diff --git a/src/conn.rs b/src/conn.rs
index 140c890f..c4510b52 100644
--- a/src/conn.rs
+++ b/src/conn.rs
@@ -185,7 +185,7 @@ pub trait Pullable {
 }
 
 pub trait Syncable {
-    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> ::std::result::Result<(), ::failure::Error>;
+    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> Result<()>;
 }
 
 /// Represents an in-progress, not yet committed, set of changes to the store.
diff --git a/src/errors.rs b/src/errors.rs
index 337aad52..dfb84d0b 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -29,6 +29,7 @@ use mentat_query_algebrizer;
 use mentat_query_projector;
 use mentat_query_pull;
 use mentat_sql;
+use mentat_tolstoy;
 
 pub type Result<T> = std::result::Result<T, MentatError>;
 
@@ -105,6 +106,9 @@ pub enum MentatError {
 
     #[fail(display = "{}", _0)]
     SQLError(#[cause] mentat_sql::SQLError),
+
+    #[fail(display = "{}", _0)]
+    TolstoyError(#[cause] mentat_tolstoy::TolstoyError),
 }
 
 impl From<std::io::Error> for MentatError {
@@ -154,3 +158,9 @@ impl From<mentat_sql::SQLError> for MentatError {
         MentatError::SQLError(error)
     }
 }
+
+impl From<mentat_tolstoy::TolstoyError> for MentatError {
+    fn from(error: mentat_tolstoy::TolstoyError) -> MentatError {
+        MentatError::TolstoyError(error)
+    }
+}
diff --git a/src/store.rs b/src/store.rs
index 52a37d5c..b11deddf 100644
--- a/src/store.rs
+++ b/src/store.rs
@@ -234,7 +234,7 @@ impl Pullable for Store {
 }
 
 impl Syncable for Store {
-    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> ::std::result::Result<(), ::failure::Error> {
+    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> Result<()> {
         let uuid = Uuid::parse_str(&user_uuid).map_err(|_| MentatError::BadUuid(user_uuid.clone()))?;
         Ok(Syncer::flow(&mut self.sqlite, server_uri, &uuid)?)
     }
diff --git a/tolstoy/src/errors.rs b/tolstoy/src/errors.rs
index 3b0a2e3c..7c633632 100644
--- a/tolstoy/src/errors.rs
+++ b/tolstoy/src/errors.rs
@@ -8,9 +8,13 @@
 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
 // specific language governing permissions and limitations under the License.
 
-#![allow(dead_code)]
+use std;
+use rusqlite;
+use uuid;
+use hyper;
+use serde_json;
 
-use failure::Error;
+use mentat_db;
 
 #[macro_export]
 macro_rules! bail {
@@ -19,7 +23,7 @@ macro_rules! bail {
     )
 }
 
-pub type Result<T> = ::std::result::Result<T, Error>;
+pub type Result<T> = ::std::result::Result<T, TolstoyError>;
 
 #[derive(Debug, Fail)]
 pub enum TolstoyError {
@@ -40,4 +44,69 @@ pub enum TolstoyError {
 
     #[fail(display = "not yet implemented: {}", _0)]
     NotYetImplemented(String),
+
+    #[fail(display = "{}", _0)]
+    DbError(#[cause] mentat_db::DbError),
+
+    #[fail(display = "{}", _0)]
+    SerializationError(#[cause] serde_json::Error),
+
+    // It would be better to capture the underlying `rusqlite::Error`, but that type doesn't
+    // implement many useful traits, including `Clone`, `Eq`, and `PartialEq`.
+    #[fail(display = "SQL error: _0")]
+    RusqliteError(String),
+
+    #[fail(display = "{}", _0)]
+    IoError(#[cause] std::io::Error),
+
+    #[fail(display = "{}", _0)]
+    UuidError(#[cause] uuid::ParseError),
+
+    #[fail(display = "{}", _0)]
+    NetworkError(#[cause] hyper::Error),
+
+    #[fail(display = "{}", _0)]
+    UriError(#[cause] hyper::error::UriError),
+}
+
+impl From<mentat_db::DbError> for TolstoyError {
+    fn from(error: mentat_db::DbError) -> TolstoyError {
+        TolstoyError::DbError(error)
+    }
+}
+
+impl From<serde_json::Error> for TolstoyError {
+    fn from(error: serde_json::Error) -> TolstoyError {
+        TolstoyError::SerializationError(error)
+    }
+}
+
+impl From<rusqlite::Error> for TolstoyError {
+    fn from(error: rusqlite::Error) -> TolstoyError {
+        TolstoyError::RusqliteError(error.to_string())
+    }
+}
+
+impl From<std::io::Error> for TolstoyError {
+    fn from(error: std::io::Error) -> TolstoyError {
+        TolstoyError::IoError(error)
+    }
+}
+
+impl From<uuid::ParseError> for TolstoyError {
+    fn from(error: uuid::ParseError) -> TolstoyError {
+        TolstoyError::UuidError(error)
+    }
+}
+
+impl From<hyper::Error> for TolstoyError {
+    fn from(error: hyper::Error) -> TolstoyError {
+        TolstoyError::NetworkError(error)
+    }
+}
+
+impl From<hyper::error::UriError> for TolstoyError {
+    fn from(error: hyper::error::UriError) -> TolstoyError {
+        TolstoyError::UriError(error)
+    }
 }