diff --git a/claude-mux/.gitignore b/claude-mux/.gitignore
new file mode 100644
index 0000000..b07f35c
--- /dev/null
+++ b/claude-mux/.gitignore
@@ -0,0 +1,10 @@
+# Local build output (the binary shares the module name).
+/claude-mux
+
+# Go build/test artifacts.
+*.test
+*.out
+/dist/
+
+# Editor / direnv cruft.
+.direnv/
diff --git a/claude-mux/README.md b/claude-mux/README.md
index f162296..b2032d0 100644
--- a/claude-mux/README.md
+++ b/claude-mux/README.md
@@ -24,6 +24,7 @@ a session there are exactly two chords plus a detach, under the `C-x` prefix:
 | `C-x l` | Float a picker of **every** Claude session for this project       |
 | `C-x r` | Float the remote-control (`claude rc`) toggle for this project     |
 | `C-x n` | Start a fresh Claude session in a new window (current keeps going) |
+| `C-x u` | Float the current Claude usage (limits) for this project          |
 | `C-x d` | Detach — everything keeps running in the background               |
 | `C-x C-x` | Send a literal `C-x` through to Claude                           |
 
@@ -82,6 +83,15 @@ idle one resumes it (`claude --resume`) in a new window. With `ctrl+a` (or
 `claude-mux list --all`) the picker shows sessions from every project, labelled by
 project; resuming one there opens (or switches to) that project's session.
 
+### Usage (`C-x u`)
+
+`C-x u` floats a pane showing your current Claude usage — session and weekly
+limits with their progress bars, plus what is driving them. It renders Claude's
+interactive `/usage` panel (the pretty, coloured one) off-screen in a throwaway
+tmux pane and snapshots it, so you get the real view without a full session
+lingering. Press `q` (or `esc` / `ctrl+c`) to close it. If the interactive
+render is unavailable it falls back to the plain-text `claude -p /usage` report.
+
 ### Remote control (`C-x r`)
 
 [`claude rc`](https://claude.com/claude-code) (remote-control) runs a persistent
@@ -119,7 +129,11 @@ are always available without having to open each project by hand.
 - **Running status** is tracked by launching every window through
   `claude-mux run`, which assigns a known session id (`claude --session-id`) and
   records it as a tmux window option (`@claude_session_id`). That id is what lets
-  the picker tell a live session apart and jump straight to its window.
+  the picker tell a live session apart and jump straight to its window. Claude's
+  live session id can drift from the one baked in at launch — `/clear`, in-app
+  `/resume` and context compaction each mint a fresh id in the same window — so
+  the status hook re-tags its own window with the id it reports, keeping the tag
+  pointed at the session that is actually running there.
 - Each project directory gets its own tmux session on the shared socket, named
   after the directory (basename + a short path hash).
 
@@ -138,6 +152,7 @@ claude-mux list       Interactive session picker (used by the C-x l chord)
 claude-mux list --all   Picker across every project (also toggled with ctrl+a)
 claude-mux list --dump  Print the session listing as plain text (scripting/debug)
 claude-mux rc         Remote-control toggle popup (used by the C-x r chord)
+claude-mux usage      Show the current Claude usage/limits (used by the C-x u chord)
 claude-mux new        Start a fresh Claude session in the current directory
 claude-mux kill       Kill the running sessions for the current directory
 claude-mux kill --all Kill every running session across all projects
diff --git a/claude-mux/go.mod b/claude-mux/go.mod
index 2c6eb84..4d55cc2 100644
--- a/claude-mux/go.mod
+++ b/claude-mux/go.mod
@@ -5,6 +5,7 @@ go 1.26.5
 require (
 	github.com/charmbracelet/bubbletea v1.3.10
 	github.com/charmbracelet/lipgloss v1.1.0
+	github.com/charmbracelet/x/term v0.2.1
 )
 
 require (
@@ -12,7 +13,6 @@ require (
 	github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc // indirect
 	github.com/charmbracelet/x/ansi v0.10.1 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd // indirect
-	github.com/charmbracelet/x/term v0.2.1 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
diff --git a/claude-mux/internal/tmux/tmux.go b/claude-mux/internal/tmux/tmux.go
index d7e9230..c36c022 100644
--- a/claude-mux/internal/tmux/tmux.go
+++ b/claude-mux/internal/tmux/tmux.go
@@ -10,8 +10,10 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"syscall"
+	"time"
 
 	"claude-mux/internal/claude"
 	"claude-mux/internal/paths"
@@ -151,9 +153,13 @@ bind -T prefix r display-popup -d "#{@claude_project_dir}" -w 60%% -h 40%% -E "'
 # does not expand formats there, so an embedded --dir '#{@claude_project_dir}'
 # would reach run as a literal path, fail to chdir, and drop the whole session.
 bind -T prefix n new-window -c "#{@claude_project_dir}" -n claude "exec '%s' run"
+# C-x u : float the current Claude usage (limits). The command stays up until
+# the user presses q (claude-mux usage blocks on a keypress), so -E can close
+# the popup on exit without it flashing away the instant claude prints.
+bind -T prefix u display-popup -d "#{@claude_project_dir}" -w 80%% -h 75%% -E "'%s' usage"
 # C-x d : detach and leave everything running in the background.
 bind -T prefix d detach-client
-`, binPath, socket, binPath, socket, binPath)
+`, binPath, socket, binPath, socket, binPath, binPath)
 
 	path := configPath()
 	if err := os.WriteFile(path, []byte(conf), 0o644); err != nil {
@@ -251,6 +257,16 @@ func (s *Server) TagWindow(paneTarget, sessionID string) error {
 	return err
 }
 
+// WindowSessionID returns the Claude session id currently tagged on the window
+// containing paneTarget, or "" when it is untagged or cannot be resolved.
+func (s *Server) WindowSessionID(paneTarget string) string {
+	out, err := s.run("show-options", "-wqv", "-t", paneTarget, sessionIDOption)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(out)
+}
+
 // hasSession reports whether a session named slug exists.
 func (s *Server) hasSession(slug string) bool {
 	_, err := s.run("has-session", "-t", slug)
@@ -338,6 +354,58 @@ func (s *Server) NewWindowFresh(dir string) error {
 	return err
 }
 
+// usageSocket is the throwaway tmux socket used to render `claude /usage`
+// headlessly. It is deliberately a *different* socket from the claude-mux
+// server so the render never creates a window, session or picker entry there.
+const usageSocket = "claude-mux-usage"
+
+// CaptureUsage renders Claude's interactive `/usage` panel (the one with the
+// coloured progress bars) in a throwaway, off-screen tmux pane sized cols×rows,
+// then returns the captured screen with its ANSI colours preserved so a popup
+// can print it verbatim. `/usage` draws as a full-screen overlay, so the whole
+// pane is the panel — no composer to strip.
+//
+// The render runs on its own tmux socket (see usageSocket) which is torn down
+// before returning, so it never touches the claude-mux server. It polls until
+// the bars have painted (or times out), because Claude takes a moment to boot.
+func CaptureUsage(dir string, cols, rows int) (string, error) {
+	run := func(args ...string) (string, error) {
+		out, err := exec.Command("tmux", append([]string{"-L", usageSocket}, args...)...).Output()
+		return string(out), err
+	}
+	// Start clean in case a previous render was left behind, and always tear the
+	// scratch server down on the way out.
+	_, _ = run("kill-server")
+	defer func() { _, _ = run("kill-server") }()
+
+	// Pass Claude's config dir through explicitly: a fresh tmux server does not
+	// inherit arbitrary env vars, and the render must read the same transcripts.
+	newArgs := []string{"new-session", "-d", "-s", "u",
+		"-x", strconv.Itoa(cols), "-y", strconv.Itoa(rows), "-c", dir}
+	if cfg := os.Getenv("CLAUDE_CONFIG_DIR"); cfg != "" {
+		newArgs = append(newArgs, "-e", "CLAUDE_CONFIG_DIR="+cfg)
+	}
+	newArgs = append(newArgs, `claude "/usage"`)
+	if _, err := run(newArgs...); err != nil {
+		return "", err
+	}
+
+	var last string
+	for i := 0; i < 60; i++ {
+		out, err := run("capture-pane", "-p", "-e", "-t", "u")
+		if err == nil {
+			last = out
+			// The panel has painted once a progress bar (█) and a "% used"
+			// label are both on screen.
+			if strings.Contains(out, "% used") && strings.Contains(out, "█") {
+				return strings.TrimRight(out, "\n"), nil
+			}
+		}
+		time.Sleep(250 * time.Millisecond)
+	}
+	return strings.TrimRight(last, "\n"), fmt.Errorf("timed out waiting for usage to render")
+}
+
 // rcSuffix is appended to a project's slug to name its dedicated tmux session
 // hosting the Claude remote-control (`claude rc`) server. Keeping rc in its own
 // session (rather than a window in the project session) means an rc-enabled
diff --git a/claude-mux/main.go b/claude-mux/main.go
index 15ea8f9..03d32f8 100644
--- a/claude-mux/main.go
+++ b/claude-mux/main.go
@@ -5,11 +5,13 @@
 //	C-x l   float a picker of every Claude session for the project
 //	C-x r   toggle a persistent `claude rc` (remote-control) server for the project
 //	C-x n   start a fresh Claude session in a new window
+//	C-x u   float the current Claude usage (limits) for the project
 //
 // See README.md for the full picture.
 package main
 
 import (
+	"bufio"
 	"crypto/rand"
 	"encoding/json"
 	"flag"
@@ -21,6 +23,8 @@ import (
 	"strings"
 	"syscall"
 
+	"github.com/charmbracelet/x/term"
+
 	"claude-mux/internal/manager"
 	"claude-mux/internal/rc"
 	"claude-mux/internal/state"
@@ -46,6 +50,8 @@ func run(args []string) error {
 			return cmdNew(args[1:])
 		case "run":
 			return cmdRun(args[1:])
+		case "usage":
+			return cmdUsage(args[1:])
 		case "kill":
 			return cmdKill(args[1:])
 		case "hook":
@@ -72,6 +78,7 @@ Inside a session:
   C-x l   list every Claude session for this project
   C-x r   toggle a persistent remote-control (claude rc) server for this project
   C-x n   new Claude session in a background window
+  C-x u   show the current Claude usage (limits) in a floating pane
   C-x d   detach (everything keeps running)
 
 In the picker: enter open · n new · x kill selected · ctrl+a all · q cancel
@@ -198,6 +205,26 @@ func cmdHook(args []string) error {
 	if st == "closed" {
 		return state.Clear(payload.SessionID)
 	}
+
+	// Keep the hosting tmux window's session-id tag in sync with the id Claude is
+	// actually reporting. claude-mux tags a window with the id it launched (see
+	// cmdRun), but Claude's live session id diverges from that whenever a new id
+	// is minted in the same window — /clear, in-app /resume, context compaction.
+	// Left alone, the window would point at a dead id (the picker shows it "open"
+	// and its real, running state — keyed to the new id — has no window, so it
+	// reads as closed). Re-tagging on every hook self-heals that: the window now
+	// carries the live id, and the id it used to host is no longer live here, so
+	// its stale state is cleared rather than left to accumulate.
+	if pane := os.Getenv("TMUX_PANE"); pane != "" {
+		srv := tmux.New()
+		if srv.InsideOurServer() {
+			if old := srv.WindowSessionID(pane); old != "" && old != payload.SessionID {
+				_ = state.Clear(old)
+			}
+			_ = srv.TagWindow(pane, payload.SessionID)
+		}
+	}
+
 	return state.Set(payload.SessionID, st)
 }
 
@@ -224,6 +251,76 @@ func cmdNew(args []string) error {
 	return execClaude(dir)
 }
 
+// cmdUsage renders the current Claude usage into the floating pane opened by
+// the C-x u chord. It snapshots Claude's interactive `/usage` panel — the one
+// with the coloured progress bars — by rendering it in a throwaway off-screen
+// tmux pane sized to this popup and printing the captured screen verbatim. It
+// then blocks until the user presses q (or Esc / Ctrl-C) so the popup stays up
+// to be read instead of closing the instant the command exits.
+//
+// If the interactive render is unavailable (no tmux, or it times out) it falls
+// back to the plain-text `claude -p /usage` report so something still shows.
+func cmdUsage(args []string) error {
+	fs := flag.NewFlagSet("usage", flag.ContinueOnError)
+	dirFlag := fs.String("dir", "", "project directory (defaults to cwd)")
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+	dir := resolveDir(*dirFlag)
+
+	// Reserve the bottom row for the "press q" hint so it never scrolls the top
+	// of the panel out of view.
+	cols, rows := 80, 24
+	if w, h, err := term.GetSize(os.Stdout.Fd()); err == nil && w > 0 && h > 0 {
+		cols, rows = w, h
+	}
+	renderRows := rows - 1
+	if renderRows < 8 {
+		renderRows = rows
+	}
+
+	if screen, err := tmux.CaptureUsage(dir, cols, renderRows); err == nil && strings.Contains(screen, "% used") {
+		os.Stdout.WriteString(screen)
+	} else {
+		cmd := exec.Command("claude", "-p", "/usage")
+		cmd.Dir = dir
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		if runErr := cmd.Run(); runErr != nil {
+			fmt.Fprintln(os.Stderr, "\nfailed to fetch usage:", runErr)
+		}
+	}
+
+	fmt.Print("\n\x1b[2m─── press q to close ───\x1b[0m")
+	waitForQuit()
+	return nil
+}
+
+// waitForQuit blocks until the user presses q/Q, Esc or Ctrl-C. It puts the
+// terminal in raw mode so a single keypress is enough; if raw mode is
+// unavailable (stdin is not a tty) it falls back to reading a line.
+func waitForQuit() {
+	fd := os.Stdin.Fd()
+	old, err := term.MakeRaw(fd)
+	if err != nil {
+		bufio.NewReader(os.Stdin).ReadString('\n')
+		return
+	}
+	defer term.Restore(fd, old)
+
+	buf := make([]byte, 1)
+	for {
+		n, err := os.Stdin.Read(buf)
+		if err != nil || n == 0 {
+			return
+		}
+		switch buf[0] {
+		case 'q', 'Q', 3, 27: // q, Q, Ctrl-C, Esc
+			return
+		}
+	}
+}
+
 // cmdList runs the picker and carries out the chosen action.
 func cmdList(args []string) error {
 	fs := flag.NewFlagSet("list", flag.ContinueOnError)
diff --git a/claude-mux/shell.nix b/claude-mux/shell.nix
new file mode 100644
index 0000000..ac6946c
--- /dev/null
+++ b/claude-mux/shell.nix
@@ -0,0 +1,9 @@
+{pkgs ? import <nixpkgs> {}}:
+pkgs.mkShell {
+  packages = with pkgs; [
+    go
+    gopls
+    gotools
+    tmux
+  ];
+}
diff --git a/modules/cli/home.nix b/modules/cli/home.nix
index 172a2d1..8d58447 100644
--- a/modules/cli/home.nix
+++ b/modules/cli/home.nix
@@ -94,6 +94,9 @@
       hooks.Notification = [
         {hooks = [{type = "command"; command = "${lib.getExe pkgs.claude-mux} hook --status questions";}];}
       ];
+      hooks.SessionStart = [
+        {hooks = [{type = "command"; command = "${lib.getExe pkgs.claude-mux} hook --status idle";}];}
+      ];
       hooks.SessionEnd = [
         {hooks = [{type = "command"; command = "${lib.getExe pkgs.claude-mux} hook --status closed";}];}
       ];