diff --git a/input/steam-gamepad-filter.js b/input/steam-gamepad-filter.js
new file mode 100644
index 0000000..f9cfa8d
--- /dev/null
+++ b/input/steam-gamepad-filter.js
@@ -0,0 +1,103 @@
+// Frametop gaze first: a filter in Steam's UI (SharedJSContext, through Steam's CEF debugger on
+// 127.0.0.1:8080) that keeps the Frame controllers' gamepad input away from Steam's UI while
+// gaze mode has the dashboard (docs/gaze-first.md). Steam reads the controllers as its own
+// virtual gamepad (Steam Input), so no SteamVR binding can do this.
+//
+// Steam's gamepad input source (webpack module 17900, class E) turns each controller message
+// into this.OnButtonDown / OnButtonUp / OnAnalogPad calls, which live on its base class. The
+// filter defines wrappers on E's prototype, so both live instances go through them. They look
+// up window.__frametopGaze at every call, so evaluating this file again updates the logic in
+// place; a wrapper from an older version is replaced. It returns the state as JSON.
+//
+// The dashboard's mode (laser or gamepad) is SteamVR's, not the UI's: the UI only mirrors it
+// (VRFocus, module 84114: J.Instance.ShowGamepadFocusMode, from SteamVR's
+// system_panel_interaction_mode).
+//
+// window.__frametopGaze:
+//   mode    "off" (pass everything), "log" (pass, and log), "block" (drop all but `allow`),
+//           "auto" (block while the dashboard is in laser mode, pass in gamepad mode)
+//   allow   buttons that always pass: the Steam button's guide and quick menu, and Steam's
+//           own dummy input
+//   log     the last 256 events: [ms, "down"|"up"|"analog", button, controller, passed]
+//   modes   the dashboard's mode changes: [ms, "gamepad"|"laser"] (sampled every 50 ms)
+// A release passes if its press did, so nothing stays held when blocking starts.
+// Buttons (Steam's enum): 1 OK 2 CANCEL 3 SECONDARY 4 OPTIONS 5/6 bumpers 7/8 triggers 9-12 dpad
+// 13 SELECT 14 START 15/16 stick clicks 17/18 stick touch 23-26 rear buttons (24 left grip,
+// 26 right grip) 27 STEAM_GUIDE 28 STEAM_QUICK_MENU 29 DUMMY_INPUT.
+(() => {
+    const VERSION = 2;
+    if (!window.__ftreq) {
+        const name = Object.keys(window).find(k => k.startsWith("webpackChunk"));
+        window[name].push([[Symbol("frametop")], {}, r => { window.__ftreq = r; }]);
+    }
+    const E = window.__ftreq(17900).E;
+    const proto = E.prototype;
+    if (!("HandleControllerInputMessages" in proto)) throw new Error("Steam's gamepad source moved (module 17900)");
+    const base = Object.getPrototypeOf(proto);
+    const G = window.__frametopGaze || (window.__frametopGaze = {mode: "log", allow: [27, 28, 29], log: [], held: {}, dropped: 0});
+    G.modes = G.modes || [];
+    G.gamepadMode = () => {
+        try { return !!window.__ftreq(84114).J.Instance?.ShowGamepadFocusMode; } catch (e) { return false; }
+    };
+    G.note = (ev, button, controller, passed) => {
+        G.log.push([Math.round(performance.now()), ev, button, controller, passed]);
+        if (G.log.length > 256) G.log.shift();
+    };
+    G.blocks = button => {
+        if (G.allow.includes(button)) return false;
+        return G.mode === "block" || (G.mode === "auto" && !G.gamepadMode());
+    };
+    if (proto.OnButtonDown && proto.OnButtonDown.__frametop !== VERSION) {
+        delete proto.OnButtonDown;
+        delete proto.OnButtonUp;
+        delete proto.OnAnalogPad;
+    }
+    if (!Object.prototype.hasOwnProperty.call(proto, "OnButtonDown")) {
+        proto.OnButtonDown = function (button, controller, ...rest) {
+            let pass = true;
+            try {
+                const g = window.__frametopGaze;
+                g.inst = this;
+                pass = !g.blocks(button);
+                if (g.mode !== "off") g.note("down", button, controller, pass);
+                if (pass) g.held[controller + ":" + button] = true;
+                else g.dropped++;
+            } catch (e) { pass = true; }
+            if (pass) return base.OnButtonDown.call(this, button, controller, ...rest);
+        };
+        proto.OnButtonUp = function (button, controller, ...rest) {
+            let pass = true;
+            try {
+                const g = window.__frametopGaze, key = controller + ":" + button;
+                pass = !!g.held[key] || !g.blocks(button);
+                delete g.held[key];
+                if (g.mode !== "off") g.note("up", button, controller, pass);
+            } catch (e) { pass = true; }
+            if (pass) return base.OnButtonUp.call(this, button, controller, ...rest);
+        };
+        proto.OnAnalogPad = function (button, x, y, controller, ...rest) {
+            let pass = true;
+            try {
+                const g = window.__frametopGaze;
+                pass = !g.blocks(button);
+                if (g.mode !== "off" && (x || y)) g.note("analog", button, controller, pass);
+            } catch (e) { pass = true; }
+            if (pass) return base.OnAnalogPad.call(this, button, x, y, controller, ...rest);
+        };
+        for (const f of [proto.OnButtonDown, proto.OnButtonUp, proto.OnAnalogPad]) f.__frametop = VERSION;
+        G.installed = Date.now();
+    }
+    if (!G.sampler) {
+        let last = null;
+        G.sampler = setInterval(() => {
+            const m = G.gamepadMode() ? "gamepad" : "laser";
+            if (m !== last) {
+                last = m;
+                G.modes.push([Math.round(performance.now()), m]);
+                if (G.modes.length > 128) G.modes.shift();
+            }
+        }, 50);
+    }
+    return JSON.stringify({version: VERSION, mode: G.mode, gamepad: G.gamepadMode(), installed: G.installed,
+                           dropped: G.dropped, modes: G.modes.slice(-10), log: G.log.slice(-10)});
+})()