diff --git a/Cargo.lock b/Cargo.lock
index 2014b38d..b51cf14d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -14917,6 +14917,7 @@ dependencies = [
  "sp-core 34.0.0 (git+https://github.com/paritytech/polkadot-sdk?tag=polkadot-stable2409-2)",
  "sp-runtime 39.0.1",
  "sp-std 14.0.0 (git+https://github.com/paritytech/polkadot-sdk?tag=polkadot-stable2409-2)",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
diff --git a/cli/polka-storage-provider/server/src/db.rs b/cli/polka-storage-provider/server/src/db.rs
index 59034877..f0d8d188 100644
--- a/cli/polka-storage-provider/server/src/db.rs
+++ b/cli/polka-storage-provider/server/src/db.rs
@@ -3,7 +3,7 @@ use std::{
     sync::atomic::{AtomicU32, Ordering},
 };
 
-use primitives_proofs::SectorNumber;
+use primitives_proofs::{SectorNumber, SectorNumberError};
 use rocksdb::{ColumnFamily, ColumnFamilyDescriptor, Options as DBOptions, DB as RocksDB};
 use serde::{de::DeserializeOwned, Serialize};
 use storagext::types::market::{ConversionError, DealProposal};
@@ -184,7 +184,7 @@ impl DealDB {
 
     /// Atomically increments sector_id counter, so it can be used as an identifier by a sector.
     /// Prior to all of the calls to this function, `initialize_biggest_sector_id` must be called at the node start-up.
-    pub fn next_sector_number(&self) -> Result<SectorNumber, &'static str> {
+    pub fn next_sector_number(&self) -> Result<SectorNumber, SectorNumberError> {
         // [`Ordering::Relaxed`] can be used here, as it's an update on a single variable.
         // It does not depend on other Atomic variables and it does not matter which thread makes it first.
         // We just need it to be different on every thread that calls it concurrently, so the ids are not duplicated.
diff --git a/primitives/commitment/src/piece.rs b/primitives/commitment/src/piece.rs
index 7ef3b959..f4c9b4a9 100644
--- a/primitives/commitment/src/piece.rs
+++ b/primitives/commitment/src/piece.rs
@@ -35,6 +35,14 @@ impl From<PieceInfo> for filecoin_proofs::PieceInfo {
     }
 }
 
+#[derive(PartialEq, Debug, Eq, Clone, Copy, thiserror::Error)]
+pub enum UnpaddedPieceError {
+    #[error("minimum piece size is 127 bytes")]
+    TooSmall,
+    #[error("unpadded piece size must be a power of 2 multiple of 127")]
+    WrongSize,
+}
+
 /// Size of a piece in bytes. Unpadded piece size should be power of two
 /// multiple of 127.
 #[cfg_attr(feature = "serde", derive(::serde::Deserialize, ::serde::Serialize))]
@@ -47,14 +55,14 @@ impl UnpaddedPieceSize {
 
     /// Initialize new unpadded piece size. Error is returned if the size is
     /// invalid.
-    pub fn new(size: u64) -> Result<Self, &'static str> {
+    pub fn new(size: u64) -> Result<Self, UnpaddedPieceError> {
         if size < 127 {
-            return Err("minimum piece size is 127 bytes");
+            return Err(UnpaddedPieceError::TooSmall);
         }
 
         // is 127 * 2^n
         if size >> size.trailing_zeros() != 127 {
-            return Err("unpadded piece size must be a power of 2 multiple of 127");
+            return Err(UnpaddedPieceError::WrongSize);
         }
 
         Ok(Self(size))
@@ -236,7 +244,7 @@ mod tests {
         );
         assert_eq!(
             UnpaddedPieceSize::new(126),
-            Err("minimum piece size is 127 bytes")
+            Err(UnpaddedPieceError::TooSmall)
         );
         assert_eq!(
             PaddedPieceSize::new(0b10000001),
@@ -244,7 +252,7 @@ mod tests {
         );
         assert_eq!(
             UnpaddedPieceSize::new(0b1110111000),
-            Err("unpadded piece size must be a power of 2 multiple of 127")
+            Err(UnpaddedPieceError::WrongSize)
         );
         assert!(UnpaddedPieceSize::new(0b1111111000).is_ok());
     }
diff --git a/primitives/proofs/Cargo.toml b/primitives/proofs/Cargo.toml
index 3916659c..9a29c296 100644
--- a/primitives/proofs/Cargo.toml
+++ b/primitives/proofs/Cargo.toml
@@ -18,6 +18,7 @@ sp-api = { workspace = true, default-features = false }
 sp-core = { workspace = true, default-features = false }
 sp-runtime = { workspace = true, default-features = false }
 sp-std = { workspace = true, default-features = false }
+thiserror = { workspace = true, default-features = false }
 
 clap = { workspace = true, features = ["derive"], optional = true }
 serde = { workspace = true, features = ["derive"], optional = true }
diff --git a/primitives/proofs/src/types.rs b/primitives/proofs/src/types.rs
index 8099825f..b5cfa10c 100644
--- a/primitives/proofs/src/types.rs
+++ b/primitives/proofs/src/types.rs
@@ -37,9 +37,9 @@ impl SectorNumber {
     ///
     /// Returns a `Result` containing the new `SectorNumber` if valid,
     /// or an error message if the sector number exceeds `MAX_SECTORS`.
-    pub fn new(sector_number: u32) -> Result<Self, &'static str> {
+    pub fn new(sector_number: u32) -> Result<Self, SectorNumberError> {
         if sector_number > MAX_SECTORS {
-            return Err("Sector number is too large");
+            return Err(SectorNumberError::NumberTooLarge);
         }
 
         Ok(Self(sector_number))
@@ -69,6 +69,25 @@ impl Decode for SectorNumber {
     }
 }
 
+#[derive(
+    Clone,
+    Copy,
+    PartialEq,
+    Ord,
+    PartialOrd,
+    Eq,
+    Encode,
+    EncodeAsType,
+    TypeInfo,
+    RuntimeDebug,
+    MaxEncodedLen,
+    thiserror::Error,
+)]
+pub enum SectorNumberError {
+    #[error("Sector number is too large")]
+    NumberTooLarge,
+}
+
 // Implement the `Visitor` trait to define how to go from SCALE
 // values into this type.
 pub struct SectorNumberVisitor<R>(PhantomData<R>);
@@ -130,7 +149,7 @@ impl From<u16> for SectorNumber {
 }
 
 impl TryFrom<u32> for SectorNumber {
-    type Error = &'static str;
+    type Error = SectorNumberError;
 
     fn try_from(value: u32) -> Result<Self, Self::Error> {
         Self::new(value)