src/cli/add_command.rs

@@ -72,6 +72,13 @@ impl LprsCommand for Add {
                 )));
             }
         }
+        if self
+            .custom_fields
+            .iter()
+            .any(|(k, _)| k.starts_with(crate::RESERVED_FIELD_PREFIX))
+        {
+            return Err(LprsError::ReservedPrefix(crate::RESERVED_FIELD_PREFIX));
+        }
 
         Ok(())
     }

src/cli/edit_command.rs

@@ -109,6 +109,13 @@ impl LprsCommand for Edit {
                 )));
             }
         }
+        if self
+            .custom_fields
+            .iter()
+            .any(|(k, _)| k.starts_with(crate::RESERVED_FIELD_PREFIX))
+        {
+            return Err(LprsError::ReservedPrefix(crate::RESERVED_FIELD_PREFIX));
+        }
 
         Ok(())
     }

src/cli/import_command.rs

@@ -71,6 +71,14 @@ impl LprsCommand for Import {
                         .unwrap_or(&vault_manager.master_password),
                     &fs::read(self.path)?,
                 )?;
+
+                if vaults.iter().any(|v| {
+                    v.custom_fields
+                        .iter()
+                        .any(|(k, _)| k.starts_with(crate::RESERVED_FIELD_PREFIX))
+                }) {
+                    return Err(LprsError::ReservedPrefix(crate::RESERVED_FIELD_PREFIX));
+                }
                 let vaults_len = vaults.len();
 
                 vault_manager.vaults.extend(vaults);

src/errors.rs

@@ -39,6 +39,11 @@ pub enum Error {
     InvalidVaultIndex(String),
     #[error("{0}")]
     ArgParse(String),
+    #[error(
+        "Reserved Prefix Error: Sorry, but the following prefix is reserved and cannot be used in \
+         custom fields {0}"
+    )]
+    ReservedPrefix(&'static str),
     #[error("{0}")]
     Other(String),
 

src/main.rs

@@ -48,6 +48,8 @@ pub const VERSION: &str = env!("CARGO_PKG_VERSION");
 #[cfg(feature = "update-notify")]
 /// The last version check file. Used to store the last version check time.
 pub const LAST_VERSION_CHECK_FILE: &str = ".last_version_check";
+/// The prefix of the reserved custom fields
+const RESERVED_FIELD_PREFIX: &str = ".lprsfield.";
 
 fn main() -> ExitCode {
     let lprs_cli = cli::Cli::parse();

src/vault/mod.rs

@@ -267,7 +267,12 @@ impl fmt::Display for Vault {
             write!(f, "\nNote:\n{note}")?;
         }
         for (key, value) in &self.custom_fields {
-            write!(f, "\n{key}: {value}")?;
+            write!(
+                f,
+                "\n{}: {value}",
+                key.strip_prefix(crate::RESERVED_FIELD_PREFIX)
+                    .unwrap_or(key)
+            )?;
         }
 
         Ok(())