diff --git a/oden-js-sys/src/lib.rs b/oden-js-sys/src/lib.rs
index 28fd1a09..49d5c5a7 100644
--- a/oden-js-sys/src/lib.rs
+++ b/oden-js-sys/src/lib.rs
@@ -7,9 +7,34 @@ include!("static-functions.rs");
 
 use std::fmt;
 
+fn tag_name(tag: i64) -> &'static str {
+    match tag.try_into() {
+        Ok(tag) => match tag {
+            JS_TAG_BIG_DECIMAL => "JS_TAG_BIG_DECIMAL",
+            JS_TAG_BIG_INT => "JS_TAG_BIG_INT",
+            JS_TAG_BIG_FLOAT => "JS_TAG_BIG_FLOAT",
+            JS_TAG_SYMBOL => "JS_TAG_SYMBOL",
+            JS_TAG_MODULE => "JS_TAG_MODULE",
+            JS_TAG_FUNCTION_BYTECODE => "JS_TAG_FUNCTION_BYTECODE",
+            JS_TAG_STRING => "JS_TAG_STRING",
+            JS_TAG_OBJECT => "JS_TAG_OBJECT",
+            JS_TAG_INT => "JS_TAG_INT",
+            JS_TAG_BOOL => "JS_TAG_BOOL",
+            JS_TAG_NULL => "JS_TAG_NULL",
+            JS_TAG_UNDEFINED => "JS_TAG_UNDEFINED",
+            JS_TAG_UNINITIALIZED => "JS_TAG_UNINITIALIZED",
+            JS_TAG_CATCH_OFFSET => "JS_TAG_CATCH_OFFSET",
+            JS_TAG_EXCEPTION => "JS_TAG_EXCEPTION",
+            JS_TAG_FLOAT64 => "JS_TAG_FLOAT64",
+            _ => "???",
+        },
+        Err(_) => "???",
+    }
+}
+
 impl fmt::Debug for JSValue {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "JS[{}", self.tag)?;
+        write!(f, "JS[{} ({})", tag_name(self.tag), self.tag)?;
         if self.tag < 0 {
             write!(f, " {:?}]", unsafe { self.u.ptr })
         } else {
diff --git a/oden-js-sys/src/static-functions.rs b/oden-js-sys/src/static-functions.rs
index fb40a012..25222d25 100644
--- a/oden-js-sys/src/static-functions.rs
+++ b/oden-js-sys/src/static-functions.rs
@@ -8,25 +8,25 @@ extern "C" {
     fn JS_DupValueRT_real(rt: *mut JSRuntime, v: JSValue);
     fn JS_FreeValue_real(ctx: *mut JSContext, v: JSValue);
     fn JS_FreeValueRT_real(rt: *mut JSRuntime, v: JSValue);
-    fn JS_NewBool_real(ctx: *mut JSContext, v: bool) -> JSValue;
+    fn JS_NewBool_real(ctx: *mut JSContext, v: ::std::os::raw::c_int) -> JSValue;
     fn JS_NewInt32_real(ctx: *mut JSContext, v: i32) -> JSValue;
     fn JS_NewUint32_real(ctx: *mut JSContext, v: u32) -> JSValue;
     fn JS_NewFloat64_real(ctx: *mut JSContext, v: f64) -> JSValue;
-    fn JS_VALUE_IS_NAN_real(v: JSValue) -> bool;
+    fn JS_VALUE_IS_NAN_real(v: JSValue) -> ::std::os::raw::c_int;
     fn JS_VALUE_GET_FLOAT64_real(v: JSValue) -> f64;
     fn JS_VALUE_GET_NORM_TAG_real(v: JSValue) -> ::std::os::raw::c_int;
-    fn JS_IsNumber_real(v: JSValue) -> bool;
-    fn JS_IsBigInt_real(ctx: *mut JSContext, v: JSValue) -> bool;
-    fn JS_IsBigFloat_real(v: JSValue) -> bool;
-    fn JS_IsBigDecimal_real(v: JSValue) -> bool;
-    fn JS_IsBool_real(v: JSValue) -> bool;
-    fn JS_IsNull_real(v: JSValue) -> bool;
-    fn JS_IsUndefined_real(v: JSValue) -> bool;
-    fn JS_IsException_real(v: JSValue) -> bool;
-    fn JS_IsUninitialized_real(v: JSValue) -> bool;
-    fn JS_IsString_real(v: JSValue) -> bool;
-    fn JS_IsSymbol_real(v: JSValue) -> bool;
-    fn JS_IsObject_real(v: JSValue) -> bool;
+    fn JS_IsNumber_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsBigInt_real(ctx: *mut JSContext, v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsBigFloat_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsBigDecimal_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsBool_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsNull_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsUndefined_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsException_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsUninitialized_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsString_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsSymbol_real(v: JSValue) -> ::std::os::raw::c_int;
+    fn JS_IsObject_real(v: JSValue) -> ::std::os::raw::c_int;
     fn JS_ToUint32_real(ctx: *mut JSContext, pres: *mut u32, val: JSValue) -> i32;
     fn JS_GetProperty_real(ctx: *mut JSContext, this_obj: JSValue, prop: JSAtom) -> JSValue;
     fn JS_SetProperty_real(
@@ -82,7 +82,7 @@ pub unsafe fn JS_FreeValueRT(rt: *mut JSRuntime, v: JSValue) {
 }
 
 /// create a new boolean value
-pub unsafe fn JS_NewBool(ctx: *mut JSContext, v: bool) -> JSValue {
+pub unsafe fn JS_NewBool(ctx: *mut JSContext, v: ::std::os::raw::c_int) -> JSValue {
     JS_NewBool_real(ctx, v)
 }
 
@@ -102,7 +102,7 @@ pub unsafe fn JS_NewFloat64(ctx: *mut JSContext, v: f64) -> JSValue {
 }
 
 /// check if a JSValue is a NaN value
-pub unsafe fn JS_VALUE_IS_NAN(v: JSValue) -> bool {
+pub unsafe fn JS_VALUE_IS_NAN(v: JSValue) -> ::std::os::raw::c_int {
     JS_VALUE_IS_NAN_real(v)
 }
 
@@ -117,62 +117,62 @@ pub unsafe fn JS_VALUE_GET_NORM_TAG(v: JSValue) -> ::std::os::raw::c_int {
 }
 
 /// check if a JSValue is a Number
-pub unsafe fn JS_IsNumber(v: JSValue) -> bool {
+pub unsafe fn JS_IsNumber(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsNumber_real(v)
 }
 
 /// check if a JSValue is a BigInt
-pub unsafe fn JS_IsBigInt(ctx: *mut JSContext, v: JSValue) -> bool {
+pub unsafe fn JS_IsBigInt(ctx: *mut JSContext, v: JSValue) -> ::std::os::raw::c_int {
     JS_IsBigInt_real(ctx, v)
 }
 
 /// check if a JSValue is a BigFloat
-pub unsafe fn JS_IsBigFloat(v: JSValue) -> bool {
+pub unsafe fn JS_IsBigFloat(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsBigFloat_real(v)
 }
 
 /// check if a JSValue is a BigDecimal
-pub unsafe fn JS_IsBigDecimal(v: JSValue) -> bool {
+pub unsafe fn JS_IsBigDecimal(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsBigDecimal_real(v)
 }
 
 /// check if a JSValue is a Boolean
-pub unsafe fn JS_IsBool(v: JSValue) -> bool {
+pub unsafe fn JS_IsBool(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsBool_real(v)
 }
 
 /// check if a JSValue is null
-pub unsafe fn JS_IsNull(v: JSValue) -> bool {
+pub unsafe fn JS_IsNull(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsNull_real(v)
 }
 
 /// check if a JSValue is Undefined
-pub unsafe fn JS_IsUndefined(v: JSValue) -> bool {
+pub unsafe fn JS_IsUndefined(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsUndefined_real(v)
 }
 
 /// check if a JSValue is an Exception
-pub unsafe fn JS_IsException(v: JSValue) -> bool {
+pub unsafe fn JS_IsException(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsException_real(v)
 }
 
 /// check if a JSValue is initialized
-pub unsafe fn JS_IsUninitialized(v: JSValue) -> bool {
+pub unsafe fn JS_IsUninitialized(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsUninitialized_real(v)
 }
 
 /// check if a JSValue is a String
-pub unsafe fn JS_IsString(v: JSValue) -> bool {
+pub unsafe fn JS_IsString(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsString_real(v)
 }
 
 /// check if a JSValue is a Symbol
-pub unsafe fn JS_IsSymbol(v: JSValue) -> bool {
+pub unsafe fn JS_IsSymbol(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsSymbol_real(v)
 }
 
 /// check if a JSValue is an Object
-pub unsafe fn JS_IsObject(v: JSValue) -> bool {
+pub unsafe fn JS_IsObject(v: JSValue) -> ::std::os::raw::c_int {
     JS_IsObject_real(v)
 }
 
diff --git a/oden-js/src/context.rs b/oden-js/src/context.rs
index b7b09239..2004fb65 100644
--- a/oden-js/src/context.rs
+++ b/oden-js/src/context.rs
@@ -182,7 +182,8 @@ impl ContextRef {
     where
         T: Into<bool>,
     {
-        self.check_exception(unsafe { sys::JS_NewBool(self.ctx, value.into()) })
+        let b = if value.into() { 1 } else { 0 };
+        self.check_exception(unsafe { sys::JS_NewBool(self.ctx, b) })
     }
 
     /// Construct a new value that wraps a strongly-typed closure.
diff --git a/oden-js/src/conversion/into.rs b/oden-js/src/conversion/into.rs
index cff22a69..2e4960bf 100644
--- a/oden-js/src/conversion/into.rs
+++ b/oden-js/src/conversion/into.rs
@@ -77,7 +77,9 @@ impl TryIntoValue for f64 {
 impl TryIntoValue for bool {
     #[inline]
     fn try_into_value(self, ctx: &ContextRef) -> ValueResult {
-        ctx.new_bool(self)
+        let result = ctx.new_bool(self);
+        // eprintln!("{self} -> {result:?}");
+        result
     }
 }
 
diff --git a/oden-js/src/conversion/mod.rs b/oden-js/src/conversion/mod.rs
index b95c0bc1..ae0c43d8 100644
--- a/oden-js/src/conversion/mod.rs
+++ b/oden-js/src/conversion/mod.rs
@@ -6,3 +6,26 @@ pub use from::*;
 
 mod function;
 pub use function::*;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{Context, ContextRef, Runtime};
+
+    fn check_round_trip<T>(ctx: &ContextRef, v: T)
+    where
+        T: TryIntoValue + TryFromValue + PartialEq + Clone + std::fmt::Debug,
+    {
+        let val = v.clone().try_into_value(ctx).expect("Could not make value");
+        let new = T::try_from_value(&val, ctx).expect("Could not unwrap value");
+        assert_eq!(v, new);
+    }
+
+    #[test]
+    fn round_trip() {
+        let ctx = Context::new(Runtime::new());
+        check_round_trip(&ctx, true);
+        check_round_trip(&ctx, false);
+        check_round_trip(&ctx, 12);
+    }
+}