diff --git a/README.md b/README.md
index 85610b4..ae53363 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,8 @@ This repository is **P2 complete**: the engine, the wire, the descent, the quarr
 
 ![P2 · the choir](preview-p2-agent.png)
 
+![P2 · the native app with the host, the arrangement and the choir](preview-p2-tauri.png)
+
 ## What is real
 
 - **Rust engine.** `cpal` output at 48 kHz, five veins, a sixteen-step phrase, a fixed voice pool, per-vein levels and gains, a bar clock. Procedural voices for empty pattern rows; real sample voices for rows with a face. No Web Audio.
diff --git a/app/src-tauri/Cargo.lock b/app/src-tauri/Cargo.lock
index 8c4bb6b..97d3c46 100644
--- a/app/src-tauri/Cargo.lock
+++ b/app/src-tauri/Cargo.lock
@@ -166,6 +166,12 @@ version = "0.21.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d297deb1925b89f2ccc13d7635fa0714f12c87adce1c75356b39ca9b7178567"
 
+[[package]]
+name = "base64"
+version = "0.22.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
+
 [[package]]
 name = "base64"
 version = "0.23.1"
@@ -410,6 +416,12 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f079e83a288787bcd14a6aea84cee5c87a67c5a3e660c30f557a3d24761b3527"
+
 [[package]]
 name = "chacha20"
 version = "0.10.2"
@@ -1297,6 +1309,19 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "libc",
+ "wasi",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.3.4"
@@ -1316,9 +1341,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "300e883d756b2e4ec94e02791f39b04b522276138852cfc41d9fb7e904106099"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "r-efi 6.0.0",
  "rand_core",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -1511,6 +1538,12 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "hound"
+version = "3.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62adaabb884c94955b19907d60019f4e145d091c75345379e70d1ee696f7854f"
+
 [[package]]
 name = "html5ever"
 version = "0.39.0"
@@ -1588,6 +1621,22 @@ dependencies = [
  "want",
 ]
 
+[[package]]
+name = "hyper-rustls"
+version = "0.27.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dfa8e654703247911e29c23fbeaa261834bd9bb74efba2f9acddc37bfb127f53"
+dependencies = [
+ "http",
+ "hyper",
+ "hyper-util",
+ "rustls",
+ "tokio",
+ "tokio-rustls",
+ "tower-service",
+ "webpki-roots",
+]
+
 [[package]]
 name = "hyper-util"
 version = "0.1.21"
@@ -2096,6 +2145,12 @@ version = "0.4.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d15f86d12da44cd8d4ec3c73984537eb7f4cadcb9776a575a0a8a05ca11005c"
 
+[[package]]
+name = "lru-slab"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4050469837a6ff301cd14c1f8f24f88549e6d548f24f64e2148eb0f72cebc51f"
+
 [[package]]
 name = "mach2"
 version = "0.6.0"
@@ -2812,6 +2867,62 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "quinn"
+version = "0.11.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4051e23e9185c255a7e33ef59cdbca87a22d359052eecd22fc6b901fb37d9d11"
+dependencies = [
+ "bytes",
+ "cfg_aliases",
+ "pin-project-lite",
+ "quinn-proto",
+ "quinn-udp",
+ "rustc-hash",
+ "rustls",
+ "socket2",
+ "thiserror 2.0.21",
+ "tokio",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-proto"
+version = "0.11.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e750cca55fe4f0439a15d0bb529da9651e79993e8e72c61a899a36d462befbe"
+dependencies = [
+ "bytes",
+ "getrandom 0.4.3",
+ "lru-slab",
+ "rand",
+ "rand_pcg",
+ "ring",
+ "rustc-hash",
+ "rustls",
+ "rustls-pki-types",
+ "slab",
+ "thiserror 2.0.21",
+ "tinyvec",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-udp"
+version = "0.5.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af66907df18639dcf4db56ca65490cabc4b27a97dbadd96f2926cca73298f016"
+dependencies = [
+ "cfg_aliases",
+ "libc",
+ "once_cell",
+ "socket2",
+ "tracing",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.47"
@@ -2850,6 +2961,15 @@ version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "63b8176103e19a2643978565ca18b50549f6101881c443590420e4dc998a3c69"
 
+[[package]]
+name = "rand_pcg"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "caa0f4137e1c0a72f4c651489402276c8e8e1cf081f3b0ba156d2cbeef09e86a"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "raw-window-handle"
 version = "0.6.2"
@@ -2924,6 +3044,44 @@ version = "0.8.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6f6ff9a378485b298a5286656da665ba74413d36db0979633275d2e708145d4"
 
+[[package]]
+name = "reqwest"
+version = "0.12.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eddd3ca559203180a307f12d114c268abf583f59b03cb906fd0b3ff8646c1147"
+dependencies = [
+ "base64 0.22.1",
+ "bytes",
+ "futures-core",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-rustls",
+ "hyper-util",
+ "js-sys",
+ "log",
+ "percent-encoding",
+ "pin-project-lite",
+ "quinn",
+ "rustls",
+ "rustls-pki-types",
+ "serde",
+ "serde_json",
+ "serde_urlencoded",
+ "sync_wrapper",
+ "tokio",
+ "tokio-rustls",
+ "tower",
+ "tower-http",
+ "tower-service",
+ "url",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "webpki-roots",
+]
+
 [[package]]
 name = "reqwest"
 version = "0.13.5"
@@ -2958,6 +3116,20 @@ dependencies = [
  "web-sys",
 ]
 
+[[package]]
+name = "ring"
+version = "0.17.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4689e6c2294d81e88dc6261c768b63bc4fcdb852be6d1352498b114f61383b7"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "getrandom 0.2.17",
+ "libc",
+ "untrusted",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "rsqlite-vfs"
 version = "0.2.0"
@@ -3003,12 +3175,53 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "rustls"
+version = "0.23.46"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48e13bd8c0e9365c43cfa5c9e8f9ad49d3c8444926c9aac819e0e4dc503c8fdf"
+dependencies = [
+ "once_cell",
+ "ring",
+ "rustls-pki-types",
+ "rustls-webpki",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-pki-types"
+version = "1.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f4925028c7eb5d1fcdaf196971378ed9d2c1c4efc7dc5d011256f76c99c0a96"
+dependencies = [
+ "web-time",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-webpki"
+version = "0.103.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4443b1b6d39d7c663139942cc4558262562d2c84123bb6282ef177009ca8b281"
+dependencies = [
+ "ring",
+ "rustls-pki-types",
+ "untrusted",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf54715a573b99ac80df0bc206da022bcd442c974952c7b9720069370852e21f"
 
+[[package]]
+name = "ryu"
+version = "1.0.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9774ba4a74de5f7b1c1451ed6cd5285a32eddb5cccb8cc655a4e50009e06477f"
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -3199,6 +3412,18 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "serde_urlencoded"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3491c14715ca2294c4d6a88f15e84739788c1d030eed8c110436aafdaa2f3fd"
+dependencies = [
+ "form_urlencoded",
+ "itoa",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "serde_with"
 version = "3.24.0"
@@ -3460,6 +3685,12 @@ version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
+[[package]]
+name = "subtle"
+version = "2.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
+
 [[package]]
 name = "swift-rs"
 version = "1.0.9"
@@ -3756,7 +3987,7 @@ dependencies = [
  "percent-encoding",
  "plist",
  "raw-window-handle",
- "reqwest",
+ "reqwest 0.13.5",
  "serde",
  "serde_json",
  "serde_repr",
@@ -4071,6 +4302,16 @@ dependencies = [
  "syn 3.0.9",
 ]
 
+[[package]]
+name = "tokio-rustls"
+version = "0.26.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c9cc2678c2cdd569ef8215e2afd7954ada2ae20b4fdd2c5fe6139a3b02d105db"
+dependencies = [
+ "rustls",
+ "tokio",
+]
+
 [[package]]
 name = "tokio-tungstenite"
 version = "0.30.0"
@@ -4366,6 +4607,12 @@ version = "1.13.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6f5d3c3b1bf09027a88a6bc961fc00497d651009560b5463668dc81b0fa87a8"
 
+[[package]]
+name = "untrusted"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
+
 [[package]]
 name = "url"
 version = "2.5.8"
@@ -4646,6 +4893,15 @@ dependencies = [
  "system-deps",
 ]
 
+[[package]]
+name = "webpki-roots"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f5f280bbb2b287bc8e7de7e3852945a0ff50d1bbcb5ed42b6c7a568c546df171"
+dependencies = [
+ "rustls-pki-types",
+]
+
 [[package]]
 name = "webview2-com"
 version = "0.39.1"
@@ -4834,7 +5090,16 @@ version = "0.45.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "75283be5efb2831d37ea142365f009c02ec203cd29a3ebecbc093d52315b66d0"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.42.2",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets 0.52.6",
 ]
 
 [[package]]
@@ -4852,13 +5117,29 @@ version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8e5180c00cd44c9b1c88adb3693291f1cd93605ded80c250a75d472756b4d071"
 dependencies = [
- "windows_aarch64_gnullvm",
- "windows_aarch64_msvc",
- "windows_i686_gnu",
- "windows_i686_msvc",
- "windows_x86_64_gnu",
- "windows_x86_64_gnullvm",
- "windows_x86_64_msvc",
+ "windows_aarch64_gnullvm 0.42.2",
+ "windows_aarch64_msvc 0.42.2",
+ "windows_i686_gnu 0.42.2",
+ "windows_i686_msvc 0.42.2",
+ "windows_x86_64_gnu 0.42.2",
+ "windows_x86_64_gnullvm 0.42.2",
+ "windows_x86_64_msvc 0.42.2",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm 0.52.6",
+ "windows_aarch64_msvc 0.52.6",
+ "windows_i686_gnu 0.52.6",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc 0.52.6",
+ "windows_x86_64_gnu 0.52.6",
+ "windows_x86_64_gnullvm 0.52.6",
+ "windows_x86_64_msvc 0.52.6",
 ]
 
 [[package]]
@@ -4885,42 +5166,90 @@ version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "597a5118570b68bc08d8d59125332c54f1ba9d9adeedeef5b99b02ba2b0698f8"
 
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
 [[package]]
 name = "windows_aarch64_msvc"
 version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e08e8864a60f06ef0d0ff4ba04124db8b0fb3be5776a5cd47641e942e58c4d43"
 
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
 [[package]]
 name = "windows_i686_gnu"
 version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c61d927d8da41da96a81f029489353e68739737d3beca43145c8afec9a31a84f"
 
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
 [[package]]
 name = "windows_i686_msvc"
 version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "44d840b6ec649f480a41c8d80f9c65108b92d89345dd94027bfe06ac444d1060"
 
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
 [[package]]
 name = "windows_x86_64_gnu"
 version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8de912b8b8feb55c064867cf047dda097f92d51efad5b491dfb98f6bbb70cb36"
 
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
 [[package]]
 name = "windows_x86_64_gnullvm"
 version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "26d41b46a36d453748aedef1486d5c7a85db22e56aff34643984ea85514e94a3"
 
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
 [[package]]
 name = "windows_x86_64_msvc"
 version = "0.42.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9aec5da331524158c6d1a4ac0ab1541149c0b9505fde06423b02f5ef0106b9f0"
 
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
 [[package]]
 name = "winnow"
 version = "0.5.40"
@@ -5069,6 +5398,12 @@ dependencies = [
  "synstructure",
 ]
 
+[[package]]
+name = "zeroize"
+version = "1.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e13084392c5e4bc371903e2935a5eaeed24905a7511356b883835e18a78f6879"
+
 [[package]]
 name = "zerotrie"
 version = "0.2.5"
@@ -5131,6 +5466,8 @@ dependencies = [
  "anyhow",
  "clap",
  "futures-util",
+ "hound",
+ "reqwest 0.12.28",
  "serde_json",
  "tokio",
  "tokio-tungstenite",
diff --git a/preview-p2-tauri.png b/preview-p2-tauri.png
new file mode 100644
index 0000000..9c51284
Binary files /dev/null and b/preview-p2-tauri.png differ
diff --git a/ui/src/components/Descent.svelte b/ui/src/components/Descent.svelte
index 7d2fd64..b9a2ee4 100644
--- a/ui/src/components/Descent.svelte
+++ b/ui/src/components/Descent.svelte
@@ -43,7 +43,7 @@
 
   const veins = $derived(state?.veins ?? []);
   const meta = $derived(
-    `two bars · sixteen steps · ${state ? Math.round(state.transport.bpm) : 128} bpm`
+    `${state?.arrangement.length ?? 4} sections · ${(state?.arrangement.length ?? 4) * 2} bars · ${state ? Math.round(state.transport.bpm) : 128} bpm`
   );
 </script>