diff --git a/.gitea/workflows/deploy-music.yml b/.gitea/workflows/deploy-music.yml
index f8e59d8..904ae15 100644
--- a/.gitea/workflows/deploy-music.yml
+++ b/.gitea/workflows/deploy-music.yml
@@ -19,6 +19,7 @@ jobs:
       APP: music
       NS: cube-music
       IMAGE: registry.famzheng.me/mochi/music
+      CHORD_IMAGE: registry.famzheng.me/mochi/music-chord
     steps:
       - uses: actions/checkout@v4
 
@@ -38,13 +39,19 @@ jobs:
           npm ci
           npm run build
 
-      - name: Build & push image
+      - name: Build & push images
         env:
           REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
         run: |
           echo "$REGISTRY_TOKEN" | docker login registry.famzheng.me -u mochi --password-stdin
+          # main app
           docker build -f "apps/$APP/Dockerfile" -t "$IMAGE:${{ steps.tag.outputs.sha }}" .
           docker push "$IMAGE:${{ steps.tag.outputs.sha }}"
+          # chord-fetcher sidecar (python + chromium)
+          docker build -f "apps/$APP/chord/Dockerfile" \
+            -t "$CHORD_IMAGE:${{ steps.tag.outputs.sha }}" \
+            "apps/$APP/chord"
+          docker push "$CHORD_IMAGE:${{ steps.tag.outputs.sha }}"
 
       - name: Initialize K8s resources
         run: |
@@ -52,5 +59,7 @@ jobs:
 
       - name: Roll out to k3s
         run: |
-          kubectl -n "$NS" set image "deploy/$APP" "$APP=$IMAGE:${{ steps.tag.outputs.sha }}"
-          kubectl -n "$NS" rollout status "deploy/$APP" --timeout=120s
+          kubectl -n "$NS" set image "deploy/$APP" \
+            "$APP=$IMAGE:${{ steps.tag.outputs.sha }}" \
+            "chord-fetcher=$CHORD_IMAGE:${{ steps.tag.outputs.sha }}"
+          kubectl -n "$NS" rollout status "deploy/$APP" --timeout=300s
diff --git a/Cargo.lock b/Cargo.lock
index 69b951e..3e21f73 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -96,12 +96,24 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "base64"
+version = "0.22.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
+
 [[package]]
 name = "bitflags"
 version = "2.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c4512299f36f043ab09a583e57bceb5a5aab7a73db1805848e8fef3c9e8c78b3"
 
+[[package]]
+name = "bumpalo"
+version = "3.20.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
+
 [[package]]
 name = "bytes"
 version = "1.11.1"
@@ -124,6 +136,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
 [[package]]
 name = "cube"
 version = "0.1.0"
@@ -143,6 +161,17 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "displaydoc"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97369cbbc041bc366949bc74d34658d6cda5621039731c6310521892a3a20ae0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -159,7 +188,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -228,6 +257,33 @@ dependencies = [
  "slab",
 ]
 
+[[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"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "libc",
+ "r-efi",
+ "wasip2",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.5"
@@ -315,6 +371,23 @@ dependencies = [
  "pin-project-lite",
  "smallvec",
  "tokio",
+ "want",
+]
+
+[[package]]
+name = "hyper-rustls"
+version = "0.27.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33ca68d021ef39cf6463ab54c1d0f5daf03377b70561305bb89a8f83aab66e0f"
+dependencies = [
+ "http",
+ "hyper",
+ "hyper-util",
+ "rustls",
+ "tokio",
+ "tokio-rustls",
+ "tower-service",
+ "webpki-roots",
 ]
 
 [[package]]
@@ -323,13 +396,140 @@ version = "0.1.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96547c2556ec9d12fb1578c4eaf448b04993e7fb79cbaad930a656880a6bdfa0"
 dependencies = [
+ "base64",
  "bytes",
+ "futures-channel",
+ "futures-util",
  "http",
  "http-body",
  "hyper",
+ "ipnet",
+ "libc",
+ "percent-encoding",
  "pin-project-lite",
+ "socket2",
  "tokio",
  "tower-service",
+ "tracing",
+]
+
+[[package]]
+name = "icu_collections"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2984d1cd16c883d7935b9e07e44071dca8d917fd52ecc02c04d5fa0b5a3f191c"
+dependencies = [
+ "displaydoc",
+ "potential_utf",
+ "utf8_iter",
+ "yoke",
+ "zerofrom",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_locale_core"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92219b62b3e2b4d88ac5119f8904c10f8f61bf7e95b640d25ba3075e6cac2c29"
+dependencies = [
+ "displaydoc",
+ "litemap",
+ "tinystr",
+ "writeable",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_normalizer"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c56e5ee99d6e3d33bd91c5d85458b6005a22140021cc324cea84dd0e72cff3b4"
+dependencies = [
+ "icu_collections",
+ "icu_normalizer_data",
+ "icu_properties",
+ "icu_provider",
+ "smallvec",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_normalizer_data"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da3be0ae77ea334f4da67c12f149704f19f81d1adf7c51cf482943e84a2bad38"
+
+[[package]]
+name = "icu_properties"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bee3b67d0ea5c2cca5003417989af8996f8604e34fb9ddf96208a033901e70de"
+dependencies = [
+ "icu_collections",
+ "icu_locale_core",
+ "icu_properties_data",
+ "icu_provider",
+ "zerotrie",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_properties_data"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e2bbb201e0c04f7b4b3e14382af113e17ba4f63e2c9d2ee626b720cbce54a14"
+
+[[package]]
+name = "icu_provider"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "139c4cf31c8b5f33d7e199446eff9c1e02decfc2f0eec2c8d71f65befa45b421"
+dependencies = [
+ "displaydoc",
+ "icu_locale_core",
+ "writeable",
+ "yoke",
+ "zerofrom",
+ "zerotrie",
+ "zerovec",
+]
+
+[[package]]
+name = "idna"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b0875f23caa03898994f6ddc501886a45c7d3d62d04d2d90788d47be1b1e4de"
+dependencies = [
+ "idna_adapter",
+ "smallvec",
+ "utf8_iter",
+]
+
+[[package]]
+name = "idna_adapter"
+version = "1.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb68373c0d6620ef8105e855e7745e18b0d00d3bdb07fb532e434244cdb9a714"
+dependencies = [
+ "icu_normalizer",
+ "icu_properties",
+]
+
+[[package]]
+name = "ipnet"
+version = "2.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d98f6fed1fde3f8c21bc40a1abb88dd75e67924f9cffc3ef95607bad8017f8e2"
+
+[[package]]
+name = "iri-string"
+version = "0.7.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25e659a4bb38e810ebc252e53b5814ff908a8c58c2a9ce2fae1bbec24cbf4e20"
+dependencies = [
+ "memchr",
+ "serde",
 ]
 
 [[package]]
@@ -338,6 +538,18 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
+[[package]]
+name = "js-sys"
+version = "0.3.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67df7112613f8bfd9150013a0314e196f4800d3201ae742489d999db2f979f08"
+dependencies = [
+ "cfg-if",
+ "futures-util",
+ "once_cell",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -361,6 +573,12 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "litemap"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92daf443525c4cce67b150400bc2316076100ce0b3686209eb8cf3c31612e6f0"
+
 [[package]]
 name = "lock_api"
 version = "0.4.14"
@@ -376,6 +594,12 @@ version = "0.4.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 
+[[package]]
+name = "lru-slab"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "112b39cec0b298b6c1999fee3e31427f74f676e4cb9879ed1a121b43661a4154"
+
 [[package]]
 name = "matchers"
 version = "0.2.0"
@@ -421,7 +645,7 @@ checksum = "50b7e5b27aa02a74bac8c3f23f448f8d87ff11f92d3aac1a6ed369ee08cc56c1"
 dependencies = [
  "libc",
  "wasi",
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -447,6 +671,7 @@ version = "0.1.0"
 dependencies = [
  "axum",
  "cube-core",
+ "reqwest",
  "rusqlite",
  "serde",
  "serde_json",
@@ -462,7 +687,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -512,6 +737,24 @@ version = "0.3.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19f132c84eca552bf34cab8ec81f1c1dcc229b811638f9d283dceabe58c5569e"
 
+[[package]]
+name = "potential_utf"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0103b1cef7ec0cf76490e969665504990193874ea05c85ff9bab8b911d0a0564"
+dependencies = [
+ "zerovec",
+]
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.106"
@@ -521,6 +764,61 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "quinn"
+version = "0.11.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e20a958963c291dc322d98411f541009df2ced7b5a4f2bd52337638cfccf20"
+dependencies = [
+ "bytes",
+ "cfg_aliases",
+ "pin-project-lite",
+ "quinn-proto",
+ "quinn-udp",
+ "rustc-hash",
+ "rustls",
+ "socket2",
+ "thiserror",
+ "tokio",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-proto"
+version = "0.11.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "434b42fec591c96ef50e21e886936e66d3cc3f737104fdb9b737c40ffb94c098"
+dependencies = [
+ "bytes",
+ "getrandom 0.3.4",
+ "lru-slab",
+ "rand",
+ "ring",
+ "rustc-hash",
+ "rustls",
+ "rustls-pki-types",
+ "slab",
+ "thiserror",
+ "tinyvec",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-udp"
+version = "0.5.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "addec6a0dcad8a8d96a771f815f0eaf55f9d1805756410b39f5fa81332574cbd"
+dependencies = [
+ "cfg_aliases",
+ "libc",
+ "once_cell",
+ "socket2",
+ "tracing",
+ "windows-sys 0.60.2",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.45"
@@ -530,6 +828,41 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
+[[package]]
+name = "rand"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44c5af06bb1b7d3216d91932aed5265164bf384dc89cd6ba05cf59a35f5f76ea"
+dependencies = [
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76afc826de14238e6e8c374ddcc1fa19e374fd8dd986b0d2af0d02377261d83c"
+dependencies = [
+ "getrandom 0.3.4",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.18"
@@ -556,6 +889,58 @@ version = "0.8.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
+[[package]]
+name = "reqwest"
+version = "0.12.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eddd3ca559203180a307f12d114c268abf583f59b03cb906fd0b3ff8646c1147"
+dependencies = [
+ "base64",
+ "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 = "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 = "rusqlite"
 version = "0.32.1"
@@ -570,6 +955,47 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "rustc-hash"
+version = "2.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94300abf3f1ae2e2b8ffb7b58043de3d399c73fa6f4b73826402a5c457614dbe"
+
+[[package]]
+name = "rustls"
+version = "0.23.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef86cd5876211988985292b91c96a8f2d298df24e75989a43a3c73f2d4d8168b"
+dependencies = [
+ "once_cell",
+ "ring",
+ "rustls-pki-types",
+ "rustls-webpki",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-pki-types"
+version = "1.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "30a7197ae7eb376e574fe940d068c30fe0462554a3ddbe4eca7838e049c937a9"
+dependencies = [
+ "web-time",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-webpki"
+version = "0.103.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61c429a8649f110dddef65e2a5ad240f747e85f7758a6bccc7e5777bd33f756e"
+dependencies = [
+ "ring",
+ "rustls-pki-types",
+ "untrusted",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.22"
@@ -711,7 +1137,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a766e1110788c36f4fa1c2b71b387a7815aa65f88ce0229841826633d93723e"
 dependencies = [
  "libc",
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -720,6 +1146,18 @@ version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 
+[[package]]
+name = "stable_deref_trait"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ce2be8dc25455e1f91df71bfa12ad37d7af1092ae736f3a6cd0e37bc7810596"
+
+[[package]]
+name = "subtle"
+version = "2.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
+
 [[package]]
 name = "syn"
 version = "2.0.117"
@@ -736,6 +1174,40 @@ name = "sync_wrapper"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
+dependencies = [
+ "futures-core",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "728a70f3dbaf5bab7f0c4b1ac8d7ae5ea60a4b5549c8a5914361c99147a709d2"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "thiserror"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ebc4ee7f67670e9b64d05fa4253e753e016c6c95ff35b89b7941d6b856dec1d5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
 
 [[package]]
 name = "thread_local"
@@ -746,6 +1218,31 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "tinystr"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8323304221c2a851516f22236c5722a72eaa19749016521d6dff0824447d96d"
+dependencies = [
+ "displaydoc",
+ "zerovec",
+]
+
+[[package]]
+name = "tinyvec"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3e61e67053d25a4e82c844e8424039d9745781b3fc4f32b8d55ed50f5f667ef3"
+dependencies = [
+ "tinyvec_macros",
+]
+
+[[package]]
+name = "tinyvec_macros"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
+
 [[package]]
 name = "tokio"
 version = "1.52.1"
@@ -760,7 +1257,7 @@ dependencies = [
  "signal-hook-registry",
  "socket2",
  "tokio-macros",
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -774,6 +1271,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tokio-rustls"
+version = "0.26.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1729aa945f29d91ba541258c8df89027d5792d85a8841fb65e8bf0f4ede4ef61"
+dependencies = [
+ "rustls",
+ "tokio",
+]
+
 [[package]]
 name = "tokio-util"
 version = "0.7.18"
@@ -818,12 +1325,14 @@ dependencies = [
  "http-body-util",
  "http-range-header",
  "httpdate",
+ "iri-string",
  "mime",
  "mime_guess",
  "percent-encoding",
  "pin-project-lite",
  "tokio",
  "tokio-util",
+ "tower",
  "tower-layer",
  "tower-service",
  "tracing",
@@ -916,6 +1425,12 @@ dependencies = [
  "tracing-serde",
 ]
 
+[[package]]
+name = "try-lock"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
+
 [[package]]
 name = "unicase"
 version = "2.9.0"
@@ -928,6 +1443,30 @@ version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
 
+[[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"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff67a8a4397373c3ef660812acab3268222035010ab8680ec4215f38ba3d0eed"
+dependencies = [
+ "form_urlencoded",
+ "idna",
+ "percent-encoding",
+ "serde",
+]
+
+[[package]]
+name = "utf8_iter"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
+
 [[package]]
 name = "valuable"
 version = "0.1.1"
@@ -946,18 +1485,138 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
+[[package]]
+name = "want"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa7760aed19e106de2c7c0b581b509f2f25d3dacaf737cb82ac61bc6d760b0e"
+dependencies = [
+ "try-lock",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
+[[package]]
+name = "wasip2"
+version = "1.0.3+wasi-0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20064672db26d7cdc89c7798c48a0fdfac8213434a1186e5ef29fd560ae223d6"
+dependencies = [
+ "wit-bindgen",
+]
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49ace1d07c165b0864824eee619580c4689389afa9dc9ed3a4c75040d82e6790"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+ "rustversion",
+ "wasm-bindgen-macro",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-futures"
+version = "0.4.71"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96492d0d3ffba25305a7dc88720d250b1401d7edca02cc3bcd50633b424673b8"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e68e6f4afd367a562002c05637acb8578ff2dea1943df76afb9e83d177c8578"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d95a9ec35c64b2a7cb35d3fead40c4238d0940c86d107136999567a4703259f2"
+dependencies = [
+ "bumpalo",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4e0100b01e9f0d03189a92b96772a1fb998639d981193d7dbab487302513441"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "web-sys"
+version = "0.3.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b572dff8bcf38bad0fa19729c89bb5748b2b9b1d8be70cf90df697e3a8f32aa"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "webpki-roots"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52f5ee44c96cf55f1b349600768e3ece3a8f26010c05265ab73f945bb1a2eb9d"
+dependencies = [
+ "rustls-pki-types",
+]
+
 [[package]]
 name = "windows-link"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
+[[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]]
+name = "windows-sys"
+version = "0.60.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2f500e4d28234f72040990ec9d39e3a6b950f9f22d3dba18416c35882612bcb"
+dependencies = [
+ "windows-targets 0.53.5",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.61.2"
@@ -967,6 +1626,170 @@ dependencies = [
  "windows-link",
 ]
 
+[[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 0.52.6",
+ "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]]
+name = "windows-targets"
+version = "0.53.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4945f9f551b88e0d65f3db0bc25c33b8acea4d9e41163edf90dcd0b19f9069f3"
+dependencies = [
+ "windows-link",
+ "windows_aarch64_gnullvm 0.53.1",
+ "windows_aarch64_msvc 0.53.1",
+ "windows_i686_gnu 0.53.1",
+ "windows_i686_gnullvm 0.53.1",
+ "windows_i686_msvc 0.53.1",
+ "windows_x86_64_gnu 0.53.1",
+ "windows_x86_64_gnullvm 0.53.1",
+ "windows_x86_64_msvc 0.53.1",
+]
+
+[[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_gnullvm"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9d8416fa8b42f5c947f8482c43e7d89e73a173cead56d044f6a56104a6d1b53"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9d782e804c2f632e395708e99a94275910eb9100b2114651e04744e9b125006"
+
+[[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_gnu"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "960e6da069d81e09becb0ca57a65220ddff016ff2d6af6a223cf372a506593a3"
+
+[[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_gnullvm"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa7359d10048f68ab8b09fa71c3daccfb0e9b559aed648a8f95469c27057180c"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e7ac75179f18232fe9c285163565a57ef8d3c89254a30685b57d83a38d326c2"
+
+[[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_gnu"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c3842cdd74a865a8066ab39c8a7a473c0778a3f29370b5fd6b4b9aa7df4a499"
+
+[[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_gnullvm"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ffa179e2d07eee8ad8f57493436566c7cc30ac536a3379fdf008f47f6bb7ae1"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6bbff5f0aada427a1e5a6da5f1f98158182f26556f345ac9e04d36d0ebed650"
+
+[[package]]
+name = "wit-bindgen"
+version = "0.57.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"
+
+[[package]]
+name = "writeable"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ffae5123b2d3fc086436f8834ae3ab053a283cfac8fe0a0b8eaae044768a4c4"
+
+[[package]]
+name = "yoke"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abe8c5fda708d9ca3df187cae8bfb9ceda00dd96231bed36e445a1a48e66f9ca"
+dependencies = [
+ "stable_deref_trait",
+ "yoke-derive",
+ "zerofrom",
+]
+
+[[package]]
+name = "yoke-derive"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de844c262c8848816172cef550288e7dc6c7b7814b4ee56b3e1553f275f1858e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "synstructure",
+]
+
 [[package]]
 name = "zerocopy"
 version = "0.8.48"
@@ -987,6 +1810,66 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "zerofrom"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69faa1f2a1ea75661980b013019ed6687ed0e83d069bc1114e2cc74c6c04c4df"
+dependencies = [
+ "zerofrom-derive",
+]
+
+[[package]]
+name = "zerofrom-derive"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11532158c46691caf0f2593ea8358fed6bbf68a0315e80aae9bd41fbade684a1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "synstructure",
+]
+
+[[package]]
+name = "zeroize"
+version = "1.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b97154e67e32c85465826e8bcc1c59429aaaf107c1e4a9e53c8d8ccd5eff88d0"
+
+[[package]]
+name = "zerotrie"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0f9152d31db0792fa83f70fb2f83148effb5c1f5b8c7686c3459e361d9bc20bf"
+dependencies = [
+ "displaydoc",
+ "yoke",
+ "zerofrom",
+]
+
+[[package]]
+name = "zerovec"
+version = "0.11.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90f911cbc359ab6af17377d242225f4d75119aec87ea711a880987b18cd7b239"
+dependencies = [
+ "yoke",
+ "zerofrom",
+ "zerovec-derive",
+]
+
+[[package]]
+name = "zerovec-derive"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "625dc425cab0dca6dc3c3319506e6593dcb08a9f387ea3b284dbd52a92c40555"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "zmij"
 version = "1.0.21"
diff --git a/Cargo.toml b/Cargo.toml
index dbade88..4e7e540 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,6 +22,7 @@ tracing-subscriber = { version = "0.3", features = ["env-filter", "json"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 rusqlite = { version = "0.32", features = ["bundled"] }
+reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls"] }
 
 [profile.release]
 opt-level = "z"
diff --git a/apps/music/Cargo.toml b/apps/music/Cargo.toml
index 60ec3b0..7a34143 100644
--- a/apps/music/Cargo.toml
+++ b/apps/music/Cargo.toml
@@ -16,3 +16,4 @@ tracing = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 rusqlite = { workspace = true }
+reqwest = { workspace = true }
diff --git a/apps/music/chord/Dockerfile b/apps/music/chord/Dockerfile
new file mode 100644
index 0000000..28bcc83
--- /dev/null
+++ b/apps/music/chord/Dockerfile
@@ -0,0 +1,24 @@
+# music chord-fetcher sidecar
+# 抓 yopu.co 截图的 selenium 服务，跟 music 主容器同 pod 共享 PVC。
+
+FROM python:3.11-slim-bookworm
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    chromium chromium-driver fonts-noto-cjk ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+ENV CHROME_BIN=/usr/bin/chromium
+ENV CHROMEDRIVER_PATH=/usr/bin/chromedriver
+ENV PYTHONUNBUFFERED=1
+
+RUN pip install --no-cache-dir \
+    selenium==4.27.1 \
+    pillow==11.0.0 \
+    fastapi==0.115.6 \
+    uvicorn==0.34.0
+
+WORKDIR /app
+COPY yopu.py chord_server.py ./
+
+EXPOSE 8001
+CMD ["uvicorn", "chord_server:app", "--host", "0.0.0.0", "--port", "8001"]
diff --git a/apps/music/chord/chord_server.py b/apps/music/chord/chord_server.py
new file mode 100644
index 0000000..f809a1f
--- /dev/null
+++ b/apps/music/chord/chord_server.py
@@ -0,0 +1,127 @@
+"""
+chord-fetcher sidecar 的 HTTP service。
+
+跟 music 主容器同 pod，监听 :8001。被 music backend 通过 localhost 调用。
+worker 单线程串行（chromium 一次跑一个，省资源），文件落 /data/chord-fetch/{piece_id}.png。
+"""
+
+import json
+import logging
+import queue
+import threading
+import os
+from pathlib import Path
+from typing import Optional
+
+from fastapi import FastAPI, HTTPException
+from fastapi.responses import FileResponse
+
+import yopu
+
+logging.basicConfig(level=logging.INFO,
+                    format='%(asctime)s %(levelname)s %(name)s: %(message)s')
+logger = logging.getLogger('chord-server')
+
+OUT_DIR = Path(os.getenv('CHORD_OUT_DIR', '/data/chord-fetch'))
+OUT_DIR.mkdir(parents=True, exist_ok=True)
+
+app = FastAPI()
+
+
+# in-memory job state. piece_id -> {status, error, query}
+state: dict[int, dict] = {}
+state_lock = threading.Lock()
+job_q: queue.Queue = queue.Queue()
+
+
+def out_path(piece_id: int) -> Path:
+    return OUT_DIR / f"{piece_id}.png"
+
+
+def worker():
+    while True:
+        piece_id, query = job_q.get()
+        with state_lock:
+            state[piece_id] = {'status': 'processing', 'error': '', 'query': query}
+        logger.info("[piece=%d] start fetch query=%r", piece_id, query)
+        try:
+            ok, msg = yopu.fetch_chord_chart(query, str(out_path(piece_id)))
+            with state_lock:
+                if ok:
+                    state[piece_id] = {'status': 'completed', 'error': '', 'query': query}
+                    logger.info("[piece=%d] completed: %s", piece_id, msg)
+                else:
+                    state[piece_id] = {'status': 'failed', 'error': msg, 'query': query}
+                    logger.warning("[piece=%d] failed: %s", piece_id, msg)
+        except Exception as e:
+            logger.exception("[piece=%d] worker crash", piece_id)
+            with state_lock:
+                state[piece_id] = {'status': 'failed', 'error': str(e), 'query': query}
+        finally:
+            job_q.task_done()
+
+
+threading.Thread(target=worker, daemon=True).start()
+
+
+@app.get('/healthz')
+def healthz():
+    return {'ok': True}
+
+
+@app.post('/fetch')
+def fetch(piece_id: int, query: str):
+    """加入 fetch 队列。query 一般是 '<artist> <title>'。
+    幂等：已 completed 且文件还在，直接返回 completed。"""
+    if piece_id <= 0 or not query.strip():
+        raise HTTPException(400, 'piece_id / query required')
+
+    with state_lock:
+        cur = state.get(piece_id, {})
+        if cur.get('status') == 'completed' and out_path(piece_id).exists():
+            return {'status': 'completed'}
+        if cur.get('status') in ('pending', 'processing'):
+            return {'status': cur['status']}
+        state[piece_id] = {'status': 'pending', 'error': '', 'query': query}
+
+    job_q.put((piece_id, query))
+    return {'status': 'pending'}
+
+
+@app.get('/status/{piece_id}')
+def status(piece_id: int):
+    with state_lock:
+        cur = state.get(piece_id, {})
+    file_exists = out_path(piece_id).exists()
+    if cur.get('status') == 'completed' and not file_exists:
+        return {'status': 'failed', 'error': 'png 文件丢了'}
+    if not cur and file_exists:
+        return {'status': 'completed'}
+    return {
+        'status': cur.get('status', 'none'),
+        'error': cur.get('error', ''),
+        'query': cur.get('query', ''),
+        'file_exists': file_exists,
+    }
+
+
+@app.get('/image/{piece_id}')
+def image(piece_id: int):
+    p = out_path(piece_id)
+    if not p.exists():
+        raise HTTPException(404, 'not found')
+    return FileResponse(p, media_type='image/png')
+
+
+@app.delete('/state/{piece_id}')
+def reset(piece_id: int):
+    """music backend import 完后清状态 + 删 png（防 PVC 越积越多）。"""
+    with state_lock:
+        state.pop(piece_id, None)
+    p = out_path(piece_id)
+    if p.exists():
+        try:
+            p.unlink()
+        except Exception as e:
+            logger.warning("[piece=%d] cleanup unlink: %s", piece_id, e)
+    return {'ok': True}
diff --git a/apps/music/chord/yopu.py b/apps/music/chord/yopu.py
new file mode 100644
index 0000000..e1dcd5d
--- /dev/null
+++ b/apps/music/chord/yopu.py
@@ -0,0 +1,304 @@
+#!/usr/bin/env python3
+"""
+yopu.co 和弦谱抓取（v2）
+
+跟旧 guitar 版相比，UI 改了：现在是分立的 row：
+- "谱面样式" → 选 "功能谱"
+- "和弦样式" → 选 "级数名"
+- "和弦图"   → 默认（不动）
+
+抓取流程：
+  1. /explore#q=<query>  搜索
+  2. 找第一个含「和弦谱」字样的结果 → 进 /view/<id>
+  3. 在 row label = X 的行里，点 button.option 文本 = Y
+  4. 撑开 div.sheet-container 容器把 overflow / max-height 砍掉，让全部内容渲染
+  5. 截图整个 container element
+  6. PIL 裁白边 + padding，存 PNG
+"""
+
+import os
+import time
+import logging
+from pathlib import Path
+from urllib.parse import quote, urlparse, urljoin
+
+from selenium import webdriver
+from selenium.webdriver.chrome.service import Service
+from selenium.webdriver.common.by import By
+from selenium.webdriver.support.ui import WebDriverWait
+from selenium.webdriver.support import expected_conditions as EC
+from selenium.webdriver.chrome.options import Options
+from selenium.common.exceptions import TimeoutException
+from PIL import Image
+
+logger = logging.getLogger(__name__)
+
+
+def setup_driver(window="1920,5000"):
+    o = Options()
+    o.add_argument('--headless=new')
+    o.add_argument('--no-sandbox')
+    o.add_argument('--disable-dev-shm-usage')
+    o.add_argument('--disable-gpu')
+    o.add_argument(f'--window-size={window}')
+    o.add_argument('--lang=zh-CN')
+    o.add_argument('user-agent=Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) '
+                   'AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36')
+    o.add_experimental_option('prefs', {'intl.accept_languages': 'zh-CN,zh,en-US,en'})
+
+    service = None
+    if cdp := os.getenv('CHROMEDRIVER_PATH'):
+        service = Service(cdp)
+    if cb := os.getenv('CHROME_BIN'):
+        o.binary_location = cb
+    return webdriver.Chrome(service=service, options=o)
+
+
+def find_first_chord_chart(driver, search_url):
+    """在搜索页找第一个「和弦谱」结果，返回 view url 和 title。"""
+    logger.info("loading search: %s", search_url)
+    driver.get(search_url)
+    time.sleep(3)
+
+    chord_links = driver.execute_script("""
+        var hits = [];
+        var posts = document.querySelectorAll('a.post-main');
+        for (var i = 0; i < posts.length; i++) {
+            var info = posts[i].querySelector('.one-line-info');
+            var t = info ? (info.textContent || info.innerText || '') : '';
+            if (t.indexOf('和弦') >= 0 && t.indexOf('谱') >= 0) {
+                hits.push({
+                    href: posts[i].href,
+                    title: (posts[i].querySelector('.title-line .title, .title') || {}).textContent || '',
+                    text: t.trim(),
+                });
+            }
+        }
+        return hits;
+    """)
+
+    if not chord_links:
+        logger.warning("no '和弦谱' hits in search results")
+        return None
+    first = chord_links[0]
+    href = first['href']
+    if href.startswith('/'):
+        p = urlparse(search_url)
+        href = f"{p.scheme}://{p.netloc}{href}"
+    elif not href.startswith('http'):
+        href = urljoin(search_url, href)
+    logger.info("matched: %s — %s", first.get('title'), href)
+    return {'url': href, 'title': first.get('title') or '', 'text': first.get('text') or ''}
+
+
+def select_option_in_row(driver, row_label, button_text, timeout=10):
+    """在 label 含 row_label 的 row 里，点 button.option 文本含 button_text 的按钮。
+    返回 True 表示点了；False 表示找不到（不算错误，可能是 UI 文案变了）。"""
+    wait = WebDriverWait(driver, timeout)
+    try:
+        row = wait.until(EC.presence_of_element_located((
+            By.XPATH,
+            f"//div[contains(@class, 'row')][.//div[contains(@class, 'label') "
+            f"and contains(normalize-space(.), '{row_label}')]]"
+        )))
+    except TimeoutException:
+        logger.warning("row '%s' not found", row_label)
+        return False
+
+    buttons = row.find_elements(By.CSS_SELECTOR, "button.option, button")
+    for btn in buttons:
+        txt = (btn.text or '').strip()
+        if button_text in txt:
+            try:
+                driver.execute_script("arguments[0].scrollIntoView({block: 'center'});", btn)
+                time.sleep(0.3)
+                btn.click()
+                logger.info("clicked '%s' in row '%s'", button_text, row_label)
+                time.sleep(1.2)
+                return True
+            except Exception as e:
+                logger.warning("click failed in row '%s' / '%s': %s", row_label, button_text, e)
+                return False
+    logger.warning("button '%s' not found in row '%s' (had: %s)",
+                   button_text, row_label, [(b.text or '').strip() for b in buttons])
+    return False
+
+
+def expand_sheet_container(driver, container):
+    """把 sheet-container 跟它的祖先一起把 overflow / max-height 拆掉，
+    让 scrollHeight 全暴露，截图能拿到完整谱面。"""
+    return driver.execute_script("""
+        var c = arguments[0];
+        var origStyle = c.getAttribute('style') || '';
+        var modified = [];
+        var node = c;
+        while (node && node !== document.body) {
+            var cs = window.getComputedStyle(node);
+            if (cs.overflow === 'hidden' || cs.overflow === 'auto'
+                || cs.overflowY === 'hidden' || cs.overflowY === 'auto'
+                || cs.maxHeight !== 'none') {
+                modified.push({ el: node, orig: node.getAttribute('style') || '' });
+                node.style.overflow = 'visible';
+                node.style.overflowY = 'visible';
+                node.style.maxHeight = 'none';
+                node.style.height = 'auto';
+            }
+            node = node.parentElement;
+        }
+        c.style.overflow = 'visible';
+        c.style.maxHeight = 'none';
+        c.style.height = 'auto';
+        c.style.minHeight = c.scrollHeight + 'px';
+        c.offsetHeight; // force reflow
+        c.setAttribute('data-orig-style', origStyle);
+        window.__yopuModified = modified;
+        return { scrollHeight: c.scrollHeight, modified: modified.length };
+    """, container)
+
+
+def crop_white(path, pad_top=20, pad_bottom=50, pad_left=20, pad_right=20, white_th=250):
+    """裁掉四边的白边，加点 padding。"""
+    img = Image.open(path)
+    w, h = img.size
+    if img.mode != 'RGB':
+        img = img.convert('RGB')
+    px = img.load()
+
+    def row_white_ratio(y):
+        wp = 0
+        for x in range(w):
+            r, g, b = px[x, y]
+            if r > white_th and g > white_th and b > white_th:
+                wp += 1
+        return wp / w
+
+    def col_white_ratio(x, y0, y1):
+        wp = 0
+        rng = max(1, y1 - y0)
+        for y in range(y0, y1):
+            r, g, b = px[x, y]
+            if r > white_th and g > white_th and b > white_th:
+                wp += 1
+        return wp / rng
+
+    top = 0
+    for y in range(h):
+        if row_white_ratio(y) < 0.99:
+            top = y
+            break
+    bottom = h
+    for y in range(h - 1, -1, -1):
+        if row_white_ratio(y) < 0.99:
+            bottom = y + 1
+            break
+    if top >= bottom:
+        return  # all white, give up
+
+    left = 0
+    for x in range(w):
+        if col_white_ratio(x, top, bottom) < 0.99:
+            left = x
+            break
+    right = w
+    for x in range(w - 1, -1, -1):
+        if col_white_ratio(x, top, bottom) < 0.99:
+            right = x + 1
+            break
+    if left >= right:
+        return
+
+    box = (
+        max(0, left - pad_left),
+        max(0, top - pad_top),
+        min(w, right + pad_right),
+        min(h, bottom + pad_bottom),
+    )
+    img.crop(box).save(path, 'PNG')
+    logger.info("cropped to %s", box)
+
+
+def fetch_chord_chart(query: str, output_path: str, *,
+                      sheet_style: str = '功能谱',
+                      chord_style: str = '级数名',
+                      verbose: bool = False) -> tuple[bool, str]:
+    """
+    搜 yopu.co、进 view 页、按 row 选样式、截图。
+    返回 (ok, msg)。msg 在失败时是错误说明。
+    """
+    if verbose:
+        logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)s %(message)s')
+    else:
+        logging.basicConfig(level=logging.INFO, format='%(asctime)s %(levelname)s %(message)s')
+
+    search_url = f"https://yopu.co/explore#q={quote(query)}"
+    driver = None
+    try:
+        driver = setup_driver()
+        result = find_first_chord_chart(driver, search_url)
+        if not result:
+            return False, '未找到和弦谱'
+        view_url = result['url']
+
+        logger.info("loading view: %s", view_url)
+        driver.get(view_url)
+        time.sleep(3)
+
+        # 选样式（写死的 MVP 组合）
+        select_option_in_row(driver, '谱面样式', sheet_style)
+        select_option_in_row(driver, '和弦样式', chord_style)
+
+        # 等内容刷新
+        time.sleep(1.5)
+
+        wait = WebDriverWait(driver, 15)
+        sheet = wait.until(EC.presence_of_element_located(
+            (By.CSS_SELECTOR, "div.sheet-container")
+        ))
+
+        driver.execute_script("arguments[0].scrollIntoView(true);", sheet)
+        time.sleep(0.5)
+
+        dims = expand_sheet_container(driver, sheet)
+        logger.debug("expanded scrollHeight=%s, modified=%s ancestors", dims['scrollHeight'], dims['modified'])
+        time.sleep(1.5)
+
+        # incrButton：放大字号 / chord size，跟旧版一样点 3 次
+        try:
+            buttons = driver.find_elements(By.CSS_SELECTOR, "button.incrButton")
+            if buttons:
+                driver.execute_script("arguments[0].scrollIntoView({block: 'center'});", buttons[0])
+                time.sleep(0.3)
+                for _ in range(3):
+                    buttons[0].click()
+                    time.sleep(0.4)
+        except Exception as e:
+            logger.warning("incrButton failed: %s", e)
+
+        time.sleep(1.0)
+
+        # 滚 sheet 内部回到顶部，截整个 container
+        driver.execute_script("arguments[0].scrollTop = 0;", sheet)
+        time.sleep(0.4)
+
+        out = Path(output_path)
+        out.parent.mkdir(parents=True, exist_ok=True)
+        sheet.screenshot(str(out))
+        if not out.exists() or out.stat().st_size < 100:
+            return False, '截图为空'
+        logger.info("screenshot: %s (%d bytes)", out, out.stat().st_size)
+
+        try:
+            crop_white(str(out))
+        except Exception as e:
+            logger.warning("crop failed: %s", e)
+
+        return True, str(out)
+    except Exception as e:
+        logger.error("fetch failed: %s", e, exc_info=True)
+        return False, str(e)
+    finally:
+        if driver:
+            try:
+                driver.quit()
+            except Exception:
+                pass
diff --git a/apps/music/frontend/src/lib/api.js b/apps/music/frontend/src/lib/api.js
index 002ec06..cf9a710 100644
--- a/apps/music/frontend/src/lib/api.js
+++ b/apps/music/frontend/src/lib/api.js
@@ -57,3 +57,11 @@ export function deleteAttachment(id) {
 export function attachmentUrl(id) {
   return `/api/attachments/${id}`
 }
+
+export function chordFetch(pieceId) {
+  return fetch(`/api/pieces/${pieceId}/chord/fetch`, { method: 'POST' }).then(jsonOrThrow)
+}
+
+export function chordStatus(pieceId) {
+  return fetch(`/api/pieces/${pieceId}/chord/status`).then(jsonOrThrow)
+}
diff --git a/apps/music/frontend/src/views/PlayerView.vue b/apps/music/frontend/src/views/PlayerView.vue
index b819707..0cfed45 100644
--- a/apps/music/frontend/src/views/PlayerView.vue
+++ b/apps/music/frontend/src/views/PlayerView.vue
@@ -103,6 +103,29 @@
                 :alt="att.filename"
                 class="sheet-img"
               />
+              <!-- 吉他谱专属：没图时给个自动抓取按钮 -->
+              <div
+                v-if="activeTab === 'chord' && roleAttachments('chord').length === 0"
+                class="auto-fetch"
+              >
+                <p v-if="chordState === 'idle'" class="hint-line">
+                  从 yopu.co 抓 <b>功能谱 + 级数名</b>。
+                </p>
+                <p v-else-if="chordState === 'pending' || chordState === 'processing'" class="hint-line">
+                  正在抓取，浏览器后台跑 chromium 截图，约 30-60s…
+                </p>
+                <p v-else-if="chordState === 'failed'" class="hint-line err">
+                  抓取失败：{{ chordError }}
+                </p>
+                <button
+                  class="btn-fetch"
+                  :disabled="chordState === 'pending' || chordState === 'processing'"
+                  @click="startChordFetch"
+                >
+                  <span v-if="chordState === 'pending' || chordState === 'processing'" class="spin">⏳</span>
+                  <span v-else>🎸 自动抓取吉他谱</span>
+                </button>
+              </div>
             </div>
 
             <!-- PDF -->
@@ -182,6 +205,8 @@ import {
   patchPiece,
   recordPlay,
   attachmentUrl as attUrl,
+  chordFetch,
+  chordStatus,
 } from '../lib/api.js'
 import { parseLrc } from '../lib/lrc.js'
 
@@ -211,6 +236,12 @@ let notesTimer = null
 let randomSeed = Math.random()
 let lastReportedId = null
 
+// chord auto-fetch state
+const chordState = ref('idle') // idle | pending | processing | completed | failed
+const chordError = ref('')
+let chordPollTimer = null
+let chordPollStarted = 0
+
 const lyricsLines = computed(() => parseLrc(selected.value?.lyrics || ''))
 
 const activeLyricIdx = computed(() => {
@@ -240,16 +271,14 @@ const tabs = computed(() => {
   if (!selected.value) return []
   const list = []
   if (selected.value.lyrics) list.push({ key: 'lyrics', label: '歌词', count: 0 })
-  const chord = roleAttachments('chord').length
-  if (chord) list.push({ key: 'chord', label: '吉他谱', count: chord })
+  // 吉他谱 tab 永远给（没图时显示自动抓取按钮）
+  list.push({ key: 'chord', label: '吉他谱', count: roleAttachments('chord').length })
   const num = roleAttachments('numbered').length
   if (num) list.push({ key: 'numbered', label: '简谱', count: num })
   const staff = roleAttachments('staff').length
   if (staff) list.push({ key: 'staff', label: '五线谱', count: staff })
   if (pdfAttachments.value.length) list.push({ key: 'pdf', label: '乐谱 PDF', count: pdfAttachments.value.length })
   if (videoAttachments.value.length) list.push({ key: 'video', label: '视频', count: videoAttachments.value.length })
-  // 没歌词也至少给一个 fallback tab
-  if (list.length === 0) list.push({ key: 'lyrics', label: '歌词', count: 0 })
   return list
 })
 
@@ -332,6 +361,10 @@ async function loadPieces() {
 async function loadPiece(id) {
   selected.value = null
   notesDraft.value = ''
+  // 切歌时清空 chord state（避免 polling 漂到新曲目）
+  stopChordPoll()
+  chordState.value = 'idle'
+  chordError.value = ''
   if (!id) return
   try {
     const p = await getPiece(id)
@@ -460,6 +493,69 @@ function setTab(k) {
   activeTab.value = k
 }
 
+async function startChordFetch() {
+  if (!selectedId.value) return
+  chordState.value = 'pending'
+  chordError.value = ''
+  try {
+    const r = await chordFetch(selectedId.value)
+    if (r.status === 'completed') {
+      // 已经有谱（或刚 import）：刷新 piece
+      await reloadPiece()
+      chordState.value = 'completed'
+      return
+    }
+    chordState.value = r.status || 'pending'
+    chordPollStarted = Date.now()
+    if (chordPollTimer) clearInterval(chordPollTimer)
+    chordPollTimer = setInterval(pollChord, 3000)
+  } catch (e) {
+    chordState.value = 'failed'
+    chordError.value = e.message || String(e)
+  }
+}
+
+async function pollChord() {
+  if (!selectedId.value) { stopChordPoll(); return }
+  // 90s 超时保护
+  if (Date.now() - chordPollStarted > 90_000) {
+    stopChordPoll()
+    chordState.value = 'failed'
+    chordError.value = '抓取超时（>90s），可能 yopu 限流或 selector 失效'
+    return
+  }
+  try {
+    const r = await chordStatus(selectedId.value)
+    chordState.value = r.status || 'pending'
+    chordError.value = r.error || ''
+    if (r.status === 'completed') {
+      stopChordPoll()
+      await reloadPiece()
+    } else if (r.status === 'failed') {
+      stopChordPoll()
+    }
+  } catch (e) {
+    // 暂时性错误就不立即放弃，下一轮再试
+    chordError.value = e.message || String(e)
+  }
+}
+
+function stopChordPoll() {
+  if (chordPollTimer) {
+    clearInterval(chordPollTimer)
+    chordPollTimer = null
+  }
+}
+
+async function reloadPiece() {
+  if (!selectedId.value) return
+  try {
+    const fresh = await getPiece(selectedId.value)
+    // 保留正在播的 audio.src 不动
+    selected.value = fresh
+  } catch {}
+}
+
 // notes auto-save
 function onNotesInput() {
   if (!selectedId.value) return
@@ -523,6 +619,7 @@ onMounted(async () => {
 onBeforeUnmount(() => {
   document.removeEventListener('keydown', onKeyDown)
   if (notesTimer) clearTimeout(notesTimer)
+  stopChordPoll()
 })
 </script>
 
@@ -784,6 +881,35 @@ onBeforeUnmount(() => {
   background: #fff;
 }
 
+.auto-fetch {
+  margin-top: 40px;
+  text-align: center;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 14px;
+}
+.auto-fetch .hint-line {
+  color: var(--text-mute);
+  font-size: 14px;
+  line-height: 1.6;
+}
+.auto-fetch .hint-line b { color: var(--accent); }
+.auto-fetch .hint-line.err { color: var(--accent-red); }
+.btn-fetch {
+  background: var(--accent-strong);
+  color: #fff;
+  padding: 12px 22px;
+  border-radius: 8px;
+  font-size: 14px;
+  font-weight: 600;
+  transition: background 0.15s, transform 0.05s;
+}
+.btn-fetch:hover:not(:disabled) { background: var(--accent); }
+.btn-fetch:active:not(:disabled) { transform: scale(0.97); }
+.btn-fetch .spin { display: inline-block; animation: spin-anim 1.5s linear infinite; }
+@keyframes spin-anim { to { transform: rotate(360deg); } }
+
 .pdf-box { display: flex; flex-direction: column; gap: 16px; }
 .pdf-frame {
   width: 100%;
diff --git a/apps/music/k8s/all.yaml b/apps/music/k8s/all.yaml
index b0d178e..0ed0252 100644
--- a/apps/music/k8s/all.yaml
+++ b/apps/music/k8s/all.yaml
@@ -51,6 +51,8 @@ spec:
               value: /data/app.db
             - name: BLOBS_DIR
               value: /data/blobs
+            - name: CHORD_URL
+              value: http://localhost:8001
           readinessProbe:
             httpGet:
               path: /healthz
@@ -73,6 +75,38 @@ spec:
           volumeMounts:
             - name: data
               mountPath: /data
+        - name: chord-fetcher
+          image: registry.famzheng.me/mochi/music-chord:latest
+          imagePullPolicy: IfNotPresent
+          ports:
+            - containerPort: 8001
+              name: chord
+          env:
+            - name: CHORD_OUT_DIR
+              value: /data/chord-fetch
+          readinessProbe:
+            httpGet:
+              path: /healthz
+              port: chord
+            initialDelaySeconds: 3
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: chord
+            initialDelaySeconds: 30
+            periodSeconds: 30
+          resources:
+            requests:
+              cpu: 50m
+              memory: 256Mi
+            # chromium 内存峰值很容易飙到 ~600MB
+            limits:
+              cpu: 2000m
+              memory: 1Gi
+          volumeMounts:
+            - name: data
+              mountPath: /data
       volumes:
         - name: data
           persistentVolumeClaim:
diff --git a/apps/music/src/main.rs b/apps/music/src/main.rs
index 6f65ca0..9d67f1e 100644
--- a/apps/music/src/main.rs
+++ b/apps/music/src/main.rs
@@ -37,6 +37,9 @@ const REQUEST_BYTES: usize = 5 * 1024 * 1024 * 1024; // 5 GiB / 单次上传
 struct AppState {
     db: Arc<Mutex<Connection>>,
     blobs_dir: PathBuf,
+    /// 同 pod 的 chord-fetcher sidecar root（默认 http://localhost:8001）。
+    chord_url: String,
+    http: reqwest::Client,
 }
 
 #[tokio::main]
@@ -82,9 +85,18 @@ async fn main() -> std::io::Result<()> {
     .expect("init schema");
     tracing::info!(%db_path, blobs = %blobs_dir.display(), "music ready");
 
+    let chord_url =
+        std::env::var("CHORD_URL").unwrap_or_else(|_| "http://localhost:8001".into());
+    let http = reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(15))
+        .build()
+        .expect("build reqwest client");
+
     let state = AppState {
         db: Arc::new(Mutex::new(conn)),
         blobs_dir,
+        chord_url,
+        http,
     };
 
     let api = Router::new()
@@ -94,6 +106,8 @@ async fn main() -> std::io::Result<()> {
             get(get_piece).patch(patch_piece).delete(delete_piece),
         )
         .route("/pieces/:id/play", post(record_play))
+        .route("/pieces/:id/chord/fetch", post(chord_fetch))
+        .route("/pieces/:id/chord/status", get(chord_status))
         .route(
             "/pieces/:id/attachments",
             post(upload_attachments).layer(DefaultBodyLimit::max(REQUEST_BYTES)),
@@ -417,6 +431,143 @@ async fn delete_piece(
     Ok(JsonResp(json!({ "ok": true })))
 }
 
+// ---------- handlers: chord auto-fetch ----------
+
+/// `POST /api/pieces/:id/chord/fetch` — 触发 sidecar 抓取 yopu 和弦谱。
+/// 已经有 chord attachment 的曲目直接返回 completed。
+async fn chord_fetch(
+    State(s): State<AppState>,
+    Path(piece_id): Path<i64>,
+) -> Result<JsonResp<Value>, AppError> {
+    let (title, artist, has_chord) = chord_piece_meta(&s, piece_id)?;
+    if has_chord {
+        return Ok(JsonResp(json!({ "status": "completed", "reason": "已有吉他谱" })));
+    }
+    let query = match artist.as_deref() {
+        Some(a) if !a.is_empty() => format!("{a} {title}"),
+        _ => title,
+    };
+    let url = format!("{}/fetch", s.chord_url);
+    let resp = s
+        .http
+        .post(&url)
+        .query(&[("piece_id", piece_id.to_string()), ("query", query)])
+        .send()
+        .await
+        .map_err(|e| AppError::sidecar(format!("post fetch: {e}")))?;
+    if !resp.status().is_success() {
+        let st = resp.status();
+        let body = resp.text().await.unwrap_or_default();
+        return Err(AppError::sidecar(format!("sidecar {st}: {body}")));
+    }
+    let body: Value = resp
+        .json()
+        .await
+        .map_err(|e| AppError::sidecar(format!("decode: {e}")))?;
+    Ok(JsonResp(body))
+}
+
+/// `GET /api/pieces/:id/chord/status` — 查询抓取状态。完成时把 png import 成 attachment。
+async fn chord_status(
+    State(s): State<AppState>,
+    Path(piece_id): Path<i64>,
+) -> Result<JsonResp<Value>, AppError> {
+    let (_title, _artist, has_chord) = chord_piece_meta(&s, piece_id)?;
+    if has_chord {
+        return Ok(JsonResp(json!({ "status": "completed", "imported": true })));
+    }
+
+    let url = format!("{}/status/{}", s.chord_url, piece_id);
+    let resp = s
+        .http
+        .get(&url)
+        .send()
+        .await
+        .map_err(|e| AppError::sidecar(format!("get status: {e}")))?;
+    if !resp.status().is_success() {
+        return Err(AppError::sidecar(format!("sidecar status: {}", resp.status())));
+    }
+    let body: Value = resp
+        .json()
+        .await
+        .map_err(|e| AppError::sidecar(format!("decode: {e}")))?;
+
+    let st = body.get("status").and_then(|v| v.as_str()).unwrap_or("none");
+    let file_exists = body
+        .get("file_exists")
+        .and_then(|v| v.as_bool())
+        .unwrap_or(false);
+
+    if st == "completed" && file_exists {
+        let attachment_id = import_chord_png(&s, piece_id).await?;
+        // 通知 sidecar 清掉 state + 文件，避免重复 import
+        let _ = s
+            .http
+            .delete(format!("{}/state/{}", s.chord_url, piece_id))
+            .send()
+            .await;
+        return Ok(JsonResp(json!({
+            "status": "completed",
+            "imported": true,
+            "attachment_id": attachment_id,
+        })));
+    }
+
+    Ok(JsonResp(body))
+}
+
+fn chord_piece_meta(
+    s: &AppState,
+    piece_id: i64,
+) -> Result<(String, Option<String>, bool), AppError> {
+    let conn = s.db.lock().unwrap();
+    let row: Option<(String, Option<String>)> = conn
+        .query_row(
+            "SELECT title, artist FROM pieces WHERE id = ?1",
+            params![piece_id],
+            |r| Ok((r.get(0)?, r.get(1)?)),
+        )
+        .optional()?;
+    let (title, artist) = row.ok_or(AppError::NotFound)?;
+    let has_chord: bool = conn
+        .query_row(
+            "SELECT 1 FROM attachments
+             WHERE piece_id = ?1 AND kind = 'image' AND role = 'chord' LIMIT 1",
+            params![piece_id],
+            |_| Ok(true),
+        )
+        .optional()?
+        .unwrap_or(false);
+    Ok((title, artist, has_chord))
+}
+
+async fn import_chord_png(s: &AppState, piece_id: i64) -> Result<i64, AppError> {
+    let src = std::path::PathBuf::from(format!("/data/chord-fetch/{piece_id}.png"));
+    let bytes = tokio::fs::metadata(&src).await.map_err(AppError::Io)?;
+    let size = bytes.len() as i64;
+
+    let attachment_id = {
+        let conn = s.db.lock().unwrap();
+        conn.execute(
+            "INSERT INTO attachments
+                (piece_id, kind, role, mime, filename, size_bytes, sort_order)
+             VALUES (?1, 'image', 'chord', 'image/png', 'chord.png', ?2,
+                COALESCE((SELECT MAX(sort_order) FROM attachments WHERE piece_id = ?1), 0) + 1)",
+            params![piece_id, size],
+        )?;
+        conn.last_insert_rowid()
+    };
+
+    let dst = s.blobs_dir.join(attachment_id.to_string());
+    if let Err(e) = tokio::fs::copy(&src, &dst).await {
+        // 失败回滚 db 行
+        let conn = s.db.lock().unwrap();
+        let _ = conn.execute("DELETE FROM attachments WHERE id = ?1", params![attachment_id]);
+        return Err(AppError::Io(e));
+    }
+    Ok(attachment_id)
+}
+
 // ---------- handlers: attachments ----------
 
 /// `POST /api/pieces/:id/attachments?role=chord|numbered|staff` — multipart 流式上传。
@@ -652,12 +803,16 @@ enum AppError {
     NotFound,
     Db(rusqlite::Error),
     Io(std::io::Error),
+    Sidecar(String),
 }
 
 impl AppError {
     fn bad_request(msg: impl Into<String>) -> Self {
         Self::BadRequest(msg.into())
     }
+    fn sidecar(msg: impl Into<String>) -> Self {
+        Self::Sidecar(msg.into())
+    }
 }
 
 impl From<rusqlite::Error> for AppError {
@@ -679,6 +834,10 @@ impl IntoResponse for AppError {
                 tracing::error!(error = %e, "io error");
                 (StatusCode::INTERNAL_SERVER_ERROR, "io error").into_response()
             }
+            Self::Sidecar(msg) => {
+                tracing::warn!(error = %msg, "chord sidecar");
+                (StatusCode::BAD_GATEWAY, msg).into_response()
+            }
         }
     }
 }