /// the selection-gated details poll never refilled it: a frozen, orphaned
+    /// window.
+    fn close_details_for_gone_process(&mut self, pid: u32) {
+        if self.modal_manager.close_process_details(pid) {
+            self.clear_process_details();
+            if let Some(next_pid) = self.modal_manager.topmost_process_details() {
+                self.selected_process_pid = Some(next_pid);
+                // Fire the details poll on the next tick rather than waiting
+                // out the interval.
+                self.last_process_details_poll = Instant::now()
+                    .checked_sub(self.process_details_interval)
+                    .unwrap_or_else(Instant::now);
+            }
+        }
+    }
+
+    /// Drop a process from the cached view without waiting for the agent, and
+    /// give up any selection pointing at it — a hint offering to kill a process
+    /// that no longer exists is worse than no hint.
+    fn forget_process_row(&mut self, pid: u32) {
+        let Some(m) = self.last_metrics.as_mut() else {
+            return;
+        };
+        let before = m.top_processes.len();
+        m.top_processes.retain(|p| p.pid != pid);
+        if m.top_processes.len() == before {
+            return; // wasn't on screen; nothing to reconcile
+        }
+        // Keep the header's "(N total)" honest until the next real poll.
+        m.process_count = m.process_count.map(|c| c.saturating_sub(1));
+        if self.selected_process_pid == Some(pid) {
+            self.selected_process_pid = None;
+            self.selected_process_index = None;
+        }
+        self.invalidate_procs_filter();
+        if let Some(mm) = self.last_metrics.as_ref() {
+            self.procs_row_peak_cpu =
+                crate::ui::processes::rebuild_row_cache(mm, &mut self.procs_row_cache);
+        }
+    }
+
     /// Show a connection error modal
     pub fn show_connection_error(&mut self, message: String) {
         if !self.modal_manager.is_active() {
@@ -757,18 +1025,47 @@ impl App {
                                 continue; // Skip normal key processing
                             }
                             ModalAction::Cancel | ModalAction::Dismiss => {
-                                // If ProcessDetails modal was dismissed, clear the data to save resources
+                                // If a ProcessDetails view is what we landed on,
-                                if let Some(crate::ui::modal::ModalType::ProcessDetails {
+                                // clear the stale data AND point the poll at it —
-                                    ..
+                                // Esc-ing back from a parent view otherwise left
-                                }) = self.modal_manager.current_modal()
+                                // the selection on the parent, refilling the
+                                // child-titled view with the parent's data.
+                                if let Some(crate::ui::modal::ModalType::ProcessDetails { pid }) =
+                                    self.modal_manager.current_modal()
                                 {
+                                    let pid = *pid;
                                     self.clear_process_details();
+                                    self.selected_process_pid = Some(pid);
+                                    self.last_process_details_poll = Instant::now()
+                                        .checked_sub(self.process_details_interval)
+                                        .unwrap_or_else(Instant::now);
                                 }
+                                // Abandon any pending kill the user backed out of.
+                                self.pending_kill = None;
                                 // Modal was dismissed, skip normal key processing
                                 continue;
                             }
                             ModalAction::Confirm => {
-                                // Handle confirmation action here if needed in the future
+                                // The only confirmation in the app is the
+                                // process-kill prompt; Confirm is the polite
+                                // signal, ConfirmForce the forceful one.
+                                if self.pending_kill.is_some() {
+                                    self.run_pending_kill(KillSignal::Term);
+                                    continue;
+                                }
+                            }
+                            ModalAction::ConfirmForce => {
+                                if self.pending_kill.is_some() {
+                                    self.run_pending_kill(KillSignal::Kill);
+                                    continue;
+                                }
+                            }
+                            ModalAction::KillSelected(pid) => {
+                                // `t` from inside the details modal. The
+                                // confirmation stacks on top of it, so
+                                // cancelling returns to the details view.
+                                self.prompt_kill(pid);
+                                continue;
                             }
                             ModalAction::SwitchToParentProcess(_current_pid) => {
                                 // Get parent PID from current process details
@@ -880,6 +1177,20 @@ impl App {
                         self.modal_manager.push_modal(ModalType::Help);
                     }
 
+                    // Kill the selected process — local agents only. `t` is the
+                    // one kill key everywhere: `k` scrolls the thread table in
+                    // the details modal so it could not be reused there, and one
+                    // key for both entry points is one thing to remember.
+                    // SIGTERM vs SIGKILL is chosen in the confirmation modal.
+                    if self.is_local
+                        && !self.modal_manager.is_active()
+                        && matches!(k.code, KeyCode::Char('t') | KeyCode::Char('T'))
+                        && let Some(pid) = self.selected_process_pid
+                    {
+                        self.prompt_kill(pid);
+                        continue;
+                    }
+
                     // Per-core scroll via keys (Up/Down/PageUp/PageDown/Home/End)
                     let sz = terminal.size()?;
                     let area = Rect::new(0, 0, sz.width, sz.height);
@@ -1117,8 +1428,21 @@ impl App {
                         self.consecutive_request_timeouts = 0;
                         self.update_with_metrics(m);
 
-                        // Only poll processes every 2s
+                        // A process signalled a moment ago may have exited
-                        if self.last_procs_poll.elapsed() >= self.procs_interval {
+                        // since. Checked here, on every tick, so its row goes
+                        // as soon as it is actually gone rather than at the
+                        // next full process poll.
+                        self.poll_kill_watch();
+
+                        // Only poll processes every 2s — unless a kill asked for
+                        // a refresh, which jumps the queue.
+                        let forced = self
+                            .procs_refresh_due_at
+                            .is_some_and(|due| Instant::now() >= due);
+                        if forced || self.last_procs_poll.elapsed() >= self.procs_interval {
+                            if forced {
+                                self.procs_refresh_due_at = None;
+                            }
                             let mut updated = false;
                             match timeout(REQUEST_TIMEOUT, ws.request(AgentRequest::Processes))
                                 .await
@@ -1148,6 +1472,14 @@ impl App {
                                             &mut self.procs_row_cache,
                                         );
                                 }
+                                // The agent's snapshot can predate a kill by up
+                                // to its cache TTL, so strip anything we already
+                                // know is gone before it reaches the screen.
+                                self.drop_tombstoned_rows();
+                                // And a selection whose process is no longer in
+                                // the list would otherwise still be the target
+                                // of `t`.
+                                self.drop_vanished_selection();
                             }
                             self.last_procs_poll = Instant::now();
                         }
@@ -1252,11 +1584,44 @@ impl App {
 
                                             self.process_details = Some(details);
                                             self.process_details_unsupported = false;
+                                            // This agent demonstrably answers
+                                            // details requests, which is what
+                                            // lets the error arm below read a
+                                            // later failure as "that process is
+                                            // gone" rather than "old agent".
+                                            self.process_details_answered = true;
                                         }
                                         Ok(Err(_)) => {
-                                            // Agent responded with an error: endpoint
+                                            // An error reply means one of two very
-                                            // not supported.
+                                            // different things, and the wire cannot
-                                            self.process_details_unsupported = true;
+                                            // tell them apart: the agent lacks the
+                                            // endpoint, or this PID is gone (the
+                                            // agent sends {"error":"Process N not
+                                            // found"}, which fails to deserialize
+                                            // and arrives here identically).
+                                            //
+                                            // If the agent has already answered a
+                                            // details request this session, the
+                                            // endpoint plainly works, so the PID is
+                                            // the problem — close the view instead
+                                            // of claiming the agent needs updating.
+                                            //
+                                            // Unless the process is still in the
+                                            // agent's own list: then this error is a
+                                            // transient (socket blip, torn frame),
+                                            // not a death — keep the view and let
+                                            // the next poll retry.
+                                            if self.process_details_answered {
+                                                let still_listed =
+                                                    self.last_metrics.as_ref().is_some_and(|m| {
+                                                        m.top_processes.iter().any(|p| p.pid == pid)
+                                                    });
+                                                if !still_listed {
+                                                    self.close_details_for_gone_process(pid);
+                                                }
+                                            } else {
+                                                self.process_details_unsupported = true;
+                                            }
                                         }
                                         Err(_) => {
                                             // No reply at all: old agents IGNORE
@@ -1583,6 +1948,7 @@ impl App {
                 filtered_indices: &self.procs_filtered,
                 cached_rows: &self.procs_row_cache,
                 peak_cpu: self.procs_row_peak_cpu,
+                is_local: self.is_local,
             },
         );
 
@@ -1603,6 +1969,7 @@ impl App {
                     },
                     max_mem_bytes: self.max_process_mem_bytes,
                     unsupported: self.process_details_unsupported,
+                    is_local: self.is_local,
                 },
             );
         }
@@ -1614,3 +1981,418 @@ impl Default for App {
         Self::new()
     }
 }
+
+#[cfg(test)]
+mod kill_refresh_tests {
+    use super::*;
+    use socktop_connector::{Metrics, ProcessInfo};
+
+    fn proc(pid: u32, name: &str) -> ProcessInfo {
+        ProcessInfo {
+            pid,
+            name: name.into(),
+            cpu_usage: 1.0,
+            mem_bytes: 1_000,
+        }
+    }
+
+    fn app_with(pids: &[u32]) -> App {
+        let mut app = App::new();
+        app.last_metrics = Some(Metrics {
+            sampled_at_ms: None,
+            cpu_total: 0.0,
+            cpu_per_core: vec![],
+            mem_total: 1_000_000,
+            mem_used: 0,
+            swap_total: 0,
+            swap_used: 0,
+            hostname: "t".into(),
+            cpu_temp_c: None,
+            disks: vec![],
+            networks: vec![],
+            top_processes: pids.iter().map(|p| proc(*p, "victim")).collect(),
+            gpus: None,
+            process_count: Some(pids.len()),
+        });
+        app
+    }
+
+    #[test]
+    fn dropping_a_row_updates_the_list_count_and_selection() {
+        let mut app = app_with(&[1, 2, 3]);
+        app.selected_process_pid = Some(2);
+        app.selected_process_index = Some(1);
+
+        app.forget_process_row(2);
+
+        let m = app.last_metrics.as_ref().unwrap();
+        assert_eq!(
+            m.top_processes.iter().map(|p| p.pid).collect::<Vec<_>>(),
+            vec![1, 3]
+        );
+        assert_eq!(m.process_count, Some(2), "header count went stale");
+        assert_eq!(
+            app.selected_process_pid, None,
+            "selection still points at a dead process"
+        );
+        assert_eq!(app.selected_process_index, None);
+    }
+
+    /// A process that was never on screen (outside the top-N) must not decrement
+    /// the total or disturb the selection.
+    #[test]
+    fn dropping_an_offscreen_row_changes_nothing() {
+        let mut app = app_with(&[1, 2, 3]);
+        app.selected_process_pid = Some(1);
+        app.forget_process_row(999);
+        let m = app.last_metrics.as_ref().unwrap();
+        assert_eq!(m.top_processes.len(), 3);
+        assert_eq!(m.process_count, Some(3));
+        assert_eq!(app.selected_process_pid, Some(1));
+    }
+
+    /// A dead process disappears immediately, and a refresh is still scheduled
+    /// so the agent's own view catches up past its cache TTL.
+    #[test]
+    fn a_confirmed_dead_process_leaves_at_once() {
+        let mut child = std::process::Command::new("true").spawn().expect("spawn");
+        let pid = child.id();
+        child.wait().expect("reap");
+
+        let mut app = app_with(&[pid, 4242]);
+        app.refresh_after_kill(pid);
+
+        let m = app.last_metrics.as_ref().unwrap();
+        assert_eq!(
+            m.top_processes.iter().map(|p| p.pid).collect::<Vec<_>>(),
+            vec![4242],
+            "a process known to be gone should not still be listed"
+        );
+        assert!(app.procs_refresh_due_at.is_some(), "no refresh scheduled");
+    }
+
+    /// A process that survived the signal keeps its row — better a row that is
+    /// still true than one that vanishes and comes back.
+    #[test]
+    fn a_surviving_process_keeps_its_row_until_the_refresh() {
+        let mut child = std::process::Command::new("sleep")
+            .arg("30")
+            .spawn()
+            .expect("spawn");
+        let pid = child.id();
+
+        let mut app = app_with(&[pid]);
+        app.refresh_after_kill(pid);
+        let listed = app
+            .last_metrics
+            .as_ref()
+            .unwrap()
+            .top_processes
+            .iter()
+            .any(|p| p.pid == pid);
+
+        let _ = child.kill();
+        let _ = child.wait();
+
+        assert!(listed, "row for a live process was removed optimistically");
+        assert!(app.procs_refresh_due_at.is_some());
+    }
+
+    /// The scheduled refresh must land after the agent's process cache TTL,
+    /// or it just re-reads the pre-kill snapshot.
+    #[test]
+    fn the_forced_refresh_waits_out_the_agent_cache() {
+        assert!(
+            PROC_CACHE_SETTLE_FLOOR >= Duration::from_millis(1_500),
+            "agent serves Processes from a 1500ms cache by default"
+        );
+    }
+
+    /// Users who raise the agent's Processes TTL raise the client interval to
+    /// match, so the settle window (and the tombstone that must outlive it)
+    /// scales with the interval instead of assuming the default TTL.
+    #[test]
+    fn settle_and_tombstone_scale_with_the_processes_interval() {
+        // The default processes interval is 2s, which already exceeds the
+        // 1.6s floor — so the default settle is the interval itself.
+        let mut app = App::new();
+        assert_eq!(app.proc_refresh_settle(), Duration::from_secs(2));
+
+        app = app.with_intervals(None, Some(10_000));
+        assert_eq!(app.proc_refresh_settle(), Duration::from_secs(10));
+        assert!(app.kill_tombstone_for() > app.proc_refresh_settle());
+
+        // A tiny interval never drops the settle below the default-TTL floor.
+        app = app.with_intervals(None, Some(200));
+        assert_eq!(app.proc_refresh_settle(), PROC_CACHE_SETTLE_FLOOR);
+    }
+}
+
+#[cfg(test)]
+mod parent_chain_tests {
+    use super::*;
+    use crate::ui::modal::ModalType;
+
+    /// Kill a parent reached via P-navigation: the child's view resurfaces and
+    /// must resume polling. Reported as: "I can still see the orphaned window
+    /// if I open a process, hit P, then terminate that process with t".
+    #[test]
+    fn killing_a_navigated_to_parent_retargets_the_child_view() {
+        let mut app = App::new();
+        let (child, parent) = (200u32, 100u32);
+        app.modal_manager
+            .push_modal(ModalType::ProcessDetails { pid: child });
+        app.modal_manager
+            .push_modal(ModalType::ProcessDetails { pid: parent });
+        // The kill flow stacks the "Signal sent" Info on top, and the watch
+        // usually confirms the death while it is still up.
+        app.modal_manager.push_modal(ModalType::Info {
+            title: "Signal sent".into(),
+            message: "Sent SIGTERM".into(),
+        });
+        // forget_process_row has already cleared the selection by this point.
+        app.selected_process_pid = None;
+
+        app.close_details_for_gone_process(parent);
+
+        assert_eq!(
+            app.selected_process_pid,
+            Some(child),
+            "resurfaced child view has no selection: its poll never runs and \
+             the window sits frozen"
+        );
+        assert_eq!(app.modal_manager.topmost_process_details(), Some(child));
+        assert!(
+            app.last_process_details_poll.elapsed() >= app.process_details_interval,
+            "poll should be due immediately"
+        );
+    }
+}
+
+#[cfg(test)]
+mod details_close_tests {
+    use super::*;
+    use crate::ui::modal::ModalType;
+    use socktop_connector::{Metrics, ProcessInfo};
+
+    fn app_viewing(pid: u32) -> App {
+        let mut app = App::new();
+        app.last_metrics = Some(Metrics {
+            sampled_at_ms: None,
+            cpu_total: 0.0,
+            cpu_per_core: vec![],
+            mem_total: 1_000_000,
+            mem_used: 0,
+            swap_total: 0,
+            swap_used: 0,
+            hostname: "t".into(),
+            cpu_temp_c: None,
+            disks: vec![],
+            networks: vec![],
+            top_processes: vec![ProcessInfo {
+                pid,
+                name: "victim".into(),
+                cpu_usage: 1.0,
+                mem_bytes: 1_000,
+            }],
+            gpus: None,
+            process_count: Some(1),
+        });
+        app.selected_process_pid = Some(pid);
+        app.selected_process_index = Some(0);
+        app.modal_manager
+            .push_modal(ModalType::ProcessDetails { pid });
+        app.max_process_mem_bytes = 12_345; // stand-in for collected history
+        app
+    }
+
+    /// Killing the process you are looking at should not leave you staring at
+    /// its details — especially since the details poll keys off the selection,
+    /// which is cleared at the same time.
+    #[test]
+    fn killing_the_viewed_process_closes_its_details() {
+        let mut child = std::process::Command::new("true").spawn().expect("spawn");
+        let pid = child.id();
+        child.wait().expect("reap");
+
+        let mut app = app_viewing(pid);
+        app.refresh_after_kill(pid);
+
+        assert!(
+            !app.modal_manager.is_active(),
+            "details modal stayed open for a dead process"
+        );
+        assert_eq!(
+            app.max_process_mem_bytes, 0,
+            "details state was not cleared"
+        );
+        assert!(app.last_metrics.as_ref().unwrap().top_processes.is_empty());
+    }
+
+    /// A process that survived the signal keeps both its row and its details.
+    #[test]
+    fn a_surviving_process_keeps_its_details_open() {
+        let mut child = std::process::Command::new("sleep")
+            .arg("30")
+            .spawn()
+            .expect("spawn");
+        let pid = child.id();
+
+        let mut app = app_viewing(pid);
+        app.refresh_after_kill(pid);
+        let still_open = app.modal_manager.is_active();
+
+        let _ = child.kill();
+        let _ = child.wait();
+
+        assert!(still_open, "closed the details of a process still running");
+    }
+}
+
+#[cfg(test)]
+mod kill_watch_tests {
+    use super::*;
+    use socktop_connector::{Metrics, ProcessInfo};
+
+    fn metrics_with(pids: &[(u32, &str)]) -> Metrics {
+        Metrics {
+            sampled_at_ms: None,
+            cpu_total: 0.0,
+            cpu_per_core: vec![],
+            mem_total: 1_000_000,
+            mem_used: 0,
+            swap_total: 0,
+            swap_used: 0,
+            hostname: "t".into(),
+            cpu_temp_c: None,
+            disks: vec![],
+            networks: vec![],
+            top_processes: pids
+                .iter()
+                .map(|(pid, name)| ProcessInfo {
+                    pid: *pid,
+                    name: (*name).into(),
+                    cpu_usage: 1.0,
+                    mem_bytes: 1_000,
+                })
+                .collect(),
+            gpus: None,
+            process_count: Some(pids.len()),
+        }
+    }
+
+    fn listed(app: &App, pid: u32) -> bool {
+        app.last_metrics
+            .as_ref()
+            .is_some_and(|m| m.top_processes.iter().any(|p| p.pid == pid))
+    }
+
+    /// The reported bug: SIGTERM is a request, so the process is normally still
+    /// alive at signal time. The row must go when it actually exits, not stay
+    /// until the next full poll.
+    #[test]
+    fn a_row_goes_as_soon_as_the_process_actually_exits() {
+        let mut child = std::process::Command::new("sleep")
+            .arg("30")
+            .spawn()
+            .expect("spawn");
+        let pid = child.id();
+
+        let mut app = App::new();
+        app.last_metrics = Some(metrics_with(&[(pid, "sleep"), (1, "init")]));
+        app.selected_process_pid = Some(pid);
+
+        // Signalled, but it has not exited yet: the row stays.
+        app.refresh_after_kill(pid);
+        assert!(
+            listed(&app, pid),
+            "row vanished while the process was alive"
+        );
+
+        // It exits (as a SIGTERM'd process does, a moment later).
+        let _ = child.kill();
+        let _ = child.wait();
+
+        // The next tick notices.
+        app.poll_kill_watch();
+        assert!(!listed(&app, pid), "row survived the process exiting");
+        assert_eq!(app.selected_process_pid, None, "selection left on a corpse");
+    }
+
+    /// Also reported: after terminating, the row came back. The agent serves
+    /// `Processes` from a 1500ms cache, so its next answer can predate the kill.
+    #[test]
+    fn a_stale_agent_snapshot_cannot_resurrect_a_killed_process() {
+        let mut child = std::process::Command::new("true").spawn().expect("spawn");
+        let pid = child.id();
+        child.wait().expect("reap");
+
+        let mut app = App::new();
+        app.last_metrics = Some(metrics_with(&[(pid, "true"), (1, "init")]));
+        app.refresh_after_kill(pid);
+        assert!(!listed(&app, pid), "confirmed-dead row should be gone");
+
+        // The agent answers with a snapshot taken before the kill.
+        app.last_metrics = Some(metrics_with(&[(pid, "true"), (1, "init")]));
+        app.drop_tombstoned_rows();
+        assert!(!listed(&app, pid), "stale snapshot put the row back");
+        assert!(listed(&app, 1), "unrelated processes must survive");
+    }
+
+    /// His exact path: find the process with `/`, then kill it. The filtered
+    /// view is derived from the same list, so it must lose the row too.
+    #[test]
+    fn a_search_filtered_view_loses_the_row_as_well() {
+        let mut child = std::process::Command::new("true").spawn().expect("spawn");
+        let pid = child.id();
+        child.wait().expect("reap");
+
+        let mut app = App::new();
+        app.last_metrics = Some(metrics_with(&[(pid, "victim"), (1, "init")]));
+        app.process_search_query = "victim".into();
+        assert_eq!(
+            app.procs_filter().len(),
+            1,
+            "search should match the victim"
+        );
+
+        app.refresh_after_kill(pid);
+
+        assert!(
+            app.procs_filter().is_empty(),
+            "killed process still present in the filtered list"
+        );
+    }
+
+    #[test]
+    fn a_selection_that_leaves_the_list_is_dropped() {
+        let mut app = App::new();
+        app.last_metrics = Some(metrics_with(&[(1, "init")]));
+        app.selected_process_pid = Some(4242);
+        app.selected_process_index = Some(7);
+        app.drop_vanished_selection();
+        assert_eq!(app.selected_process_pid, None);
+        assert_eq!(app.selected_process_index, None);
+    }
+
+    #[test]
+    fn a_selection_still_in_the_list_is_kept() {
+        let mut app = App::new();
+        app.last_metrics = Some(metrics_with(&[(1, "init")]));
+        app.selected_process_pid = Some(1);
+        app.drop_vanished_selection();
+        assert_eq!(app.selected_process_pid, Some(1));
+    }
+
+    /// A process that ignores the signal must not be watched forever.
+    #[test]
+    fn the_watch_expires() {
+        let mut app = App::new();
+        app.last_metrics = Some(metrics_with(&[(1, "init")]));
+        // Already-expired deadline, for a PID that certainly exists (ourselves).
+        let me = std::process::id();
+        app.kill_watch.push((me, Instant::now()));
+        app.poll_kill_watch();
+        assert!(app.kill_watch.is_empty(), "expired watch was not dropped");
+    }
+}

socktop/src/local.rs

@@ -0,0 +1,85 @@
+//! Detection of whether the connected agent is running on this same machine.
+//!
+//! Process-kill is only offered for *local* agents. The reasoning is a
+//! security one: the PIDs shown in the UI are reported by the agent, and when
+//! the user asks to kill one, socktop sends the signal with its OWN local OS
+//! privileges (a direct syscall — never over the network; see [`crate::proc_kill`]).
+//! A PID is therefore only meaningful — and only safe to act on — when the
+//! agent lives on this machine. If we acted on a remote agent's PIDs we would
+//! be signalling whatever unrelated *local* process happened to share that
+//! number.
+//!
+//! An address is considered local when it is loopback, or when we can bind an
+//! ephemeral socket to it: a bind only succeeds for an address assigned to one
+//! of this host's own network interfaces, so it also covers the case of an
+//! agent reached over this machine's LAN IP. Detection fails closed — any
+//! parse/resolution failure, or any resolved address that is not local,
+//! disables the feature.
+
+use std::net::{IpAddr, ToSocketAddrs, UdpSocket};
+
+/// Returns true only if the agent reached at `ws_url` is on this machine.
+pub fn agent_is_local(ws_url: &str) -> bool {
+    let Ok(parsed) = url::Url::parse(ws_url) else {
+        return false;
+    };
+    match parsed.host() {
+        // IP literals can be checked directly without any name resolution.
+        Some(url::Host::Ipv4(ip)) => ip_is_local(IpAddr::V4(ip)),
+        Some(url::Host::Ipv6(ip)) => ip_is_local(IpAddr::V6(ip)),
+        // A hostname (e.g. "localhost", or a LAN name) must resolve, and every
+        // address it resolves to must be local. ws=80, wss=443 are the known
+        // default ports; an explicit port in the URL is honored.
+        Some(url::Host::Domain(domain)) => {
+            let port = parsed.port_or_known_default().unwrap_or(0);
+            match (domain, port).to_socket_addrs() {
+                Ok(addrs) => {
+                    let mut saw_any = false;
+                    for addr in addrs {
+                        saw_any = true;
+                        if !ip_is_local(addr.ip()) {
+                            return false;
+                        }
+                    }
+                    saw_any
+                }
+                Err(_) => false,
+            }
+        }
+        None => false,
+    }
+}
+
+/// An address is local if it is loopback, or if we can bind an ephemeral
+/// socket to it (only possible for an address on one of our own interfaces).
+/// Port 0 requests an ephemeral port and sends no traffic.
+fn ip_is_local(ip: IpAddr) -> bool {
+    ip.is_loopback() || UdpSocket::bind((ip, 0)).is_ok()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::agent_is_local;
+
+    #[test]
+    fn loopback_hosts_are_local() {
+        assert!(agent_is_local("ws://127.0.0.1:3000/ws"));
+        assert!(agent_is_local("ws://localhost:3000/ws"));
+        assert!(agent_is_local("ws://[::1]:3000/ws"));
+        assert!(agent_is_local("wss://127.0.0.1/ws"));
+    }
+
+    #[test]
+    fn public_addresses_are_not_local() {
+        // 8.8.8.8 is not assigned to any local interface.
+        assert!(!agent_is_local("ws://8.8.8.8:3000/ws"));
+        // Documentation-range address, guaranteed not bound locally.
+        assert!(!agent_is_local("ws://203.0.113.1:3000/ws"));
+    }
+
+    #[test]
+    fn garbage_fails_closed() {
+        assert!(!agent_is_local("not a url"));
+        assert!(!agent_is_local(""));
+    }
+}

socktop/src/main.rs

@@ -2,6 +2,8 @@
 
 mod app;
 mod history;
+mod local;
+mod proc_kill;
 mod profiles;
 mod retry;
 mod types;
@@ -321,10 +323,15 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let is_tls = url.starts_with("wss://");
     let has_token = url.contains("token=");
+    // Only enable local process-kill when the agent is verified to be on this
+    // machine; otherwise on-screen PIDs refer to a remote host and acting on
+    // them locally would signal the wrong process. See local::agent_is_local.
+    let is_local = local::agent_is_local(&url);
     let mut app = App::new()
         .with_intervals(metrics_interval_ms, processes_interval_ms)
         .with_status(is_tls, has_token)
-        .with_compact(parsed.compact);
+        .with_compact(parsed.compact)
+        .with_local(is_local);
     if parsed.dry_run {
         return Ok(());
     }
@@ -404,7 +411,12 @@ async fn run_demo_mode(
         }
         Err(e) => return Err(e.into()),
     };
-    let mut app = App::new().with_compact(compact);
+    // Demo mode runs the real agent on loopback, so its PIDs are real local
+    // processes — enable the local process-kill feature, gated the same way as
+    // the normal connect path (loopback resolves local).
+    let mut app = App::new()
+        .with_compact(compact)
+        .with_local(local::agent_is_local(&url));
     // Demo mode connects to localhost, so disable hostname verification
     tokio::select! { res=app.run(&url,None,false)=>{ drop(child); res } _=tokio::signal::ctrl_c()=>{ drop(child); Ok(()) } }
 }

socktop/src/proc_kill.rs

@@ -0,0 +1,181 @@
+//! Local process termination.
+//!
+//! Signals are sent by socktop itself, using this process's own OS privileges,
+//! via a direct `sysinfo` call. Nothing is transmitted to the agent — the
+//! agent and connector have no kill capability at all. This code path is only
+//! reachable once the agent has been verified to be local (see
+//! [`crate::local`]), which guarantees the PID refers to a process on this
+//! machine.
+
+use sysinfo::{ProcessRefreshKind, ProcessesToUpdate, Signal, System};
+
+/// The signals socktop can send. Deliberately limited to the two btop-style
+/// primaries; no arbitrary-signal chooser.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum KillSignal {
+    /// SIGTERM — polite request to terminate.
+    Term,
+    /// SIGKILL — forceful, cannot be caught.
+    Kill,
+}
+
+impl KillSignal {
+    fn as_sysinfo(self) -> Signal {
+        match self {
+            KillSignal::Term => Signal::Term,
+            KillSignal::Kill => Signal::Kill,
+        }
+    }
+
+    /// Human-facing label for confirmation/result messages.
+    pub fn label(self) -> &'static str {
+        match self {
+            KillSignal::Term => "SIGTERM",
+            KillSignal::Kill => "SIGKILL",
+        }
+    }
+}
+
+/// Is `pid` still a live local process?
+///
+/// A zombie counts as gone: after a kill the entry can linger until the parent
+/// reaps it, and showing a row for a process that no longer runs is exactly the
+/// staleness this check exists to avoid.
+pub fn process_exists(pid: u32) -> bool {
+    let spid = sysinfo::Pid::from_u32(pid);
+    let mut sys = System::new();
+    sys.refresh_processes_specifics(
+        ProcessesToUpdate::Some(&[spid]),
+        false,
+        ProcessRefreshKind::nothing(),
+    );
+    match sys.process(spid) {
+        Some(p) => p.status() != sysinfo::ProcessStatus::Zombie,
+        None => false,
+    }
+}
+
+/// Send `signal` to local process `pid`. Returns `Ok(())` on success, or an
+/// `Err` with a human-readable reason (process gone, PID reused, permission
+/// denied, signal unsupported on this platform).
+///
+/// `expected_name`, when given, is compared against the process that owns the
+/// PID **right now**: the PID came from an agent snapshot and the confirmation
+/// dialog can sit open indefinitely, so by signal time the kernel may have
+/// recycled the number for an unrelated process. Both names come from the
+/// same sysinfo source, so a live, unchanged target compares equal.
+pub fn kill_local_process(
+    pid: u32,
+    expected_name: Option<&str>,
+    signal: KillSignal,
+) -> Result<(), String> {
+    let spid = sysinfo::Pid::from_u32(pid);
+
+    // Refresh just this one PID — we don't need a full process scan to signal it.
+    let mut sys = System::new();
+    sys.refresh_processes_specifics(
+        ProcessesToUpdate::Some(&[spid]),
+        false,
+        ProcessRefreshKind::nothing(),
+    );
+
+    let Some(proc_) = sys.process(spid) else {
+        return Err(format!("Process {pid} no longer exists"));
+    };
+
+    if let Some(expected) = expected_name {
+        let current = proc_.name().to_string_lossy();
+        if current != expected {
+            return Err(format!(
+                "PID {pid} now belongs to \"{current}\", not \"{expected}\" — \
+                 not signalling. Reselect the process and try again."
+            ));
+        }
+    }
+
+    match proc_.kill_with(signal.as_sysinfo()) {
+        Some(true) => Ok(()),
+        Some(false) => Err(format!(
+            "Could not send {} to PID {pid} (permission denied?)",
+            signal.label()
+        )),
+        None => Err(format!(
+            "{} is not supported on this platform",
+            signal.label()
+        )),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::process::Command;
+    use std::time::{Duration, Instant};
+
+    /// The path that matters: a real, live, local process must actually receive
+    /// the signal. Exercises the `refresh_processes_specifics` lookup as well —
+    /// if that call does not populate the process map, `sys.process()` returns
+    /// None and a live PID is reported as "no longer exists".
+    #[test]
+    fn signals_a_real_child_process() {
+        let mut child = Command::new("sleep")
+            .arg("30")
+            .spawn()
+            .expect("spawn sleep for the test");
+        let pid = child.id();
+
+        let result = kill_local_process(pid, Some("sleep"), KillSignal::Term);
+
+        // Reap on every path before asserting, so a failing assert cannot leak a
+        // 30s sleep and cannot trip clippy's zombie_processes lint.
+        let deadline = Instant::now() + Duration::from_secs(5);
+        let mut exited = false;
+        while Instant::now() < deadline {
+            if matches!(child.try_wait(), Ok(Some(_))) {
+                exited = true;
+                break;
+            }
+            std::thread::sleep(Duration::from_millis(20));
+        }
+        if !exited {
+            let _ = child.kill();
+        }
+        let _ = child.wait();
+
+        assert!(result.is_ok(), "kill_local_process returned {result:?}");
+        assert!(
+            exited,
+            "SIGTERM was reported sent but the child never exited"
+        );
+    }
+
+    /// The reuse guard: a live PID whose owner does not match the name the
+    /// user confirmed must NOT be signalled. This also proves the name is
+    /// populated under ProcessRefreshKind::nothing() — if it weren't, the
+    /// matching-name test above would fail instead.
+    #[test]
+    fn refuses_a_pid_owned_by_a_different_process() {
+        let mut child = Command::new("sleep")
+            .arg("30")
+            .spawn()
+            .expect("spawn sleep");
+        let pid = child.id();
+
+        let result = kill_local_process(pid, Some("firefox"), KillSignal::Term);
+
+        let _ = child.kill();
+        let _ = child.wait();
+
+        let err = result.expect_err("signalled a process under the wrong name");
+        assert!(err.contains("firefox") && err.contains("sleep"), "{err}");
+    }
+
+    #[test]
+    fn reports_a_pid_that_is_gone() {
+        let mut child = Command::new("true").spawn().expect("spawn true");
+        let pid = child.id();
+        child.wait().expect("reap");
+        // The PID is now free; signalling it must fail cleanly, not panic.
+        assert!(kill_local_process(pid, None, KillSignal::Term).is_err());
+    }
+}

socktop/src/ui/modal.rs

@@ -1,6 +1,10 @@
 //! Modal window system for socktop TUI application
 
-use super::theme::MODAL_DIM_BG;
+use super::fit;
+use super::theme::{
+    BTN_EXIT_BG_ACTIVE, BTN_RETRY_BG_ACTIVE, MODAL_BG, MODAL_BORDER_FG, MODAL_DIM_BG, MODAL_FG,
+    MODAL_TITLE_FG,
+};
 use crossterm::event::KeyCode;
 use ratatui::{
     Frame,
@@ -26,6 +30,10 @@ pub struct ModalManager {
     pub help_scroll_offset: usize,
 }
 
+/// Key hints shown under the confirmation buttons. Also sets the minimum
+/// width of that dialog — sizing from the question alone clipped this line.
+const CONFIRM_HINT: &str = "Tab ← → choose  ·  Enter run  ·  Esc cancel";
+
 impl ModalManager {
     pub fn new() -> Self {
         Self {
@@ -83,6 +91,52 @@ impl ModalManager {
         }
         m
     }
+    /// Close the details view for `pid` WHEREVER it sits in the stack.
+    /// Returns whether anything was closed.
+    ///
+    /// Not just the top: killing from inside the details view stacks the
+    /// "Signal sent" Info modal on top of it, and a SIGKILL victim is usually
+    /// confirmed dead on the very next tick — while that Info is still up. A
+    /// top-only check missed the close, and since a gone PID is processed
+    /// once, the details view stayed open (frozen on the dead process's last
+    /// sample) with nothing left to ever close it.
+    ///
+    /// Per-PID matching keeps the parent-navigation property: only the dead
+    /// process's view goes; parent views underneath are other processes that
+    /// may still be alive and close themselves the same way.
+    pub fn close_process_details(&mut self, pid: u32) -> bool {
+        let was_top =
+            matches!(self.stack.last(), Some(ModalType::ProcessDetails { pid: p }) if *p == pid);
+        let before = self.stack.len();
+        self.stack
+            .retain(|m| !matches!(m, ModalType::ProcessDetails { pid: p } if *p == pid));
+        if self.stack.len() == before {
+            return false;
+        }
+        // Mirror pop_modal's focus bookkeeping when the top changed.
+        if was_top && let Some(next) = self.stack.last() {
+            self.active_button = match next {
+                ModalType::ConnectionError { .. } => ModalButton::Retry,
+                ModalType::ProcessDetails { .. } => ModalButton::Ok,
+                ModalType::About => ModalButton::Ok,
+                ModalType::Help => ModalButton::Ok,
+                ModalType::Confirmation { .. } => ModalButton::Confirm,
+                ModalType::Info { .. } => ModalButton::Ok,
+            };
+        }
+        true
+    }
+
+    /// PID of the uppermost ProcessDetails view, looking through any
+    /// Info/Confirmation stacked above it. What the user will land on when
+    /// transient modals are dismissed.
+    pub fn topmost_process_details(&self) -> Option<u32> {
+        self.stack.iter().rev().find_map(|m| match m {
+            ModalType::ProcessDetails { pid } => Some(*pid),
+            _ => None,
+        })
+    }
+
     pub fn update_connection_error_countdown(&mut self, new_countdown: Option<u64>) {
         if let Some(ModalType::ConnectionError {
             auto_retry_countdown,
@@ -110,6 +164,16 @@ impl ModalManager {
                 self.prev_button();
                 ModalAction::None
             }
+            // Kill the process being viewed. `t` rather than `k` because `k`
+            // scrolls the thread table in this modal — and using the same key
+            // here as on the processes pane means one thing to remember.
+            KeyCode::Char('t') | KeyCode::Char('T') => {
+                if let Some(ModalType::ProcessDetails { pid }) = self.stack.last() {
+                    ModalAction::KillSelected(*pid)
+                } else {
+                    ModalAction::None
+                }
+            }
             KeyCode::Char('r') | KeyCode::Char('R') => {
                 if matches!(self.stack.last(), Some(ModalType::ConnectionError { .. })) {
                     ModalAction::RetryConnection
@@ -241,7 +305,16 @@ impl ModalManager {
                 ModalAction::Dismiss
             }
             (Some(ModalType::Confirmation { .. }), ModalButton::Confirm) => ModalAction::Confirm,
-            (Some(ModalType::Confirmation { .. }), ModalButton::Cancel) => ModalAction::Cancel,
+            (Some(ModalType::Confirmation { .. }), ModalButton::ConfirmForce) => {
+                ModalAction::ConfirmForce
+            }
+            (Some(ModalType::Confirmation { .. }), ModalButton::Cancel) => {
+                // Pop here so Enter-on-Cancel behaves like Esc (which pops in
+                // handle_key); the app's Cancel handler can then assume the
+                // modal is already gone.
+                self.pop_modal();
+                ModalAction::Cancel
+            }
             (Some(ModalType::Info { .. }), ModalButton::Ok) => {
                 self.pop_modal();
                 ModalAction::Dismiss
@@ -253,12 +326,29 @@ impl ModalManager {
         self.active_button = match (&self.stack.last(), &self.active_button) {
             (Some(ModalType::ConnectionError { .. }), ModalButton::Retry) => ModalButton::Exit,
             (Some(ModalType::ConnectionError { .. }), ModalButton::Exit) => ModalButton::Retry,
-            (Some(ModalType::Confirmation { .. }), ModalButton::Confirm) => ModalButton::Cancel,
+            // Confirmation cycles through three: the safe affirmative, the
+            // escalated one, then cancel.
+            (Some(ModalType::Confirmation { .. }), ModalButton::Confirm) => {
+                ModalButton::ConfirmForce
+            }
+            (Some(ModalType::Confirmation { .. }), ModalButton::ConfirmForce) => {
+                ModalButton::Cancel
+            }
             (Some(ModalType::Confirmation { .. }), ModalButton::Cancel) => ModalButton::Confirm,
             _ => self.active_button.clone(),
         };
     }
     fn prev_button(&mut self) {
+        // Confirmation has three buttons, so stepping back is not the same as
+        // stepping forward; everything else is a two-way toggle.
+        if let Some(ModalType::Confirmation { .. }) = self.stack.last() {
+            self.active_button = match self.active_button {
+                ModalButton::Confirm => ModalButton::Cancel,
+                ModalButton::ConfirmForce => ModalButton::Confirm,
+                _ => ModalButton::ConfirmForce,
+            };
+            return;
+        }
         self.next_button();
     }
 
@@ -280,6 +370,150 @@ impl ModalManager {
         );
     }
 
+    /// Wrap `text` to at most `width` columns on word boundaries, so a dialog
+    /// can be sized from its content instead of guessing.
+    fn wrap_cols(text: &str, width: u16) -> Vec<String> {
+        let mut lines = Vec::new();
+        let mut current = String::new();
+        for word in text.split_whitespace() {
+            let candidate = if current.is_empty() {
+                word.to_string()
+            } else {
+                format!("{current} {word}")
+            };
+            if fit::cols(&candidate) <= width || current.is_empty() {
+                current = candidate;
+            } else {
+                lines.push(std::mem::take(&mut current));
+                current = word.to_string();
+            }
+        }
+        if !current.is_empty() {
+            lines.push(current);
+        }
+        if lines.is_empty() {
+            lines.push(String::new());
+        }
+        lines
+    }
+
+    /// A centered box just big enough for `message` plus `footer_rows` of
+    /// buttons/hints. Never exceeds the screen, and never gets so narrow that
+    /// the title is clipped.
+    ///
+    /// `min_content_w` is the width the footer needs. Sizing from the message
+    /// alone clipped the key-hint line, which is longer than most questions.
+    fn dialog_rect(area: Rect, message: &str, footer_rows: u16, min_content_w: u16) -> Rect {
+        // 2 border columns + 2 columns of breathing room on each side.
+        const CHROME_W: u16 = 6;
+        const MAX_TEXT_W: u16 = 64;
+        const MIN_TEXT_W: u16 = 24;
+
+        let avail_text = area.width.saturating_sub(CHROME_W).max(1);
+        let text_w = fit::cols(message)
+            .min(MAX_TEXT_W)
+            .min(avail_text)
+            .max(MIN_TEXT_W.min(avail_text));
+        let lines = Self::wrap_cols(message, text_w);
+        let widest = lines
+            .iter()
+            .map(|l| fit::cols(l))
+            .max()
+            .unwrap_or(text_w)
+            .max(min_content_w.min(avail_text));
+
+        let width = (widest + CHROME_W).min(area.width);
+        // borders + blank + message + blank + footer
+        let height = (lines.len() as u16 + footer_rows + 4).min(area.height);
+        Rect {
+            x: area.x + (area.width.saturating_sub(width)) / 2,
+            y: area.y + (area.height.saturating_sub(height)) / 2,
+            width,
+            height,
+        }
+    }
+
+    /// Shared chrome for the small dialogs: themed border, centered message
+    /// with real padding, and the footer row(s) returned for the caller to
+    /// fill with buttons.
+    ///
+    /// The old versions laid their content out over `area` rather than the
+    /// block's inner rect, which put the first line of text on top of the
+    /// border and pushed the buttons against the frame.
+    fn render_dialog_frame(
+        f: &mut Frame,
+        area: Rect,
+        title: &str,
+        message: &str,
+        footer_rows: u16,
+    ) -> Rect {
+        let block = Block::default()
+            .title(
+                Line::from(format!(" {title} ")).style(
+                    Style::default()
+                        .fg(MODAL_TITLE_FG)
+                        .add_modifier(Modifier::BOLD),
+                ),
+            )
+            .borders(Borders::ALL)
+            .border_style(Style::default().fg(MODAL_BORDER_FG))
+            .style(Style::default().bg(MODAL_BG));
+        let inner = block.inner(area);
+        f.render_widget(block, area);
+
+        // Pad one column each side so text never touches the border.
+        let padded = Rect {
+            x: inner.x + 1,
+            y: inner.y,
+            width: inner.width.saturating_sub(2),
+            height: inner.height,
+        };
+        let rows = Layout::default()
+            .direction(Direction::Vertical)
+            .constraints([
+                Constraint::Length(1),           // breathing room under the title
+                Constraint::Min(1),              // message
+                Constraint::Length(1),           // gap above the footer
+                Constraint::Length(footer_rows), // buttons / hints
+            ])
+            .split(padded);
+
+        f.render_widget(
+            Paragraph::new(message)
+                .style(Style::default().fg(MODAL_FG))
+                .alignment(Alignment::Center)
+                .wrap(Wrap { trim: true }),
+            rows[1],
+        );
+        rows[3]
+    }
+
+    /// One button, sized to its label and centered in `area`.
+    fn render_button(f: &mut Frame, area: Rect, label: &str, active: bool, accent: Color) {
+        let style = if active {
+            Style::default()
+                .bg(accent)
+                .fg(MODAL_BG)
+                .add_modifier(Modifier::BOLD)
+        } else {
+            Style::default().fg(accent)
+        };
+        let text = format!(" {label} ");
+        let w = fit::cols(&text).min(area.width);
+        let btn = Rect {
+            x: area.x + (area.width.saturating_sub(w)) / 2,
+            y: area.y,
+            width: w,
+            height: 1,
+        };
+        f.render_widget(
+            Paragraph::new(text)
+                .style(style)
+                .alignment(Alignment::Center),
+            btn,
+        );
+    }
+
     fn render_modal_content(&mut self, f: &mut Frame, modal: &ModalType, data: ProcessModalData) {
         let area = f.area();
         // Different sizes for different modal types
@@ -296,6 +530,13 @@ impl ModalManager {
                 // Help modal uses medium size
                 self.centered_rect(70, 80, area)
             }
+            // Confirmation and Info are one-question dialogs. A fixed 70%x50%
+            // box left a short question floating in a mostly-empty pane, so
+            // these size themselves to their content instead.
+            ModalType::Confirmation { message, .. } => {
+                Self::dialog_rect(area, message, 3, fit::cols(CONFIRM_HINT))
+            }
+            ModalType::Info { message, .. } => Self::dialog_rect(area, message, 1, 16),
             _ => {
                 // Other modals use smaller size
                 self.centered_rect(70, 50, area)
@@ -340,86 +581,64 @@ impl ModalManager {
         confirm_text: &str,
         cancel_text: &str,
     ) {
-        let chunks = Layout::default()
+        // Three buttons + a key hint line.
+        let footer = Self::render_dialog_frame(f, area, title, message, 3);
+        let rows = Layout::default()
             .direction(Direction::Vertical)
-            .constraints([Constraint::Min(1), Constraint::Length(3)])
+            .constraints([
-            .split(area);
+                Constraint::Length(1), // buttons
-        let block = Block::default()
+                Constraint::Length(1), // spacer
-            .title(format!(" {title} "))
+                Constraint::Length(1), // key hints
-            .borders(Borders::ALL)
+            ])
-            .style(Style::default().bg(Color::Black));
+            .split(footer);
-        f.render_widget(block, area);
+
-        f.render_widget(
+        let cols = Layout::default()
-            Paragraph::new(message)
-                .style(Style::default().fg(Color::White))
-                .alignment(Alignment::Center)
-                .wrap(Wrap { trim: true }),
-            chunks[0],
-        );
-        let buttons = Layout::default()
             .direction(Direction::Horizontal)
-            .constraints([Constraint::Percentage(50), Constraint::Percentage(50)])
+            .constraints([
-            .split(chunks[1]);
+                Constraint::Ratio(1, 3),
-        let confirm_style = if self.active_button == ModalButton::Confirm {
+                Constraint::Ratio(1, 3),
-            Style::default()
+                Constraint::Ratio(1, 3),
-                .bg(Color::Green)
+            ])
-                .fg(Color::Black)
+            .split(rows[0]);
-                .add_modifier(Modifier::BOLD)
+
-        } else {
+        Self::render_button(
-            Style::default().fg(Color::Green)
+            f,
-        };
+            cols[0],
-        let cancel_style = if self.active_button == ModalButton::Cancel {
+            confirm_text,
-            Style::default()
+            self.active_button == ModalButton::Confirm,
-                .bg(Color::Red)
+            BTN_RETRY_BG_ACTIVE,
-                .fg(Color::Black)
-                .add_modifier(Modifier::BOLD)
-        } else {
-            Style::default().fg(Color::Red)
-        };
-        f.render_widget(
-            Paragraph::new(confirm_text)
-                .style(confirm_style)
-                .alignment(Alignment::Center),
-            buttons[0],
         );
+        Self::render_button(
+            f,
+            cols[1],
+            "Force kill",
+            self.active_button == ModalButton::ConfirmForce,
+            MODAL_TITLE_FG,
+        );
+        Self::render_button(
+            f,
+            cols[2],
+            cancel_text,
+            self.active_button == ModalButton::Cancel,
+            BTN_EXIT_BG_ACTIVE,
+        );
+
         f.render_widget(
-            Paragraph::new(cancel_text)
+            Paragraph::new(CONFIRM_HINT)
-                .style(cancel_style)
+                .style(Style::default().fg(MODAL_FG).add_modifier(Modifier::DIM))
                 .alignment(Alignment::Center),
-            buttons[1],
+            rows[2],
         );
     }
 
     fn render_info(&self, f: &mut Frame, area: Rect, title: &str, message: &str) {
-        let chunks = Layout::default()
+        let footer = Self::render_dialog_frame(f, area, title, message, 1);
-            .direction(Direction::Vertical)
+        Self::render_button(
-            .constraints([Constraint::Min(1), Constraint::Length(3)])
+            f,
-            .split(area);
+            footer,
-        let block = Block::default()
+            "Enter — OK",
-            .title(format!(" {title} "))
+            self.active_button == ModalButton::Ok,
-            .borders(Borders::ALL)
+            BTN_RETRY_BG_ACTIVE,
-            .style(Style::default().bg(Color::Black));
-        f.render_widget(block, area);
-        f.render_widget(
-            Paragraph::new(message)
-                .style(Style::default().fg(Color::White))
-                .alignment(Alignment::Center)
-                .wrap(Wrap { trim: true }),
-            chunks[0],
-        );
-        let ok_style = if self.active_button == ModalButton::Ok {
-            Style::default()
-                .bg(Color::Blue)
-                .fg(Color::White)
-                .add_modifier(Modifier::BOLD)
-        } else {
-            Style::default().fg(Color::Blue)
-        };
-        f.render_widget(
-            Paragraph::new("[ Enter ] OK")
-                .style(ok_style)
-                .alignment(Alignment::Center),
-            chunks[1],
         );
     }
 
@@ -505,6 +724,9 @@ impl ModalManager {
             "  ↑/↓ ............ Select/navigate processes",
             "  Enter .......... Open Process Details",
             "  x/X ............ Clear selection",
+            "  t .............. Signal selected process — local agent only",
+            "                   (also works inside Process Details; the prompt",
+            "                    offers Terminate/SIGTERM or Force kill/SIGKILL)",
             "  Click header ... Sort by column (CPU/Mem)",
             "  Click row ...... Select process",
             "",
@@ -632,3 +854,254 @@ impl ModalManager {
             .split(vert[1])[1]
     }
 }
+
+#[cfg(test)]
+mod confirm_tests {
+    use super::*;
+
+    fn confirm_modal() -> ModalManager {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::Confirmation {
+            title: "Confirm signal".into(),
+            message: "Send a signal to bash (PID 42)?".into(),
+            confirm_text: "Terminate".into(),
+            cancel_text: "Cancel".into(),
+        });
+        m
+    }
+
+    /// The safe option is focused first, so a reflexive Enter terminates rather
+    /// than force-kills.
+    #[test]
+    fn opens_on_the_safe_option() {
+        let mut m = confirm_modal();
+        assert_eq!(m.active_button, ModalButton::Confirm);
+        assert_eq!(m.handle_key(KeyCode::Enter), ModalAction::Confirm);
+    }
+
+    #[test]
+    fn tab_cycles_all_three_buttons_forward() {
+        let mut m = confirm_modal();
+        m.handle_key(KeyCode::Tab);
+        assert_eq!(m.active_button, ModalButton::ConfirmForce);
+        m.handle_key(KeyCode::Tab);
+        assert_eq!(m.active_button, ModalButton::Cancel);
+        m.handle_key(KeyCode::Tab);
+        assert_eq!(m.active_button, ModalButton::Confirm);
+    }
+
+    /// With three buttons, back is not the same as forward — the old
+    /// prev_button just called next_button, which only worked for two.
+    #[test]
+    fn shift_tab_cycles_backward() {
+        let mut m = confirm_modal();
+        m.handle_key(KeyCode::BackTab);
+        assert_eq!(m.active_button, ModalButton::Cancel);
+        m.handle_key(KeyCode::BackTab);
+        assert_eq!(m.active_button, ModalButton::ConfirmForce);
+        m.handle_key(KeyCode::BackTab);
+        assert_eq!(m.active_button, ModalButton::Confirm);
+    }
+
+    #[test]
+    fn force_kill_reports_its_own_action() {
+        let mut m = confirm_modal();
+        m.handle_key(KeyCode::Tab);
+        assert_eq!(m.handle_key(KeyCode::Enter), ModalAction::ConfirmForce);
+    }
+
+    #[test]
+    fn escape_cancels_and_closes() {
+        let mut m = confirm_modal();
+        assert_eq!(m.handle_key(KeyCode::Esc), ModalAction::Cancel);
+        assert!(!m.is_active());
+    }
+
+    /// Enter on Cancel must behave like Esc, including closing the modal.
+    #[test]
+    fn enter_on_cancel_closes_too() {
+        let mut m = confirm_modal();
+        m.handle_key(KeyCode::Tab);
+        m.handle_key(KeyCode::Tab);
+        assert_eq!(m.handle_key(KeyCode::Enter), ModalAction::Cancel);
+        assert!(!m.is_active());
+    }
+
+    /// `t` inside process details asks the app to raise the kill prompt for the
+    /// process being viewed — not for whatever is selected in the list behind it.
+    #[test]
+    fn t_in_process_details_targets_that_pid() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::ProcessDetails { pid: 4242 });
+        assert_eq!(
+            m.handle_key(KeyCode::Char('t')),
+            ModalAction::KillSelected(4242)
+        );
+    }
+
+    /// `k` still scrolls the thread table, which is why `t` is the kill key.
+    #[test]
+    fn k_in_process_details_still_scrolls() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::ProcessDetails { pid: 1 });
+        m.thread_scroll_max = 5;
+        m.handle_key(KeyCode::Char('j'));
+        assert_eq!(m.thread_scroll_offset, 1);
+        assert_eq!(m.handle_key(KeyCode::Char('k')), ModalAction::Handled);
+        assert_eq!(m.thread_scroll_offset, 0);
+    }
+
+    #[test]
+    fn t_elsewhere_is_not_a_kill() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::Help);
+        assert_eq!(m.handle_key(KeyCode::Char('t')), ModalAction::None);
+    }
+
+    /// A one-line question must not be handed a half-screen box.
+    #[test]
+    fn dialog_is_sized_to_its_content() {
+        let screen = Rect::new(0, 0, 120, 40);
+        let r = ModalManager::dialog_rect(
+            screen,
+            "Send a signal to bash (PID 42)?",
+            3,
+            fit::cols(CONFIRM_HINT),
+        );
+        assert!(r.width < screen.width, "dialog took the full width");
+        assert!(r.height <= 12, "dialog was {} rows tall", r.height);
+        assert!(r.height >= 7, "dialog too short to hold its own footer");
+        // Centered to within the rounding of integer division.
+        let center_delta = (r.x + r.width / 2) as i32 - (screen.width / 2) as i32;
+        assert!(center_delta.abs() <= 1, "off-center by {center_delta}");
+    }
+
+    #[test]
+    fn dialog_never_exceeds_a_small_screen() {
+        let screen = Rect::new(0, 0, 20, 8);
+        let long = "a".repeat(400);
+        let r = ModalManager::dialog_rect(screen, &long, 3, fit::cols(CONFIRM_HINT));
+        assert!(r.width <= screen.width && r.height <= screen.height);
+    }
+}
+
+#[cfg(test)]
+mod button_style_tests {
+    use super::*;
+    use ratatui::Terminal;
+    use ratatui::backend::TestBackend;
+
+    /// The focused button must be the highlighted one — the whole point of the
+    /// three-button layout is that you can see which action Enter will run.
+    #[test]
+    fn focus_moves_the_highlight() {
+        let msg = "Send a signal to bash (PID 42)?";
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::Confirmation {
+            title: "Confirm signal".into(),
+            message: msg.into(),
+            confirm_text: "Terminate".into(),
+            cancel_text: "Cancel".into(),
+        });
+
+        // Background colors present on the button row, per focused button.
+        let bgs = |m: &ModalManager| -> Vec<Color> {
+            let screen = Rect::new(0, 0, 100, 30);
+            let area = ModalManager::dialog_rect(screen, msg, 3, fit::cols(CONFIRM_HINT));
+            let mut t = Terminal::new(TestBackend::new(100, 30)).unwrap();
+            t.draw(|f| {
+                m.render_confirmation(f, area, "Confirm signal", msg, "Terminate", "Cancel")
+            })
+            .unwrap();
+            let buf = t.backend().buffer();
+            // Buttons sit on the first footer row: title, gap, message, gap.
+            let row = area.y + 4;
+            (area.x..area.x + area.width)
+                .map(|x| buf[(x, row)].bg)
+                .collect()
+        };
+
+        let terminate_focused = bgs(&m);
+        assert!(
+            terminate_focused.contains(&BTN_RETRY_BG_ACTIVE),
+            "Terminate should be highlighted when focused"
+        );
+        assert!(
+            !terminate_focused.contains(&BTN_EXIT_BG_ACTIVE),
+            "Cancel must not be highlighted while Terminate has focus"
+        );
+
+        m.handle_key(KeyCode::Tab);
+        m.handle_key(KeyCode::Tab);
+        let cancel_focused = bgs(&m);
+        assert!(
+            cancel_focused.contains(&BTN_EXIT_BG_ACTIVE),
+            "Cancel should be highlighted after two Tabs"
+        );
+        assert!(
+            !cancel_focused.contains(&BTN_RETRY_BG_ACTIVE),
+            "Terminate must not stay highlighted"
+        );
+    }
+}
+
+#[cfg(test)]
+mod close_details_tests {
+    use super::*;
+
+    #[test]
+    fn closes_the_view_for_that_pid() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::ProcessDetails { pid: 4242 });
+        assert!(m.close_process_details(4242));
+        assert!(!m.is_active());
+    }
+
+    #[test]
+    fn leaves_a_different_pid_alone() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::ProcessDetails { pid: 4242 });
+        assert!(!m.close_process_details(1));
+        assert!(m.is_active());
+    }
+
+    /// Walking up to a parent stacks details views. Only the dead process's
+    /// view goes — whichever position it holds — and the survivor stays put.
+    #[test]
+    fn closes_only_the_dead_pids_view_in_a_parent_chain() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::ProcessDetails { pid: 100 }); // parent
+        m.push_modal(ModalType::ProcessDetails { pid: 200 }); // child, on top
+
+        // Parent dies while the child is viewed: its view is removed from
+        // UNDER the top, so closing the child later lands on the process list
+        // instead of a frozen corpse view.
+        assert!(m.close_process_details(100));
+        assert!(matches!(
+            m.current_modal(),
+            Some(ModalType::ProcessDetails { pid: 200 })
+        ));
+        assert!(m.close_process_details(200));
+        assert!(!m.is_active());
+    }
+
+    /// The F1 regression: killing from inside the details view stacks the
+    /// "Signal sent" Info on top, and the death is usually confirmed while
+    /// that Info is still up. The details view must close anyway — a top-only
+    /// check left it open forever, frozen on the dead process.
+    #[test]
+    fn closes_details_beneath_a_stacked_info_modal() {
+        let mut m = ModalManager::new();
+        m.push_modal(ModalType::ProcessDetails { pid: 7 });
+        m.push_modal(ModalType::Info {
+            title: "Signal sent".into(),
+            message: "Sent SIGKILL".into(),
+        });
+
+        assert!(m.close_process_details(7));
+        // The Info survives on top; dismissing it lands on the process list.
+        assert!(matches!(m.current_modal(), Some(ModalType::Info { .. })));
+        m.pop_modal();
+        assert!(!m.is_active());
+    }
+}

socktop/src/ui/modal_process.rs

@@ -95,7 +95,7 @@ impl ModalManager {
         }
 
         // Help line
-        let help_text = vec![Line::from(vec![
+        let mut help_text = vec![Line::from(vec![
             Span::styled(
                 "X ",
                 Style::default()
@@ -129,6 +129,23 @@ impl ModalManager {
             Span::styled("journal", Style::default().add_modifier(Modifier::DIM)),
         ])];
 
+        // Kill from here too — same key as the processes pane, and only shown
+        // when the agent is local, since that is the only case where it works.
+        if data.is_local
+            && let Some(line) = help_text.first_mut()
+        {
+            line.spans.push(Span::styled(
+                "  t ",
+                Style::default()
+                    .fg(PROCESS_DETAILS_ACCENT)
+                    .add_modifier(Modifier::BOLD),
+            ));
+            line.spans.push(Span::styled(
+                "kill",
+                Style::default().add_modifier(Modifier::DIM),
+            ));
+        }
+
         let help = Paragraph::new(Text::from(help_text))
             .alignment(Alignment::Center)
             .style(Style::default());

socktop/src/ui/modal_types.rs

@@ -19,6 +19,9 @@ pub struct ProcessModalData<'a> {
     pub history: ProcessHistoryData<'a>,
     pub max_mem_bytes: u64,
     pub unsupported: bool,
+    /// Whether the agent is on this machine. Only used to decide whether the
+    /// `t` kill hint is shown — the kill itself is gated in `App`.
+    pub is_local: bool,
 }
 
 /// Parameters for rendering scatter plot
@@ -64,9 +67,15 @@ pub enum ModalAction {
     RetryConnection,
     ExitApp,
     Confirm,
+    /// Confirmation modal's second affirmative: the same action, escalated.
+    /// Used by the kill prompt for SIGKILL, where `Confirm` means SIGTERM.
+    ConfirmForce,
     Cancel,
     Dismiss,
     SwitchToParentProcess(u32), // Switch to viewing parent process details
+    /// `t` pressed while viewing a process's details — the app decides whether
+    /// the agent is local and, if so, raises the kill confirmation.
+    KillSelected(u32),
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -74,6 +83,10 @@ pub enum ModalButton {
     Retry,
     Exit,
     Confirm,
+    /// Escalated affirmative on a Confirmation modal (SIGKILL for the kill
+    /// prompt). Separate button rather than a separate keybinding so the
+    /// destructive option has to be selected deliberately.
+    ConfirmForce,
     Cancel,
     Ok,
 }

socktop/src/ui/processes.rs

@@ -5,13 +5,14 @@ use ratatui::style::Modifier;
 use ratatui::{
     layout::{Constraint, Direction, Layout, Rect},
     style::{Color, Style},
-    text::Span,
+    text::{Line, Span},
     widgets::{Block, Borders, Paragraph, Scrollbar, ScrollbarOrientation, ScrollbarState, Table},
 };
 use std::cmp::Ordering;
 
 use crate::types::Metrics;
 use crate::ui::cpu::{per_core_clamp, per_core_handle_scrollbar_mouse};
+use crate::ui::fit;
 use crate::ui::theme::{
     PROCESS_SELECTION_BG, PROCESS_SELECTION_FG, PROCESS_TOOLTIP_BG, PROCESS_TOOLTIP_FG, SB_ARROW,
     SB_THUMB, SB_TRACK,
@@ -86,6 +87,9 @@ pub struct ProcessDisplayParams<'a> {
     /// Peak cpu_usage from the most recent cache build; used to bold the
     /// busiest process. -1.0 if no cache.
     pub peak_cpu: f32,
+    /// Agent is on this machine, so the `t` kill hint applies. Without it the
+    /// hint would advertise a key that deliberately does nothing.
+    pub is_local: bool,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
@@ -449,16 +453,60 @@ pub fn draw_top_processes(f: &mut ratatui::Frame<'_>, area: Rect, params: Proces
             format!("PID {selected_pid}")
         };
 
-        let tooltip_text = format!("{process_info} | Enter for details • X to unselect");
+        // Key hints, built as spans so the keys read as keys. `t` only appears
-        let tooltip_width = tooltip_text.len() as u16 + 2; // Add padding
+        // for a local agent, since that is the only case where it does anything.
-        let tooltip_height = 3;
+        let key = Style::default()
+            .fg(PROCESS_TOOLTIP_FG)
+            .add_modifier(Modifier::BOLD);
+        let label = Style::default().fg(PROCESS_TOOLTIP_FG);
+        let mut hints: Vec<Span> = vec![
+            Span::styled("⏎", key),
+            Span::styled(" details", label),
+            Span::styled("  ·  ", label),
+        ];
+        if params.is_local {
+            hints.push(Span::styled("t", key));
+            hints.push(Span::styled(" kill", label));
+            hints.push(Span::styled("  ·  ", label));
+        }
+        hints.push(Span::styled("x", key));
+        hints.push(Span::styled(" unselect", label));
 
-        // Position tooltip at bottom-right of the processes area
+        let hints_w: u16 = hints.iter().map(|s| fit::cols(&s.content)).sum();
-        if area.width > tooltip_width + 2 && area.height > tooltip_height + 1 {
+        // One row, borders on both sides, a space of padding each side.
+        let tooltip_height = 3;
+        let max_w = area.width.saturating_sub(2);
+        if max_w > hints_w + 6 && area.height > tooltip_height + 1 {
+            // The process name is the elastic part: truncate it so the hint
+            // always fits. The old version sized the box from the full string
+            // and skipped rendering entirely when a long process name made it
+            // wider than the pane — so the hint silently vanished exactly when
+            // a long-named process was selected.
+            let room_for_info = max_w - hints_w - 6;
+            let info = fit::truncate_cols(&process_info, room_for_info);
+            let mut spans: Vec<Span> = vec![
+                Span::styled(" ", label),
+                Span::styled(
+                    info.clone(),
+                    Style::default()
+                        .fg(PROCESS_TOOLTIP_FG)
+                        .add_modifier(Modifier::BOLD),
+                ),
+                Span::styled("  │  ", label),
+            ];
+            spans.extend(hints);
+            spans.push(Span::styled(" ", label));
+
+            let width = spans
+                .iter()
+                .map(|s| fit::cols(&s.content))
+                .sum::<u16>()
+                .saturating_add(2)
+                .min(area.width);
             let tooltip_area = Rect {
-                x: area.x + area.width.saturating_sub(tooltip_width + 1),
+                x: area.x + area.width.saturating_sub(width + 1),
                 y: area.y + area.height.saturating_sub(tooltip_height + 1),
-                width: tooltip_width,
+                width,
                 height: tooltip_height,
             };
 
@@ -468,11 +516,10 @@ pub fn draw_top_processes(f: &mut ratatui::Frame<'_>, area: Rect, params: Proces
                     .fg(PROCESS_TOOLTIP_FG),
             );
 
-            let tooltip_paragraph = Paragraph::new(tooltip_text)
+            f.render_widget(
-                .block(tooltip_block)
+                Paragraph::new(Line::from(spans)).block(tooltip_block),
-                .wrap(ratatui::widgets::Wrap { trim: true });
+                tooltip_area,
-
+            );
-            f.render_widget(tooltip_paragraph, tooltip_area);
         }
     }
 
@@ -905,6 +952,7 @@ mod click_tests {
                         filtered_indices: &idxs,
                         cached_rows: &cache,
                         peak_cpu: peak,
+                        is_local: false,
                     },
                 )
             })
@@ -984,3 +1032,110 @@ mod click_tests {
         }
     }
 }
+
+#[cfg(test)]
+mod tooltip_tests {
+    use super::*;
+    use ratatui::Terminal;
+    use ratatui::backend::TestBackend;
+    use ratatui::layout::Rect;
+    use socktop_connector::{Metrics, ProcessInfo};
+
+    fn metrics(name: &str) -> Metrics {
+        Metrics {
+            sampled_at_ms: None,
+            cpu_total: 0.0,
+            cpu_per_core: vec![],
+            mem_total: 32_000_000_000,
+            mem_used: 0,
+            swap_total: 0,
+            swap_used: 0,
+            hostname: "t".into(),
+            cpu_temp_c: None,
+            disks: vec![],
+            networks: vec![],
+            top_processes: vec![ProcessInfo {
+                pid: 4242,
+                name: name.into(),
+                cpu_usage: 1.5,
+                mem_bytes: 1_000_000,
+            }],
+            gpus: None,
+            process_count: Some(1),
+        }
+    }
+
+    /// Render the pane with a selection and return the whole buffer as text.
+    fn rendered(name: &str, width: u16, is_local: bool) -> String {
+        let m = metrics(name);
+        let mut cache = Vec::new();
+        let peak = rebuild_row_cache(&m, &mut cache);
+        let idxs = [0usize];
+        let mut terminal = Terminal::new(TestBackend::new(width, 12)).unwrap();
+        terminal
+            .draw(|f| {
+                draw_top_processes(
+                    f,
+                    Rect::new(0, 0, width, 12),
+                    ProcessDisplayParams {
+                        metrics: Some(&m),
+                        scroll_offset: 0,
+                        sort_by: ProcSortBy::CpuDesc,
+                        selected_process_pid: Some(4242),
+                        selected_process_index: Some(0),
+                        search_query: "",
+                        search_active: false,
+                        filtered_indices: &idxs,
+                        cached_rows: &cache,
+                        peak_cpu: peak,
+                        is_local,
+                    },
+                )
+            })
+            .unwrap();
+        let buf = terminal.backend().buffer();
+        let mut out = String::new();
+        for y in 0..12 {
+            for x in 0..width {
+                out.push_str(buf[(x, y)].symbol());
+            }
+            out.push('\n');
+        }
+        out
+    }
+
+    #[test]
+    fn hint_offers_kill_for_a_local_agent() {
+        let out = rendered("some-process", 80, true);
+        assert!(out.contains("details"), "no hint rendered at all:\n{out}");
+        assert!(
+            out.contains("kill"),
+            "local agent should offer kill:\n{out}"
+        );
+        assert!(out.contains("unselect"));
+    }
+
+    /// The key does nothing for a remote agent, so advertising it would be a lie.
+    #[test]
+    fn hint_omits_kill_for_a_remote_agent() {
+        let out = rendered("some-process", 80, false);
+        assert!(out.contains("details"), "no hint rendered at all:\n{out}");
+        assert!(
+            !out.contains("kill"),
+            "remote agent must not offer kill:\n{out}"
+        );
+    }
+
+    /// Regression: the hint used to be sized from the full label including the
+    /// process name, and was skipped entirely when that made it wider than the
+    /// pane — so it vanished exactly when a long-named process was selected.
+    #[test]
+    fn hint_survives_a_very_long_process_name() {
+        let long = "/usr/lib/firefox-esr/firefox-esr-with-a-really-long-suffix";
+        let out = rendered(long, 80, true);
+        assert!(
+            out.contains("details") && out.contains("kill"),
+            "hint disappeared for a long process name:\n{out}"
+        );
+    }
+}

socktop_agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "socktop_agent"
-version = "1.60.0"
+version = "1.60.1"
 authors = ["Jason Witty <jasonpwitty+socktop@proton.me>"]
 description = "Socktop agent daemon. Serves host metrics over WebSocket."
 edition = "2024"

socktop_agent/src/metrics.rs

@@ -588,9 +588,17 @@ pub async fn collect_processes_all(state: &AppState) -> ProcessesPayload {
     // filter when downgrading to a minimal refresh spec.
     let mut sys_guard = state.sys.lock().await;
     let sys = &mut *sys_guard;
+    // `true` = remove processes that no longer exist. With `false`, this
+    // long-lived System kept every process it had ever seen: the list grew
+    // without bound (21,648 entries on a machine with 289 processes after a
+    // few hours of build churn), process_count was meaningless, and — the
+    // reason this was found — a process you killed kept its row forever,
+    // because the agent went on reporting it. Safe here only because this is
+    // `ProcessesToUpdate::All`; with `Some(pids)` it would treat every process
+    // outside that list as dead and drop it.
     sys.refresh_processes_specifics(
         ProcessesToUpdate::All,
-        false,
+        true,
         ProcessRefreshKind::nothing().with_memory().without_tasks(),
     );
 
@@ -719,8 +727,11 @@ pub async fn collect_processes_all(state: &AppState) -> ProcessesPayload {
 
         //JW too complicated. simplify to remove strange behavior
 
-        // For active systems, get accurate CPU metrics
+        // For active systems, get accurate CPU metrics.
-        sys.refresh_processes_specifics(ProcessesToUpdate::All, false, kind.with_cpu());
+        // `true` = drop processes that have exited; see the Linux path above for
+        // what `false` cost us (an ever-growing list that kept reporting dead
+        // processes). Correct only because this is `ProcessesToUpdate::All`.
+        sys.refresh_processes_specifics(ProcessesToUpdate::All, true, kind.with_cpu());
 
         // } else {
         //     // For idle systems, just get basic process info

socktop_connector/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "socktop_connector"
-version = "1.60.0"
+version = "1.60.1"
 edition = "2024"
 license = "MIT"
 description = "WebSocket connector library for socktop agent communication"