diff --git a/src/config/bookmarks/aws_s3.rs b/src/config/bookmarks/aws_s3.rs
index 9522b99..649514f 100644
--- a/src/config/bookmarks/aws_s3.rs
+++ b/src/config/bookmarks/aws_s3.rs
@@ -1,3 +1,7 @@
+//! ## Bookmark S3 Parameters
+//!
+//! Stores the bookmark-specific representation of AWS S3 connection settings.
+
 use serde::{Deserialize, Serialize};
 
 use crate::filetransfer::params::AwsS3Params;
@@ -5,13 +9,20 @@ use crate::filetransfer::params::AwsS3Params;
 /// Connection parameters for Aws s3 protocol
 #[derive(Clone, Deserialize, Serialize, Debug, PartialEq, Eq, Default)]
 pub struct S3Params {
+    /// Bucket name to open.
     pub bucket: String,
+    /// AWS region used for the bucket.
     pub region: Option<String>,
+    /// Custom endpoint URL for S3-compatible services.
     pub endpoint: Option<String>,
+    /// Shared credentials profile name.
     pub profile: Option<String>,
+    /// Static access key identifier.
     pub access_key: Option<String>,
+    /// Static secret access key.
     pub secret_access_key: Option<String>,
     /// NOTE: there are no session token and security token since they are always temporary
+    /// Whether to force path-style bucket addressing.
     pub new_path_style: Option<bool>,
 }
 
diff --git a/src/config/bookmarks/kube.rs b/src/config/bookmarks/kube.rs
index 25c9647..53e9421 100644
--- a/src/config/bookmarks/kube.rs
+++ b/src/config/bookmarks/kube.rs
@@ -1,3 +1,7 @@
+//! ## Bookmark Kube Parameters
+//!
+//! Stores bookmark-specific Kubernetes connection settings.
+
 use serde::{Deserialize, Serialize};
 
 use crate::filetransfer::params::KubeProtocolParams;
@@ -5,10 +9,15 @@ use crate::filetransfer::params::KubeProtocolParams;
 /// Extra Connection parameters for Kube protocol
 #[derive(Clone, Deserialize, Serialize, Debug, PartialEq, Eq, Default)]
 pub struct KubeParams {
+    /// Optional default namespace.
     pub namespace: Option<String>,
+    /// Optional cluster API URL.
     pub cluster_url: Option<String>,
+    /// Optional Kubernetes username override.
     pub username: Option<String>,
+    /// Optional client certificate path.
     pub client_cert: Option<String>,
+    /// Optional client key path.
     pub client_key: Option<String>,
 }
 
diff --git a/src/config/bookmarks/smb.rs b/src/config/bookmarks/smb.rs
index 31b8366..2c79fa6 100644
--- a/src/config/bookmarks/smb.rs
+++ b/src/config/bookmarks/smb.rs
@@ -1,3 +1,7 @@
+//! ## Bookmark SMB Parameters
+//!
+//! Stores bookmark-specific SMB share configuration.
+
 use serde::{Deserialize, Serialize};
 
 use crate::filetransfer::params::SmbParams as TransferSmbParams;
@@ -5,7 +9,9 @@ use crate::filetransfer::params::SmbParams as TransferSmbParams;
 /// Extra Connection parameters for SMB protocol
 #[derive(Clone, Deserialize, Serialize, Debug, PartialEq, Eq, Default)]
 pub struct SmbParams {
+    /// SMB share name.
     pub share: String,
+    /// Optional SMB workgroup used on POSIX platforms.
     pub workgroup: Option<String>,
 }
 
diff --git a/src/filetransfer/host_bridge_builder.rs b/src/filetransfer/host_bridge_builder.rs
index 5ce30de..0b8ec1b 100644
--- a/src/filetransfer/host_bridge_builder.rs
+++ b/src/filetransfer/host_bridge_builder.rs
@@ -1,13 +1,19 @@
+//! ## Host Bridge Builder
+//!
+//! Builds host bridge implementations from persisted host bridge parameters and
+//! the active configuration client.
+
 use super::{HostBridgeParams, RemoteFsBuilder};
 use crate::host::{HostBridge, Localhost, RemoteBridged};
 use crate::system::config_client::ConfigClient;
 
+/// Builds the host-side filesystem bridge used during file transfer sessions.
 pub struct HostBridgeBuilder;
 
 impl HostBridgeBuilder {
-    /// Build Host Bridge from parms
+    /// Builds a host bridge from serialized parameters.
     ///
-    /// if protocol and parameters are inconsistent, the function will return an error.
+    /// Returns an error when the selected host protocol and parameters are inconsistent.
     pub fn build(
         params: HostBridgeParams,
         config_client: &ConfigClient,
diff --git a/src/host/remote_bridged/temp_mapped_file.rs b/src/host/remote_bridged/temp_mapped_file.rs
index 4783cef..142942e 100644
--- a/src/host/remote_bridged/temp_mapped_file.rs
+++ b/src/host/remote_bridged/temp_mapped_file.rs
@@ -1,3 +1,8 @@
+//! ## Temp Mapped File
+//!
+//! Provides a temporary local file that mirrors a remote file while keeping a
+//! lazily opened read/write handle.
+
 use std::fs::File;
 use std::io::{self, Read, Write};
 use std::sync::{Arc, Mutex};
@@ -34,6 +39,7 @@ impl Read for TempMappedFile {
 }
 
 impl TempMappedFile {
+    /// Creates an empty temporary file container for a downloaded remote file.
     pub fn new() -> HostResult<Self> {
         NamedTempFile::new()
             .map(|tempfile| TempMappedFile {
diff --git a/src/system/auto_update.rs b/src/system/auto_update.rs
index d01ad3e..4a3dda3 100644
--- a/src/system/auto_update.rs
+++ b/src/system/auto_update.rs
@@ -23,7 +23,9 @@ pub enum UpdateStatus {
 /// Info related to a github release
 #[derive(Debug)]
 pub struct Release {
+    /// Release version string returned by GitHub.
     pub version: String,
+    /// Release notes body returned by GitHub.
     pub body: String,
 }
 
@@ -48,6 +50,7 @@ impl Update {
         self
     }
 
+    /// Installs the latest available release using the configured update options.
     pub fn upgrade(self) -> Result<UpdateStatus, UpdateError> {
         info!("Updating termscp...");
         GithubUpdater::configure()