diff --git a/cozo-core/src/data/value.rs b/cozo-core/src/data/value.rs
index a883199e..cb531454 100644
--- a/cozo-core/src/data/value.rs
+++ b/cozo-core/src/data/value.rs
@@ -17,8 +17,9 @@ use serde::{Deserialize, Deserializer, Serialize};
 use smartstring::{LazyCompact, SmartString};
 use uuid::Uuid;
 
+/// UUID value in the database
 #[derive(Clone, Hash, Eq, PartialEq, serde_derive::Deserialize, serde_derive::Serialize)]
-pub struct UuidWrapper(pub(crate) Uuid);
+pub struct UuidWrapper(pub Uuid);
 
 impl PartialOrd<Self> for UuidWrapper {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
@@ -37,8 +38,9 @@ impl Ord for UuidWrapper {
     }
 }
 
+/// A Regex in the database. Used internally in functions.
 #[derive(Clone)]
-pub struct RegexWrapper(pub(crate) Regex);
+pub struct RegexWrapper(pub Regex);
 
 impl Hash for RegexWrapper {
     fn hash<H: Hasher>(&self, state: &mut H) {
@@ -84,6 +86,7 @@ impl PartialOrd for RegexWrapper {
     }
 }
 
+/// Timestamp part of validity
 #[derive(
     Copy,
     Clone,
@@ -98,6 +101,7 @@ impl PartialOrd for RegexWrapper {
 )]
 pub struct ValidityTs(pub Reverse<i64>);
 
+/// Validity for time travel
 #[derive(
     Copy,
     Clone,
@@ -110,25 +114,39 @@ pub struct ValidityTs(pub Reverse<i64>);
     Hash,
 )]
 pub struct Validity {
-    pub(crate) timestamp: ValidityTs,
-    pub(crate) is_assert: Reverse<bool>,
+    /// Timestamp, sorted descendingly
+    pub timestamp: ValidityTs,
+    /// Whether this validity is an assertion, sorted descendingly
+    pub is_assert: Reverse<bool>,
 }
 
+/// A Value in the database
 #[derive(
     Clone, PartialEq, Eq, PartialOrd, Ord, serde_derive::Deserialize, serde_derive::Serialize, Hash,
 )]
 pub enum DataValue {
+    /// null
     Null,
+    /// boolean
     Bool(bool),
+    /// number, may be int or float
     Num(Num),
+    /// string
     Str(SmartString<LazyCompact>),
+    /// bytes
     #[serde(with = "serde_bytes")]
     Bytes(Vec<u8>),
+    /// UUID
     Uuid(UuidWrapper),
+    /// Regex, used internally only
     Regex(RegexWrapper),
+    /// list
     List(Vec<DataValue>),
+    /// set, used internally only
     Set(BTreeSet<DataValue>),
+    /// validity
     Validity(Validity),
+    /// bottom type, used internally only
     Bot,
 }
 
@@ -162,9 +180,12 @@ impl From<bool> for DataValue {
     }
 }
 
+/// Representing a number
 #[derive(Copy, Clone, serde_derive::Deserialize, serde_derive::Serialize)]
 pub enum Num {
+    /// intger number
     Int(i64),
+    /// float number
     Float(f64),
 }
 
@@ -340,6 +361,7 @@ impl DataValue {
             _ => None,
         }
     }
+    /// Returns bool if this one is.
     pub fn get_bool(&self) -> Option<bool> {
         match self {
             DataValue::Bool(b) => Some(*b),
diff --git a/cozo-core/src/lib.rs b/cozo-core/src/lib.rs
index 0e6da4e4..4e5cde12 100644
--- a/cozo-core/src/lib.rs
+++ b/cozo-core/src/lib.rs
@@ -45,6 +45,7 @@ use miette::{
 };
 use serde_json::json;
 
+pub use data::value::{DataValue, Num, RegexWrapper, UuidWrapper, Validity, ValidityTs};
 pub use fixed_rule::FixedRule;
 pub use runtime::db::Db;
 pub use runtime::db::NamedRows;
@@ -153,7 +154,7 @@ impl DbInstance {
     pub fn run_script(
         &self,
         payload: &str,
-        params: BTreeMap<String, JsonValue>,
+        params: BTreeMap<String, DataValue>,
     ) -> Result<NamedRows> {
         match self {
             DbInstance::Mem(db) => db.run_script(payload, params),
@@ -172,7 +173,7 @@ impl DbInstance {
     pub fn run_script_fold_err(
         &self,
         payload: &str,
-        params: BTreeMap<String, JsonValue>,
+        params: BTreeMap<String, DataValue>,
     ) -> JsonValue {
         #[cfg(not(target_arch = "wasm32"))]
         let start = Instant::now();
@@ -198,7 +199,10 @@ impl DbInstance {
             BTreeMap::default()
         } else {
             match serde_json::from_str::<BTreeMap<String, JsonValue>>(params) {
-                Ok(map) => map,
+                Ok(map) => map
+                    .into_iter()
+                    .map(|(k, v)| (k, DataValue::from(v)))
+                    .collect(),
                 Err(_) => {
                     return json!({"ok": false, "message": "params argument is not a JSON map"})
                         .to_string()
diff --git a/cozo-core/src/runtime/db.rs b/cozo-core/src/runtime/db.rs
index 8423d0cc..30a58637 100644
--- a/cozo-core/src/runtime/db.rs
+++ b/cozo-core/src/runtime/db.rs
@@ -163,13 +163,9 @@ impl<'s, S: Storage<'s>> Db<S> {
     pub fn run_script(
         &'s self,
         payload: &str,
-        params: BTreeMap<String, JsonValue>,
+        params: BTreeMap<String, DataValue>,
     ) -> Result<NamedRows> {
         let cur_vld = current_validity();
-        let params = params
-            .into_iter()
-            .map(|(k, v)| (k, DataValue::from(v)))
-            .collect();
         self.do_run_script(payload, &params, cur_vld)
     }
     /// Export relations to JSON data.
diff --git a/cozo-lib-python/src/lib.rs b/cozo-lib-python/src/lib.rs
index f263dbdc..685fe715 100644
--- a/cozo-lib-python/src/lib.rs
+++ b/cozo-lib-python/src/lib.rs
@@ -8,9 +8,95 @@
 
 use pyo3::exceptions::PyException;
 use pyo3::prelude::*;
+use pyo3::types::{PyDict, PyList};
+use std::collections::BTreeMap;
 
 use cozo::*;
 
+fn py_to_value(ob: &PyAny) -> PyResult<DataValue> {
+    Ok(if ob.is_none() {
+        DataValue::Null
+    } else if let Ok(i) = ob.extract::<i64>() {
+        DataValue::from(i)
+    } else if let Ok(f) = ob.extract::<f64>() {
+        DataValue::from(f)
+    } else if let Ok(s) = ob.extract::<String>() {
+        DataValue::from(s)
+    } else if let Ok(b) = ob.extract::<Vec<u8>>() {
+        DataValue::Bytes(b)
+    } else if let Ok(l) = ob.downcast::<PyList>() {
+        let mut coll = Vec::with_capacity(l.len());
+        for el in l {
+            let el = py_to_value(el)?;
+            coll.push(el)
+        }
+        DataValue::List(coll)
+    } else if let Ok(d) = ob.downcast::<PyDict>() {
+        let mut coll = Vec::with_capacity(d.len());
+        for (k, v) in d {
+            let k = py_to_value(k)?;
+            let v = py_to_value(v)?;
+            coll.push(DataValue::List(vec![k, v]))
+        }
+        DataValue::List(coll)
+    } else {
+        return Err(PyException::new_err(format!("Cannot convert {} into Cozo value", ob)).into());
+    })
+}
+
+fn convert_params(ob: &PyDict) -> PyResult<BTreeMap<String, DataValue>> {
+    let mut ret = BTreeMap::new();
+    for (k, v) in ob {
+        let k: String = k.extract()?;
+        let v = py_to_value(v)?;
+        ret.insert(k, v);
+    }
+    Ok(ret)
+}
+
+fn value_to_py(val: DataValue, py: Python<'_>) -> PyObject {
+    match val {
+        DataValue::Null => py.None(),
+        DataValue::Bool(b) => b.into_py(py),
+        DataValue::Num(num) => match num {
+            Num::Int(i) => i.into_py(py),
+            Num::Float(f) => f.into_py(py),
+        },
+        DataValue::Str(s) => s.as_str().into_py(py),
+        DataValue::Bytes(b) => b.into_py(py),
+        DataValue::Uuid(uuid) => uuid.0.to_string().into_py(py),
+        DataValue::Regex(rx) => rx.0.as_str().into_py(py),
+        DataValue::List(l) => {
+            let vs: Vec<_> = l.into_iter().map(|v| value_to_py(v, py)).collect();
+            vs.into_py(py)
+        }
+        DataValue::Set(l) => {
+            let vs: Vec<_> = l.into_iter().map(|v| value_to_py(v, py)).collect();
+            vs.into_py(py)
+        }
+        DataValue::Validity(vld) => {
+            [vld.timestamp.0 .0.into_py(py), vld.is_assert.0.into_py(py)].into_py(py)
+        }
+        DataValue::Bot => py.None(),
+    }
+}
+
+fn named_rows_to_py(named_rows: NamedRows, py: Python<'_>) -> PyObject {
+    let rows = named_rows
+        .rows
+        .into_iter()
+        .map(|row| {
+            row.into_iter()
+                .map(|val| value_to_py(val, py))
+                .collect::<Vec<_>>()
+                .into_py(py)
+        })
+        .collect::<Vec<_>>()
+        .into_py(py);
+    let headers = named_rows.headers.into_py(py);
+    BTreeMap::from([("rows", rows), ("headers", headers)]).into_py(py)
+}
+
 #[pyclass]
 struct CozoDbPy {
     db: Option<DbInstance>,
@@ -27,6 +113,20 @@ impl CozoDbPy {
             Err(err) => Err(PyException::new_err(format!("{err:?}"))),
         }
     }
+    pub fn run_script(&self, py: Python<'_>, query: &str, params: &PyDict) -> PyResult<PyObject> {
+        if let Some(db) = &self.db {
+            let params = convert_params(params)?;
+            match py.allow_threads(|| db.run_script(query, params)) {
+                Ok(rows) => Ok(named_rows_to_py(rows, py)),
+                Err(err) => {
+                    let reports = format_error_as_json(err, Some(query)).to_string();
+                    Err(PyException::new_err(reports))
+                }
+            }
+        } else {
+            Err(PyException::new_err(DB_CLOSED_MSG))
+        }
+    }
     pub fn run_query(&self, py: Python<'_>, query: &str, params: &str) -> String {
         if let Some(db) = &self.db {
             py.allow_threads(|| db.run_script_str(query, params))