diff --git a/bridges/s3-bridge/s3_bridge.py b/bridges/s3-bridge/s3_bridge.py
index 4f1d46b..f3e1770 100644
--- a/bridges/s3-bridge/s3_bridge.py
+++ b/bridges/s3-bridge/s3_bridge.py
@@ -93,8 +93,11 @@ class SessionLogger:
         self._bin_fh = open(bin_path, "ab", buffering=0)
         self._lock = threading.Lock()
         # Optional pure-byte taps (no headers). BW=Blastware tx, S3=device tx.
+        # These can be opened/closed on demand via start_raw_capture/stop_raw_capture.
         self._raw_bw = open(raw_bw_path, "ab", buffering=0) if raw_bw_path else None
         self._raw_s3 = open(raw_s3_path, "ab", buffering=0) if raw_s3_path else None
+        self._cap_bw_path: Optional[str] = raw_bw_path
+        self._cap_s3_path: Optional[str] = raw_s3_path
 
     def log_line(self, line: str) -> None:
         with self._lock:
@@ -124,6 +127,43 @@ class SessionLogger:
         self.log_line(f"[{ts}] [INFO] {msg}")
         self.bin_write_record(REC_INFO, msg.encode("utf-8", errors="replace"))
 
+    def start_raw_capture(self, label: str, logdir: str) -> tuple:
+        """Open new raw tap files for a named capture.  Returns (bw_path, s3_path)."""
+        ts = _dt.datetime.now().strftime("%Y%m%d_%H%M%S")
+        safe = "".join(c if c.isalnum() or c in "-_" else "_" for c in label)[:40] if label else ""
+        suffix = f"_{safe}" if safe else ""
+        bw_path = os.path.join(logdir, f"raw_bw_{ts}{suffix}.bin")
+        s3_path = os.path.join(logdir, f"raw_s3_{ts}{suffix}.bin")
+        with self._lock:
+            # Close any previously open taps first
+            if self._raw_bw:
+                self._raw_bw.close()
+            if self._raw_s3:
+                self._raw_s3.close()
+            self._raw_bw = open(bw_path, "ab", buffering=0)
+            self._raw_s3 = open(s3_path, "ab", buffering=0)
+            self._cap_bw_path = bw_path
+            self._cap_s3_path = s3_path
+        self.log_info(f"raw capture started: label={label!r} bw={bw_path} s3={s3_path}")
+        return bw_path, s3_path
+
+    def stop_raw_capture(self) -> tuple:
+        """Close raw tap files.  Returns (bw_path, s3_path) for the capture just closed."""
+        with self._lock:
+            bw = self._cap_bw_path
+            s3 = self._cap_s3_path
+            if self._raw_bw:
+                self._raw_bw.close()
+                self._raw_bw = None
+            if self._raw_s3:
+                self._raw_s3.close()
+                self._raw_s3 = None
+            self._cap_bw_path = None
+            self._cap_s3_path = None
+        if bw:
+            self.log_info(f"raw capture stopped: bw={bw} s3={s3}")
+        return bw, s3
+
     def close(self) -> None:
         with self._lock:
             try:
@@ -291,8 +331,18 @@ def forward_loop(
             time.sleep(0.002)
 
 
-def annotation_loop(logger: SessionLogger, stop: threading.Event) -> None:
-    print("[MARK] Type 'm' + Enter to annotate the capture. Ctrl+C to stop.")
+def annotation_loop(logger: SessionLogger, logdir: str, stop: threading.Event) -> None:
+    """
+    Reads stdin commands while the bridge runs.
+
+    Commands:
+      m                      — prompt for a mark label (interactive)
+      CAP_START:<label>      — begin a raw tap capture with the given label
+      CAP_STOP               — stop the current raw tap capture
+    Responses (printed to stdout, parsed by the GUI):
+      [CAP_START] <bw_path>\\t<s3_path>
+      [CAP_STOP]  <bw_path>\\t<s3_path>
+    """
     while not stop.is_set():
         try:
             line = input()
@@ -303,7 +353,21 @@ def annotation_loop(logger: SessionLogger, stop: threading.Event) -> None:
         if not line:
             continue
 
-        if line.lower() == "m":
+        if line.startswith("CAP_START:"):
+            label = line[10:].strip()
+            bw_path, s3_path = logger.start_raw_capture(label, logdir)
+            print(f"[CAP_START] {bw_path}\t{s3_path}")
+            sys.stdout.flush()
+
+        elif line == "CAP_STOP":
+            bw_path, s3_path = logger.stop_raw_capture()
+            if bw_path:
+                print(f"[CAP_STOP] {bw_path}\t{s3_path}")
+            else:
+                print("[CAP_STOP] no active capture")
+            sys.stdout.flush()
+
+        elif line.lower() == "m":
             try:
                 sys.stdout.write("  Label: ")
                 sys.stdout.flush()
@@ -315,8 +379,9 @@ def annotation_loop(logger: SessionLogger, stop: threading.Event) -> None:
                 print(f"  [MARK written] {label}")
             else:
                 print("  (empty label — mark cancelled)")
+
         else:
-            print("  (type 'm' + Enter to annotate)")
+            print(f"  (unknown command: {line!r})")
 
 
 def main() -> int:
@@ -391,7 +456,7 @@ def main() -> int:
     t_ann = threading.Thread(
         target=annotation_loop,
         name="Annotator",
-        args=(logger, stop),
+        args=(logger, args.logdir, stop),
         daemon=True,
     )
 
diff --git a/seismo_lab.py b/seismo_lab.py
index 2c85222..899f85e 100644
--- a/seismo_lab.py
+++ b/seismo_lab.py
@@ -97,16 +97,24 @@ class AnalyzerState:
 class BridgePanel(tk.Frame):
     """
     All bridge controls and live log output.
-    Calls on_bridge_started(raw_bw_path, raw_s3_path) when the bridge starts
-    so the parent can wire up the Analyzer.
+    Calls on_bridge_started(struct_bin_path) when the bridge starts.
+    Calls on_capture_started(bw_path, s3_path, label) when a capture begins.
+    Calls on_capture_complete(bw_path, s3_path, label) when a capture ends.
     """
 
-    def __init__(self, parent: tk.Widget, on_bridge_started, on_bridge_stopped, **kw):
+    def __init__(self, parent: tk.Widget, on_bridge_started, on_bridge_stopped,
+                 on_capture_started=None, on_capture_complete=None, **kw):
         super().__init__(parent, bg=BG2, **kw)
-        self._on_started = on_bridge_started  # signature: (raw_bw, raw_s3, struct_bin)
-        self._on_stopped = on_bridge_stopped
+        self._on_started  = on_bridge_started   # signature: (struct_bin)
+        self._on_stopped  = on_bridge_stopped
+        self._on_cap_started   = on_capture_started    # (bw, s3, label)
+        self._on_cap_complete  = on_capture_complete   # (bw, s3, label)
         self.process: Optional[subprocess.Popen] = None
         self._stdout_q: queue.Queue[str] = queue.Queue()
+        # Capture state
+        self._capturing   = False
+        self._cap_label: Optional[str] = None
+        self._cap_history: list[dict]  = []   # {label, status, bw, s3}
         self._build()
         self._poll_stdout()
 
@@ -146,17 +154,7 @@ class BridgePanel(tk.Frame):
         tk.Button(cfg, text="Browse", bg=BG3, fg=FG, relief="flat", cursor="hand2",
                   font=MONO, command=self._choose_dir).grid(row=1, column=5, **pad)
 
-        # Row 2: raw taps (always enabled — timestamped names generated at start)
-        self._raw_bw_on = tk.BooleanVar(value=True)
-        self._raw_s3_on = tk.BooleanVar(value=True)
-        tk.Checkbutton(cfg, text="Capture BW->S3 raw", variable=self._raw_bw_on,
-                       bg=BG2, fg=FG, selectcolor=BG3, activebackground=BG2,
-                       font=MONO).grid(row=2, column=0, columnspan=2, sticky="w", **pad)
-        tk.Checkbutton(cfg, text="Capture S3->BW raw", variable=self._raw_s3_on,
-                       bg=BG2, fg=FG, selectcolor=BG3, activebackground=BG2,
-                       font=MONO).grid(row=2, column=2, columnspan=2, sticky="w", **pad)
-
-        # Row 3: buttons + status
+        # Row 2: buttons + status
         btn_row = tk.Frame(self, bg=BG2)
         btn_row.pack(side=tk.TOP, fill=tk.X, padx=4, pady=2)
 
@@ -170,6 +168,18 @@ class BridgePanel(tk.Frame):
                                   command=self.stop_bridge, state="disabled")
         self.stop_btn.pack(side=tk.LEFT, padx=4)
 
+        tk.Frame(btn_row, bg=BG2, width=16).pack(side=tk.LEFT)  # spacer
+
+        self.cap_btn = tk.Button(btn_row, text="⬤  New Capture", bg=ORANGE, fg="#000000",
+                                 relief="flat", padx=10, cursor="hand2", font=MONO_B,
+                                 command=self._start_capture, state="disabled")
+        self.cap_btn.pack(side=tk.LEFT, padx=4)
+
+        self.stop_cap_btn = tk.Button(btn_row, text="■  Stop Capture", bg=BG3, fg=RED,
+                                      relief="flat", padx=10, cursor="hand2", font=MONO_B,
+                                      command=self._stop_capture, state="disabled")
+        self.stop_cap_btn.pack(side=tk.LEFT, padx=4)
+
         self.mark_btn = tk.Button(btn_row, text="Add Mark", bg=BG3, fg=FG,
                                   relief="flat", padx=10, cursor="hand2", font=MONO,
                                   command=self.add_mark, state="disabled")
@@ -179,9 +189,34 @@ class BridgePanel(tk.Frame):
         tk.Label(btn_row, textvariable=self.status_var,
                  bg=BG2, fg=FG_DIM, font=MONO).pack(side=tk.LEFT, padx=10)
 
+        # Capture history panel
+        hist_outer = tk.Frame(self, bg=BG2)
+        hist_outer.pack(side=tk.TOP, fill=tk.X, padx=4, pady=(2, 0))
+
+        tk.Label(hist_outer, text="Captures:", bg=BG2, fg=FG_DIM,
+                 font=MONO_SM, anchor="w").pack(side=tk.LEFT, padx=(4, 6))
+
+        hist_inner = tk.Frame(hist_outer, bg=BG2)
+        hist_inner.pack(side=tk.LEFT, fill=tk.X, expand=True)
+
+        self._hist_lb = tk.Listbox(
+            hist_inner, bg=BG3, fg=FG, font=MONO_SM,
+            height=3, relief="flat", selectbackground=BG,
+            selectforeground=ACCENT, activestyle="none",
+            highlightthickness=0,
+        )
+        hist_vsb = ttk.Scrollbar(hist_inner, orient="vertical", command=self._hist_lb.yview)
+        self._hist_lb.configure(yscrollcommand=hist_vsb.set)
+        hist_vsb.pack(side=tk.RIGHT, fill=tk.Y)
+        self._hist_lb.pack(side=tk.LEFT, fill=tk.X, expand=True)
+        self._hist_lb.bind("<Double-Button-1>", self._on_hist_dblclick)
+
+        tk.Label(hist_outer, text="dbl-click to reload", bg=BG2, fg=FG_DIM,
+                 font=MONO_SM, anchor="e").pack(side=tk.RIGHT, padx=6)
+
         # Log output
         self.log_view = scrolledtext.ScrolledText(
-            self, height=18, font=MONO_SM,
+            self, height=14, font=MONO_SM,
             bg=BG, fg=FG, insertbackground=FG,
             relief="flat", state="disabled",
         )
@@ -221,14 +256,8 @@ class BridgePanel(tk.Frame):
 
         args = [sys.executable, str(BRIDGE_PATH),
                 "--bw", bw, "--s3", s3, "--baud", baud, "--logdir", logdir]
-
-        raw_bw_path = raw_s3_path = None
-        if self._raw_bw_on.get():
-            raw_bw_path = os.path.join(logdir, f"raw_bw_{ts}.bin")
-            args += ["--raw-bw", raw_bw_path]
-        if self._raw_s3_on.get():
-            raw_s3_path = os.path.join(logdir, f"raw_s3_{ts}.bin")
-            args += ["--raw-s3", raw_s3_path]
+        # Raw BW/S3 taps are NOT opened at bridge start.
+        # Use "New Capture" to start a labeled tap on demand.
 
         # Structured bin path — written by bridge automatically, named by ts
         struct_bin_path = os.path.join(logdir, f"s3_session_{ts}.bin")
@@ -250,11 +279,12 @@ class BridgePanel(tk.Frame):
         self.status_var.set(f"Running  —  {bw} <-> {s3}")
         self.start_btn.configure(state="disabled")
         self.stop_btn.configure(state="normal", bg=RED)
-        self.mark_btn.configure(state="normal")
+        self.cap_btn.configure(state="normal")
         self._append_log(f"== Bridge started  [{ts}] ==\n")
+        self._append_log("   Click 'New Capture' when ready to record a setting change.\n")
 
-        # Notify parent so Analyzer can wire up live mode
-        self._on_started(raw_bw_path, raw_s3_path, struct_bin_path)
+        # Notify parent — no raw files yet, just the structured bin path
+        self._on_started(struct_bin_path)
 
     def stop_bridge(self) -> None:
         if self.process and self.process.poll() is None:
@@ -270,7 +300,11 @@ class BridgePanel(tk.Frame):
         self.status_var.set("Stopped")
         self.start_btn.configure(state="normal")
         self.stop_btn.configure(state="disabled", bg=BG3)
+        self.cap_btn.configure(state="disabled")
+        self.stop_cap_btn.configure(state="disabled", bg=BG3)
         self.mark_btn.configure(state="disabled")
+        self._capturing = False
+        self._cap_label = None
         self._append_log("== Bridge stopped ==\n")
 
     def _reader_thread(self) -> None:
@@ -288,12 +322,120 @@ class BridgePanel(tk.Frame):
                     self._bridge_ended()
                     self._on_stopped()
                     break
+
+                stripped = line.strip()
+
+                # Handle capture lifecycle events from bridge
+                if stripped.startswith("[CAP_START] ") and "\t" in stripped:
+                    parts = stripped[12:].split("\t", 1)
+                    if len(parts) == 2:
+                        bw_path, s3_path = parts[0].strip(), parts[1].strip()
+                        self._on_cap_started_msg(bw_path, s3_path)
+
+                elif stripped.startswith("[CAP_STOP] ") and "\t" in stripped:
+                    parts = stripped[11:].split("\t", 1)
+                    if len(parts) == 2:
+                        bw_path, s3_path = parts[0].strip(), parts[1].strip()
+                        self._on_cap_stopped_msg(bw_path, s3_path)
+
                 self._append_log(line)
         except queue.Empty:
             pass
         finally:
             self.after(100, self._poll_stdout)
 
+    # ── capture control ───────────────────────────────────────────────────
+
+    def _start_capture(self) -> None:
+        """Ask for a label and tell the bridge to start writing raw tap files."""
+        if not self.process or self.process.poll() is not None:
+            return
+        label = simpledialog.askstring(
+            "New Capture",
+            "Label for this capture\n(e.g. 'recording_mode_continuous').\nLeave blank for timestamp only:",
+            parent=self,
+        )
+        if label is None:
+            return  # user hit Cancel
+        label = label.strip()
+        try:
+            self.process.stdin.write(f"CAP_START:{label}\n")
+            self.process.stdin.flush()
+        except Exception as e:
+            messagebox.showerror("Error", f"Failed to start capture:\n{e}")
+            return
+        self._capturing = True
+        self._cap_label = label or datetime.datetime.now().strftime("%H%M%S")
+        self.cap_btn.configure(state="disabled")
+        self.stop_cap_btn.configure(state="normal", bg=RED)
+        self.mark_btn.configure(state="normal")
+        self._append_log(f"[CAPTURE] Starting: {self._cap_label!r}...\n")
+        # Add to history as recording (paths filled in when [CAP_START] arrives)
+        self._cap_history.append({"label": self._cap_label, "status": "recording",
+                                   "bw": None, "s3": None})
+        self._refresh_hist()
+
+    def _stop_capture(self) -> None:
+        """Tell the bridge to flush and close the current raw tap files."""
+        if not self.process or self.process.poll() is not None:
+            return
+        try:
+            self.process.stdin.write("CAP_STOP\n")
+            self.process.stdin.flush()
+        except Exception as e:
+            messagebox.showerror("Error", f"Failed to stop capture:\n{e}")
+        # UI is updated when [CAP_STOP] arrives in stdout
+
+    def _on_cap_started_msg(self, bw_path: str, s3_path: str) -> None:
+        """Called when bridge confirms capture has started (files are open)."""
+        # Fill in paths for the last 'recording' history entry
+        for entry in reversed(self._cap_history):
+            if entry["status"] == "recording" and entry["bw"] is None:
+                entry["bw"] = bw_path
+                entry["s3"] = s3_path
+                break
+        if self._on_cap_started:
+            self._on_cap_started(bw_path, s3_path, self._cap_label or "")
+
+    def _on_cap_stopped_msg(self, bw_path: str, s3_path: str) -> None:
+        """Called when bridge confirms capture has stopped (files are closed)."""
+        label = self._cap_label or "capture"
+        # Mark history entry as done
+        for entry in reversed(self._cap_history):
+            if entry["status"] == "recording":
+                entry["status"] = "done"
+                entry["bw"] = bw_path
+                entry["s3"] = s3_path
+                break
+        self._refresh_hist()
+        self._capturing = False
+        self._cap_label = None
+        self.cap_btn.configure(state="normal")
+        self.stop_cap_btn.configure(state="disabled", bg=BG3)
+        self._append_log(f"[CAPTURE] Done: {label!r}  — ready in Analyzer\n")
+        if self._on_cap_complete:
+            self._on_cap_complete(bw_path, s3_path, label)
+
+    def _refresh_hist(self) -> None:
+        self._hist_lb.delete(0, tk.END)
+        for entry in self._cap_history:
+            icon = "🔴" if entry["status"] == "recording" else "✅"
+            label = entry["label"] or "(unlabeled)"
+            self._hist_lb.insert(tk.END, f"  {icon}  {label}")
+        if self._cap_history:
+            self._hist_lb.see(tk.END)
+
+    def _on_hist_dblclick(self, _e=None) -> None:
+        sel = self._hist_lb.curselection()
+        if not sel:
+            return
+        entry = self._cap_history[sel[0]]
+        if entry["status"] == "done" and entry["bw"] and entry["s3"]:
+            if self._on_cap_complete:
+                self._on_cap_complete(entry["bw"], entry["s3"], entry["label"])
+
+    # ── mark ──────────────────────────────────────────────────────────────
+
     def add_mark(self) -> None:
         if not self.process or not self.process.stdin or self.process.poll() is not None:
             return
@@ -1884,6 +2026,8 @@ class SeismoLab(tk.Tk):
             nb,
             on_bridge_started=self._on_bridge_started,
             on_bridge_stopped=self._on_bridge_stopped,
+            on_capture_started=self._on_capture_started,
+            on_capture_complete=self._on_capture_complete,
         )
         nb.add(self._bridge_panel, text="  Bridge  ")
 
@@ -1905,16 +2049,27 @@ class SeismoLab(tk.Tk):
         self._nb = nb
         self.protocol("WM_DELETE_WINDOW", self._on_close)
 
-    def _on_bridge_started(self, raw_bw: Optional[str], raw_s3: Optional[str],
-                           struct_bin: Optional[str] = None) -> None:
-        """Bridge started — inject paths into analyzer and start live mode."""
-        self._analyzer_panel.set_live_files(raw_bw, raw_s3, struct_bin)
-        # Switch to Analyzer tab so the user can watch it update
-        self._nb.select(1)
+    def _on_bridge_started(self, struct_bin: Optional[str] = None) -> None:
+        """Bridge started — stash the structured bin path; stay on Bridge tab."""
+        if struct_bin:
+            self._analyzer_panel.bin_var.set(struct_bin)
 
     def _on_bridge_stopped(self) -> None:
         self._analyzer_panel.stop_live()
 
+    def _on_capture_started(self, bw_path: str, s3_path: str, label: str) -> None:
+        """A capture began — wire up live mode in the Analyzer and switch tabs."""
+        self._analyzer_panel.set_live_files(bw_path, s3_path)
+        self._nb.select(1)
+
+    def _on_capture_complete(self, bw_path: str, s3_path: str, label: str) -> None:
+        """A capture stopped — stop live mode, run full analysis, switch to Analyzer."""
+        self._analyzer_panel.stop_live()
+        self._analyzer_panel.s3_var.set(s3_path)
+        self._analyzer_panel.bw_var.set(bw_path)
+        self._analyzer_panel._run_analyze()
+        self._nb.select(1)
+
     def _on_console_send_to_analyzer(self, raw_s3_path: str) -> None:
         """Console captured bytes → inject into Analyzer S3 field and switch tab."""
         self._analyzer_panel.s3_var.set(raw_s3_path)