diff --git a/aicirt/src/bintokens.rs b/aicirt/src/bintokens.rs
index 53661409..677e00f0 100644
--- a/aicirt/src/bintokens.rs
+++ b/aicirt/src/bintokens.rs
@@ -3,7 +3,7 @@ use aici_abi::bytes::TokRxInfo;
 use anyhow::{anyhow, bail, Result};
 use serde::{Deserialize, Serialize};
 use std::collections::BTreeMap;
-use tokenizers::{FromPretrainedParameters, Tokenizer};
+use tokenizers::{normalizers::Sequence, FromPretrainedParameters, NormalizerWrapper, Tokenizer};
 
 #[derive(Serialize, Deserialize)]
 pub struct ByteTokenizer {
@@ -190,11 +190,28 @@ fn from_hex(hex_str: &str) -> Result<Vec<u8>> {
 }
 
 impl ByteTokenizer {
-    pub fn from_tokenizer(hft: Tokenizer) -> Result<ByteTokenizer> {
+    pub fn from_tokenizer(mut hft: Tokenizer) -> Result<ByteTokenizer> {
         let mut is_byte_level = false;
         let mut is_byte_fallback = false;
         let mut space_ch = ' ';
 
+        // remove the "Prepend space"
+        if let Some(n) = hft.get_normalizer() {
+            let n = match n {
+                NormalizerWrapper::Sequence(x) => NormalizerWrapper::Sequence(Sequence::new(
+                    x.get_normalizers()
+                        .iter()
+                        .filter_map(|n| match n {
+                            NormalizerWrapper::Prepend(_) => None,
+                            _ => Some(n.clone()),
+                        })
+                        .collect(),
+                )),
+                _ => n.clone(),
+            };
+            hft.with_normalizer(n);
+        }
+
         if let Some(d) = hft.get_decoder() {
             let v = serde_json::to_value(d).unwrap();
             if v["type"].as_str() == Some("ByteLevel") {