wip: clawsync + clawhdf5-onion in-progress (ci-doctor branch)

crates/clawhdf5-onion/benches/tdt_bench.rs

@@ -73,8 +73,7 @@ fn bench_compress(data: &[u8], codec: Codec) -> usize {
 fn bench_tdt_compress(c: &mut Criterion) {
     let sizes = [4096usize, 65536];
 
-    type DataGen = fn(usize) -> Vec<u8>;
-    let datasets: &[(&str, DataGen, usize)] = &[
+    let datasets: &[(&str, fn(usize) -> Vec<u8>, usize)] = &[
         ("f32_smooth", make_f32_smooth, 4),
         ("f32_random", make_f32_random, 4),
         ("int32_random", make_int32_random, 4),

crates/clawhdf5-onion/src/branch.rs

@@ -33,9 +33,14 @@ pub enum MergeStrategy {
 /// Public summary of a branch.
 #[derive(Debug, Clone)]
 pub struct BranchInfo {
+    /// Unique numeric branch identifier (`0` = `main`).
     pub id: u32,
+    /// Human-readable branch name.
     pub name: String,
+    /// Revision number of the current HEAD on this branch.
     pub head_rev: u64,
+    /// Revision at which this branch was forked from its parent;
+    /// [`crate::format::NO_PARENT`] for the root (`main`) branch.
     pub fork_rev: u64,
 }
 

crates/clawhdf5-onion/src/error.rs

@@ -32,8 +32,11 @@ pub enum OnionError {
     /// Page data BLAKE3 hash does not match stored hash — integrity failure.
     #[error("BLAKE3 hash mismatch on revision {revision}: stored {stored}, computed {computed}")]
     HashMismatch {
+        /// The revision number whose page data failed the integrity check.
         revision: u64,
+        /// The BLAKE3 hex string recorded in the revision index.
         stored: String,
+        /// The BLAKE3 hex string computed from the actual page bytes.
         computed: String,
     },
 
@@ -47,7 +50,12 @@ pub enum OnionError {
 
     /// A merge was attempted on a branch with no common ancestor.
     #[error("no common ancestor found between branches {a:?} and {b:?}")]
-    NoCommonAncestor { a: String, b: String },
+    NoCommonAncestor {
+        /// Name of the first branch in the attempted merge.
+        a: String,
+        /// Name of the second branch in the attempted merge.
+        b: String,
+    },
 
     /// Compression or decompression failed.
     #[error("compression error: {0}")]

crates/clawhdf5-onion/src/format.rs

@@ -47,13 +47,25 @@ pub const HEADER_SIZE: usize = 128;
 // Feature flags
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Bit-flag constants for `OnionHeader::feature_flags`.
+///
+/// Each flag is a single bit; combine with `|` when constructing a header.
 pub mod feature_flags {
+    /// Page data may be stored with a non-`None` [`super::Codec`] (zstd, lz4, etc.).
     pub const COMPRESSION: u64 = 1 << 0;
+    /// The file uses multi-branch history (`BranchEntry` table is populated).
     pub const BRANCHING: u64 = 1 << 1;
+    /// `RevisionEntry.session_uuid` and `annotation_off` fields are meaningful.
     pub const PROVENANCE: u64 = 1 << 2;
+    /// Full-file snapshots are stored in the revision index
+    /// (i.e., at least one `RevisionEntry` has `REV_FLAG_SNAPSHOT` set).
     pub const SNAPSHOTS: u64 = 1 << 3;
 }
 
+/// Feature flags enabled by default when creating a new `.onion` file.
+///
+/// Includes [`feature_flags::COMPRESSION`], [`feature_flags::BRANCHING`], and
+/// [`feature_flags::PROVENANCE`].  [`feature_flags::SNAPSHOTS`] is opt-in.
 pub const DEFAULT_FEATURE_FLAGS: u64 =
     feature_flags::COMPRESSION | feature_flags::BRANCHING | feature_flags::PROVENANCE;
 
@@ -61,12 +73,20 @@ pub const DEFAULT_FEATURE_FLAGS: u64 =
 // Codec
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Compression codec used for page data storage.
+///
+/// Stored as a single byte (`u8`) in each [`PageTableEntry`].  Unknown values
+/// cause [`OnionError::UnknownCodec`] when reading.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(u8)]
 pub enum Codec {
+    /// No compression — page bytes are stored verbatim.
     None = 0,
+    /// [Zstandard](https://facebook.github.io/zstd/) compression.
     Zstd = 1,
+    /// [LZ4](https://lz4.github.io/lz4/) compression.
     Lz4 = 2,
+    /// [Brotli](https://github.com/google/brotli) compression.
     Brotli = 3,
     /// zstd applied after TDT byte-interleaving transform (arXiv:2506.18062).
     /// Improves compression ratio ~16% for `f32`/`f16` numeric pages.
@@ -74,6 +94,22 @@ pub enum Codec {
 }
 
 impl Codec {
+    /// Parse a raw codec byte from a [`PageTableEntry`] into a [`Codec`].
+    ///
+    /// # Errors
+    ///
+    /// Returns [`OnionError::UnknownCodec`] if `v` does not correspond to a
+    /// known codec variant.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use clawhdf5_onion::format::Codec;
+    ///
+    /// assert_eq!(Codec::from_u8(0).unwrap(), Codec::None);
+    /// assert_eq!(Codec::from_u8(1).unwrap(), Codec::Zstd);
+    /// assert!(Codec::from_u8(99).is_err());
+    /// ```
     pub fn from_u8(v: u8) -> Result<Self, OnionError> {
         match v {
             0 => Ok(Codec::None),
@@ -105,27 +141,52 @@ impl Codec {
 //   [72..128) reserved     [u8; 56]
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Fixed 128-byte file header at offset 0 of every `.onion` sidecar.
+///
+/// All fields are little-endian.  Readers must call [`OnionHeader::validate`]
+/// before trusting any other field.
 #[derive(FromBytes, IntoBytes, KnownLayout, Immutable, Debug, Clone)]
 #[repr(C)]
 pub struct OnionHeader {
+    /// Magic bytes — must equal [`MAGIC`] (`b"CLAWONION"`).
     pub magic: [u8; 9],
+    /// Format version — must equal [`FORMAT_VERSION`] (`1`).
     pub format_version: u8,
+    /// Alignment padding to the next `u64` boundary; always `[0u8; 6]`.
     pub _pad_align: [u8; 6],
+    /// Bitmask of enabled features; see [`feature_flags`].
     pub feature_flags: u64,
+    /// Page size in bytes used for all page data in this file; must be a
+    /// non-zero power of two.
     pub page_size: u32,
+    /// Padding after `page_size` to keep `revision_count` at a `u64` boundary.
     pub _pad_ps: [u8; 4],
+    /// Total number of `RevisionEntry` records in the index.
     pub revision_count: u64,
+    /// Number of `BranchEntry` records; `0` when the file predates branching.
     pub branch_count: u32,
+    /// Padding after `branch_count` to keep `index_offset` at a `u64` boundary.
     pub _pad_bc: [u8; 4],
+    /// Byte offset of the first `RevisionEntry` in the file.
     pub index_offset: u64,
+    /// Byte offset of the first `BranchEntry`; `0` when `branch_count == 0`.
     pub branch_offset: u64,
+    /// Unix timestamp (seconds since epoch, as `f64`) when the file was created.
     pub created_at: f64,
+    /// Reserved bytes, always zero; available for future format extensions.
     pub reserved: [u8; 56],
 }
 
 const _: () = assert!(size_of::<OnionHeader>() == HEADER_SIZE);
 
 impl OnionHeader {
+    /// Validate the header's magic bytes and format version.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`OnionError::InvalidMagic`] if the magic bytes do not match
+    /// [`MAGIC`], or [`OnionError::UnknownVersion`] if `format_version` is not
+    /// equal to [`FORMAT_VERSION`].
     pub fn validate(&self) -> Result<(), OnionError> {
         if &self.magic != MAGIC {
             return Err(OnionError::InvalidMagic);
@@ -136,10 +197,15 @@ impl OnionHeader {
         Ok(())
     }
 
+    /// Return `true` if the feature bit `flag` is set in `feature_flags`.
+    ///
+    /// Use the constants in [`feature_flags`] as arguments.
     pub fn has_feature(&self, flag: u64) -> bool {
         self.feature_flags & flag != 0
     }
 
+    /// Construct a new header with zero revision/branch counts and
+    /// `index_offset` pointing immediately after the header.
     pub fn new(page_size: u32, feature_flags: u64, created_at: f64) -> Self {
         Self {
             magic: *MAGIC,
@@ -177,24 +243,48 @@ impl OnionHeader {
 //   [105..112) _pad_flags  [u8; 7]
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Fixed 112-byte record describing one committed revision.
+///
+/// Stored in the revision index array starting at [`OnionHeader::index_offset`].
+/// Sorted by `revision` in ascending order.
 #[derive(FromBytes, IntoBytes, KnownLayout, Immutable, Debug, Clone)]
 #[repr(C)]
 pub struct RevisionEntry {
+    /// Monotonically increasing revision number (0-based).
     pub revision: u64,
+    /// ID of the branch this revision belongs to; `0` = `main`.
     pub branch_id: u32,
+    /// Padding after `branch_id` to keep `parent_rev` at a `u64` boundary.
     pub _pad_bi: [u8; 4],
+    /// Revision number of the direct parent; [`NO_PARENT`] for the initial commit.
     pub parent_rev: u64,
+    /// Number of [`PageTableEntry`] records for this revision.
     pub page_count: u32,
+    /// Padding after `page_count` to keep `page_table_off` at a `u64` boundary.
     pub _pad_pc: [u8; 4],
+    /// Byte offset of the first [`PageTableEntry`] for this revision.
     pub page_table_off: u64,
+    /// Unix timestamp (seconds since epoch, as `f64`) when this revision was committed.
     pub timestamp: f64,
+    /// BLAKE3 hash of all page data in this revision (concatenated before hashing).
     pub blake3: [u8; 32],
+    /// UUID (16 bytes) identifying the session that produced this revision.
+    /// Zero-filled if [`feature_flags::PROVENANCE`] is not set.
     pub session_uuid: [u8; 16],
+    /// Byte offset into the annotation heap for this revision's annotation string;
+    /// `0` means no annotation.
     pub annotation_off: u64,
+    /// Per-revision bit flags; see `REV_FLAG_*` constants.
     pub flags: u8,
+    /// Padding after `flags`, also used by GC to store an epoch tag in bytes `[0..4]`.
     pub _pad_flags: [u8; 7],
 }
 
+/// Flag bit indicating that this revision is a full-state snapshot checkpoint.
+///
+/// Set in `RevisionEntry::flags`.  When this bit is set the revision stores a
+/// complete copy of all HDF5 pages (not just deltas), making it a fast restore
+/// point that does not require replaying earlier revisions.
 pub const REV_FLAG_SNAPSHOT: u8 = 1 << 0;
 
 /// Sentinel epoch value written into `RevisionEntry._pad_flags[0..4]` by
@@ -230,14 +320,25 @@ impl RevisionEntry {
 //   [32..40) created_at    f64
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Fixed 40-byte record describing one named branch.
+///
+/// Stored in the branch table starting at [`OnionHeader::branch_offset`].
+/// Branch `0` is always `main`.
 #[derive(FromBytes, IntoBytes, KnownLayout, Immutable, Debug, Clone)]
 #[repr(C)]
 pub struct BranchEntry {
+    /// Unique branch identifier; `0` = `main`.
     pub id: u32,
+    /// Padding after `id` to keep `name_off` at a `u64` boundary.
     pub _pad_id: [u8; 4],
+    /// Byte offset into the annotation heap for the branch name string.
     pub name_off: u64,
+    /// Revision number of the current HEAD on this branch.
     pub head_rev: u64,
+    /// Revision at which this branch was forked from its parent;
+    /// [`NO_PARENT`] for the root (`main`) branch.
     pub fork_rev: u64,
+    /// Unix timestamp (seconds since epoch, as `f64`) when the branch was created.
     pub created_at: f64,
 }
 
@@ -252,14 +353,25 @@ pub struct BranchEntry {
 //   [25..32) _pad          [u8; 7]
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Fixed 32-byte record mapping one HDF5 page to its stored data.
+///
+/// Each [`RevisionEntry`] is followed by `page_count` of these records in the
+/// page table.  Pages are ordered by `h5_offset` (ascending).
 #[derive(FromBytes, IntoBytes, KnownLayout, Immutable, Debug, Clone)]
 #[repr(C)]
 pub struct PageTableEntry {
+    /// Byte offset within the logical HDF5 file that this page covers.
     pub h5_offset: u64,
+    /// Byte offset within the `.onion` file where the (possibly compressed)
+    /// page data begins.
     pub data_offset: u64,
+    /// Original (uncompressed) page size in bytes.
     pub orig_size: u32,
+    /// Stored (possibly compressed) data size in bytes.
     pub data_size: u32,
+    /// Compression codec byte; parse with [`Codec::from_u8`].
     pub codec: u8,
+    /// Alignment padding; always zero.
     pub _pad: [u8; 7],
 }
 

crates/clawhdf5-onion/src/index.rs

@@ -125,8 +125,11 @@ impl<'a> Iterator for AncestorIter<'a> {
 /// Summary of branch head state, used by public query APIs.
 #[derive(Debug, Clone)]
 pub struct BranchHeadInfo {
+    /// Unique numeric branch identifier (`0` = `main`).
     pub branch_id: u32,
+    /// Revision number of the current HEAD on this branch.
     pub head_rev: u64,
+    /// Total number of revisions on this branch.
     pub revision_count: usize,
 }
 

crates/clawhdf5-onion/src/merkle.rs

@@ -66,11 +66,24 @@ pub struct MerkleNode {
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum WalkStep {
     /// Subtree [rev_lo, rev_hi] is identical on both sides — skip.
-    Skip { rev_lo: u64, rev_hi: u64 },
+    Skip {
+        /// Lowest revision number covered by this identical subtree.
+        rev_lo: u64,
+        /// Highest revision number covered by this identical subtree.
+        rev_hi: u64,
+    },
     /// Subtree differs; descend into children.
-    Descend { node: MerkleNode },
+    Descend {
+        /// The tree node whose children should be diffed next.
+        node: MerkleNode,
+    },
     /// Leaf differs; this revision needs to be transferred.
-    Leaf { revision: u64, hash: [u8; 32] },
+    Leaf {
+        /// The revision number that differs between the two trees.
+        revision: u64,
+        /// BLAKE3 hash of this revision's pages on the local side.
+        hash: [u8; 32],
+    },
 }
 
 /// Balanced binary Merkle tree over OnionFile revision BLAKE3 hashes.
@@ -339,17 +352,27 @@ fn node_hash(left: &[u8; 32], right: &[u8; 32]) -> [u8; 32] {
 // Error type
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Errors from Merkle tree serialisation/deserialisation.
 /// Errors from Merkle tree serialisation/deserialisation.
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum MerkleError {
+    /// The byte slice is too short to contain even the 13-byte header.
     #[error("truncated header (< 13 bytes)")]
     TruncatedHeader,
+    /// The first 4 bytes do not match the expected magic sequence.
     #[error("bad magic bytes")]
     BadMagic,
+    /// The format version byte is not supported by this reader.
     #[error("unknown format version {0}")]
     UnknownVersion(u8),
+    /// The payload is shorter than the length declared in the header.
     #[error("truncated payload: expected {expected} bytes, got {got}")]
-    TruncatedPayload { expected: usize, got: usize },
+    TruncatedPayload {
+        /// Number of payload bytes declared in the header.
+        expected: usize,
+        /// Number of bytes actually available.
+        got: usize,
+    },
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
@@ -540,7 +563,7 @@ mod tests {
             let all_entries: Vec<(u64, [u8; 32])> = (0..total as u64)
                 .map(|r| (r, rev_hash(r)))
                 .collect();
-            let keep_count = (total as f64 * keep_frac) as usize;
+            let keep_count = ((total as f64 * keep_frac) as usize).max(0);
             let remote_entries = &all_entries[..keep_count];
 
             let local  = RevisionMerkleTree::build(&all_entries);

crates/clawhdf5-onion/src/writer.rs

@@ -446,6 +446,9 @@ impl OnionFile {
         self.branches.iter().find(|b| b.id == id)
     }
 
+    /// Look up a `BranchEntry` by its human-readable name.
+    ///
+    /// Returns `None` if no branch with that name exists.
     pub fn branch_by_name(&self, name: &str) -> Option<&BranchEntry> {
         self.branches
             .iter()
@@ -674,12 +677,19 @@ impl OnionFile {
 /// Human-readable summary of a single revision, returned by [`OnionFile::list_revisions`].
 #[derive(Debug, Clone)]
 pub struct RevisionSummary {
+    /// Monotonically increasing revision number (0-based).
     pub revision: u64,
+    /// ID of the branch this revision belongs to; `0` = `main`.
     pub branch_id: u32,
+    /// Revision number of the direct parent; `u64::MAX` for the initial commit.
     pub parent_rev: u64,
+    /// Unix timestamp (seconds since epoch, as `f64`) when the revision was committed.
     pub timestamp: f64,
+    /// Number of page entries recorded for this revision.
     pub page_count: u32,
+    /// Optional human-readable annotation stored with the revision.
     pub annotation: Option<String>,
+    /// BLAKE3 hex digest of this revision's page data.
     pub blake3_hex: String,
     /// `true` if this revision is a full-state snapshot checkpoint.
     pub is_snapshot: bool,

crates/clawsync-agent/src/backend.rs

@@ -34,8 +34,11 @@ use crate::error::AgentSyncError;
 /// Statistics from a push or pull operation.
 #[derive(Debug, Default, Clone)]
 pub struct SyncStats {
+    /// Number of revisions actually sent or received.
     pub revisions_transferred: u64,
+    /// Total compressed bytes sent or received.
     pub bytes_transferred: u64,
+    /// Revisions that were already present on the remote and therefore skipped.
     pub revisions_skipped: u64,
 }
 
@@ -95,6 +98,10 @@ pub struct TcpSyncBackend {
 }
 
 impl TcpSyncBackend {
+    /// Create a new backend targeting `remote_addr`.
+    ///
+    /// `agent_id` is embedded in all protocol messages to identify the local
+    /// agent to the remote server.
     pub fn new(remote_addr: SocketAddr, agent_id: impl Into<String>) -> Self {
         Self {
             remote_addr,

crates/clawsync-agent/src/error.rs

@@ -2,29 +2,38 @@
 
 use thiserror::Error;
 
+/// All errors that can occur in the `clawsync-agent` autonomous sync layer.
 #[derive(Debug, Error)]
 pub enum AgentSyncError {
+    /// An error from the `clawhdf5-onion` VFD (e.g., opening or writing the sidecar).
     #[error("onion VFD error: {0}")]
     Onion(#[from] clawhdf5_onion::OnionError),
 
+    /// An error propagated from the `clawsync-onion` diffing/merging layer.
     #[error("sync-onion error: {0}")]
     SyncOnion(#[from] clawsync_onion::error::SyncOnionError),
 
+    /// An error propagated from the `clawsync-transport` layer.
     #[error("transport error: {0}")]
     Transport(#[from] clawsync_transport::error::TransportError),
 
+    /// An underlying I/O error.
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    /// The remote peer reported an application-level error.
     #[error("remote error: {0}")]
     Remote(String),
 
+    /// The remote peer violated the sync protocol.
     #[error("protocol error: {0}")]
     Protocol(String),
 
+    /// An error from the `clawhdf5-agent` memory layer (save, compact, WAL flush).
     #[error("agent memory error: {0}")]
     AgentMemory(String),
 
+    /// A restore was requested for a revision that does not exist in the sidecar.
     #[error("no revisions to restore at revision {0}")]
     RevisionNotFound(u64),
 }

crates/clawsync-agent/src/onion_memory.rs

@@ -37,9 +37,13 @@ pub struct OnionMemory {
 /// Summary of a historical snapshot.
 #[derive(Debug, Clone)]
 pub struct MemorySnapshot {
+    /// Revision number within the `.onion` sidecar.
     pub revision: u64,
+    /// Optional human-readable annotation stored when the snapshot was committed.
     pub annotation: Option<String>,
+    /// Unix timestamp (seconds since epoch, as `f64`) when the snapshot was committed.
     pub timestamp: f64,
+    /// BLAKE3 hex digest of the snapshotted HDF5 page data.
     pub blake3_hex: String,
 }
 

crates/clawsync-core/benches/cdc_bench.rs

@@ -58,10 +58,8 @@ fn cold_data(n: usize) -> Vec<u8> {
 // Benchmark
 // ─────────────────────────────────────────────────────────────────────────────
 
-type DataGen = fn(usize) -> Vec<u8>;
-
 fn bench_cdc(c: &mut Criterion) {
-    let datasets: &[(&str, DataGen)] = &[
+    let datasets: &[(&str, fn(usize) -> Vec<u8>)] = &[
         ("random", random_data),
         ("float", float_data),
         ("cold_only", cold_data),

crates/clawsync-core/src/delta.rs

@@ -44,9 +44,17 @@ pub fn compute_block_hashes(data: &[u8], block_size: usize) -> Vec<BlockHash> {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum DeltaOp {
     /// Copy `length` bytes starting at `offset` from the source.
-    Copy { offset: usize, length: usize },
+    Copy {
+        /// Byte offset in the source buffer to copy from.
+        offset: usize,
+        /// Number of bytes to copy.
+        length: usize,
+    },
     /// Insert the given literal bytes (no corresponding source region).
-    Insert { data: Vec<u8> },
+    Insert {
+        /// Literal bytes to insert at the current output position.
+        data: Vec<u8>,
+    },
 }
 
 /// Compute the delta needed to transform `source` into `target`.

crates/clawsync-core/src/error.rs

@@ -2,14 +2,24 @@
 
 use thiserror::Error;
 
+/// All errors that can occur in the `clawsync-core` low-level layer.
 #[derive(Debug, Error)]
 pub enum CoreError {
+    /// A compression operation (zstd, lz4, brotli, or ZstdTdt) failed.
     #[error("compression failed: {0}")]
     Compress(String),
+    /// A decompression operation failed (malformed or truncated input).
     #[error("decompression failed: {0}")]
     Decompress(String),
+    /// The BLAKE3 hash of a block does not match the stored/expected value.
     #[error("checksum mismatch: expected {expected}, got {actual}")]
-    ChecksumMismatch { expected: String, actual: String },
+    ChecksumMismatch {
+        /// The BLAKE3 hex string that was expected.
+        expected: String,
+        /// The BLAKE3 hex string that was computed.
+        actual: String,
+    },
+    /// An underlying I/O error.
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 }

crates/clawsync-core/src/simd_cdc.rs

@@ -114,6 +114,11 @@ pub fn chunk_data_sized_simd(
 // Scalar fallback
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Scalar (non-SIMD) content-defined chunking fallback.
+///
+/// Splits `data` into variable-size chunks using a rolling hash with the
+/// Rabin fingerprint approach.  `min`, `avg`, and `max` are the minimum,
+/// target average, and maximum chunk sizes in bytes.
 pub fn chunk_scalar(data: &[u8], min: usize, avg: usize, max: usize) -> Vec<Chunk> {
     if data.is_empty() {
         return Vec::new();
@@ -151,9 +156,6 @@ pub fn chunk_scalar(data: &[u8], min: usize, avg: usize, max: usize) -> Vec<Chun
 /// Scalar processing for a single 16-byte (or shorter) slice, folding the
 /// updated hash back out.  Used by both SIMD paths when a hot byte is detected.
 #[inline(always)]
-// Hot SIMD inner-loop helper: each arg is a distinct cursor/limit; bundling
-// into a struct would add per-call overhead in the chunker fast path.
-#[allow(clippy::too_many_arguments)]
 fn scalar_window(
     data: &[u8],
     window: &[u8],
@@ -545,7 +547,7 @@ mod tests {
         let original = chunk_data_simd(&data);
         // Flip a hot byte in the middle to force a different boundary
         let mid = 150_000;
-        data[mid] &= 0x3F; // ensure it's a hot byte (< 64)
+        data[mid] = data[mid] & 0x3F; // ensure it's a hot byte (< 64)
         data[mid] ^= 0x11;
         let mutated = chunk_data_simd(&data);
         assert_ne!(original, mutated, "mutation should change chunk boundaries");

crates/clawsync-fs/src/differ.rs

@@ -20,6 +20,7 @@ pub enum FileDiff {
 }
 
 impl FileDiff {
+    /// Return the relative path for any variant.
     pub fn path(&self) -> &str {
         match self {
             Self::Added(p) | Self::Modified(p) | Self::Removed(p) | Self::Unchanged(p) => p,

crates/clawsync-fs/src/error.rs

@@ -1,29 +1,47 @@
+//! Error types for `clawsync-fs`.
+
 use thiserror::Error;
 
+/// All errors that can occur in the `clawsync-fs` filesystem sync layer.
 #[derive(Debug, Error)]
 pub enum FsSyncError {
+    /// An underlying I/O error (file read/write, directory traversal, etc.).
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    /// An error propagated from the `clawsync-transport` layer.
     #[error("transport error: {0}")]
     Transport(#[from] clawsync_transport::TransportError),
 
+    /// A file or directory path is invalid or could not be resolved.
     #[error("path error: {0}")]
     Path(String),
 
+    /// The remote peer sent an unexpected message type during an fs-sync exchange.
     #[error("protocol error: unexpected message: {0}")]
     Protocol(String),
 
+    /// The BLAKE3 checksum of a received file does not match the expected value.
     #[error("checksum mismatch for {path}: expected {expected}, got {actual}")]
     ChecksumMismatch {
+        /// The file path whose checksum failed verification.
         path: String,
+        /// The BLAKE3 hex string that was expected.
         expected: String,
+        /// The BLAKE3 hex string computed from the received bytes.
         actual: String,
     },
 
+    /// A file could not be reassembled from the received chunks.
     #[error("reconstruction failed for {path}: {reason}")]
-    Reconstruction { path: String, reason: String },
+    Reconstruction {
+        /// The file path that failed to reconstruct.
+        path: String,
+        /// A human-readable description of the reconstruction failure.
+        reason: String,
+    },
 
+    /// A Tokio task panicked or was cancelled during an async fs-sync operation.
     #[error("task join error: {0}")]
     Join(String),
 }

crates/clawsync-fs/src/manifest.rs

@@ -158,6 +158,7 @@ pub struct LocalEntry {
 
 /// In-memory manifest of a local directory tree, sorted by `rel_path`.
 pub struct FsManifest {
+    /// All file entries in the directory tree, sorted by `rel_path`.
     pub entries: Vec<LocalEntry>,
 }
 

crates/clawsync-fs/src/session.rs

@@ -56,8 +56,11 @@ pub enum ProgressEvent {
 /// fields are `None`.
 #[derive(Debug, Default)]
 pub struct SyncStats {
+    /// Number of files newly created on the destination.
     pub files_added: u32,
+    /// Number of files overwritten on the destination.
     pub files_modified: u32,
+    /// Number of files deleted from the destination.
     pub files_removed: u32,
     /// Actual bytes sent over the wire (compressed literal chunks only).
     pub bytes_transferred: u64,
@@ -373,6 +376,10 @@ pub struct FsSyncServer {
 }
 
 impl FsSyncServer {
+    /// Create a new push server.
+    ///
+    /// `allow_delete` controls whether the server will honour delete requests
+    /// from the client (i.e., remove files absent from the client's manifest).
     pub fn new(conn: SyncPeer, serve_root: PathBuf, excludes: GlobSet, allow_delete: bool) -> Self {
         Self {
             conn,
@@ -756,6 +763,10 @@ pub struct FsSyncPullClient {
 }
 
 impl FsSyncPullClient {
+    /// Create a new pull client.
+    ///
+    /// `delete` controls whether local files absent from the server's manifest
+    /// are removed after the pull completes.
     pub fn new(conn: SyncPeer, local_root: PathBuf, excludes: GlobSet, delete: bool) -> Self {
         Self {
             conn,
@@ -972,6 +983,10 @@ pub struct FsSyncPullServer {
 }
 
 impl FsSyncPullServer {
+    /// Create a new pull server.
+    ///
+    /// `allow_delete` controls whether the server will accept client requests
+    /// to delete files from the server's serve root during a pull session.
     pub fn new(conn: SyncPeer, serve_root: PathBuf, excludes: GlobSet, allow_delete: bool) -> Self {
         Self {
             conn,

crates/clawsync-hdf5/src/differ.rs

@@ -33,6 +33,7 @@ pub struct DatasetPatch {
 /// Result of diffing two manifests.
 #[derive(Debug, Default)]
 pub struct DiffResult {
+    /// Ordered list of patches (Added, Modified, Removed) to apply to the target.
     pub patches: Vec<DatasetPatch>,
     /// Number of datasets that are identical in both manifests.
     pub unchanged_count: usize,

crates/clawsync-hdf5/src/error.rs

@@ -2,24 +2,33 @@
 
 use thiserror::Error;
 
+/// All errors that can occur in the `clawsync-hdf5` HDF5 sync layer.
 #[derive(Debug, Error)]
 pub enum Hdf5SyncError {
+    /// An error from the `clawhdf5` HDF5 parser or builder.
     #[error("HDF5 error: {0}")]
     Hdf5(#[from] clawhdf5::Error),
 
+    /// An underlying I/O error (file read/write, temp-file rename, etc.).
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    /// A dataset path referenced in a patch does not exist in the target file.
     #[error("dataset not found: {0}")]
     DatasetNotFound(String),
 
+    /// A patch attempted to overwrite a dataset with data of a different dtype.
     #[error("patch type mismatch for dataset '{path}': expected {expected}, got {actual}")]
     TypeMismatch {
+        /// HDF5 path of the mismatched dataset (e.g., `/group/weights`).
         path: String,
+        /// The dtype present in the target file.
         expected: String,
+        /// The dtype carried by the incoming patch.
         actual: String,
     },
 
+    /// A `DatasetManifest` could not be serialized or deserialized.
     #[error("manifest serialization error: {0}")]
     Serialize(String),
 }

crates/clawsync-hdf5/src/patcher.rs

@@ -24,10 +24,15 @@ use crate::error::Hdf5SyncError;
 /// Statistics from a patch operation.
 #[derive(Debug, Default, Clone)]
 pub struct PatchStats {
+    /// Number of new datasets added to the target file.
     pub datasets_added: u32,
+    /// Number of existing datasets overwritten with new data.
     pub datasets_modified: u32,
+    /// Number of datasets deleted from the target file.
     pub datasets_removed: u32,
+    /// Number of datasets copied unchanged from the old target file.
     pub datasets_unchanged: u32,
+    /// Total bytes written to the rebuilt target file.
     pub bytes_written: u64,
 }
 

crates/clawsync-onion/src/error.rs

@@ -2,36 +2,54 @@
 
 use thiserror::Error;
 
+/// All errors that can occur in the `clawsync-onion` sync layer.
 #[derive(Debug, Error)]
 pub enum SyncOnionError {
+    /// An error propagated from the underlying `clawhdf5-onion` VFD.
     #[error("onion error: {0}")]
     Onion(#[from] clawhdf5_onion::OnionError),
 
+    /// An error propagated from `clawsync-core` (compression, checksums, I/O).
     #[error("core error: {0}")]
     Core(#[from] clawsync_core::CoreError),
 
+    /// An underlying I/O error.
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    /// The requested revision number does not exist in the source `.onion` file.
     #[error("revision {0} not found in source")]
     RevisionNotFound(u64),
 
+    /// The named branch does not exist in the source `.onion` file.
     #[error("branch not found: {0}")]
     BranchNotFound(String),
 
+    /// The BLAKE3 hash of a received revision's pages does not match the expected value.
     #[error("BLAKE3 mismatch on revision {revision}: expected {expected}, got {actual}")]
     HashMismatch {
+        /// The revision number whose pages failed the integrity check.
         revision: u64,
+        /// The BLAKE3 hex string that was expected.
         expected: String,
+        /// The BLAKE3 hex string that was computed from the received pages.
         actual: String,
     },
 
+    /// A `LayerPacket` could not be serialized or deserialized.
     #[error("packet serialization error: {0}")]
     Serialization(String),
 
+    /// A merge was attempted with an empty set of packets.
     #[error("empty packet set — nothing to merge")]
     EmptyPackets,
 
+    /// Revisions arrived out of order during a merge — a gap was detected.
     #[error("revision gap: received {got}, expected {expected}")]
-    RevisionGap { expected: u64, got: u64 },
+    RevisionGap {
+        /// The next consecutive revision that was expected.
+        expected: u64,
+        /// The revision number that was actually received.
+        got: u64,
+    },
 }

crates/clawsync-onion/src/iblt.rs

@@ -100,12 +100,16 @@ pub enum IbltDecodeResult {
 // Error type
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Errors from IBLT sketch serialisation/deserialisation.
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum IbltError {
+    /// The byte slice is too short to contain a valid sketch header or payload.
     #[error("serialised data too short")]
     Truncated,
+    /// The first bytes do not match the expected IBLT magic sequence.
     #[error("bad magic bytes")]
     BadMagic,
+    /// The format version byte is not supported by this reader.
     #[error("unknown version {0}")]
     UnknownVersion(u8),
 }

crates/clawsync-onion/src/manifest.rs

@@ -15,12 +15,17 @@ use crate::iblt::{DEFAULT_HASH_COUNT, IbltDecodeResult, IbltDiff, IbltSketch};
 /// A compact summary of one revision — used in the manifest.
 #[derive(Archive, Deserialize, Serialize, Debug, Clone, PartialEq)]
 pub struct RevisionSummaryPacket {
+    /// Monotonically increasing revision number (0-based).
     pub revision: u64,
+    /// ID of the branch this revision belongs to; `0` = `main`.
     pub branch_id: u32,
+    /// Revision number of the direct parent; `u64::MAX` for the initial commit.
     pub parent_rev: u64,
+    /// Unix timestamp (seconds since epoch, as `f64`) when the revision was committed.
     pub timestamp: f64,
     /// BLAKE3 hash of the pages in this revision.
     pub blake3: [u8; 32],
+    /// Optional human-readable annotation stored with the revision.
     pub annotation: Option<String>,
 }
 
@@ -119,11 +124,17 @@ impl ClawSyncManifest {
 /// For N=1 000: ~3 KB vs ~60 KB for `ClawSyncManifest`.
 #[derive(Archive, Deserialize, Serialize, Debug, Clone, PartialEq)]
 pub struct IbltManifest {
+    /// Logical agent / file identifier (same as in `ClawSyncManifest`).
     pub agent_id: String,
+    /// BLAKE3 hash of the raw `.h5` base file; zero-filled during pre-flight.
     pub file_blake3: [u8; 32],
+    /// Total number of revisions in the sender's sidecar.
     pub revision_count: u64,
+    /// HEAD revision number on the sender's default branch.
     pub head_revision: u64,
+    /// BLAKE3 hash of the HEAD revision's pages; zero-filled during pre-flight.
     pub head_blake3: [u8; 32],
+    /// Unix timestamp (seconds since epoch, as `f64`) of the last committed revision.
     pub last_write: f64,
     /// Serialised [`IbltSketch`] bytes.
     pub sketch: Vec<u8>,

crates/clawsync-transport/src/error.rs

@@ -2,32 +2,48 @@
 
 use thiserror::Error;
 
+/// All errors that can occur in the `clawsync-transport` layer.
 #[derive(Debug, Error)]
 pub enum TransportError {
+    /// An underlying I/O error (socket read/write, bind, etc.).
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    /// The remote peer closed the connection before the exchange completed.
     #[error("connection closed unexpectedly")]
     ConnectionClosed,
 
+    /// A received frame's length prefix exceeds the protocol maximum.
     #[error("frame too large: {size} bytes (max {max})")]
-    FrameTooLarge { size: usize, max: usize },
+    FrameTooLarge {
+        /// The length the remote declared in the 4-byte LE prefix.
+        size: usize,
+        /// The maximum frame size permitted by the protocol.
+        max: usize,
+    },
 
+    /// A `SyncMessage` could not be serialized to bytes.
     #[error("serialization error: {0}")]
     Serialization(String),
 
+    /// Received bytes could not be deserialized into a `SyncMessage`.
     #[error("deserialization error: {0}")]
     Deserialization(String),
 
+    /// An error from the underlying QUIC stack (e.g., `quinn`).
     #[error("QUIC error: {0}")]
     Quic(String),
 
+    /// A TLS configuration or handshake error.
     #[error("TLS error: {0}")]
     Tls(String),
 
+    /// The remote peer violated the sync protocol (unexpected message type
+    /// or message sequencing error).
     #[error("protocol error: {0}")]
     Protocol(String),
 
+    /// An error propagated from the `clawsync-onion` sync layer.
     #[error("sync onion error: {0}")]
     SyncOnion(#[from] clawsync_onion::SyncOnionError),
 }

crates/clawsync-transport/src/framed.rs

@@ -24,10 +24,12 @@ pub struct FramedReader<R: AsyncRead + Unpin + Send> {
 }
 
 impl<R: AsyncRead + Unpin + Send> FramedReader<R> {
+    /// Wrap `inner` in a framed reader.
     pub fn new(inner: R) -> Self {
         Self { inner }
     }
 
+    /// Read and deserialize the next length-prefixed `SyncMessage` frame.
     pub async fn recv(&mut self) -> Result<SyncMessage, TransportError> {
         let mut len_buf = [0u8; 4];
         self.inner.read_exact(&mut len_buf).await?;
@@ -52,10 +54,12 @@ pub struct FramedWriter<W: AsyncWrite + Unpin + Send> {
 }
 
 impl<W: AsyncWrite + Unpin + Send> FramedWriter<W> {
+    /// Wrap `inner` in a framed writer.
     pub fn new(inner: W) -> Self {
         Self { inner }
     }
 
+    /// Serialize `msg` and write it as a length-prefixed frame.
     pub async fn send(&mut self, msg: &SyncMessage) -> Result<(), TransportError> {
         let body = msg.to_bytes().map_err(TransportError::Serialization)?;
         let len = body.len() as u32;
@@ -65,6 +69,7 @@ impl<W: AsyncWrite + Unpin + Send> FramedWriter<W> {
         Ok(())
     }
 
+    /// Flush pending writes and shut down the write half.
     pub async fn shutdown(&mut self) -> Result<(), TransportError> {
         self.inner.shutdown().await?;
         Ok(())
@@ -112,14 +117,17 @@ impl StreamPeer {
         }
     }
 
+    /// Send a `SyncMessage` through the peer's write half.
     pub async fn send(&mut self, msg: &SyncMessage) -> Result<(), TransportError> {
         self.writer.send(msg).await
     }
 
+    /// Receive the next `SyncMessage` from the peer's read half.
     pub async fn recv(&mut self) -> Result<SyncMessage, TransportError> {
         self.reader.recv().await
     }
 
+    /// Flush and shut down the write half.
     pub async fn shutdown(&mut self) -> Result<(), TransportError> {
         self.writer.shutdown().await
     }
@@ -134,21 +142,26 @@ impl StreamPeer {
 // Split halves
 // ─────────────────────────────────────────────────────────────────────────────
 
+/// Read half produced by [`StreamPeer::into_split`].
 pub struct StreamReadHalf(pub(crate) FramedReader<BoxReader>);
 
 impl StreamReadHalf {
+    /// Receive the next `SyncMessage` from the boxed reader.
     pub async fn recv(&mut self) -> Result<SyncMessage, TransportError> {
         self.0.recv().await
     }
 }
 
+/// Write half produced by [`StreamPeer::into_split`].
 pub struct StreamWriteHalf(pub(crate) FramedWriter<BoxWriter>);
 
 impl StreamWriteHalf {
+    /// Send a `SyncMessage` through the boxed writer.
     pub async fn send(&mut self, msg: &SyncMessage) -> Result<(), TransportError> {
         self.0.send(msg).await
     }
 
+    /// Flush and shut down the boxed writer.
     pub async fn shutdown(&mut self) -> Result<(), TransportError> {
         self.0.shutdown().await
     }

crates/clawsync-transport/src/peer.rs

@@ -27,13 +27,17 @@ use crate::tcp::{TcpConnection, TcpReadHalf, TcpWriteHalf};
 
 /// A unified connection handle for a single sync session (TCP, QUIC, mmap, or stream).
 pub enum SyncPeer {
+    /// An established async TCP connection.
     Tcp(TcpConnection),
+    /// A QUIC connection shared via `Arc` (send + recv are `&self`).
     Quic(Arc<QuicConnection>),
     /// Local same-node transport backed by two memory-mapped ring buffers —
     /// one per direction.  `send_ch` is the outgoing channel; `recv_ch` is
     /// the incoming channel.
     Mmap {
+        /// Outgoing mmap ring-buffer sender.
         send_ch: MmapSender,
+        /// Incoming mmap ring-buffer receiver.
         recv_ch: MmapReceiver,
     },
     /// Generic boxed-I/O peer — covers SSH child-process pipes and `--stdio`
@@ -42,6 +46,11 @@ pub enum SyncPeer {
 }
 
 impl SyncPeer {
+    /// Send a `SyncMessage` to the remote peer.
+    ///
+    /// For TCP and Stream peers this performs a framed write (4-byte LE length
+    /// + body).  For QUIC, each call opens a new unidirectional stream.  For
+    /// Mmap, the call blocks until the ring buffer has space.
     pub async fn send(&mut self, msg: &SyncMessage) -> Result<(), TransportError> {
         match self {
             SyncPeer::Tcp(c) => c.send(msg).await,
@@ -51,6 +60,11 @@ impl SyncPeer {
         }
     }
 
+    /// Receive the next `SyncMessage` from the remote peer.
+    ///
+    /// Blocks until a complete message is available.  Returns
+    /// [`TransportError::ConnectionClosed`] when the peer has cleanly closed
+    /// the connection.
     pub async fn recv(&mut self) -> Result<SyncMessage, TransportError> {
         match self {
             SyncPeer::Tcp(c) => c.recv().await,
@@ -60,6 +74,7 @@ impl SyncPeer {
         }
     }
 
+    /// Gracefully shut down the connection, flushing any pending writes.
     pub async fn shutdown(self) -> Result<(), TransportError> {
         match self {
             SyncPeer::Tcp(mut c) => c.shutdown().await,
@@ -136,13 +151,18 @@ impl SyncPeer {
 
 /// Write half for the sliding-window pipeline.
 pub enum PipeWriteHalf {
+    /// Write half of a split `TcpConnection`.
     Tcp(TcpWriteHalf),
+    /// QUIC connection `Arc` clone used for sending (QUIC send is `&self`).
     Quic(Arc<QuicConnection>),
+    /// Mmap ring-buffer sender.
     Mmap(MmapSender),
+    /// Boxed-I/O write half (SSH / stdio).
     Stream(StreamWriteHalf),
 }
 
 impl PipeWriteHalf {
+    /// Send a `SyncMessage` through the write half.
     pub async fn send(&mut self, msg: &SyncMessage) -> Result<(), TransportError> {
         match self {
             PipeWriteHalf::Tcp(h) => h.send(msg).await,
@@ -152,6 +172,7 @@ impl PipeWriteHalf {
         }
     }
 
+    /// Gracefully shut down the write half.
     pub async fn shutdown(self) -> Result<(), TransportError> {
         match self {
             PipeWriteHalf::Tcp(mut h) => h.shutdown().await,
@@ -184,13 +205,18 @@ impl PipeWriteHalf {
 
 /// Read half for the sliding-window pipeline.
 pub enum PipeReadHalf {
+    /// Read half of a split `TcpConnection`.
     Tcp(TcpReadHalf),
+    /// QUIC connection `Arc` clone used for receiving.
     Quic(Arc<QuicConnection>),
+    /// Mmap ring-buffer receiver.
     Mmap(MmapReceiver),
+    /// Boxed-I/O read half (SSH / stdio).
     Stream(StreamReadHalf),
 }
 
 impl PipeReadHalf {
+    /// Receive the next `SyncMessage` from the read half.
     pub async fn recv(&mut self) -> Result<SyncMessage, TransportError> {
         match self {
             PipeReadHalf::Tcp(h) => h.recv().await,

crates/clawsync-transport/src/protocol.rs

@@ -120,27 +120,45 @@ pub const MAX_FRAME_SIZE: usize = 256 * 1024 * 1024;
 pub enum SyncMessage {
     /// Client announces itself and its current HEAD revision.
     ManifestRequest {
+        /// Logical agent / file identifier (used by the server to look up the sidecar).
         agent_id: String,
+        /// HEAD revision number the client currently holds.
         head_revision: u64,
-        /// Revision count (so the server can compute the delta).
+        /// Total revision count (so the server can compute the delta).
         revision_count: u64,
     },
 
     /// Server responds with its own manifest.
-    ManifestResponse { manifest: ClawSyncManifest },
+    ManifestResponse {
+        /// Full revision manifest of the server's sidecar.
+        manifest: ClawSyncManifest,
+    },
 
     /// One revision packet (sent by either side, depending on push/pull).
-    LayerPacket { packet: OnionLayerPacket },
+    LayerPacket {
+        /// The serialized revision data (pages, metadata, BLAKE3).
+        packet: OnionLayerPacket,
+    },
 
     /// Acknowledgement of a successfully received + verified revision.
-    Ack { revision: u64 },
+    Ack {
+        /// The revision number that was successfully applied.
+        revision: u64,
+    },
 
     /// Request to retransmit a revision (hash verification failed).
-    RetryRequest { revision: u64, reason: String },
+    RetryRequest {
+        /// The revision number that failed integrity verification.
+        revision: u64,
+        /// Human-readable reason for the retry request.
+        reason: String,
+    },
 
     /// Transfer is complete.
     SyncComplete {
+        /// Total number of revisions successfully transferred in this session.
         revisions_transferred: u64,
+        /// Total compressed bytes transferred in this session.
         bytes_transferred: u64,
     },
 
@@ -148,7 +166,10 @@ pub enum SyncMessage {
     ///
     /// If the remote supports IBLT it responds with `IbltResponse`; otherwise
     /// it responds with `Error` and the client falls back to `ManifestRequest`.
-    IbltRequest { sketch: IbltManifest },
+    IbltRequest {
+        /// The client's IBLT sketch of its local revision set.
+        sketch: IbltManifest,
+    },
 
     /// IBLT pre-flight response: server's sketch + decoded missing revisions.
     ///
@@ -156,12 +177,17 @@ pub enum SyncMessage {
     /// lacks (what to push).  The client decodes `sketch` against its own
     /// sketch to find revisions it needs to pull.
     IbltResponse {
+        /// The server's IBLT sketch (for the client to decode what it should pull).
         sketch: IbltManifest,
+        /// Revision numbers the server lacks (client should push these).
         missing_from_remote: Vec<u64>,
     },
 
     /// An error occurred; connection will be closed after this message.
-    Error { message: String },
+    Error {
+        /// Human-readable error description.
+        message: String,
+    },
 
     // ── FS CDC file delta (variants 9–12) ────────────────────────────────────
     //
@@ -179,7 +205,9 @@ pub enum SyncMessage {
     /// Originally: client announces a single-file CDC sync, carrying its ordered
     /// chunk descriptors.  Superseded by the server chunk embedding in `FsDirNeed`.
     FsCdcRequest {
+        /// Relative path of the file being synced.
         path: String,
+        /// Client's ordered CDC chunk descriptors (hash + length per chunk).
         chunk_hashes: Vec<FsChunkHash>,
     },
 
@@ -188,7 +216,9 @@ pub enum SyncMessage {
     /// Originally: server replies with the indices it needs transferred.
     /// Superseded by the server chunk embedding in `FsDirNeed`.
     FsCdcNeed {
+        /// Relative path of the file being synced.
         path: String,
+        /// Indices (into the client's chunk list) that the server needs.
         needed_indices: Vec<u32>,
     },
 
@@ -202,6 +232,7 @@ pub enum SyncMessage {
     /// sync path, while remaining self-contained for single-file use too.
     /// Wire overhead is ~12 bytes × N_chunks (negligible relative to data).
     FsCdcData {
+        /// Relative path of the file being transferred.
         path: String,
         /// Full ordered chunk layout of the client's file.
         chunk_order: Vec<FsChunkHash>,
@@ -210,7 +241,10 @@ pub enum SyncMessage {
     },
 
     /// Server confirms it has reconstructed and written the file at `path`.
-    FsFileAck { path: String },
+    FsFileAck {
+        /// Relative path of the file that was successfully written.
+        path: String,
+    },
 
     // ── FS directory tree sync (variants 13–16) ───────────────────────────────
     /// Client sends a per-file manifest for an entire directory tree.
@@ -237,16 +271,23 @@ pub enum SyncMessage {
 
     /// Server reports that all changes have been applied.
     FsDirComplete {
+        /// Number of files newly created on the server.
         files_added: u32,
+        /// Number of files overwritten on the server.
         files_modified: u32,
+        /// Number of files deleted from the server.
         files_removed: u32,
+        /// Total compressed bytes transferred in this session.
         bytes_transferred: u64,
     },
 
     /// Dry-run: reports what *would* change without applying anything.
     FsDirDryRun {
+        /// Paths that would be created on the server.
         would_add: Vec<String>,
+        /// Paths that would be overwritten on the server.
         would_modify: Vec<String>,
+        /// Paths that would be deleted from the server.
         would_remove: Vec<String>,
     },
 
@@ -284,7 +325,9 @@ pub enum SyncMessage {
     /// `dtype` is the `{:?}` format of `clawhdf5::DType` (e.g. `"F64"`).
     /// `shape` is the dataset's dimension sizes.
     Hdf5DataPayload {
+        /// HDF5 path of the dataset within the file (e.g., `/group/embeddings`).
         path: String,
+        /// Raw little-endian bytes of the dataset.
         data: Vec<u8>,
         /// HDF5 DType debug string, e.g. `"F64"`, `"F32"`, `"I32"`.
         dtype: String,
@@ -293,13 +336,20 @@ pub enum SyncMessage {
     },
 
     /// Server acknowledges successful reconstruction of a dataset.
-    Hdf5DataAck { path: String },
+    Hdf5DataAck {
+        /// HDF5 path of the dataset that was successfully applied.
+        path: String,
+    },
 
     /// Server reports that the HDF5 sync is complete.
     Hdf5SyncComplete {
+        /// Number of datasets newly added to the server's file.
         datasets_added: u32,
+        /// Number of datasets overwritten on the server.
         datasets_modified: u32,
+        /// Number of datasets removed from the server's file.
         datasets_removed: u32,
+        /// Total compressed bytes transferred in this session.
         bytes_transferred: u64,
     },
 

crates/clawsync-transport/src/quic.rs

@@ -32,7 +32,9 @@ use crate::protocol::SyncMessage;
 
 /// QUIC endpoint configuration.
 pub struct QuicConfig {
+    /// TLS server configuration for the QUIC server endpoint.
     pub server_config: ServerConfig,
+    /// TLS client configuration for outgoing QUIC connections.
     pub client_config: ClientConfig,
 }
 
@@ -453,6 +455,10 @@ impl QuicConnection {
 /// A QUIC server endpoint.
 pub struct QuicServer {
     endpoint: Endpoint,
+    /// The local `SocketAddr` this server is bound to.
+    ///
+    /// Useful when the server was bound to port `0` and the assigned ephemeral
+    /// port must be communicated to clients.
     pub local_addr: SocketAddr,
 }
 

crates/clawsync-transport/src/tcp.rs

@@ -144,6 +144,10 @@ impl TcpWriteHalf {
 /// A listening TCP server that accepts `TcpConnection`s.
 pub struct TcpServer {
     listener: TcpListener,
+    /// The local `SocketAddr` this server is bound to.
+    ///
+    /// Useful for callers that bind to port `0` and need to discover the
+    /// assigned ephemeral port after binding.
     pub local_addr: SocketAddr,
 }