diff --git a/crates/aura-cli/src/main.rs b/crates/aura-cli/src/main.rs
index 86df3f6..3257ff8 100644
--- a/crates/aura-cli/src/main.rs
+++ b/crates/aura-cli/src/main.rs
@@ -41,7 +41,7 @@ fn synthetic_prices() -> Vec<(Timestamp, Scalar)> {
         (7, 0.9990),
     ]
     .iter()
-    .map(|&(t, p)| (Timestamp(t), Scalar::F64(p)))
+    .map(|&(t, p)| (Timestamp(t), Scalar::f64(p)))
     .collect()
 }
 
@@ -58,7 +58,7 @@ fn showcase_prices() -> Vec<(Timestamp, Scalar)> {
     ]
     .iter()
     .enumerate()
-    .map(|(i, &p)| (Timestamp(i as i64 + 1), Scalar::F64(p)))
+    .map(|(i, &p)| (Timestamp(i as i64 + 1), Scalar::f64(p)))
     .collect()
 }
 
@@ -163,9 +163,9 @@ fn run_sample() -> RunReport {
     RunReport {
         manifest: sim_optimal_manifest(
             vec![
-                ("sma_fast".to_string(), Scalar::F64(2.0)),
-                ("sma_slow".to_string(), Scalar::F64(4.0)),
-                ("exposure_scale".to_string(), Scalar::F64(0.5)),
+                ("sma_fast".to_string(), Scalar::f64(2.0)),
+                ("sma_slow".to_string(), Scalar::f64(4.0)),
+                ("exposure_scale".to_string(), Scalar::f64(0.5)),
             ],
             window,
             0,
@@ -226,9 +226,9 @@ fn run_sample_real(symbol: &str, from_ms: Option<i64>, to_ms: Option<i64>) -> Ru
     RunReport {
         manifest: sim_optimal_manifest(
             vec![
-                ("sma_fast".to_string(), Scalar::F64(2.0)),
-                ("sma_slow".to_string(), Scalar::F64(4.0)),
-                ("exposure_scale".to_string(), Scalar::F64(0.5)),
+                ("sma_fast".to_string(), Scalar::f64(2.0)),
+                ("sma_slow".to_string(), Scalar::f64(4.0)),
+                ("exposure_scale".to_string(), Scalar::f64(0.5)),
             ],
             window,
             0,
@@ -295,7 +295,7 @@ fn signals(name: &str) -> Composite {
     let blend = g.add(
         LinComb::builder(3)
             .named("blend")
-            .bind("weights[2]", Scalar::F64(0.5)),
+            .bind("weights[2]", Scalar::f64(0.5)),
     );
     let price = g.input_role("price");
     g.feed(price, [trend.input("price"), momentum.input("price")]);
@@ -351,9 +351,9 @@ fn sample_blueprint() -> Composite {
 /// Coerce a sweep point's `Scalar` value to the manifest's `f64` param type.
 /// A tuning grid carries only numeric params (`I64` lengths, `F64` scales).
 fn scalar_as_param_f64(s: &Scalar) -> f64 {
-    match s {
-        Scalar::I64(n) => *n as f64,
-        Scalar::F64(f) => *f,
+    match s.kind() {
+        ScalarKind::I64 => s.as_i64() as f64,
+        ScalarKind::F64 => s.as_f64(),
         other => unreachable!("non-numeric sweep param: {other:?}"),
     }
 }
@@ -600,9 +600,9 @@ fn mc_family() -> McFamily {
         RunReport {
             manifest: sim_optimal_manifest(
                 vec![
-                    ("sma_fast".to_string(), Scalar::F64(2.0)),
-                    ("sma_slow".to_string(), Scalar::F64(4.0)),
-                    ("exposure_scale".to_string(), Scalar::F64(0.5)),
+                    ("sma_fast".to_string(), Scalar::f64(2.0)),
+                    ("sma_slow".to_string(), Scalar::f64(4.0)),
+                    ("exposure_scale".to_string(), Scalar::f64(0.5)),
                 ],
                 window,
                 seed,
@@ -813,7 +813,7 @@ fn macd_blueprint() -> Composite {
 /// windows so the 7-tick synthetic stream still produces a non-trivial trace
 /// (conventional MACD is 12/26/9, meaningless on 7 points).
 fn macd_point() -> Vec<Scalar> {
-    vec![Scalar::I64(2), Scalar::I64(4), Scalar::I64(3), Scalar::F64(0.5)]
+    vec![Scalar::i64(2), Scalar::i64(4), Scalar::i64(3), Scalar::f64(0.5)]
 }
 
 /// A longer synthetic stream than the SMA sample's 7 ticks: MACD's EMAs each warm
@@ -826,7 +826,7 @@ fn macd_prices() -> Vec<(Timestamp, Scalar)> {
     ]
     .iter()
     .enumerate()
-    .map(|(i, &p)| (Timestamp(i as i64 + 1), Scalar::F64(p)))
+    .map(|(i, &p)| (Timestamp(i as i64 + 1), Scalar::f64(p)))
     .collect()
 }
 
@@ -856,10 +856,10 @@ fn run_macd() -> RunReport {
     RunReport {
         manifest: sim_optimal_manifest(
             vec![
-                ("ema_fast".to_string(), Scalar::F64(2.0)),
-                ("ema_slow".to_string(), Scalar::F64(4.0)),
-                ("ema_signal".to_string(), Scalar::F64(3.0)),
-                ("exposure_scale".to_string(), Scalar::F64(0.5)),
+                ("ema_fast".to_string(), Scalar::f64(2.0)),
+                ("ema_slow".to_string(), Scalar::f64(4.0)),
+                ("ema_signal".to_string(), Scalar::f64(3.0)),
+                ("exposure_scale".to_string(), Scalar::f64(0.5)),
             ],
             window,
             0,
@@ -957,9 +957,9 @@ mod tests {
         let report = RunReport {
             manifest: sim_optimal_manifest(
                 vec![
-                    ("sma_fast".to_string(), Scalar::F64(2.0)),
-                    ("sma_slow".to_string(), Scalar::F64(4.0)),
-                    ("exposure_scale".to_string(), Scalar::F64(0.5)),
+                    ("sma_fast".to_string(), Scalar::f64(2.0)),
+                    ("sma_slow".to_string(), Scalar::f64(4.0)),
+                    ("exposure_scale".to_string(), Scalar::f64(0.5)),
                 ],
                 window,
                 seed,
diff --git a/crates/aura-core/src/any.rs b/crates/aura-core/src/any.rs
index 84a9d70..adacb7e 100644
--- a/crates/aura-core/src/any.rs
+++ b/crates/aura-core/src/any.rs
@@ -60,34 +60,34 @@ impl AnyColumn {
     /// kind; the column is left untouched (C7 guard). The hot path bypasses this
     /// by taking the concrete `Column<T>` once via `as_*_mut`.
     pub fn push(&mut self, v: Scalar) -> Result<(), KindMismatch> {
-        match (self, v) {
-            (AnyColumn::I64(c), Scalar::I64(x)) => {
-                c.push(x);
+        match (self, v.kind()) {
+            (AnyColumn::I64(c), ScalarKind::I64) => {
+                c.push(v.as_i64());
                 Ok(())
             }
-            (AnyColumn::F64(c), Scalar::F64(x)) => {
-                c.push(x);
+            (AnyColumn::F64(c), ScalarKind::F64) => {
+                c.push(v.as_f64());
                 Ok(())
             }
-            (AnyColumn::Bool(c), Scalar::Bool(x)) => {
-                c.push(x);
+            (AnyColumn::Bool(c), ScalarKind::Bool) => {
+                c.push(v.as_bool());
                 Ok(())
             }
-            (AnyColumn::Ts(c), Scalar::Ts(x)) => {
-                c.push(x);
+            (AnyColumn::Ts(c), ScalarKind::Timestamp) => {
+                c.push(v.as_ts());
                 Ok(())
             }
-            (this, v) => Err(KindMismatch { expected: this.kind(), got: v.kind() }),
+            (this, got) => Err(KindMismatch { expected: this.kind(), got }),
         }
     }
 
     /// Read one type-erased value (0 = newest). `None` if cold / out of range.
     pub fn get(&self, k: usize) -> Option<Scalar> {
         match self {
-            AnyColumn::I64(c) => c.get(k).map(Scalar::I64),
-            AnyColumn::F64(c) => c.get(k).map(Scalar::F64),
-            AnyColumn::Bool(c) => c.get(k).map(Scalar::Bool),
-            AnyColumn::Ts(c) => c.get(k).map(Scalar::Ts),
+            AnyColumn::I64(c) => c.get(k).map(Scalar::i64),
+            AnyColumn::F64(c) => c.get(k).map(Scalar::f64),
+            AnyColumn::Bool(c) => c.get(k).map(Scalar::bool),
+            AnyColumn::Ts(c) => c.get(k).map(Scalar::ts),
         }
     }
 
@@ -160,20 +160,20 @@ mod tests {
     #[test]
     fn same_kind_push_round_trips() {
         let mut e = AnyColumn::with_capacity(ScalarKind::F64, 4);
-        e.push(Scalar::F64(1.5)).unwrap();
-        e.push(Scalar::F64(2.5)).unwrap();
+        e.push(Scalar::f64(1.5)).unwrap();
+        e.push(Scalar::f64(2.5)).unwrap();
         assert_eq!(e.kind(), ScalarKind::F64);
         assert_eq!(e.len(), 2);
         assert_eq!(e.run_count(), 2);
-        assert_eq!(e.get(0), Some(Scalar::F64(2.5))); // newest
-        assert_eq!(e.get(1), Some(Scalar::F64(1.5)));
+        assert_eq!(e.get(0), Some(Scalar::f64(2.5))); // newest
+        assert_eq!(e.get(1), Some(Scalar::f64(1.5)));
         assert_eq!(e.get(2), None);
     }
 
     #[test]
     fn wrong_kind_push_is_rejected() {
         let mut edge = AnyColumn::with_capacity(ScalarKind::I64, 8);
-        let err = edge.push(Scalar::F64(1.5)).unwrap_err(); // f64 into an i64 edge
+        let err = edge.push(Scalar::f64(1.5)).unwrap_err(); // f64 into an i64 edge
         assert_eq!(err, KindMismatch { expected: ScalarKind::I64, got: ScalarKind::F64 });
         assert_eq!(edge.len(), 0); // nothing was stored
         assert_eq!(edge.run_count(), 0); // and the counter did not move
@@ -188,7 +188,7 @@ mod tests {
         assert!(e.as_ts_mut().is_none());
         // hot-path push through the concrete column, monomorphic:
         e.as_f64_mut().unwrap().push(3.0);
-        assert_eq!(e.get(0), Some(Scalar::F64(3.0)));
+        assert_eq!(e.get(0), Some(Scalar::f64(3.0)));
         assert_eq!(e.run_count(), 1);
     }
 
@@ -208,7 +208,7 @@ mod tests {
     #[test]
     fn timestamp_edge_round_trips() {
         let mut e = AnyColumn::with_capacity(ScalarKind::Timestamp, 2);
-        e.push(Scalar::Ts(Timestamp(1_700_000_000_000_000_000))).unwrap();
-        assert_eq!(e.get(0), Some(Scalar::Ts(Timestamp(1_700_000_000_000_000_000))));
+        e.push(Scalar::ts(Timestamp(1_700_000_000_000_000_000))).unwrap();
+        assert_eq!(e.get(0), Some(Scalar::ts(Timestamp(1_700_000_000_000_000_000))));
     }
 }
diff --git a/crates/aura-core/src/cell.rs b/crates/aura-core/src/cell.rs
new file mode 100644
index 0000000..3d89e8b
--- /dev/null
+++ b/crates/aura-core/src/cell.rs
@@ -0,0 +1,60 @@
+//! `Cell` — a type-erased 64-bit word holding one scalar value with its kind
+//! stripped away (C7). The type lives in the schema / column / port, never in
+//! the value, so a cell is read back only by naming its type via a typed
+//! accessor. `Scalar` is built on top of this; `Cell` itself knows nothing of
+//! `Scalar` or `ScalarKind`.
+
+use crate::scalar::Timestamp;
+
+/// A type-erased 64-bit cell: the raw storage of one scalar value with its kind
+/// stripped away. The bits are meaningless on their own — the type lives in the
+/// schema/column/port, not in the value (C7), so the word is recovered **only**
+/// by naming the type at the call site via a typed accessor ([`Cell::i64`],
+/// [`Cell::f64`], [`Cell::bool`], [`Cell::ts`]). Each reinterprets the word with
+/// no tag to check and therefore no branch — the caller's choice of accessor
+/// *is* the type context the hot path already holds. The inner word is private;
+/// there is no kind-free way to read it.
+///
+/// All four base types fit one 64-bit word: `i64`/`Timestamp`/`bool` reuse the
+/// same integer word, `f64` via its IEEE-754 bit pattern. `Eq`/`Hash` are
+/// bit-exact (so `+0.0`/`-0.0` differ and a `NaN` bit pattern equals itself) —
+/// the semantics of a raw word, not of a number.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct Cell(u64);
+
+impl Cell {
+    /// Store an `i64` (identity bit-cast).
+    pub fn from_i64(v: i64) -> Self {
+        Cell(v as u64)
+    }
+    /// Store an `f64` as its IEEE-754 bit pattern.
+    pub fn from_f64(v: f64) -> Self {
+        Cell(v.to_bits())
+    }
+    /// Store a `bool` as `0`/`1`.
+    pub fn from_bool(v: bool) -> Self {
+        Cell(v as u64)
+    }
+    /// Store a [`Timestamp`] (its `i64` epoch-ns, bit-cast).
+    pub fn from_ts(v: Timestamp) -> Self {
+        Cell(v.0 as u64)
+    }
+
+    /// Read the word as `i64` (identity bit-cast). The caller asserts the type
+    /// by choosing this accessor; there is no tag to check, hence no branch.
+    pub fn i64(self) -> i64 {
+        self.0 as i64
+    }
+    /// Read the word as `f64` from its IEEE-754 bit pattern. Branch-free.
+    pub fn f64(self) -> f64 {
+        f64::from_bits(self.0)
+    }
+    /// Read the word as `bool` (any non-zero word is `true`). Branch-free.
+    pub fn bool(self) -> bool {
+        self.0 != 0
+    }
+    /// Read the word as a [`Timestamp`] (identity bit-cast). Branch-free.
+    pub fn ts(self) -> Timestamp {
+        Timestamp(self.0 as i64)
+    }
+}
diff --git a/crates/aura-core/src/ctx.rs b/crates/aura-core/src/ctx.rs
index d855691..78b8c9b 100644
--- a/crates/aura-core/src/ctx.rs
+++ b/crates/aura-core/src/ctx.rs
@@ -76,7 +76,7 @@ mod tests {
     fn ctx_hands_financial_indexed_windows() {
         let mut inputs = vec![AnyColumn::with_capacity(ScalarKind::F64, 4)];
         for v in [10.0_f64, 20.0, 30.0] {
-            inputs[0].push(Scalar::F64(v)).unwrap();
+            inputs[0].push(Scalar::f64(v)).unwrap();
         }
         let ctx = Ctx::new(&inputs, Timestamp(0));
         let w = ctx.f64_in(0);
@@ -91,8 +91,8 @@ mod tests {
             AnyColumn::with_capacity(ScalarKind::F64, 2),
             AnyColumn::with_capacity(ScalarKind::I64, 2),
         ];
-        inputs[0].push(Scalar::F64(1.5)).unwrap();
-        inputs[1].push(Scalar::I64(42)).unwrap();
+        inputs[0].push(Scalar::f64(1.5)).unwrap();
+        inputs[1].push(Scalar::i64(42)).unwrap();
         let ctx = Ctx::new(&inputs, Timestamp(0));
         assert_eq!(ctx.f64_in(0)[0], 1.5);
         assert_eq!(ctx.i64_in(1)[0], 42);
@@ -102,7 +102,7 @@ mod tests {
     #[should_panic(expected = "engine bug")]
     fn ctx_panics_on_kind_mismatch() {
         let mut inputs = vec![AnyColumn::with_capacity(ScalarKind::I64, 2)];
-        inputs[0].push(Scalar::I64(7)).unwrap();
+        inputs[0].push(Scalar::i64(7)).unwrap();
         let ctx = Ctx::new(&inputs, Timestamp(0));
         let _ = ctx.f64_in(0); // wrong kind → panic
     }
diff --git a/crates/aura-core/src/lib.rs b/crates/aura-core/src/lib.rs
index 1e44e27..2be6bf5 100644
--- a/crates/aura-core/src/lib.rs
+++ b/crates/aura-core/src/lib.rs
@@ -29,6 +29,7 @@
 //! (C18/C22).
 
 mod any;
+mod cell;
 mod column;
 mod ctx;
 mod error;
@@ -36,6 +37,7 @@ mod node;
 mod scalar;
 
 pub use any::AnyColumn;
+pub use cell::Cell;
 pub use column::{Column, Window};
 pub use ctx::Ctx;
 pub use error::KindMismatch;
diff --git a/crates/aura-core/src/node.rs b/crates/aura-core/src/node.rs
index 4f9c55a..15e02f9 100644
--- a/crates/aura-core/src/node.rs
+++ b/crates/aura-core/src/node.rs
@@ -435,45 +435,45 @@ mod tests {
     #[test]
     fn bind_removes_slot_and_reconstructs_positionally() {
         // chained bind of b then a (reverse slot order); c stays open
-        let bound = probe3().bind("b", Scalar::I64(8)).bind("a", Scalar::I64(7));
+        let bound = probe3().bind("b", Scalar::i64(8)).bind("a", Scalar::i64(7));
         assert_eq!(
             bound.params().iter().map(|p| p.name.as_str()).collect::<Vec<_>>(),
             ["c"], // only c remains open
         );
-        let built = bound.build(&[Scalar::F64(9.0)]); // inject c
+        let built = bound.build(&[Scalar::f64(9.0)]); // inject c
         assert_eq!(
             built.label(),
-            format!("{:?}", vec![Scalar::I64(7), Scalar::I64(8), Scalar::F64(9.0)]),
+            format!("{:?}", vec![Scalar::i64(7), Scalar::i64(8), Scalar::f64(9.0)]),
         );
 
         // partial: bind only b; a and c stay open and keep their positions
         let built2 = probe3()
-            .bind("b", Scalar::I64(8))
-            .build(&[Scalar::I64(7), Scalar::F64(9.0)]); // a, c injected in order
+            .bind("b", Scalar::i64(8))
+            .build(&[Scalar::i64(7), Scalar::f64(9.0)]); // a, c injected in order
         assert_eq!(
             built2.label(),
-            format!("{:?}", vec![Scalar::I64(7), Scalar::I64(8), Scalar::F64(9.0)]),
+            format!("{:?}", vec![Scalar::i64(7), Scalar::i64(8), Scalar::f64(9.0)]),
         );
     }
 
     #[test]
     fn bind_records_bound_param_at_original_position() {
         // middle-of-three: binding `b` records its ORIGINAL slot position (1).
-        let mid = probe3().bind("b", Scalar::I64(8));
+        let mid = probe3().bind("b", Scalar::i64(8));
         assert_eq!(
             mid.bound_params(),
-            [BoundParam { pos: 1, name: "b".into(), kind: ScalarKind::I64, value: Scalar::I64(8) }]
+            [BoundParam { pos: 1, name: "b".into(), kind: ScalarKind::I64, value: Scalar::i64(8) }]
                 .as_slice(),
         );
 
         // chained reverse-order bind (b then a): each entry carries its ORIGINAL
         // position regardless of the shrinking array — positions {1, 0} in call order.
-        let pair = probe3().bind("b", Scalar::I64(8)).bind("a", Scalar::I64(7));
+        let pair = probe3().bind("b", Scalar::i64(8)).bind("a", Scalar::i64(7));
         assert_eq!(
             pair.bound_params(),
             [
-                BoundParam { pos: 1, name: "b".into(), kind: ScalarKind::I64, value: Scalar::I64(8) },
-                BoundParam { pos: 0, name: "a".into(), kind: ScalarKind::I64, value: Scalar::I64(7) },
+                BoundParam { pos: 1, name: "b".into(), kind: ScalarKind::I64, value: Scalar::i64(8) },
+                BoundParam { pos: 0, name: "a".into(), kind: ScalarKind::I64, value: Scalar::i64(7) },
             ]
             .as_slice(),
         );
@@ -494,7 +494,7 @@ mod tests {
             },
             |_| Box::new(Bare),
         );
-        let _ = b.bind("width", Scalar::I64(2)); // "width" is not a declared param
+        let _ = b.bind("width", Scalar::i64(2)); // "width" is not a declared param
     }
 
     #[test]
@@ -512,7 +512,7 @@ mod tests {
             },
             |_| Box::new(Bare),
         );
-        let _ = b.bind("dup", Scalar::I64(1)); // two slots named "dup"
+        let _ = b.bind("dup", Scalar::i64(1)); // two slots named "dup"
     }
 
     #[test]
@@ -527,7 +527,7 @@ mod tests {
             },
             |_| Box::new(Bare),
         );
-        let _ = b.bind("length", Scalar::F64(2.0)); // F64 value for an I64 slot
+        let _ = b.bind("length", Scalar::f64(2.0)); // F64 value for an I64 slot
     }
 }
 
@@ -542,12 +542,12 @@ mod zip_params_tests {
             ParamSpec { name: "fast".into(), kind: ScalarKind::I64 },
             ParamSpec { name: "scale".into(), kind: ScalarKind::F64 },
         ];
-        let point = vec![Scalar::I64(2), Scalar::F64(0.5)];
+        let point = vec![Scalar::i64(2), Scalar::f64(0.5)];
         assert_eq!(
             zip_params(&space, &point),
             vec![
-                ("fast".to_string(), Scalar::I64(2)),
-                ("scale".to_string(), Scalar::F64(0.5)),
+                ("fast".to_string(), Scalar::i64(2)),
+                ("scale".to_string(), Scalar::f64(0.5)),
             ],
         );
     }
@@ -558,7 +558,7 @@ mod zip_params_tests {
             ParamSpec { name: "a".into(), kind: ScalarKind::I64 },
             ParamSpec { name: "b".into(), kind: ScalarKind::I64 },
         ];
-        let point = vec![Scalar::I64(7), Scalar::I64(9)];
+        let point = vec![Scalar::i64(7), Scalar::i64(9)];
         let hand: Vec<(String, Scalar)> =
             space.iter().zip(&point).map(|(ps, v)| (ps.name.clone(), *v)).collect();
         assert_eq!(zip_params(&space, &point), hand);
diff --git a/crates/aura-core/src/scalar.rs b/crates/aura-core/src/scalar.rs
index 5767167..d4b63db 100644
--- a/crates/aura-core/src/scalar.rs
+++ b/crates/aura-core/src/scalar.rs
@@ -1,6 +1,10 @@
-//! The closed four-type scalar set streamed on aura's hot path (C7):
-//! `i64`, `f64`, `bool`, and `Timestamp` (epoch-ns UTC). The carrier `Scalar`
-//! is a `Copy` POD enum — no type-erased payloads, no heap, no reference counting.
+//! The closed four-type scalar set streamed on aura's hot path (C7): `i64`,
+//! `f64`, `bool`, and `Timestamp` (epoch-ns UTC). The raw value is a type-erased
+//! [`Cell`] — one 64-bit word, no tag; a [`Scalar`] pairs a `Cell` with its
+//! [`ScalarKind`] for the dynamic boundaries. Both are `Copy` PODs — no heap, no
+//! reference counting.
+
+use crate::cell::Cell;
 
 /// Canonical engine time: epoch-nanoseconds UTC. Newtype over `i64` (C7).
 /// `Default` (epoch 0) lets `Column<Timestamp>` pre-size its ring.
@@ -16,53 +20,110 @@ pub enum ScalarKind {
     Timestamp,
 }
 
-/// The four scalar base types, type-erased into one `Copy` carrier (C7).
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum Scalar {
-    I64(i64),
-    F64(f64),
-    Bool(bool),
-    Ts(Timestamp),
+/// One scalar value: a type-erased [`Cell`] plus its [`ScalarKind`] tag — the
+/// self-describing form for the dynamic boundaries (builder binding,
+/// serialization, rendering). The hot path uses the bare [`Cell`]; a `Scalar`
+/// is the fatter form that remembers its own type.
+///
+/// Reading is the caller's responsibility. Each `as_*` accessor `debug_assert`s
+/// that the stored kind matches, then hands back the **native** value — in
+/// release the assert is gone, so an accessor *is* the bare cell read
+/// (branch-free). Calling the wrong `as_*` for the stored kind is a caller bug
+/// (debug-asserted), not a recoverable error.
+///
+/// `PartialEq` is **value** equality (hand-written, not derived — the derived
+/// one would inherit the `Cell`'s bitwise compare). Two scalars are equal iff
+/// their kinds match and their native payloads compare equal, so `f64` keeps
+/// IEEE-754 semantics (`NaN != NaN`, `+0.0 == -0.0`) exactly as the former enum
+/// did, and a kind mismatch is never equal even when the words coincide
+/// (`i64(0) != f64(0.0)`).
+#[derive(Clone, Copy, Debug)]
+pub struct Scalar {
+    kind: ScalarKind,
+    cell: Cell,
 }
 
 impl Scalar {
-    /// The kind tag of this scalar.
+    /// Construct an `i64` scalar.
+    pub fn i64(v: i64) -> Self {
+        Scalar { kind: ScalarKind::I64, cell: Cell::from_i64(v) }
+    }
+    /// Construct an `f64` scalar.
+    pub fn f64(v: f64) -> Self {
+        Scalar { kind: ScalarKind::F64, cell: Cell::from_f64(v) }
+    }
+    /// Construct a `bool` scalar.
+    pub fn bool(v: bool) -> Self {
+        Scalar { kind: ScalarKind::Bool, cell: Cell::from_bool(v) }
+    }
+    /// Construct a [`Timestamp`] scalar.
+    pub fn ts(v: Timestamp) -> Self {
+        Scalar { kind: ScalarKind::Timestamp, cell: Cell::from_ts(v) }
+    }
+
+    /// The kind tag of this scalar (a field read, no branch).
     pub fn kind(self) -> ScalarKind {
-        match self {
-            Scalar::I64(_) => ScalarKind::I64,
-            Scalar::F64(_) => ScalarKind::F64,
-            Scalar::Bool(_) => ScalarKind::Bool,
-            Scalar::Ts(_) => ScalarKind::Timestamp,
+        self.kind
+    }
+
+    /// Read as `i64`. The caller asserts the kind by choosing this accessor; a
+    /// mismatch is a caller bug (debug-asserted, free in release).
+    pub fn as_i64(self) -> i64 {
+        debug_assert_eq!(self.kind, ScalarKind::I64);
+        self.cell.i64()
+    }
+    /// Read as `f64`. Caller asserts the kind (debug-asserted, free in release).
+    pub fn as_f64(self) -> f64 {
+        debug_assert_eq!(self.kind, ScalarKind::F64);
+        self.cell.f64()
+    }
+    /// Read as `bool`. Caller asserts the kind (debug-asserted, free in release).
+    pub fn as_bool(self) -> bool {
+        debug_assert_eq!(self.kind, ScalarKind::Bool);
+        self.cell.bool()
+    }
+    /// Read as [`Timestamp`]. Caller asserts the kind (debug-asserted, free in release).
+    pub fn as_ts(self) -> Timestamp {
+        debug_assert_eq!(self.kind, ScalarKind::Timestamp);
+        self.cell.ts()
+    }
+}
+
+/// Value equality, not the `Cell`'s bitwise one: kinds must match, then the
+/// native payloads compare — so `f64` keeps IEEE-754 semantics (`NaN != NaN`,
+/// `+0.0 == -0.0`), matching the pre-`Cell` enum's behaviour.
+impl PartialEq for Scalar {
+    fn eq(&self, other: &Self) -> bool {
+        if self.kind != other.kind {
+            return false;
+        }
+        match self.kind {
+            ScalarKind::I64 => self.as_i64() == other.as_i64(),
+            ScalarKind::F64 => self.as_f64() == other.as_f64(),
+            ScalarKind::Bool => self.as_bool() == other.as_bool(),
+            ScalarKind::Timestamp => self.as_ts() == other.as_ts(),
         }
-    }
-    /// The `i64` payload, or `None` if this scalar is not an `I64`.
-    pub fn as_i64(self) -> Option<i64> {
-        if let Scalar::I64(v) = self { Some(v) } else { None }
-    }
-    /// The `f64` payload, or `None` if this scalar is not an `F64`.
-    pub fn as_f64(self) -> Option<f64> {
-        if let Scalar::F64(v) = self { Some(v) } else { None }
     }
 }
 
 impl From<i64> for Scalar {
     fn from(v: i64) -> Self {
-        Scalar::I64(v)
+        Scalar::i64(v)
     }
 }
 impl From<f64> for Scalar {
     fn from(v: f64) -> Self {
-        Scalar::F64(v)
+        Scalar::f64(v)
     }
 }
 impl From<bool> for Scalar {
     fn from(v: bool) -> Self {
-        Scalar::Bool(v)
+        Scalar::bool(v)
     }
 }
 impl From<Timestamp> for Scalar {
     fn from(v: Timestamp) -> Self {
-        Scalar::Ts(v)
+        Scalar::ts(v)
     }
 }
 
@@ -72,18 +133,18 @@ mod tests {
 
     #[test]
     fn kind_matches_variant() {
-        assert_eq!(Scalar::I64(1).kind(), ScalarKind::I64);
-        assert_eq!(Scalar::F64(1.0).kind(), ScalarKind::F64);
-        assert_eq!(Scalar::Bool(true).kind(), ScalarKind::Bool);
-        assert_eq!(Scalar::Ts(Timestamp(1)).kind(), ScalarKind::Timestamp);
+        assert_eq!(Scalar::i64(1).kind(), ScalarKind::I64);
+        assert_eq!(Scalar::f64(1.0).kind(), ScalarKind::F64);
+        assert_eq!(Scalar::bool(true).kind(), ScalarKind::Bool);
+        assert_eq!(Scalar::ts(Timestamp(1)).kind(), ScalarKind::Timestamp);
     }
 
     #[test]
     fn from_widenings() {
-        assert_eq!(Scalar::from(7i64), Scalar::I64(7));
-        assert_eq!(Scalar::from(2.5f64), Scalar::F64(2.5));
-        assert_eq!(Scalar::from(true), Scalar::Bool(true));
-        assert_eq!(Scalar::from(Timestamp(9)), Scalar::Ts(Timestamp(9)));
+        assert_eq!(Scalar::from(7i64), Scalar::i64(7));
+        assert_eq!(Scalar::from(2.5f64), Scalar::f64(2.5));
+        assert_eq!(Scalar::from(true), Scalar::bool(true));
+        assert_eq!(Scalar::from(Timestamp(9)), Scalar::ts(Timestamp(9)));
     }
 
     #[test]
@@ -97,8 +158,8 @@ mod tests {
         fn lower(v: impl Into<Scalar>) -> Scalar {
             v.into()
         }
-        assert_eq!(lower(2), Scalar::I64(2));
-        assert_eq!(lower(0.5), Scalar::F64(0.5));
+        assert_eq!(lower(2), Scalar::i64(2));
+        assert_eq!(lower(0.5), Scalar::f64(0.5));
     }
 
     #[test]
@@ -108,16 +169,38 @@ mod tests {
     }
 
     #[test]
-    fn scalar_value_accessors_are_kind_exact() {
-        assert_eq!(Scalar::I64(3).as_i64(), Some(3));
-        assert_eq!(Scalar::I64(3).as_f64(), None);
-        assert_eq!(Scalar::F64(0.5).as_f64(), Some(0.5));
-        assert_eq!(Scalar::F64(0.5).as_i64(), None);
+    fn scalar_value_accessors_return_native_payload() {
+        assert_eq!(Scalar::i64(3).as_i64(), 3);
+        assert_eq!(Scalar::f64(0.5).as_f64(), 0.5);
+        assert!(Scalar::bool(true).as_bool());
+        assert_eq!(Scalar::ts(Timestamp(7)).as_ts(), Timestamp(7));
+    }
+
+    #[test]
+    fn scalar_eq_is_value_not_bitwise() {
+        // f64 follows IEEE-754 exactly as the former enum did: a NaN is never
+        // equal to itself, and +0.0 equals -0.0 — value equality, NOT the
+        // bitwise equality the underlying `Cell` carries (those two cases are
+        // precisely where bit- and value-equality diverge).
+        assert_ne!(Scalar::f64(f64::NAN), Scalar::f64(f64::NAN));
+        assert_eq!(Scalar::f64(0.0), Scalar::f64(-0.0));
+        assert_eq!(Scalar::f64(2.5), Scalar::f64(2.5));
+        // i64 / bool / timestamp compare by native value.
+        assert_eq!(Scalar::i64(7), Scalar::i64(7));
+        assert_ne!(Scalar::i64(7), Scalar::i64(8));
+        assert_eq!(Scalar::bool(true), Scalar::bool(true));
+        assert_ne!(Scalar::bool(true), Scalar::bool(false));
+        assert_eq!(Scalar::ts(Timestamp(9)), Scalar::ts(Timestamp(9)));
+        // A kind mismatch is never equal — even when the words coincide:
+        // i64(0) and f64(0.0) share the bit pattern 0; bool(true) and i64(1)
+        // share 1. Value equality still separates them by kind.
+        assert_ne!(Scalar::i64(0), Scalar::f64(0.0));
+        assert_ne!(Scalar::i64(1), Scalar::bool(true));
     }
 
     #[test]
     fn scalar_is_copy() {
-        let s = Scalar::F64(1.0);
+        let s = Scalar::f64(1.0);
         let a = s;
         let b = s; // Copy: `s` still usable after move-by-value
         assert_eq!(a, b);
diff --git a/crates/aura-engine/src/blueprint.rs b/crates/aura-engine/src/blueprint.rs
index 9893e64..b646752 100644
--- a/crates/aura-engine/src/blueprint.rs
+++ b/crates/aura-engine/src/blueprint.rs
@@ -827,16 +827,16 @@ mod tests {
             ParamSpec { name: "scale".into(), kind: ScalarKind::F64 },
         ];
         let axes = vec![
-            ("scale".to_string(), vec![Scalar::F64(0.5)]),
-            ("sma_cross.fast".to_string(), vec![Scalar::I64(2), Scalar::I64(3)]),
-            ("sma_cross.slow".to_string(), vec![Scalar::I64(4), Scalar::I64(5)]),
+            ("scale".to_string(), vec![Scalar::f64(0.5)]),
+            ("sma_cross.fast".to_string(), vec![Scalar::i64(2), Scalar::i64(3)]),
+            ("sma_cross.slow".to_string(), vec![Scalar::i64(4), Scalar::i64(5)]),
         ];
         assert_eq!(
             resolve_axes(&space, &axes),
             Ok(vec![
-                vec![Scalar::I64(2), Scalar::I64(3)],
-                vec![Scalar::I64(4), Scalar::I64(5)],
-                vec![Scalar::F64(0.5)],
+                vec![Scalar::i64(2), Scalar::i64(3)],
+                vec![Scalar::i64(4), Scalar::i64(5)],
+                vec![Scalar::f64(0.5)],
             ]),
         );
     }
@@ -857,7 +857,7 @@ mod tests {
             ParamSpec { name: "b".into(), kind: ScalarKind::I64 },
         ];
         assert_eq!(
-            resolve_axes(&space, &[("a".to_string(), vec![Scalar::I64(1)])]),
+            resolve_axes(&space, &[("a".to_string(), vec![Scalar::i64(1)])]),
             Err(BindError::MissingKnob("b".to_string())),
         );
     }
@@ -867,7 +867,7 @@ mod tests {
         // a MIXED-kind axis: the second element mismatches; per-element check must
         // catch it (a first-element-only check would pass it through to a panic).
         let space = vec![ParamSpec { name: "scale".into(), kind: ScalarKind::F64 }];
-        let axes = vec![("scale".to_string(), vec![Scalar::F64(0.5), Scalar::I64(1)])];
+        let axes = vec![("scale".to_string(), vec![Scalar::f64(0.5), Scalar::i64(1)])];
         assert_eq!(
             resolve_axes(&space, &axes),
             Err(BindError::KindMismatch {
@@ -907,16 +907,16 @@ mod tests {
         let named = resolve_axes(
             &space,
             &[
-                ("sma_cross.fast.length".to_string(), vec![Scalar::I64(2), Scalar::I64(3)]),
-                ("sma_cross.slow.length".to_string(), vec![Scalar::I64(4), Scalar::I64(5)]),
-                ("exposure.scale".to_string(), vec![Scalar::F64(0.5)]),
+                ("sma_cross.fast.length".to_string(), vec![Scalar::i64(2), Scalar::i64(3)]),
+                ("sma_cross.slow.length".to_string(), vec![Scalar::i64(4), Scalar::i64(5)]),
+                ("exposure.scale".to_string(), vec![Scalar::f64(0.5)]),
             ],
         )
         .expect("named axes resolve");
         let positional = vec![
-            vec![Scalar::I64(2), Scalar::I64(3)],
-            vec![Scalar::I64(4), Scalar::I64(5)],
-            vec![Scalar::F64(0.5)],
+            vec![Scalar::i64(2), Scalar::i64(3)],
+            vec![Scalar::i64(4), Scalar::i64(5)],
+            vec![Scalar::f64(0.5)],
         ];
         let named_pts = GridSpace::new(&space, named).expect("named grid").points();
         let pos_pts = GridSpace::new(&space, positional).expect("positional grid").points();
@@ -932,13 +932,13 @@ mod tests {
             ParamSpec { name: "scale".into(), kind: ScalarKind::F64 },
         ];
         let bound = vec![
-            ("scale".to_string(), Scalar::F64(0.5)),
-            ("sma_cross.fast".to_string(), Scalar::I64(2)),
-            ("sma_cross.slow".to_string(), Scalar::I64(4)),
+            ("scale".to_string(), Scalar::f64(0.5)),
+            ("sma_cross.fast".to_string(), Scalar::i64(2)),
+            ("sma_cross.slow".to_string(), Scalar::i64(4)),
         ];
         assert_eq!(
             resolve(&space, &bound),
-            Ok(vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)]),
+            Ok(vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)]),
         );
     }
 
@@ -946,7 +946,7 @@ mod tests {
     fn resolve_unknown_knob() {
         let space = vec![ParamSpec { name: "scale".into(), kind: ScalarKind::F64 }];
         assert_eq!(
-            resolve(&space, &[("nope".to_string(), Scalar::F64(0.5))]),
+            resolve(&space, &[("nope".to_string(), Scalar::f64(0.5))]),
             Err(BindError::UnknownKnob("nope".to_string())),
         );
     }
@@ -958,7 +958,7 @@ mod tests {
             ParamSpec { name: "b".into(), kind: ScalarKind::I64 },
         ];
         assert_eq!(
-            resolve(&space, &[("a".to_string(), Scalar::I64(1))]),
+            resolve(&space, &[("a".to_string(), Scalar::i64(1))]),
             Err(BindError::MissingKnob("b".to_string())),
         );
     }
@@ -967,7 +967,7 @@ mod tests {
     fn resolve_kind_mismatch() {
         let space = vec![ParamSpec { name: "scale".into(), kind: ScalarKind::F64 }];
         assert_eq!(
-            resolve(&space, &[("scale".to_string(), Scalar::I64(2))]),
+            resolve(&space, &[("scale".to_string(), Scalar::i64(2))]),
             Err(BindError::KindMismatch {
                 knob: "scale".to_string(),
                 expected: ScalarKind::F64,
@@ -982,7 +982,7 @@ mod tests {
         assert_eq!(
             resolve(
                 &space,
-                &[("a".to_string(), Scalar::I64(1)), ("a".to_string(), Scalar::I64(2))],
+                &[("a".to_string(), Scalar::i64(1)), ("a".to_string(), Scalar::i64(2))],
             ),
             Err(BindError::DuplicateBinding("a".to_string())),
         );
@@ -993,8 +993,8 @@ mod tests {
         // Phase-1 (unknown) wins over Phase-2 (kind mismatch)
         let space = vec![ParamSpec { name: "scale".into(), kind: ScalarKind::F64 }];
         let bound = vec![
-            ("typo".to_string(), Scalar::I64(9)),
-            ("scale".to_string(), Scalar::I64(2)),
+            ("typo".to_string(), Scalar::i64(9)),
+            ("scale".to_string(), Scalar::i64(2)),
         ];
         assert_eq!(resolve(&space, &bound), Err(BindError::UnknownKnob("typo".to_string())));
     }
@@ -1004,8 +1004,8 @@ mod tests {
         // intra-binding: check a (unknown) precedes check d (duplicate)
         let space = vec![ParamSpec { name: "a".into(), kind: ScalarKind::I64 }];
         let bound = vec![
-            ("typo".to_string(), Scalar::I64(1)),
-            ("typo".to_string(), Scalar::I64(2)),
+            ("typo".to_string(), Scalar::i64(1)),
+            ("typo".to_string(), Scalar::i64(2)),
         ];
         assert_eq!(resolve(&space, &bound), Err(BindError::UnknownKnob("typo".to_string())));
     }
@@ -1027,7 +1027,7 @@ mod tests {
 
         let (bp2, pos_eq, pos_ex) = composite_sma_cross_harness();
         let mut positional = bp2
-            .bootstrap_with_params(vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)])
+            .bootstrap_with_params(vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)])
             .expect("positional bootstrap");
         positional.run(vec![Box::new(VecSource::new(synthetic_prices()))]);
         let pos_eq_v = pos_eq.try_iter().collect::<Vec<_>>();
@@ -1066,7 +1066,7 @@ mod tests {
             if a.is_empty() || b.is_empty() {
                 return None;
             }
-            self.out[0] = Scalar::F64(a[0] + b[0]);
+            self.out[0] = Scalar::f64(a[0] + b[0]);
             Some(&self.out)
         }
     }
@@ -1084,7 +1084,7 @@ mod tests {
             if w.is_empty() {
                 return None;
             }
-            self.out[0] = Scalar::F64(w[0]);
+            self.out[0] = Scalar::f64(w[0]);
             Some(&self.out)
         }
     }
@@ -1116,7 +1116,7 @@ mod tests {
         PrimitiveBuilder::new(
             "Pass1",
             NodeSchema { inputs: vec![f64_any()], output: out_v(), params: vec![] },
-            |_| Box::new(Pass1 { out: [Scalar::F64(0.0)] }),
+            |_| Box::new(Pass1 { out: [Scalar::f64(0.0)] }),
         )
         .into()
     }
@@ -1124,7 +1124,7 @@ mod tests {
         PrimitiveBuilder::new(
             "Join2",
             NodeSchema { inputs: vec![f64_any(), f64_any()], output: out_v(), params: vec![] },
-            |_| Box::new(Join2 { out: [Scalar::F64(0.0)] }),
+            |_| Box::new(Join2 { out: [Scalar::f64(0.0)] }),
         )
         .into()
     }
@@ -1236,7 +1236,7 @@ mod tests {
         // distinct node names -> fan-in distinguishable -> compiles (the two SMA
         // length params are supplied so the only thing under test is the fan-in)
         let bp = sma_cross_under_root(true);
-        assert!(bp.compile_with_params(&[Scalar::I64(2), Scalar::I64(4)]).is_ok());
+        assert!(bp.compile_with_params(&[Scalar::i64(2), Scalar::i64(4)]).is_ok());
     }
 
     #[test]
@@ -1745,7 +1745,7 @@ mod tests {
         // (b) the same graph authored as a composite blueprint, compiled
         let (bp, comp_eq, comp_ex) = composite_sma_cross_harness();
         let mut composed = bp
-            .bootstrap_with_params(vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)])
+            .bootstrap_with_params(vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)])
             .expect("composite blueprint compiles");
         composed.run(vec![Box::new(VecSource::new(prices))]);
 
@@ -1808,7 +1808,7 @@ mod tests {
             vec![], // output
         );
         let mut h = bp
-            .bootstrap_with_params(vec![Scalar::I64(2), Scalar::I64(4)])
+            .bootstrap_with_params(vec![Scalar::i64(2), Scalar::i64(4)])
             .expect("multi-output composite bootstraps");
         h.run(vec![Box::new(VecSource::new(prices))]);
 
@@ -1825,13 +1825,13 @@ mod tests {
     fn injecting_a_different_vector_changes_the_run() {
         let prices = synthetic_prices();
         let (bp, eq, _ex) = composite_sma_cross_harness();
-        let mut a = bp.bootstrap_with_params(vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)])
+        let mut a = bp.bootstrap_with_params(vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)])
             .expect("compiles");
         a.run(vec![Box::new(VecSource::new(prices.clone()))]);
         let a_eq = eq.try_iter().collect::<Vec<_>>();
 
         let (bp2, eq2, _ex2) = composite_sma_cross_harness();
-        let mut b = bp2.bootstrap_with_params(vec![Scalar::I64(5), Scalar::I64(20), Scalar::F64(1.0)])
+        let mut b = bp2.bootstrap_with_params(vec![Scalar::i64(5), Scalar::i64(20), Scalar::f64(1.0)])
             .expect("compiles");
         b.run(vec![Box::new(VecSource::new(prices))]);
         let b_eq = eq2.try_iter().collect::<Vec<_>>();
@@ -1844,7 +1844,7 @@ mod tests {
     fn wrong_kind_is_a_param_kind_mismatch() {
         let (bp, _eq, _ex) = composite_sma_cross_harness();
         // slot 0 is I64 (an SMA length); inject F64 there
-        let err = bp.bootstrap_with_params(vec![Scalar::F64(2.0), Scalar::I64(4), Scalar::F64(0.5)])
+        let err = bp.bootstrap_with_params(vec![Scalar::f64(2.0), Scalar::i64(4), Scalar::f64(0.5)])
             .unwrap_err();
         assert!(matches!(err, CompileError::ParamKindMismatch { slot: 0, .. }));
     }
@@ -1853,13 +1853,13 @@ mod tests {
     fn wrong_arity_is_a_param_arity_error() {
         let (short, _e1, _x1) = composite_sma_cross_harness();
         assert!(matches!(
-            short.bootstrap_with_params(vec![Scalar::I64(2)]).unwrap_err(),
+            short.bootstrap_with_params(vec![Scalar::i64(2)]).unwrap_err(),
             CompileError::ParamArity { expected: 3, got: 1 }
         ));
         let (long, _e2, _x2) = composite_sma_cross_harness();
         assert!(matches!(
             long.bootstrap_with_params(
-                vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5), Scalar::F64(0.0)]
+                vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5), Scalar::f64(0.0)]
             ).unwrap_err(),
             CompileError::ParamArity { expected: 3, got: 4 }
         ));
@@ -1869,11 +1869,11 @@ mod tests {
     fn same_vector_bootstraps_identically() {
         let prices = synthetic_prices();
         let (bp, eq, _ex) = composite_sma_cross_harness();
-        let mut a = bp.bootstrap_with_params(vec![Scalar::I64(3), Scalar::I64(9), Scalar::F64(0.7)])
+        let mut a = bp.bootstrap_with_params(vec![Scalar::i64(3), Scalar::i64(9), Scalar::f64(0.7)])
             .expect("compiles");
         a.run(vec![Box::new(VecSource::new(prices.clone()))]);
         let (bp2, eq2, _ex2) = composite_sma_cross_harness();
-        let mut b = bp2.bootstrap_with_params(vec![Scalar::I64(3), Scalar::I64(9), Scalar::F64(0.7)])
+        let mut b = bp2.bootstrap_with_params(vec![Scalar::i64(3), Scalar::i64(9), Scalar::f64(0.7)])
             .expect("compiles");
         b.run(vec![Box::new(VecSource::new(prices))]);
         assert_eq!(eq.try_iter().collect::<Vec<_>>(), eq2.try_iter().collect::<Vec<_>>());
@@ -1896,7 +1896,7 @@ mod tests {
 
         // the same blueprint, actually compiled to its flat node array; each flat
         // node's own declared params, concatenated in flat-node order
-        let flat = bp.compile_with_params(&[Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)]).expect("harness compiles");
+        let flat = bp.compile_with_params(&[Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)]).expect("harness compiles");
         let from_flat: Vec<ParamSpec> =
             flat.signatures.iter().flat_map(|s| s.params.clone()).collect();
 
@@ -1981,7 +1981,7 @@ mod tests {
         let strat = Composite::new(
             "sma2_entry",
             vec![
-                Sma::builder().named("bias").bind("length", Scalar::I64(2)).into(),
+                Sma::builder().named("bias").bind("length", Scalar::i64(2)).into(),
                 Exposure::builder().named("exp").into(),
             ],
             vec![], // edges — irrelevant to param_space()
@@ -2055,7 +2055,7 @@ mod tests {
 
         // the same blueprint, compiled to its flat node array; each flat node's
         // own declared params, concatenated in flat-node order
-        let flat = bp.compile_with_params(&[Scalar::I64(2), Scalar::I64(4), Scalar::F64(1.0), Scalar::F64(-1.0)]).expect("nested composite compiles");
+        let flat = bp.compile_with_params(&[Scalar::i64(2), Scalar::i64(4), Scalar::f64(1.0), Scalar::f64(-1.0)]).expect("nested composite compiles");
         let from_flat: Vec<ParamSpec> =
             flat.signatures.iter().flat_map(|s| s.params.clone()).collect();
 
@@ -2190,7 +2190,7 @@ mod tests {
             vec![Role { name: "price".into(), targets: vec![Target { node: 0, slot: 0 }], source: Some(ScalarKind::F64) }],
             vec![],
         );
-        let err = root.compile_with_params(&[Scalar::I64(3)]);
+        let err = root.compile_with_params(&[Scalar::i64(3)]);
         // kind fault caught pre-build (no panic) — same variant bootstrap would give
         assert!(matches!(
             err,
@@ -2209,7 +2209,7 @@ mod tests {
         );
         // the Ok arm holds a FlatGraph (not Debug), so assert via the Err arm.
         assert_eq!(
-            root.compile_with_params(&[Scalar::I64(3)]).err(),
+            root.compile_with_params(&[Scalar::i64(3)]).err(),
             Some(CompileError::UnboundRootRole { role: 0 })
         );
     }
@@ -2262,7 +2262,7 @@ mod tests {
         // two params declared (one per SMA); supply both so the only failure under
         // test is the duplicate path (green today, DuplicateParamPath after).
         assert_eq!(
-            bp.compile_with_params(&[Scalar::I64(2), Scalar::I64(3)]).err(),
+            bp.compile_with_params(&[Scalar::i64(2), Scalar::i64(3)]).err(),
             Some(CompileError::DuplicateParamPath("dup.sma.length".to_string()))
         );
     }
@@ -2280,7 +2280,7 @@ mod tests {
         let paramless_sma = PrimitiveBuilder::new(
             "Pass1",
             NodeSchema { inputs: vec![f64_any()], output: out_v(), params: vec![] },
-            |_| Box::new(Pass1 { out: [Scalar::F64(0.0)] }),
+            |_| Box::new(Pass1 { out: [Scalar::f64(0.0)] }),
         )
         .named("sma");
         let asym = Composite::new(
@@ -2312,7 +2312,7 @@ mod tests {
             bp.param_space().into_iter().map(|p| p.name).collect::<Vec<_>>(),
             ["asym.sma.length"]
         );
-        assert!(bp.compile_with_params(&[Scalar::I64(2)]).is_ok());
+        assert!(bp.compile_with_params(&[Scalar::i64(2)]).is_ok());
     }
 
     #[test]
diff --git a/crates/aura-engine/src/builder.rs b/crates/aura-engine/src/builder.rs
index a87f38b..e7aa224 100644
--- a/crates/aura-engine/src/builder.rs
+++ b/crates/aura-engine/src/builder.rs
@@ -240,7 +240,7 @@ mod tests {
         // cancels in the comparison. Params size buffers, not topology (C11), so
         // edges/sources are param-independent; a fixed vector just satisfies the
         // arity gate compile() (no-param) trips on this value-empty harness.
-        let params = [Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)];
+        let params = [Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)];
 
         // hand-wired reference harness -> FlatGraph
         let (hand_bp, _rx_eq, _rx_ex) = composite_sma_cross_harness();
@@ -290,7 +290,7 @@ mod tests {
         let compiled = g
             .build()
             .expect("all port/field names resolve")
-            .compile_with_params(&[Scalar::F64(0.5)]);
+            .compile_with_params(&[Scalar::f64(0.5)]);
         assert_eq!(
             compiled.err(),
             Some(CompileError::UnconnectedPort { node: 1, slot: 0 })
diff --git a/crates/aura-engine/src/graph_model.rs b/crates/aura-engine/src/graph_model.rs
index 4fbaa48..8014c20 100644
--- a/crates/aura-engine/src/graph_model.rs
+++ b/crates/aura-engine/src/graph_model.rs
@@ -25,12 +25,12 @@ fn kind_str(k: ScalarKind) -> &'static str {
 /// whole values (`1.0`, not `1`) so a bound f64 is never mistaken for an i64 in
 /// the render. The value side of `kind_str`.
 fn scalar_str(s: aura_core::Scalar) -> String {
-    use aura_core::Scalar;
-    match s {
-        Scalar::I64(n) => n.to_string(),
-        Scalar::F64(f) => format!("{f:?}"),
-        Scalar::Bool(b) => b.to_string(),
-        Scalar::Ts(t) => t.0.to_string(),
+    use aura_core::ScalarKind;
+    match s.kind() {
+        ScalarKind::I64 => s.as_i64().to_string(),
+        ScalarKind::F64 => format!("{:?}", s.as_f64()),
+        ScalarKind::Bool => s.as_bool().to_string(),
+        ScalarKind::Timestamp => s.as_ts().0.to_string(),
     }
 }
 
@@ -426,13 +426,13 @@ mod tests {
     #[test]
     fn prim_record_emits_bound_only_when_bound() {
         // a bound i64 param → a "bound" field carrying [pos,"name","kind","value"]
-        let bound = prim_record(&Sma::builder().bind("length", Scalar::I64(5)));
+        let bound = prim_record(&Sma::builder().bind("length", Scalar::i64(5)));
         assert!(bound.contains(r#""bound":[[0,"length","i64","5"]]"#), "{bound}");
         // the bound slot also leaves the tunable "params" surface (bind's tuning side)
         assert!(bound.contains(r#""params":[]"#), "{bound}");
 
         // a bound f64 value renders canonically (shortest round-trip), e.g. 0.5
-        let f = prim_record(&Exposure::builder().bind("scale", Scalar::F64(0.5)));
+        let f = prim_record(&Exposure::builder().bind("scale", Scalar::f64(0.5)));
         assert!(f.contains(r#""bound":[[0,"scale","f64","0.5"]]"#), "{f}");
 
         // an unbound builder → no "bound" field at all
diff --git a/crates/aura-engine/src/harness.rs b/crates/aura-engine/src/harness.rs
index d158547..e67125f 100644
--- a/crates/aura-engine/src/harness.rs
+++ b/crates/aura-engine/src/harness.rs
@@ -183,7 +183,7 @@ impl SyntheticSpec {
             .map(|i| {
                 let shock = (rng.next_f64() - 0.5) * 0.004; // ±0.2% per step
                 price *= 1.0 + shock;
-                (Timestamp(i as i64 * self.step + 1), Scalar::F64(price))
+                (Timestamp(i as i64 * self.step + 1), Scalar::f64(price))
             })
             .collect();
         VecSource::new(stream)
@@ -492,7 +492,7 @@ mod tests {
 
     /// Build an f64 source stream from (timestamp, value) points.
     fn f64_stream(points: &[(i64, f64)]) -> Vec<(Timestamp, Scalar)> {
-        points.iter().map(|&(t, v)| (Timestamp(t), Scalar::F64(v))).collect()
+        points.iter().map(|&(t, v)| (Timestamp(t), Scalar::f64(v))).collect()
     }
 
     #[test]
@@ -527,19 +527,19 @@ mod tests {
 
     #[test]
     fn vec_source_peek_is_non_consuming_and_idempotent() {
-        let mut s = VecSource::new(vec![(Timestamp(1), Scalar::F64(10.0)), (Timestamp(2), Scalar::F64(20.0))]);
+        let mut s = VecSource::new(vec![(Timestamp(1), Scalar::f64(10.0)), (Timestamp(2), Scalar::f64(20.0))]);
         // peek twice: same head, no advance.
         assert_eq!(s.peek(), Some(Timestamp(1)));
         assert_eq!(s.peek(), Some(Timestamp(1)));
         // next pops it; peek now reflects the new head.
-        assert_eq!(Source::next(&mut s), Some((Timestamp(1), Scalar::F64(10.0))));
+        assert_eq!(Source::next(&mut s), Some((Timestamp(1), Scalar::f64(10.0))));
         assert_eq!(s.peek(), Some(Timestamp(2)));
     }
 
     #[test]
     fn vec_source_exhaustion_yields_none() {
-        let mut s = VecSource::new(vec![(Timestamp(5), Scalar::I64(7))]);
-        assert_eq!(Source::next(&mut s), Some((Timestamp(5), Scalar::I64(7))));
+        let mut s = VecSource::new(vec![(Timestamp(5), Scalar::i64(7))]);
+        assert_eq!(Source::next(&mut s), Some((Timestamp(5), Scalar::i64(7))));
         assert_eq!(s.peek(), None);
         assert_eq!(Source::next(&mut s), None);
     }
@@ -639,7 +639,7 @@ mod tests {
             if a.is_empty() || b.is_empty() {
                 return None;
             }
-            self.out[0] = Scalar::F64(a[0] + b[0]);
+            self.out[0] = Scalar::f64(a[0] + b[0]);
             Some(&self.out)
         }
     }
@@ -663,7 +663,7 @@ mod tests {
             vec![1, 1]
         }
         fn eval(&mut self, ctx: Ctx<'_>) -> Option<&[Scalar]> {
-            self.out[0] = Scalar::F64(ctx.f64_in(0)[0] + ctx.f64_in(1)[0]);
+            self.out[0] = Scalar::f64(ctx.f64_in(0)[0] + ctx.f64_in(1)[0]);
             Some(&self.out)
         }
     }
@@ -698,7 +698,7 @@ mod tests {
             if a.is_empty() || b.is_empty() || c.is_empty() {
                 return None;
             }
-            self.out[0] = Scalar::F64(a[0] + b[0] + c[0]);
+            self.out[0] = Scalar::f64(a[0] + b[0] + c[0]);
             Some(&self.out)
         }
     }
@@ -735,7 +735,7 @@ mod tests {
                 if w.is_empty() {
                     return None; // not yet warmed
                 }
-                self.out[i] = Scalar::F64(w[0]);
+                self.out[i] = Scalar::f64(w[0]);
             }
             Some(&self.out) // one 5-field record, all fields co-fresh
         }
@@ -765,8 +765,8 @@ mod tests {
             vec![1]
         }
         fn eval(&mut self, _ctx: Ctx<'_>) -> Option<&[Scalar]> {
-            self.out[0] = Scalar::F64(0.0);
-            self.out[1] = Scalar::I64(0);
+            self.out[0] = Scalar::f64(0.0);
+            self.out[1] = Scalar::i64(0);
             Some(&self.out)
         }
     }
@@ -797,8 +797,8 @@ mod tests {
                 return None;
             }
             let v = w[0];
-            let _ = self.tx.send((ctx.now(), vec![Scalar::F64(v)])); // sink side effect
-            self.out[0] = Scalar::F64(v);
+            let _ = self.tx.send((ctx.now(), vec![Scalar::f64(v)])); // sink side effect
+            self.out[0] = Scalar::f64(v);
             Some(&self.out) // producer output: engine forwards it
         }
     }
@@ -827,9 +827,9 @@ mod tests {
         assert_eq!(
             got,
             vec![
-                (Timestamp(3), vec![Scalar::F64(2.0)]),
-                (Timestamp(4), vec![Scalar::F64(3.0)]),
-                (Timestamp(5), vec![Scalar::F64(4.0)]),
+                (Timestamp(3), vec![Scalar::f64(2.0)]),
+                (Timestamp(4), vec![Scalar::f64(3.0)]),
+                (Timestamp(5), vec![Scalar::f64(4.0)]),
             ]
         );
     }
@@ -874,9 +874,9 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(4), vec![Scalar::F64(2.0)]),
-                (Timestamp(5), vec![Scalar::F64(2.0)]),
-                (Timestamp(6), vec![Scalar::F64(2.0)]),
+                (Timestamp(4), vec![Scalar::f64(2.0)]),
+                (Timestamp(5), vec![Scalar::f64(2.0)]),
+                (Timestamp(6), vec![Scalar::f64(2.0)]),
             ]
         );
 
@@ -895,7 +895,7 @@ mod tests {
         let build = |tx| {
             boot(
                 vec![
-                    Box::new(AsOfSum { out: [Scalar::F64(0.0)] }),
+                    Box::new(AsOfSum { out: [Scalar::f64(0.0)] }),
                     Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
                 ],
             vec![
@@ -921,10 +921,10 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(2), vec![Scalar::F64(120.0)]),
-                (Timestamp(3), vec![Scalar::F64(130.0)]),
-                (Timestamp(4), vec![Scalar::F64(140.0)]),
-                (Timestamp(4), vec![Scalar::F64(240.0)]),
+                (Timestamp(2), vec![Scalar::f64(120.0)]),
+                (Timestamp(3), vec![Scalar::f64(130.0)]),
+                (Timestamp(4), vec![Scalar::f64(140.0)]),
+                (Timestamp(4), vec![Scalar::f64(240.0)]),
             ]
         );
 
@@ -941,7 +941,7 @@ mod tests {
         let build = |tx| {
             boot(
                 vec![
-                    Box::new(BarrierSum { out: [Scalar::F64(0.0)] }),
+                    Box::new(BarrierSum { out: [Scalar::f64(0.0)] }),
                     Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
                 ],
             vec![
@@ -967,8 +967,8 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(2), vec![Scalar::F64(120.0)]),
-                (Timestamp(4), vec![Scalar::F64(240.0)]),
+                (Timestamp(2), vec![Scalar::f64(120.0)]),
+                (Timestamp(4), vec![Scalar::f64(240.0)]),
             ]
         );
 
@@ -990,7 +990,7 @@ mod tests {
                 vec![
                     Box::new(Sma::new(2)),
                     Box::new(Sma::new(4)),
-                    Box::new(BarrierSum { out: [Scalar::F64(0.0)] }),
+                    Box::new(BarrierSum { out: [Scalar::f64(0.0)] }),
                     Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
                 ],
             vec![
@@ -1022,9 +1022,9 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(4), vec![Scalar::F64(28.0)]),
-                (Timestamp(5), vec![Scalar::F64(32.0)]),
-                (Timestamp(6), vec![Scalar::F64(36.0)]),
+                (Timestamp(4), vec![Scalar::f64(28.0)]),
+                (Timestamp(5), vec![Scalar::f64(32.0)]),
+                (Timestamp(6), vec![Scalar::f64(36.0)]),
             ]
         );
 
@@ -1041,7 +1041,7 @@ mod tests {
         let (tx, rx) = mpsc::channel();
         let mut h = boot(
             vec![
-                Box::new(MixedSum { out: [Scalar::F64(0.0)] }),
+                Box::new(MixedSum { out: [Scalar::f64(0.0)] }),
                 Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
             ],
             vec![
@@ -1067,8 +1067,8 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(2), vec![Scalar::F64(221.0)]),
-                (Timestamp(3), vec![Scalar::F64(223.0)]),
+                (Timestamp(2), vec![Scalar::f64(221.0)]),
+                (Timestamp(3), vec![Scalar::f64(223.0)]),
             ]
         );
     }
@@ -1153,7 +1153,7 @@ mod tests {
         let (tx, rx) = mpsc::channel();
         let mut h = boot(
             vec![
-                Box::new(Ohlcv { out: [Scalar::F64(0.0); 5] }),
+                Box::new(Ohlcv { out: [Scalar::f64(0.0); 5] }),
                 Box::new(Recorder::new(
                     &[ScalarKind::F64, ScalarKind::F64, ScalarKind::F64, ScalarKind::F64, ScalarKind::F64],
                     Firing::Any,
@@ -1180,18 +1180,18 @@ mod tests {
             out,
             vec![
                 (Timestamp(1), vec![
-                    Scalar::F64(10.0),
-                    Scalar::F64(15.0),
-                    Scalar::F64(8.0),
-                    Scalar::F64(12.0),
-                    Scalar::F64(100.0),
+                    Scalar::f64(10.0),
+                    Scalar::f64(15.0),
+                    Scalar::f64(8.0),
+                    Scalar::f64(12.0),
+                    Scalar::f64(100.0),
                 ]),
                 (Timestamp(2), vec![
-                    Scalar::F64(20.0),
-                    Scalar::F64(25.0),
-                    Scalar::F64(19.0),
-                    Scalar::F64(22.0),
-                    Scalar::F64(200.0),
+                    Scalar::f64(20.0),
+                    Scalar::f64(25.0),
+                    Scalar::f64(19.0),
+                    Scalar::f64(22.0),
+                    Scalar::f64(200.0),
                 ]),
             ]
         );
@@ -1206,7 +1206,7 @@ mod tests {
         let build = |tx| {
             boot(
                 vec![
-                    Box::new(Ohlcv { out: [Scalar::F64(0.0); 5] }),
+                    Box::new(Ohlcv { out: [Scalar::f64(0.0); 5] }),
                     Box::new(Sub::new()),
                     Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
                 ],
@@ -1232,8 +1232,8 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(1), vec![Scalar::F64(7.0)]),
-                (Timestamp(2), vec![Scalar::F64(6.0)]),
+                (Timestamp(1), vec![Scalar::f64(7.0)]),
+                (Timestamp(2), vec![Scalar::f64(6.0)]),
             ]
         );
 
@@ -1252,7 +1252,7 @@ mod tests {
         let (tx, rx) = mpsc::channel();
         let mut h = boot(
             vec![
-                Box::new(Ohlcv { out: [Scalar::F64(0.0); 5] }),
+                Box::new(Ohlcv { out: [Scalar::f64(0.0); 5] }),
                 Box::new(Sub::new()),
                 Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
             ],
@@ -1275,8 +1275,8 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(1), vec![Scalar::F64(2.0)]),
-                (Timestamp(2), vec![Scalar::F64(2.0)]),
+                (Timestamp(1), vec![Scalar::f64(2.0)]),
+                (Timestamp(2), vec![Scalar::f64(2.0)]),
             ]
         );
     }
@@ -1304,7 +1304,7 @@ mod tests {
         // Sma(1)'s f64 input slot is a per-field kind mismatch -> KindMismatch. (The
         // mismatch is field-specific: from_field 0 would have matched.)
         let err = boot(
-            vec![Box::new(TwoField { out: [Scalar::F64(0.0), Scalar::I64(0)] }), Box::new(Sma::new(1))],
+            vec![Box::new(TwoField { out: [Scalar::f64(0.0), Scalar::i64(0)] }), Box::new(Sma::new(1))],
             vec![
                 TwoField::sig(),
                 Sma::builder().schema().clone(),
@@ -1355,17 +1355,17 @@ mod tests {
         assert_eq!(
             fast,
             vec![
-                (Timestamp(2), vec![Scalar::F64(11.0)]),
-                (Timestamp(3), vec![Scalar::F64(13.0)]),
-                (Timestamp(4), vec![Scalar::F64(15.0)]),
-                (Timestamp(5), vec![Scalar::F64(17.0)]),
+                (Timestamp(2), vec![Scalar::f64(11.0)]),
+                (Timestamp(3), vec![Scalar::f64(13.0)]),
+                (Timestamp(4), vec![Scalar::f64(15.0)]),
+                (Timestamp(5), vec![Scalar::f64(17.0)]),
             ]
         );
         assert_eq!(
             slow,
             vec![
-                (Timestamp(4), vec![Scalar::F64(13.0)]),
-                (Timestamp(5), vec![Scalar::F64(15.0)]),
+                (Timestamp(4), vec![Scalar::f64(13.0)]),
+                (Timestamp(5), vec![Scalar::f64(15.0)]),
             ]
         );
     }
@@ -1377,7 +1377,7 @@ mod tests {
         let (tx, rx) = mpsc::channel();
         let mut h = boot(
             vec![
-                Box::new(Ohlcv { out: [Scalar::F64(0.0); 5] }),
+                Box::new(Ohlcv { out: [Scalar::f64(0.0); 5] }),
                 Box::new(Recorder::new(
                     &[ScalarKind::F64, ScalarKind::F64, ScalarKind::F64, ScalarKind::F64, ScalarKind::F64],
                     Firing::Any,
@@ -1411,11 +1411,11 @@ mod tests {
         assert_eq!(
             out,
             vec![(Timestamp(1), vec![
-                Scalar::F64(10.0),
-                Scalar::F64(15.0),
-                Scalar::F64(8.0),
-                Scalar::F64(12.0),
-                Scalar::F64(100.0),
+                Scalar::f64(10.0),
+                Scalar::f64(15.0),
+                Scalar::f64(8.0),
+                Scalar::f64(12.0),
+                Scalar::f64(100.0),
             ])]
         );
     }
@@ -1446,19 +1446,19 @@ mod tests {
         )
         .expect("valid");
         h.run(vec![
-            Box::new(VecSource::new(vec![(Timestamp(1), Scalar::I64(7))])),
-            Box::new(VecSource::new(vec![(Timestamp(2), Scalar::F64(1.5))])),
-            Box::new(VecSource::new(vec![(Timestamp(3), Scalar::Bool(true))])),
-            Box::new(VecSource::new(vec![(Timestamp(4), Scalar::Ts(Timestamp(99)))])),
+            Box::new(VecSource::new(vec![(Timestamp(1), Scalar::i64(7))])),
+            Box::new(VecSource::new(vec![(Timestamp(2), Scalar::f64(1.5))])),
+            Box::new(VecSource::new(vec![(Timestamp(3), Scalar::bool(true))])),
+            Box::new(VecSource::new(vec![(Timestamp(4), Scalar::ts(Timestamp(99)))])),
         ]);
         let out: Vec<(Timestamp, Vec<Scalar>)> = rx.try_iter().collect();
         assert_eq!(
             out,
             vec![(Timestamp(4), vec![
-                Scalar::I64(7),
-                Scalar::F64(1.5),
-                Scalar::Bool(true),
-                Scalar::Ts(Timestamp(99)),
+                Scalar::i64(7),
+                Scalar::f64(1.5),
+                Scalar::bool(true),
+                Scalar::ts(Timestamp(99)),
             ])]
         );
     }
@@ -1472,7 +1472,7 @@ mod tests {
         let (tx_down, rx_down) = mpsc::channel();
         let mut h = boot(
             vec![
-                Box::new(TapForward { out: [Scalar::F64(0.0)], tx: tx_tap }),
+                Box::new(TapForward { out: [Scalar::f64(0.0)], tx: tx_tap }),
                 Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx_down)),
             ],
             vec![
@@ -1487,9 +1487,9 @@ mod tests {
         let tapped: Vec<(Timestamp, Vec<Scalar>)> = rx_tap.try_iter().collect();
         let downstream: Vec<(Timestamp, Vec<Scalar>)> = rx_down.try_iter().collect();
         let expected = vec![
-            (Timestamp(1), vec![Scalar::F64(10.0)]),
-            (Timestamp(2), vec![Scalar::F64(20.0)]),
-            (Timestamp(3), vec![Scalar::F64(30.0)]),
+            (Timestamp(1), vec![Scalar::f64(10.0)]),
+            (Timestamp(2), vec![Scalar::f64(20.0)]),
+            (Timestamp(3), vec![Scalar::f64(30.0)]),
         ];
         assert_eq!(tapped, expected); // it recorded (sink side effect)
         assert_eq!(downstream, expected); // and forwarded (producer output)
@@ -1559,8 +1559,8 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(2), vec![Scalar::F64(20.0), Scalar::F64(100.0)]),
-                (Timestamp(4), vec![Scalar::F64(40.0), Scalar::F64(200.0)]),
+                (Timestamp(2), vec![Scalar::f64(20.0), Scalar::f64(100.0)]),
+                (Timestamp(4), vec![Scalar::f64(40.0), Scalar::f64(200.0)]),
             ]
         );
     }
@@ -1595,10 +1595,10 @@ mod tests {
         assert_eq!(
             out,
             vec![
-                (Timestamp(2), vec![Scalar::F64(20.0), Scalar::F64(100.0)]),
-                (Timestamp(3), vec![Scalar::F64(30.0), Scalar::F64(100.0)]),
-                (Timestamp(4), vec![Scalar::F64(40.0), Scalar::F64(100.0)]),
-                (Timestamp(4), vec![Scalar::F64(40.0), Scalar::F64(200.0)]),
+                (Timestamp(2), vec![Scalar::f64(20.0), Scalar::f64(100.0)]),
+                (Timestamp(3), vec![Scalar::f64(30.0), Scalar::f64(100.0)]),
+                (Timestamp(4), vec![Scalar::f64(40.0), Scalar::f64(100.0)]),
+                (Timestamp(4), vec![Scalar::f64(40.0), Scalar::f64(200.0)]),
             ]
         );
     }
@@ -1611,7 +1611,7 @@ mod tests {
         let (tx, _rx) = mpsc::channel();
         let err = boot(
             vec![
-                Box::new(TwoField { out: [Scalar::F64(0.0), Scalar::I64(0)] }),
+                Box::new(TwoField { out: [Scalar::f64(0.0), Scalar::i64(0)] }),
                 Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, tx)),
             ],
             vec![
@@ -1679,9 +1679,9 @@ mod tests {
         let s3: Vec<(Timestamp, Vec<Scalar>)> = rc.try_iter().collect();
         // SMA(3) warms at cycle 3: mean(2,4,6)=4, mean(4,6,8)=6, mean(6,8,10)=8.
         let expected = vec![
-            (Timestamp(3), vec![Scalar::F64(4.0)]),
-            (Timestamp(4), vec![Scalar::F64(6.0)]),
-            (Timestamp(5), vec![Scalar::F64(8.0)]),
+            (Timestamp(3), vec![Scalar::f64(4.0)]),
+            (Timestamp(4), vec![Scalar::f64(6.0)]),
+            (Timestamp(5), vec![Scalar::f64(8.0)]),
         ];
         assert_eq!(s1, expected);
         assert_eq!(s2, expected); // every tap sees the identical shared stream
@@ -1743,17 +1743,17 @@ mod tests {
         let sub: Vec<(Timestamp, Vec<Scalar>)> = rs.try_iter().collect();
         // SMA(2): 11,13,15,17,19 at cycles 2..6 (raw tap).
         let raw_expected = vec![
-            (Timestamp(2), vec![Scalar::F64(11.0)]),
-            (Timestamp(3), vec![Scalar::F64(13.0)]),
-            (Timestamp(4), vec![Scalar::F64(15.0)]),
-            (Timestamp(5), vec![Scalar::F64(17.0)]),
-            (Timestamp(6), vec![Scalar::F64(19.0)]),
+            (Timestamp(2), vec![Scalar::f64(11.0)]),
+            (Timestamp(3), vec![Scalar::f64(13.0)]),
+            (Timestamp(4), vec![Scalar::f64(15.0)]),
+            (Timestamp(5), vec![Scalar::f64(17.0)]),
+            (Timestamp(6), vec![Scalar::f64(19.0)]),
         ];
         // Sub warms once SMA(4) is warm (cycle 4): 15-13, 17-15, 19-17 -> 2.
         let sub_expected = vec![
-            (Timestamp(4), vec![Scalar::F64(2.0)]),
-            (Timestamp(5), vec![Scalar::F64(2.0)]),
-            (Timestamp(6), vec![Scalar::F64(2.0)]),
+            (Timestamp(4), vec![Scalar::f64(2.0)]),
+            (Timestamp(5), vec![Scalar::f64(2.0)]),
+            (Timestamp(6), vec![Scalar::f64(2.0)]),
         ];
         assert_eq!(raw, raw_expected);
         assert_eq!(sub, sub_expected);
@@ -1778,7 +1778,7 @@ mod tests {
                 vec![
                     Box::new(Sma::new(2)),                                  // 0: shared producer (src A)
                     Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, t_any)), // 1: as-of tap of 0
-                    Box::new(BarrierSum { out: [Scalar::F64(0.0)] }),       // 2: SMA(2) + src B (barrier)
+                    Box::new(BarrierSum { out: [Scalar::f64(0.0)] }),       // 2: SMA(2) + src B (barrier)
                     Box::new(Recorder::new(&[ScalarKind::F64], Firing::Any, t_bar)), // 3: tap of barrier
                 ],
             vec![
@@ -1810,15 +1810,15 @@ mod tests {
         let bar: Vec<(Timestamp, Vec<Scalar>)> = rbar.try_iter().collect();
         // As-of tap records every SMA(2) fire: 11@t2, 13@t3, 15@t4.
         let any_expected = vec![
-            (Timestamp(2), vec![Scalar::F64(11.0)]),
-            (Timestamp(3), vec![Scalar::F64(13.0)]),
-            (Timestamp(4), vec![Scalar::F64(15.0)]),
+            (Timestamp(2), vec![Scalar::f64(11.0)]),
+            (Timestamp(3), vec![Scalar::f64(13.0)]),
+            (Timestamp(4), vec![Scalar::f64(15.0)]),
         ];
         // Barrier fires only where held SMA output and src B share a timestamp:
         // t=2 (SMA held=11 + B=100 = 111), t=4 (SMA held=15 + B=200 = 215).
         let bar_expected = vec![
-            (Timestamp(2), vec![Scalar::F64(111.0)]),
-            (Timestamp(4), vec![Scalar::F64(215.0)]),
+            (Timestamp(2), vec![Scalar::f64(111.0)]),
+            (Timestamp(4), vec![Scalar::f64(215.0)]),
         ];
         assert_eq!(any, any_expected);
         assert_eq!(bar, bar_expected);
@@ -1870,8 +1870,8 @@ mod tests {
         let out: Vec<(Timestamp, Vec<Scalar>)> = rx.try_iter().collect();
         // stage1 (c2..c5): 3,5,7,9. stage2 (c3..): 4,6,8. stage3 (c4..): 5,7.
         let expected = vec![
-            (Timestamp(4), vec![Scalar::F64(5.0)]),
-            (Timestamp(5), vec![Scalar::F64(7.0)]),
+            (Timestamp(4), vec![Scalar::f64(5.0)]),
+            (Timestamp(5), vec![Scalar::f64(7.0)]),
         ];
         assert_eq!(out, expected);
 
@@ -1932,19 +1932,19 @@ mod tests {
         let w3: Vec<(Timestamp, Vec<Scalar>)> = rb.try_iter().collect();
         let w4: Vec<(Timestamp, Vec<Scalar>)> = rc.try_iter().collect();
         let e2 = vec![
-            (Timestamp(2), vec![Scalar::F64(11.0)]),
-            (Timestamp(3), vec![Scalar::F64(13.0)]),
-            (Timestamp(4), vec![Scalar::F64(15.0)]),
-            (Timestamp(5), vec![Scalar::F64(17.0)]),
+            (Timestamp(2), vec![Scalar::f64(11.0)]),
+            (Timestamp(3), vec![Scalar::f64(13.0)]),
+            (Timestamp(4), vec![Scalar::f64(15.0)]),
+            (Timestamp(5), vec![Scalar::f64(17.0)]),
         ];
         let e3 = vec![
-            (Timestamp(3), vec![Scalar::F64(12.0)]),
-            (Timestamp(4), vec![Scalar::F64(14.0)]),
-            (Timestamp(5), vec![Scalar::F64(16.0)]),
+            (Timestamp(3), vec![Scalar::f64(12.0)]),
+            (Timestamp(4), vec![Scalar::f64(14.0)]),
+            (Timestamp(5), vec![Scalar::f64(16.0)]),
         ];
         let e4 = vec![
-            (Timestamp(4), vec![Scalar::F64(13.0)]),
-            (Timestamp(5), vec![Scalar::F64(15.0)]),
+            (Timestamp(4), vec![Scalar::f64(13.0)]),
+            (Timestamp(5), vec![Scalar::f64(15.0)]),
         ];
         assert_eq!(w2, e2);
         assert_eq!(w3, e3);
@@ -2005,9 +2005,9 @@ mod tests {
         let prices =
             f64_stream(&[(1, 10.0), (2, 12.0), (3, 14.0), (4, 16.0), (5, 18.0), (6, 20.0)]);
         let counts: Vec<(Timestamp, Scalar)> = vec![
-            (Timestamp(1), Scalar::I64(7)),
-            (Timestamp(2), Scalar::I64(8)),
-            (Timestamp(3), Scalar::I64(9)),
+            (Timestamp(1), Scalar::i64(7)),
+            (Timestamp(2), Scalar::i64(8)),
+            (Timestamp(3), Scalar::i64(9)),
         ];
 
         let (tr, rr) = mpsc::channel();
@@ -2019,21 +2019,21 @@ mod tests {
         let sub: Vec<(Timestamp, Vec<Scalar>)> = rs.try_iter().collect();
         let i64s: Vec<(Timestamp, Vec<Scalar>)> = ri.try_iter().collect();
         let raw_expected = vec![
-            (Timestamp(2), vec![Scalar::F64(11.0)]),
-            (Timestamp(3), vec![Scalar::F64(13.0)]),
-            (Timestamp(4), vec![Scalar::F64(15.0)]),
-            (Timestamp(5), vec![Scalar::F64(17.0)]),
-            (Timestamp(6), vec![Scalar::F64(19.0)]),
+            (Timestamp(2), vec![Scalar::f64(11.0)]),
+            (Timestamp(3), vec![Scalar::f64(13.0)]),
+            (Timestamp(4), vec![Scalar::f64(15.0)]),
+            (Timestamp(5), vec![Scalar::f64(17.0)]),
+            (Timestamp(6), vec![Scalar::f64(19.0)]),
         ];
         let sub_expected = vec![
-            (Timestamp(4), vec![Scalar::F64(2.0)]),
-            (Timestamp(5), vec![Scalar::F64(2.0)]),
-            (Timestamp(6), vec![Scalar::F64(2.0)]),
+            (Timestamp(4), vec![Scalar::f64(2.0)]),
+            (Timestamp(5), vec![Scalar::f64(2.0)]),
+            (Timestamp(6), vec![Scalar::f64(2.0)]),
         ];
         let i64_expected = vec![
-            (Timestamp(1), vec![Scalar::I64(7)]),
-            (Timestamp(2), vec![Scalar::I64(8)]),
-            (Timestamp(3), vec![Scalar::I64(9)]),
+            (Timestamp(1), vec![Scalar::i64(7)]),
+            (Timestamp(2), vec![Scalar::i64(8)]),
+            (Timestamp(3), vec![Scalar::i64(9)]),
         ];
         assert_eq!(raw, raw_expected);
         assert_eq!(sub, sub_expected);
@@ -2105,12 +2105,11 @@ mod tests {
         // flat until SMA(4) warms (cycle 4) and the held exposure meets the next
         // price move (cycle 5): the first four equities are exactly 0.
         for (_, row) in &equity[0..4] {
-            assert_eq!(row, &vec![Scalar::F64(0.0)]);
+            assert_eq!(row, &vec![Scalar::f64(0.0)]);
         }
         // cycle 5: prev_exposure 0.00175 * (1.0040 - 1.0020) / 0.0001 = 0.035 pips
-        let Scalar::F64(last) = equity[4].1[0] else {
-            panic!("equity is f64");
-        };
+        debug_assert_eq!(equity[4].1[0].kind(), ScalarKind::F64, "equity is f64");
+        let last = equity[4].1[0].as_f64();
         assert!((last - 0.035).abs() < 1e-9, "final equity = {last}, want ~0.035");
     }
 
diff --git a/crates/aura-engine/src/lib.rs b/crates/aura-engine/src/lib.rs
index b048c74..9d8b199 100644
--- a/crates/aura-engine/src/lib.rs
+++ b/crates/aura-engine/src/lib.rs
@@ -86,7 +86,7 @@ mod reexport_tests {
         use crate::{Firing, Scalar, ScalarKind, Timestamp};
         let _k: ScalarKind = ScalarKind::F64;
         let _f: Firing = Firing::Any;
-        let _s: Scalar = Scalar::F64(0.0);
+        let _s: Scalar = Scalar::f64(0.0);
         let _t: Timestamp = Timestamp(0);
     }
 }
diff --git a/crates/aura-engine/src/mc.rs b/crates/aura-engine/src/mc.rs
index bc315b7..87c0f76 100644
--- a/crates/aura-engine/src/mc.rs
+++ b/crates/aura-engine/src/mc.rs
@@ -188,7 +188,7 @@ mod tests {
 
     fn base_point() -> Vec<Scalar> {
         // matches the composite_sma_cross param_space order: fast, slow, scale
-        vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)]
+        vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)]
     }
 
     fn draws_with_metrics(values: &[f64]) -> Vec<McDraw> {
diff --git a/crates/aura-engine/src/report.rs b/crates/aura-engine/src/report.rs
index cea3189..256bdd8 100644
--- a/crates/aura-engine/src/report.rs
+++ b/crates/aura-engine/src/report.rs
@@ -8,7 +8,7 @@
 //! cycle 0029) — the same encoder the run registry uses, so a record's stdout
 //! and on-disk shapes coincide.
 
-use aura_core::{Scalar, Timestamp};
+use aura_core::{Scalar, ScalarKind, Timestamp};
 
 /// Summary metrics reduced from a run's recorded streams — the `-> metrics`
 /// half of C12's atomic sim unit. Pure function of the recorded streams.
@@ -134,10 +134,10 @@ pub fn f64_field(rows: &[(Timestamp, Vec<Scalar>)], field: usize) -> Vec<(Timest
             let Some(&scalar) = row.get(field) else {
                 panic!("f64_field: row has no field {field} (row width {})", row.len());
             };
-            let Scalar::F64(v) = scalar else {
+            if scalar.kind() != ScalarKind::F64 {
                 panic!("f64_field: field {field} is not an f64 scalar: {scalar:?}");
-            };
-            (*ts, v)
+            }
+            (*ts, scalar.as_f64())
         })
         .collect()
 }
@@ -164,7 +164,7 @@ mod tests {
     /// harness.rs test helper; the e2e test needs its own copy — the harness
     /// test module's is private to that module).
     fn f64_stream(points: &[(i64, f64)]) -> Vec<(Timestamp, Scalar)> {
-        points.iter().map(|&(t, v)| (Timestamp(t), Scalar::F64(v))).collect()
+        points.iter().map(|&(t, v)| (Timestamp(t), Scalar::f64(v))).collect()
     }
 
     /// Bootstrap the cycle-0007 signal-quality harness with TWO sinks: one on
@@ -316,8 +316,8 @@ mod tests {
     #[test]
     fn f64_field_projects_the_named_field() {
         let rows = vec![
-            (Timestamp(1), vec![Scalar::F64(1.5), Scalar::I64(9)]),
-            (Timestamp(2), vec![Scalar::F64(2.5), Scalar::I64(8)]),
+            (Timestamp(1), vec![Scalar::f64(1.5), Scalar::i64(9)]),
+            (Timestamp(2), vec![Scalar::f64(2.5), Scalar::i64(8)]),
         ];
         assert_eq!(
             f64_field(&rows, 0),
@@ -328,7 +328,7 @@ mod tests {
     #[test]
     #[should_panic(expected = "not an f64 scalar")]
     fn f64_field_panics_on_kind_mismatch() {
-        let rows = vec![(Timestamp(1), vec![Scalar::I64(7)])];
+        let rows = vec![(Timestamp(1), vec![Scalar::i64(7)])];
         let _ = f64_field(&rows, 0);
     }
 
diff --git a/crates/aura-engine/src/sweep.rs b/crates/aura-engine/src/sweep.rs
index 0e28f51..ae1b53f 100644
--- a/crates/aura-engine/src/sweep.rs
+++ b/crates/aura-engine/src/sweep.rs
@@ -217,18 +217,18 @@ mod tests {
         let grid = GridSpace::new(
             &space,
             vec![
-                vec![Scalar::I64(2), Scalar::I64(3)],
-                vec![Scalar::I64(4), Scalar::I64(5)],
+                vec![Scalar::i64(2), Scalar::i64(3)],
+                vec![Scalar::i64(4), Scalar::i64(5)],
             ],
         )
         .expect("valid grid");
         assert_eq!(
             grid.points(),
             vec![
-                vec![Scalar::I64(2), Scalar::I64(4)],
-                vec![Scalar::I64(2), Scalar::I64(5)],
-                vec![Scalar::I64(3), Scalar::I64(4)],
-                vec![Scalar::I64(3), Scalar::I64(5)],
+                vec![Scalar::i64(2), Scalar::i64(4)],
+                vec![Scalar::i64(2), Scalar::i64(5)],
+                vec![Scalar::i64(3), Scalar::i64(4)],
+                vec![Scalar::i64(3), Scalar::i64(5)],
             ],
         );
     }
@@ -243,9 +243,9 @@ mod tests {
         let grid = GridSpace::new(
             &space,
             vec![
-                vec![Scalar::I64(2), Scalar::I64(3)],
-                vec![Scalar::I64(4), Scalar::I64(5)],
-                vec![Scalar::F64(0.5)],
+                vec![Scalar::i64(2), Scalar::i64(3)],
+                vec![Scalar::i64(4), Scalar::i64(5)],
+                vec![Scalar::f64(0.5)],
             ],
         )
         .expect("valid grid");
@@ -256,14 +256,14 @@ mod tests {
     #[test]
     fn arity_mismatch_is_an_error() {
         let space = i64_space(2);
-        let err = GridSpace::new(&space, vec![vec![Scalar::I64(2)]]).unwrap_err();
+        let err = GridSpace::new(&space, vec![vec![Scalar::i64(2)]]).unwrap_err();
         assert_eq!(err, SweepError::Arity { expected: 2, got: 1 });
     }
 
     #[test]
     fn wrong_kind_is_a_kind_mismatch() {
         let space = i64_space(1);
-        let err = GridSpace::new(&space, vec![vec![Scalar::F64(1.0)]]).unwrap_err();
+        let err = GridSpace::new(&space, vec![vec![Scalar::f64(1.0)]]).unwrap_err();
         assert_eq!(
             err,
             SweepError::KindMismatch {
@@ -312,9 +312,9 @@ mod tests {
         GridSpace::new(
             &space,
             vec![
-                vec![Scalar::I64(2), Scalar::I64(3)], // fast  ∈ {2, 3}
-                vec![Scalar::I64(4), Scalar::I64(5)], // slow  ∈ {4, 5}
-                vec![Scalar::F64(0.5)],               // scale ∈ {0.5}
+                vec![Scalar::i64(2), Scalar::i64(3)], // fast  ∈ {2, 3}
+                vec![Scalar::i64(4), Scalar::i64(5)], // slow  ∈ {4, 5}
+                vec![Scalar::f64(0.5)],               // scale ∈ {0.5}
             ],
         )
         .expect("grid matches the sample param-space")
@@ -328,11 +328,11 @@ mod tests {
         // params carried in enumeration (odometer) order, self-describing
         assert_eq!(
             family.points[0].params,
-            vec![Scalar::I64(2), Scalar::I64(4), Scalar::F64(0.5)],
+            vec![Scalar::i64(2), Scalar::i64(4), Scalar::f64(0.5)],
         );
         assert_eq!(
             family.points[3].params,
-            vec![Scalar::I64(3), Scalar::I64(5), Scalar::F64(0.5)],
+            vec![Scalar::i64(3), Scalar::i64(5), Scalar::f64(0.5)],
         );
         // each point's metrics equal a direct, independent run of the same point:
         // the sweep adds enumeration + execution, never a metrics change (C1).
@@ -361,7 +361,7 @@ mod tests {
             .map(|(ps, v)| (ps.name, v))
             .collect();
         assert_eq!(family.named_params(0), expected);
-        assert_eq!(family.named_params(0)[0].1, Scalar::I64(2));
+        assert_eq!(family.named_params(0)[0].1, Scalar::i64(2));
     }
 
     #[test]
diff --git a/crates/aura-engine/src/test_fixtures.rs b/crates/aura-engine/src/test_fixtures.rs
index f998e1f..6c65011 100644
--- a/crates/aura-engine/src/test_fixtures.rs
+++ b/crates/aura-engine/src/test_fixtures.rs
@@ -21,7 +21,7 @@ pub(crate) fn synthetic_prices() -> Vec<(Timestamp, Scalar)> {
         (7, 0.9990),
     ]
     .iter()
-    .map(|&(t, p)| (Timestamp(t), Scalar::F64(p)))
+    .map(|&(t, p)| (Timestamp(t), Scalar::f64(p)))
     .collect()
 }
 
diff --git a/crates/aura-engine/src/walkforward.rs b/crates/aura-engine/src/walkforward.rs
index 1ed2c29..4edf646 100644
--- a/crates/aura-engine/src/walkforward.rs
+++ b/crates/aura-engine/src/walkforward.rs
@@ -248,9 +248,9 @@ pub fn param_stability(result: &WalkForwardResult) -> Vec<MetricStats> {
 /// scalar in a param slot is a wiring bug, surfaced like the engine's other
 /// "checked at wiring" violations.
 fn scalar_as_f64(s: Scalar) -> f64 {
-    match s {
-        Scalar::I64(n) => n as f64,
-        Scalar::F64(f) => f,
+    match s.kind() {
+        aura_core::ScalarKind::I64 => s.as_i64() as f64,
+        aura_core::ScalarKind::F64 => s.as_f64(),
         other => unreachable!("non-numeric param scalar: {other:?}"),
     }
 }
@@ -292,7 +292,7 @@ mod tests {
     fn run_window_fixture(w: WindowBounds) -> WindowRun {
         let Timestamp(k) = w.oos.0;
         WindowRun {
-            chosen_params: vec![Scalar::I64(k % 3), Scalar::F64(k as f64 * 0.5)],
+            chosen_params: vec![Scalar::i64(k % 3), Scalar::f64(k as f64 * 0.5)],
             oos_equity: vec![(w.oos.0, k as f64 * 0.1), (w.oos.1, k as f64 * 0.1 + 1.0)],
             oos_report: dummy_report(),
         }
@@ -373,7 +373,7 @@ mod tests {
                 oos: (Timestamp(0), Timestamp(0)),
             },
             run: WindowRun {
-                chosen_params: vec![Scalar::I64(a), Scalar::F64(b)],
+                chosen_params: vec![Scalar::i64(a), Scalar::f64(b)],
                 oos_equity: vec![],
                 oos_report: dummy_report(),
             },
diff --git a/crates/aura-ingest/src/lib.rs b/crates/aura-ingest/src/lib.rs
index 196356a..1c6ee3f 100644
--- a/crates/aura-ingest/src/lib.rs
+++ b/crates/aura-ingest/src/lib.rs
@@ -63,7 +63,7 @@ impl M1Columns {
     }
 
     /// The close column as an engine source stream: each normalized timestamp
-    /// zipped with its close as a [`Scalar::F64`]. Ascending in timestamp iff
+    /// zipped with its close as a [`Scalar::f64`]. Ascending in timestamp iff
     /// the bars were (the C3 ingestion precondition `Harness::run` relies on).
     /// This is the price input the SMA-cross sample strategy consumes; a project
     /// that wants another field reads the public columns and zips its own.
@@ -71,7 +71,7 @@ impl M1Columns {
         self.ts
             .iter()
             .zip(&self.close)
-            .map(|(&t, &v)| (t, Scalar::F64(v)))
+            .map(|(&t, &v)| (t, Scalar::f64(v)))
             .collect()
     }
 }
@@ -147,12 +147,12 @@ pub enum M1Field {
 /// in isolation. Time is normalized ms→epoch-ns at this one seam (C3).
 fn decode(field: M1Field, bar: &M1Parsed) -> (Timestamp, Scalar) {
     let value = match field {
-        M1Field::Open => Scalar::F64(bar.open),
-        M1Field::High => Scalar::F64(bar.high),
-        M1Field::Low => Scalar::F64(bar.low),
-        M1Field::Close => Scalar::F64(bar.close),
-        M1Field::Spread => Scalar::F64(bar.spread),
-        M1Field::Volume => Scalar::I64(bar.volume),
+        M1Field::Open => Scalar::f64(bar.open),
+        M1Field::High => Scalar::f64(bar.high),
+        M1Field::Low => Scalar::f64(bar.low),
+        M1Field::Close => Scalar::f64(bar.close),
+        M1Field::Spread => Scalar::f64(bar.spread),
+        M1Field::Volume => Scalar::i64(bar.volume),
     };
     (unix_ms_to_epoch_ns(bar.time_ms), value)
 }
@@ -313,9 +313,9 @@ mod tests {
         assert_eq!(
             stream,
             vec![
-                (Timestamp(1_000_000), Scalar::F64(10.0)),
-                (Timestamp(2_000_000), Scalar::F64(20.0)),
-                (Timestamp(3_000_000), Scalar::F64(30.0)),
+                (Timestamp(1_000_000), Scalar::f64(10.0)),
+                (Timestamp(2_000_000), Scalar::f64(20.0)),
+                (Timestamp(3_000_000), Scalar::f64(30.0)),
             ]
         );
         // ascending in timestamp (the merge precondition).
@@ -331,12 +331,12 @@ mod tests {
     fn decode_projects_each_field_to_its_scalar_kind() {
         // full_bar: open 1.0, high 2.0, low 0.5, close 1.5, spread 0.1, volume 100.
         let bar = full_bar(1_000);
-        assert_eq!(decode(M1Field::Open, &bar),   (Timestamp(1_000_000_000), Scalar::F64(1.0)));
-        assert_eq!(decode(M1Field::High, &bar),   (Timestamp(1_000_000_000), Scalar::F64(2.0)));
-        assert_eq!(decode(M1Field::Low, &bar),    (Timestamp(1_000_000_000), Scalar::F64(0.5)));
-        assert_eq!(decode(M1Field::Close, &bar),  (Timestamp(1_000_000_000), Scalar::F64(1.5)));
-        assert_eq!(decode(M1Field::Spread, &bar), (Timestamp(1_000_000_000), Scalar::F64(0.1)));
+        assert_eq!(decode(M1Field::Open, &bar),   (Timestamp(1_000_000_000), Scalar::f64(1.0)));
+        assert_eq!(decode(M1Field::High, &bar),   (Timestamp(1_000_000_000), Scalar::f64(2.0)));
+        assert_eq!(decode(M1Field::Low, &bar),    (Timestamp(1_000_000_000), Scalar::f64(0.5)));
+        assert_eq!(decode(M1Field::Close, &bar),  (Timestamp(1_000_000_000), Scalar::f64(1.5)));
+        assert_eq!(decode(M1Field::Spread, &bar), (Timestamp(1_000_000_000), Scalar::f64(0.1)));
         // volume is the one i64 column.
-        assert_eq!(decode(M1Field::Volume, &bar), (Timestamp(1_000_000_000), Scalar::I64(100)));
+        assert_eq!(decode(M1Field::Volume, &bar), (Timestamp(1_000_000_000), Scalar::i64(100)));
     }
 }
diff --git a/crates/aura-ingest/tests/streaming_seam.rs b/crates/aura-ingest/tests/streaming_seam.rs
index 58a0595..a612db9 100644
--- a/crates/aura-ingest/tests/streaming_seam.rs
+++ b/crates/aura-ingest/tests/streaming_seam.rs
@@ -178,12 +178,12 @@ fn two_field_sources_share_one_window() {
 
     let mut n_close = 0usize;
     while let Some((_, v)) = Source::next(&mut close) {
-        assert!(matches!(v, Scalar::F64(_)), "close is an f64 column");
+        assert_eq!(v.kind(), ScalarKind::F64, "close is an f64 column");
         n_close += 1;
     }
     let mut n_volume = 0usize;
     while let Some((_, v)) = Source::next(&mut volume) {
-        assert!(matches!(v, Scalar::I64(_)), "volume is an i64 column");
+        assert_eq!(v.kind(), ScalarKind::I64, "volume is an i64 column");
         n_volume += 1;
     }
     assert_eq!(n_close, n_volume, "both fields share the same ts axis ⇒ same count");
diff --git a/crates/aura-registry/src/lib.rs b/crates/aura-registry/src/lib.rs
index 97caf0c..2d8c93e 100644
--- a/crates/aura-registry/src/lib.rs
+++ b/crates/aura-registry/src/lib.rs
@@ -272,7 +272,7 @@ mod tests {
         // total_pips (3.0); the EARLIER of the two (index 1, params p=10) must
         // win, not the later (index 3, params p=30) — that pins the tie rule.
         let point = |p: f64, pips: f64| SweepPoint {
-            params: vec![Scalar::F64(p)],
+            params: vec![Scalar::f64(p)],
             report: report_with(pips, 0.5, 0),
         };
         let family = SweepFamily {
@@ -291,7 +291,7 @@ mod tests {
         assert_eq!(winner.report.metrics.total_pips, 3.0);
         // ...and ties resolve to the earliest enumeration-order point: its params
         // identify point 1, not point 3.
-        assert_eq!(winner.params, vec![Scalar::F64(10.0)]);
+        assert_eq!(winner.params, vec![Scalar::f64(10.0)]);
         // the whole winning point is returned, params AND report together.
         assert_eq!(winner, family.points[1]);
     }
diff --git a/crates/aura-std/src/add.rs b/crates/aura-std/src/add.rs
index d1df682..84d8031 100644
--- a/crates/aura-std/src/add.rs
+++ b/crates/aura-std/src/add.rs
@@ -23,7 +23,7 @@ pub struct Add {
 impl Add {
     /// Build an `Add` node.
     pub fn new() -> Self {
-        Self { out: [Scalar::F64(0.0)] }
+        Self { out: [Scalar::f64(0.0)] }
     }
 
     /// The param-generic recipe for a blueprint primitive: paramless, builds through
@@ -61,7 +61,7 @@ impl Node for Add {
         if a.is_empty() || b.is_empty() {
             return None;
         }
-        self.out[0] = Scalar::F64(a[0] + b[0]);
+        self.out[0] = Scalar::f64(a[0] + b[0]);
         Some(&self.out)
     }
 
@@ -84,12 +84,12 @@ mod tests {
         ];
 
         // only input 0 present -> None
-        inputs[0].push(Scalar::F64(10.0)).unwrap();
+        inputs[0].push(Scalar::f64(10.0)).unwrap();
         assert_eq!(add.eval(Ctx::new(&inputs, Timestamp(0))), None);
 
         // both present -> a + b
-        inputs[1].push(Scalar::F64(4.0)).unwrap();
-        assert_eq!(add.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(14.0)].as_slice()));
+        inputs[1].push(Scalar::f64(4.0)).unwrap();
+        assert_eq!(add.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(14.0)].as_slice()));
     }
 
     #[test]
diff --git a/crates/aura-std/src/ema.rs b/crates/aura-std/src/ema.rs
index a3e1ebc..0d75d97 100644
--- a/crates/aura-std/src/ema.rs
+++ b/crates/aura-std/src/ema.rs
@@ -49,7 +49,7 @@ impl Ema {
             warmup_sum: 0.0,
             count: 0,
             ema: 0.0,
-            out: [Scalar::F64(0.0)],
+            out: [Scalar::f64(0.0)],
         }
     }
 
@@ -64,7 +64,7 @@ impl Ema {
                 output: vec![FieldSpec { name: "value".into(), kind: ScalarKind::F64 }],
                 params: vec![ParamSpec { name: "length".into(), kind: ScalarKind::I64 }],
             },
-            |p| Box::new(Ema::new(p[0].as_i64().expect("length slot is I64") as usize)),
+            |p| Box::new(Ema::new(p[0].as_i64() as usize)),
         )
     }
 }
@@ -96,7 +96,7 @@ impl Node for Ema {
             // O(1) recurrence: one sub, one mul, one add.
             self.ema += self.alpha * (x - self.ema);
         }
-        self.out[0] = Scalar::F64(self.ema);
+        self.out[0] = Scalar::f64(self.ema);
         Some(&self.out)
     }
 
@@ -124,11 +124,11 @@ mod tests {
         let expect = [None, None, Some(4.0), Some(7.0)];
 
         for (v, want) in feed.iter().zip(expect) {
-            inputs[0].push(Scalar::F64(*v)).unwrap();
+            inputs[0].push(Scalar::f64(*v)).unwrap();
             let got = ema.eval(Ctx::new(&inputs, Timestamp(0)));
             match want {
                 None => assert_eq!(got, None),
-                Some(m) => assert_eq!(got, Some([Scalar::F64(m)].as_slice())),
+                Some(m) => assert_eq!(got, Some([Scalar::f64(m)].as_slice())),
             }
         }
     }
@@ -140,11 +140,11 @@ mod tests {
         let mut ema = Ema::new(1);
         let mut inputs = vec![AnyColumn::with_capacity(ScalarKind::F64, 1)];
 
-        inputs[0].push(Scalar::F64(7.0)).unwrap();
-        assert_eq!(ema.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(7.0)].as_slice()));
+        inputs[0].push(Scalar::f64(7.0)).unwrap();
+        assert_eq!(ema.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(7.0)].as_slice()));
 
-        inputs[0].push(Scalar::F64(9.0)).unwrap();
-        assert_eq!(ema.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(9.0)].as_slice()));
+        inputs[0].push(Scalar::f64(9.0)).unwrap();
+        assert_eq!(ema.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(9.0)].as_slice()));
     }
 
     #[test]
diff --git a/crates/aura-std/src/exposure.rs b/crates/aura-std/src/exposure.rs
index 0d440cb..d41d709 100644
--- a/crates/aura-std/src/exposure.rs
+++ b/crates/aura-std/src/exposure.rs
@@ -19,7 +19,7 @@ impl Exposure {
     /// Build an exposure node with saturation magnitude `scale` (must be > 0).
     pub fn new(scale: f64) -> Self {
         assert!(scale > 0.0, "Exposure scale must be > 0");
-        Self { scale, out: [Scalar::F64(0.0)] }
+        Self { scale, out: [Scalar::f64(0.0)] }
     }
 
     /// The param-generic recipe for a blueprint primitive: declares `scale` and builds
@@ -33,7 +33,7 @@ impl Exposure {
                 output: vec![FieldSpec { name: "exposure".into(), kind: ScalarKind::F64 }],
                 params: vec![ParamSpec { name: "scale".into(), kind: ScalarKind::F64 }],
             },
-            |p| Box::new(Exposure::new(p[0].as_f64().expect("scale slot is F64"))),
+            |p| Box::new(Exposure::new(p[0].as_f64())),
         )
     }
 }
@@ -48,7 +48,7 @@ impl Node for Exposure {
         if w.is_empty() {
             return None; // not yet warmed up (C8 filter)
         }
-        self.out[0] = Scalar::F64((w[0] / self.scale).clamp(-1.0, 1.0));
+        self.out[0] = Scalar::f64((w[0] / self.scale).clamp(-1.0, 1.0));
         Some(&self.out)
     }
 
@@ -75,10 +75,10 @@ mod tests {
             (-1.0, -1.0),       // saturates low
         ];
         for (sig, want) in cases {
-            inputs[0].push(Scalar::F64(sig)).unwrap();
+            inputs[0].push(Scalar::f64(sig)).unwrap();
             assert_eq!(
                 e.eval(Ctx::new(&inputs, Timestamp(0))),
-                Some([Scalar::F64(want)].as_slice())
+                Some([Scalar::f64(want)].as_slice())
             );
         }
     }
diff --git a/crates/aura-std/src/lincomb.rs b/crates/aura-std/src/lincomb.rs
index e132f70..6ecc3da 100644
--- a/crates/aura-std/src/lincomb.rs
+++ b/crates/aura-std/src/lincomb.rs
@@ -37,7 +37,7 @@ impl LinComb {
     /// Panics if `weights` is empty.
     pub fn new(weights: Vec<f64>) -> Self {
         assert!(!weights.is_empty(), "LinComb needs at least one weight");
-        Self { weights, out: [Scalar::F64(0.0)] }
+        Self { weights, out: [Scalar::f64(0.0)] }
     }
 
     /// The param-generic recipe for a blueprint primitive. The `arity` is topology
@@ -54,7 +54,7 @@ impl LinComb {
             "LinComb",
             NodeSchema { inputs, output: vec![FieldSpec { name: "value".into(), kind: ScalarKind::F64 }], params },
             |p| Box::new(LinComb::new(
-                p.iter().map(|s| s.as_f64().expect("weight slot is F64")).collect(),
+                p.iter().map(|s| s.as_f64()).collect(),
             )),
         )
     }
@@ -74,7 +74,7 @@ impl Node for LinComb {
             }
             acc += w * w_in[0];
         }
-        self.out[0] = Scalar::F64(acc);
+        self.out[0] = Scalar::f64(acc);
         Some(&self.out)
     }
 
@@ -97,12 +97,12 @@ mod tests {
         ];
 
         // only input 0 present -> None
-        inputs[0].push(Scalar::F64(10.0)).unwrap();
+        inputs[0].push(Scalar::f64(10.0)).unwrap();
         assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), None);
 
         // both present -> 0.5*10 + 2.0*3 = 11.0
-        inputs[1].push(Scalar::F64(3.0)).unwrap();
-        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(11.0)].as_slice()));
+        inputs[1].push(Scalar::f64(3.0)).unwrap();
+        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(11.0)].as_slice()));
     }
 
     #[test]
@@ -112,10 +112,10 @@ mod tests {
             AnyColumn::with_capacity(ScalarKind::F64, 1),
             AnyColumn::with_capacity(ScalarKind::F64, 1),
         ];
-        inputs[0].push(Scalar::F64(7.0)).unwrap();
-        inputs[1].push(Scalar::F64(5.0)).unwrap();
+        inputs[0].push(Scalar::f64(7.0)).unwrap();
+        inputs[1].push(Scalar::f64(5.0)).unwrap();
         // unit weights reproduce Add: 7 + 5
-        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(12.0)].as_slice()));
+        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(12.0)].as_slice()));
     }
 
     #[test]
@@ -126,14 +126,14 @@ mod tests {
             AnyColumn::with_capacity(ScalarKind::F64, 1),
             AnyColumn::with_capacity(ScalarKind::F64, 1),
         ];
-        inputs[0].push(Scalar::F64(1.0)).unwrap();
-        inputs[1].push(Scalar::F64(2.0)).unwrap();
+        inputs[0].push(Scalar::f64(1.0)).unwrap();
+        inputs[1].push(Scalar::f64(2.0)).unwrap();
         // third leg still cold -> None (withheld until every leg is present)
         assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), None);
 
-        inputs[2].push(Scalar::F64(3.0)).unwrap();
+        inputs[2].push(Scalar::f64(3.0)).unwrap();
         // all warm -> 1 + 2 + 3
-        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(6.0)].as_slice()));
+        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(6.0)].as_slice()));
     }
 
     #[test]
@@ -153,33 +153,33 @@ mod tests {
     fn chained_bind_reconstructs_positional_vector() {
         // bind BOTH weights, in reverse slot order, to DISTINCT values; build empty.
         let builder = LinComb::builder(2)
-            .bind("weights[1]", Scalar::F64(2.0))
-            .bind("weights[0]", Scalar::F64(0.5));
+            .bind("weights[1]", Scalar::f64(2.0))
+            .bind("weights[0]", Scalar::f64(0.5));
         assert!(builder.params().is_empty());
         let mut lc = builder.build(&[]);
         let mut inputs = vec![
             AnyColumn::with_capacity(ScalarKind::F64, 1),
             AnyColumn::with_capacity(ScalarKind::F64, 1),
         ];
-        inputs[0].push(Scalar::F64(10.0)).unwrap();
-        inputs[1].push(Scalar::F64(3.0)).unwrap();
+        inputs[0].push(Scalar::f64(10.0)).unwrap();
+        inputs[1].push(Scalar::f64(3.0)).unwrap();
         // 0.5*10 + 2.0*3 = 11.0 — holds ONLY if each weight landed in its right slot
         // (a swap would give 2.0*10 + 0.5*3 = 21.5)
-        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(11.0)].as_slice()));
+        assert_eq!(lc.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(11.0)].as_slice()));
 
         // partial: bind weights[0], leave weights[1] open → inject it at build
-        let partial = LinComb::builder(2).bind("weights[0]", Scalar::F64(0.5));
+        let partial = LinComb::builder(2).bind("weights[0]", Scalar::f64(0.5));
         assert_eq!(
             partial.params().iter().map(|p| p.name.as_str()).collect::<Vec<_>>(),
             ["weights[1]"],
         );
-        let mut lc2 = partial.build(&[Scalar::F64(2.0)]); // weights[1] = 2.0 injected
+        let mut lc2 = partial.build(&[Scalar::f64(2.0)]); // weights[1] = 2.0 injected
         let mut inputs2 = vec![
             AnyColumn::with_capacity(ScalarKind::F64, 1),
             AnyColumn::with_capacity(ScalarKind::F64, 1),
         ];
-        inputs2[0].push(Scalar::F64(10.0)).unwrap();
-        inputs2[1].push(Scalar::F64(3.0)).unwrap();
-        assert_eq!(lc2.eval(Ctx::new(&inputs2, Timestamp(0))), Some([Scalar::F64(11.0)].as_slice()));
+        inputs2[0].push(Scalar::f64(10.0)).unwrap();
+        inputs2[1].push(Scalar::f64(3.0)).unwrap();
+        assert_eq!(lc2.eval(Ctx::new(&inputs2, Timestamp(0))), Some([Scalar::f64(11.0)].as_slice()));
     }
 }
diff --git a/crates/aura-std/src/recorder.rs b/crates/aura-std/src/recorder.rs
index dc95657..36571b7 100644
--- a/crates/aura-std/src/recorder.rs
+++ b/crates/aura-std/src/recorder.rs
@@ -62,10 +62,10 @@ impl Node for Recorder {
         for (i, &kind) in self.kinds.iter().enumerate() {
             // newest of each column by kind; `?` returns None (warm-up) if cold.
             let scalar = match kind {
-                ScalarKind::F64 => Scalar::F64(ctx.f64_in(i).get(0)?),
-                ScalarKind::I64 => Scalar::I64(ctx.i64_in(i).get(0)?),
-                ScalarKind::Bool => Scalar::Bool(ctx.bool_in(i).get(0)?),
-                ScalarKind::Timestamp => Scalar::Ts(ctx.ts_in(i).get(0)?),
+                ScalarKind::F64 => Scalar::f64(ctx.f64_in(i).get(0)?),
+                ScalarKind::I64 => Scalar::i64(ctx.i64_in(i).get(0)?),
+                ScalarKind::Bool => Scalar::bool(ctx.bool_in(i).get(0)?),
+                ScalarKind::Timestamp => Scalar::ts(ctx.ts_in(i).get(0)?),
             };
             row.push(scalar);
         }
@@ -107,16 +107,16 @@ mod tests {
 
         // warm: returns None (pure consumer) but records (now, [F64(newest)]).
         for (t, v) in [(2_i64, 10.0_f64), (3, 20.0), (4, 30.0)] {
-            inputs[0].push(Scalar::F64(v)).unwrap();
+            inputs[0].push(Scalar::f64(v)).unwrap();
             assert_eq!(rec.eval(Ctx::new(&inputs, Timestamp(t))), None);
         }
         let rows: Vec<(Timestamp, Vec<Scalar>)> = rx.try_iter().collect();
         assert_eq!(
             rows,
             vec![
-                (Timestamp(2), vec![Scalar::F64(10.0)]),
-                (Timestamp(3), vec![Scalar::F64(20.0)]),
-                (Timestamp(4), vec![Scalar::F64(30.0)]),
+                (Timestamp(2), vec![Scalar::f64(10.0)]),
+                (Timestamp(3), vec![Scalar::f64(20.0)]),
+                (Timestamp(4), vec![Scalar::f64(30.0)]),
             ]
         );
     }
@@ -131,15 +131,15 @@ mod tests {
         ];
 
         // only column 0 present -> None, nothing recorded.
-        inputs[0].push(Scalar::F64(1.0)).unwrap();
+        inputs[0].push(Scalar::f64(1.0)).unwrap();
         assert_eq!(rec.eval(Ctx::new(&inputs, Timestamp(1))), None);
         assert!(rx.try_recv().is_err());
 
         // both present -> records the full row (still returns None).
-        inputs[1].push(Scalar::F64(2.0)).unwrap();
+        inputs[1].push(Scalar::f64(2.0)).unwrap();
         assert_eq!(rec.eval(Ctx::new(&inputs, Timestamp(2))), None);
         let rows: Vec<(Timestamp, Vec<Scalar>)> = rx.try_iter().collect();
-        assert_eq!(rows, vec![(Timestamp(2), vec![Scalar::F64(1.0), Scalar::F64(2.0)])]);
+        assert_eq!(rows, vec![(Timestamp(2), vec![Scalar::f64(1.0), Scalar::f64(2.0)])]);
     }
 
     #[test]
diff --git a/crates/aura-std/src/sim_broker.rs b/crates/aura-std/src/sim_broker.rs
index 49dfd44..9931c9d 100644
--- a/crates/aura-std/src/sim_broker.rs
+++ b/crates/aura-std/src/sim_broker.rs
@@ -51,7 +51,7 @@ impl SimBroker {
             prev_price: None,
             prev_exposure: 0.0,
             cum: 0.0,
-            out: [Scalar::F64(0.0)],
+            out: [Scalar::f64(0.0)],
         }
     }
 
@@ -91,7 +91,7 @@ impl Node for SimBroker {
         }
         self.prev_price = Some(price);
         self.prev_exposure = expo; // update AFTER taking PnL — no look-ahead (C2)
-        self.out[0] = Scalar::F64(self.cum);
+        self.out[0] = Scalar::f64(self.cum);
         Some(&self.out)
     }
 
@@ -117,11 +117,11 @@ mod tests {
     // stays empty) and a price into slot 1, then eval and return the equity.
     fn step(b: &mut SimBroker, inputs: &mut [AnyColumn], expo: Option<f64>, price: f64) -> f64 {
         if let Some(e) = expo {
-            inputs[0].push(Scalar::F64(e)).unwrap();
+            inputs[0].push(Scalar::f64(e)).unwrap();
         }
-        inputs[1].push(Scalar::F64(price)).unwrap();
+        inputs[1].push(Scalar::f64(price)).unwrap();
         match b.eval(Ctx::new(inputs, Timestamp(0))) {
-            Some([Scalar::F64(v)]) => *v,
+            Some([s]) => s.as_f64(),
             other => panic!("expected Some([F64]), got {other:?}"),
         }
     }
diff --git a/crates/aura-std/src/sma.rs b/crates/aura-std/src/sma.rs
index 96350de..a76909c 100644
--- a/crates/aura-std/src/sma.rs
+++ b/crates/aura-std/src/sma.rs
@@ -18,7 +18,7 @@ impl Sma {
     /// Build an SMA of window `length` (must be >= 1).
     pub fn new(length: usize) -> Self {
         assert!(length >= 1, "SMA length must be >= 1");
-        Self { length, out: [Scalar::F64(0.0)] }
+        Self { length, out: [Scalar::f64(0.0)] }
     }
 
     /// The param-generic recipe for a blueprint primitive: declares `length` and builds
@@ -32,7 +32,7 @@ impl Sma {
                 output: vec![FieldSpec { name: "value".into(), kind: ScalarKind::F64 }],
                 params: vec![ParamSpec { name: "length".into(), kind: ScalarKind::I64 }],
             },
-            |p| Box::new(Sma::new(p[0].as_i64().expect("length slot is I64") as usize)),
+            |p| Box::new(Sma::new(p[0].as_i64() as usize)),
         )
     }
 }
@@ -51,7 +51,7 @@ impl Node for Sma {
         for k in 0..self.length {
             sum += w[k]; // index 0 = newest (financial indexing)
         }
-        self.out[0] = Scalar::F64(sum / self.length as f64);
+        self.out[0] = Scalar::f64(sum / self.length as f64);
         Some(&self.out)
     }
 
@@ -79,11 +79,11 @@ mod tests {
         let expect = [None, None, Some(2.0), Some(3.0), Some(4.0)];
 
         for (v, want) in feed.iter().zip(expect) {
-            inputs[0].push(Scalar::F64(*v)).unwrap();
+            inputs[0].push(Scalar::f64(*v)).unwrap();
             let got = sma.eval(Ctx::new(&inputs, Timestamp(0)));
             match want {
                 None => assert_eq!(got, None),
-                Some(m) => assert_eq!(got, Some([Scalar::F64(m)].as_slice())),
+                Some(m) => assert_eq!(got, Some([Scalar::f64(m)].as_slice())),
             }
         }
     }
@@ -93,11 +93,11 @@ mod tests {
         let mut sma = Sma::new(1);
         let mut inputs = vec![AnyColumn::with_capacity(ScalarKind::F64, 1)];
 
-        inputs[0].push(Scalar::F64(7.0)).unwrap();
-        assert_eq!(sma.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(7.0)].as_slice()));
+        inputs[0].push(Scalar::f64(7.0)).unwrap();
+        assert_eq!(sma.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(7.0)].as_slice()));
 
-        inputs[0].push(Scalar::F64(9.0)).unwrap();
-        assert_eq!(sma.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(9.0)].as_slice()));
+        inputs[0].push(Scalar::f64(9.0)).unwrap();
+        assert_eq!(sma.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(9.0)].as_slice()));
     }
 
     #[test]
@@ -160,7 +160,7 @@ mod tests {
     fn bind_removes_slot_from_param_space() {
         // a bound param-bearing node reports an empty param surface — parity with the
         // SimBroker precedent (nodes_declare_expected_params, this file)
-        let sma2 = Sma::builder().named("bias").bind("length", Scalar::I64(2));
+        let sma2 = Sma::builder().named("bias").bind("length", Scalar::i64(2));
         assert!(sma2.schema().params.is_empty());
         // contrast: the length-generic SMA keeps `length` open
         assert_eq!(Sma::builder().named("bias").params().len(), 1);
@@ -169,7 +169,7 @@ mod tests {
     #[test]
     fn bound_node_builds_with_injected_value() {
         // built with an empty open slice, the bound builder yields SMA(2)
-        let node = Sma::builder().bind("length", Scalar::I64(2)).build(&[]);
+        let node = Sma::builder().bind("length", Scalar::i64(2)).build(&[]);
         assert_eq!(node.label(), "SMA(2)");
     }
 }
diff --git a/crates/aura-std/src/sub.rs b/crates/aura-std/src/sub.rs
index 4b37d5e..eaae6d1 100644
--- a/crates/aura-std/src/sub.rs
+++ b/crates/aura-std/src/sub.rs
@@ -14,7 +14,7 @@ pub struct Sub {
 impl Sub {
     /// Build a `Sub` node.
     pub fn new() -> Self {
-        Self { out: [Scalar::F64(0.0)] }
+        Self { out: [Scalar::f64(0.0)] }
     }
 
     /// The param-generic recipe for a blueprint primitive: paramless, builds through
@@ -52,7 +52,7 @@ impl Node for Sub {
         if a.is_empty() || b.is_empty() {
             return None;
         }
-        self.out[0] = Scalar::F64(a[0] - b[0]);
+        self.out[0] = Scalar::f64(a[0] - b[0]);
         Some(&self.out)
     }
 
@@ -75,12 +75,12 @@ mod tests {
         ];
 
         // only input 0 present -> None
-        inputs[0].push(Scalar::F64(10.0)).unwrap();
+        inputs[0].push(Scalar::f64(10.0)).unwrap();
         assert_eq!(sub.eval(Ctx::new(&inputs, Timestamp(0))), None);
 
         // both present -> a - b
-        inputs[1].push(Scalar::F64(4.0)).unwrap();
-        assert_eq!(sub.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::F64(6.0)].as_slice()));
+        inputs[1].push(Scalar::f64(4.0)).unwrap();
+        assert_eq!(sub.eval(Ctx::new(&inputs, Timestamp(0))), Some([Scalar::f64(6.0)].as_slice()));
     }
 
     #[test]