diff --git a/crates/zx_document_ffi/Cargo.toml b/crates/zx_document_ffi/Cargo.toml
index ac07d56..0723d20 100644
--- a/crates/zx_document_ffi/Cargo.toml
+++ b/crates/zx_document_ffi/Cargo.toml
@@ -3,4 +3,12 @@ name = "zx_document_ffi"
 version = "0.1.0"
 edition = "2021"
 
+[lib]
+crate-type = ["lib", "staticlib", "cdylib"]
+
 [dependencies]
+zx_document_core = { path = "../zx_document_core" }
+uniffi = "0.28"
+
+[build-dependencies]
+uniffi = { version = "0.28", features = ["build"] }
diff --git a/crates/zx_document_ffi/build.rs b/crates/zx_document_ffi/build.rs
new file mode 100644
index 0000000..51ea8dd
--- /dev/null
+++ b/crates/zx_document_ffi/build.rs
@@ -0,0 +1,3 @@
+fn main() {
+    uniffi::generate_scaffolding("src/zx_document.udl").unwrap();
+}
diff --git a/crates/zx_document_ffi/src/lib.rs b/crates/zx_document_ffi/src/lib.rs
index 2db0eac..8355b71 100644
--- a/crates/zx_document_ffi/src/lib.rs
+++ b/crates/zx_document_ffi/src/lib.rs
@@ -1,2 +1 @@
-// FFI bindings — generated by UniFFI
-// See zx_document.udl for interface definitions
+uniffi::setup_scaffolding!();
diff --git a/crates/zx_document_ffi/src/zx_document.udl b/crates/zx_document_ffi/src/zx_document.udl
index e69de29..77ba9ac 100644
--- a/crates/zx_document_ffi/src/zx_document.udl
+++ b/crates/zx_document_ffi/src/zx_document.udl
@@ -0,0 +1,92 @@
+namespace zx_document {};
+
+[Enum]
+interface MaterialType {
+    Markdown();
+    Text();
+    Pdf();
+    Image();
+    Epub();
+    Word();
+    Excel();
+    PowerPoint();
+    Unknown();
+};
+
+[Enum]
+interface PreviewMode {
+    NativeReader();
+    PlatformPreview();
+    ExternalOpen();
+    Unsupported();
+};
+
+dictionary DocumentInfo {
+    string material_id;
+    string title;
+    MaterialType material_type;
+    PreviewMode preview_mode;
+    u64 file_size;
+    u32? page_count;
+    u32? word_count;
+    string? created_at;
+};
+
+[Enum]
+interface ReadingPosition {
+    Markdown(string block_id, f32 scroll_progress);
+    Text(u32 line_number, f32 scroll_progress);
+    Pdf(u32 page_number, f32 page_progress, f32 overall_progress);
+    Image(f32 zoom_scale, f32 offset_x, f32 offset_y);
+    Epub(string chapter_id, f32 chapter_progress, f32 overall_progress);
+    Unknown();
+};
+
+[Enum]
+interface ReadingEvent {
+    MaterialOpened(string material_id, i64 timestamp_ms);
+    MaterialClosed(string material_id, i64 timestamp_ms, u32 active_seconds);
+    PositionChanged(string material_id, ReadingPosition position, i64 timestamp_ms);
+    Heartbeat(string material_id, u32 active_seconds, ReadingPosition? position, i64 timestamp_ms);
+    MarkedAsRead(string material_id, i64 timestamp_ms);
+};
+
+[Enum]
+interface NoteAnchor {
+    Material(string material_id);
+    MarkdownBlock(string material_id, string block_id);
+    TextLine(string material_id, u32 line_number);
+    PdfPage(string material_id, u32 page_number);
+    Image(string material_id);
+    EpubChapter(string material_id, string chapter_id);
+    KnowledgeItem(string knowledge_item_id);
+};
+
+dictionary ImageMeta {
+    u32 width;
+    u32 height;
+    string format;
+    u64 file_size;
+};
+
+dictionary SearchResult {
+    string block_id;
+    u32? line_number;
+    string snippet;
+    u64 match_start;
+    u64 match_end;
+};
+
+dictionary TextStats {
+    u32 line_count;
+    u32 word_count;
+};
+
+[Error]
+enum DocumentError {
+    "FileNotFound",
+    "UnsupportedFormat",
+    "ParseError",
+    "InvalidEncoding",
+    "IoError",
+};