diff --git a/crates/milli/src/update/new/vector_document.rs b/crates/milli/src/update/new/vector_document.rs
index dc73c5268..4a27361a9 100644
--- a/crates/milli/src/update/new/vector_document.rs
+++ b/crates/milli/src/update/new/vector_document.rs
@@ -167,7 +167,7 @@ fn entry_from_raw_value(
     value: &RawValue,
     has_configured_embedder: bool,
 ) -> std::result::Result<VectorEntry<'_>, serde_json::Error> {
-    let value: RawVectors = serde_json::from_str(value.get())?;
+    let value: RawVectors = RawVectors::from_raw_value(value)?;
 
     Ok(match value {
         RawVectors::Explicit(raw_explicit_vectors) => VectorEntry {
@@ -177,7 +177,7 @@ fn entry_from_raw_value(
         },
         RawVectors::ImplicitlyUserProvided(value) => VectorEntry {
             has_configured_embedder,
-            embeddings: Some(Embeddings::FromJsonImplicityUserProvided(value)),
+            embeddings: value.map(Embeddings::FromJsonImplicityUserProvided),
             regenerate: false,
         },
     })
diff --git a/crates/milli/src/vector/parsed_vectors.rs b/crates/milli/src/vector/parsed_vectors.rs
index 40e823f17..6ae6c1c9e 100644
--- a/crates/milli/src/vector/parsed_vectors.rs
+++ b/crates/milli/src/vector/parsed_vectors.rs
@@ -12,11 +12,96 @@ use crate::{DocumentId, FieldId, InternalError, UserError};
 
 pub const RESERVED_VECTORS_FIELD_NAME: &str = "_vectors";
 
-#[derive(serde::Serialize, serde::Deserialize, Debug)]
+#[derive(serde::Serialize, Debug)]
 #[serde(untagged)]
 pub enum RawVectors<'doc> {
     Explicit(#[serde(borrow)] RawExplicitVectors<'doc>),
-    ImplicitlyUserProvided(#[serde(borrow)] &'doc RawValue),
+    ImplicitlyUserProvided(#[serde(borrow)] Option<&'doc RawValue>),
+}
+
+impl<'doc> RawVectors<'doc> {
+    pub fn from_raw_value(raw: &'doc RawValue) -> Result<Self, serde_json::Error> {
+        use serde::de::Deserializer as _;
+        Ok(match raw.deserialize_any(RawVectorsVisitor)? {
+            RawVectorsVisitorValue::ImplicitNone => RawVectors::ImplicitlyUserProvided(None),
+            RawVectorsVisitorValue::Implicit => RawVectors::ImplicitlyUserProvided(Some(raw)),
+            RawVectorsVisitorValue::Explicit { regenerate, embeddings } => {
+                RawVectors::Explicit(RawExplicitVectors { embeddings, regenerate })
+            }
+        })
+    }
+}
+
+struct RawVectorsVisitor;
+
+enum RawVectorsVisitorValue<'doc> {
+    ImplicitNone,
+    Implicit,
+    Explicit { regenerate: bool, embeddings: Option<&'doc RawValue> },
+}
+
+impl<'doc> serde::de::Visitor<'doc> for RawVectorsVisitor {
+    type Value = RawVectorsVisitorValue<'doc>;
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(formatter, "a map containing at least `regenerate`, or an array of floats`")
+    }
+
+    fn visit_none<E>(self) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        Ok(RawVectorsVisitorValue::ImplicitNone)
+    }
+
+    fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: serde::Deserializer<'doc>,
+    {
+        deserializer.deserialize_any(self)
+    }
+
+    fn visit_unit<E>(self) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        Ok(RawVectorsVisitorValue::ImplicitNone)
+    }
+
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+    where
+        A: serde::de::SeqAccess<'doc>,
+    {
+        // must consume all elements or parsing fails
+        while let Some(_) = seq.next_element::<&RawValue>()? {}
+        Ok(RawVectorsVisitorValue::Implicit)
+    }
+
+    fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
+    where
+        A: serde::de::MapAccess<'doc>,
+    {
+        use serde::de::Error as _;
+        let mut regenerate = None;
+        let mut embeddings = None;
+        while let Some(s) = map.next_key()? {
+            match s {
+                "regenerate" => {
+                    let value: bool = map.next_value()?;
+                    regenerate = Some(value);
+                }
+                "embeddings" => {
+                    let value: &RawValue = map.next_value()?;
+                    embeddings = Some(value);
+                }
+                other => return Err(A::Error::unknown_field(other, &["regenerate", "embeddings"])),
+            }
+        }
+        let Some(regenerate) = regenerate else {
+            return Err(A::Error::missing_field("regenerate"));
+        };
+        Ok(RawVectorsVisitorValue::Explicit { regenerate, embeddings })
+    }
 }
 
 #[derive(serde::Serialize, Debug)]
@@ -86,7 +171,7 @@ impl<'doc> RawVectors<'doc> {
     }
     pub fn embeddings(&self) -> Option<&'doc RawValue> {
         match self {
-            RawVectors::ImplicitlyUserProvided(embeddings) => Some(embeddings),
+            RawVectors::ImplicitlyUserProvided(embeddings) => *embeddings,
             RawVectors::Explicit(RawExplicitVectors { embeddings, regenerate: _ }) => *embeddings,
         }
     }