diff --git a/core/src/doc.rs b/core/src/doc.rs
index c214c4b..068768a 100644
--- a/core/src/doc.rs
+++ b/core/src/doc.rs
@@ -122,6 +122,17 @@ fn is_ident(s: &str) -> bool {
 }
 
 pub fn classify_document(text: &str) -> Vec<ClassifiedLine> {
+    classify_document_with(text, |_| None)
+}
+
+/// classifies a document, letting a caller override the Cordial/Markdown verdict per line.
+/// the override feeds the same decision point as the built-in classifier, so brace tracking
+/// engages for overridden Cordial openers and multi-line blocks follow. the `/=` eval sigil
+/// is never overridable.
+pub fn classify_document_with(
+    text: &str,
+    classify_override: impl Fn(&str) -> Option<bool>,
+) -> Vec<ClassifiedLine> {
     let mut result = Vec::new();
     let mut comment_depth: usize = 0;
     let mut brace_depth: i32 = 0;
@@ -140,7 +151,16 @@ pub fn classify_document(text: &str) -> Vec<ClassifiedLine> {
             if brace_depth < 0 { brace_depth = 0; }
             result.push(ClassifiedLine { index: i, kind: LineKind::Cordial, content: line.to_string() });
         } else {
-            let cl = classify_line(i, line);
+            let base = classify_line(i, line);
+            let cl = if base.kind == LineKind::Eval {
+                base
+            } else {
+                match classify_override(line.trim()) {
+                    Some(true) => ClassifiedLine { index: i, kind: LineKind::Cordial, content: line.to_string() },
+                    Some(false) => ClassifiedLine { index: i, kind: LineKind::Markdown, content: line.to_string() },
+                    None => base,
+                }
+            };
             if cl.kind == LineKind::Cordial {
                 let trimmed = line.trim();
                 let opens = trimmed.matches('{').count() as i32;
diff --git a/core/src/eval.rs b/core/src/eval.rs
index b29d815..d0dd52a 100644
--- a/core/src/eval.rs
+++ b/core/src/eval.rs
@@ -240,7 +240,10 @@ pub fn evaluate_modules(sources: &[ModuleSource]) -> Vec<ModuleResult> {
 
 /// evaluates a document's text using a pre-populated interpreter.
 pub fn evaluate_document_with_interp(interp: &mut interp::Interpreter, text: &str) -> DocumentResult {
-    let classified = classify_document(text);
+    let classified = {
+        let interp_ref: &interp::Interpreter = interp;
+        crate::doc::classify_document_with(text, |line| interp_ref.hook_classify_line(line))
+    };
     let mut results = Vec::new();
     let mut errors = Vec::new();
 
diff --git a/core/src/interp/hooks.rs b/core/src/interp/hooks.rs
index d2a8aac..9b963a0 100644
--- a/core/src/interp/hooks.rs
+++ b/core/src/interp/hooks.rs
@@ -39,6 +39,11 @@ pub trait InterpreterHook {
         -> Option<Result<Value, String>> { None }
     fn extern_unop(&self, _i: &mut Interpreter, _op: Op, _operand: &Value, _depth: u32)
         -> Option<Result<Value, String>> { None }
+
+    /// line-classification override: None defers, true = Cordial, false = Markdown.
+    fn classify_line(&self, _trimmed: &str) -> Option<bool> { None }
+    /// names the binding on a custom assignment line.
+    fn eval_binding_name(&self, _trimmed: &str) -> Option<String> { None }
 }
 
 pub(crate) struct HookList {
diff --git a/core/src/interp/mod.rs b/core/src/interp/mod.rs
index d62eab6..c72f873 100644
--- a/core/src/interp/mod.rs
+++ b/core/src/interp/mod.rs
@@ -158,6 +158,22 @@ impl Interpreter {
             .collect()
     }
 
+    /// first hook with a line-classification verdict.
+    pub fn hook_classify_line(&self, trimmed: &str) -> Option<bool> {
+        for h in &self.hooks.hooks {
+            if let Some(v) = h.classify_line(trimmed) { return Some(v); }
+        }
+        None
+    }
+
+    /// first hook to name a custom binding line.
+    pub fn hook_eval_binding_name(&self, trimmed: &str) -> Option<String> {
+        for h in &self.hooks.hooks {
+            if let Some(v) = h.eval_binding_name(trimmed) { return Some(v); }
+        }
+        None
+    }
+
     /// hook-aware Value rendering for inline/table/tree formats.
     pub fn display_value(&self, v: &Value, fmt: DisplayFormat) -> String {
         if let Value::Extern(h) = v {
diff --git a/viewport/src/editor/mod.rs b/viewport/src/editor/mod.rs
index e3f7d71..817e116 100644
--- a/viewport/src/editor/mod.rs
+++ b/viewport/src/editor/mod.rs
@@ -571,15 +571,38 @@ impl EditorState {
                             weight: iced_wgpu::core::font::Weight::Bold,
                             ..syntax::EDITOR_FONT
                         };
+                        let value_mid: Element<'a, Message, Theme, iced_wgpu::Renderer> = match &self.eval_highlight {
+                            Some(rules) => {
+                                let spans = syntax::highlight_eval_spans(&value, rules);
+                                let mut rich: Vec<iced_wgpu::core::text::Span<'a, ()>> = Vec::new();
+                                let mut cursor = 0usize;
+                                for (range, kind) in &spans {
+                                    if range.start > cursor {
+                                        rich.push(iced_widget::span(value[cursor..range.start].to_string()).color(value_color));
+                                    }
+                                    let mut s = iced_widget::span(value[range.start..range.end].to_string())
+                                        .color(syntax::highlight_color(*kind));
+                                    if let Some(f) = syntax::highlight_font(*kind) { s = s.font(f); }
+                                    rich.push(s);
+                                    cursor = range.end;
+                                }
+                                if cursor < value.len() {
+                                    rich.push(iced_widget::span(value[cursor..].to_string()).color(value_color));
+                                }
+                                iced_widget::text::Rich::with_spans(rich).size(self.font_size).into()
+                            }
+                            None => iced_widget::text(value)
+                                .font(bold)
+                                .size(self.font_size)
+                                .color(value_color)
+                                .into(),
+                        };
                         let row = iced_widget::row![
                             iced_widget::text("→ ")
                                 .font(syntax::EDITOR_FONT)
                                 .size(self.font_size)
                                 .color(arrow_color),
-                            iced_widget::text(value)
-                                .font(bold)
-                                .size(self.font_size)
-                                .color(value_color),
+                            value_mid,
                             iced_widget::text(" ←")
                                 .font(syntax::EDITOR_FONT)
                                 .size(self.font_size)
diff --git a/viewport/src/editor/state.rs b/viewport/src/editor/state.rs
index 1c3ac78..4e06143 100644
--- a/viewport/src/editor/state.rs
+++ b/viewport/src/editor/state.rs
@@ -111,6 +111,8 @@ pub struct EditorState {
     pub(super) cached_minimap_lines: Vec<crate::minimap::MinimapLine>,
     /// custom keyword/builtin/type table layered on top of Cordial.
     pub syntax_rules: crate::syntax::SyntaxRules,
+    /// optional rules for highlighting inline eval output.
+    pub(super) eval_highlight: Option<crate::syntax::SyntaxRules>,
     /// tree-sitter rebuild gate, bumped on idle.
     pub(super) heavy_token: u64,
     /// deferred-rebuild arm; set on edit, cleared on debounce fire.
@@ -187,9 +189,15 @@ impl EditorState {
             heavy_token: 0,
             heavy_pending: false,
             interp_setup: None,
+            eval_highlight: None,
         }
     }
 
+    /// sets the rules for highlighting inline eval output.
+    pub fn set_eval_highlight(&mut self, rules: Option<crate::syntax::SyntaxRules>) {
+        self.eval_highlight = rules;
+    }
+
     /// installs a routine run on each fresh eval interpreter — register hooks,
     /// provide shared state, seed vars, add module paths.
     pub fn set_interpreter_setup<F>(&mut self, setup: F)
diff --git a/viewport/src/editor/update.rs b/viewport/src/editor/update.rs
index 39423a0..f9e08a3 100644
--- a/viewport/src/editor/update.rs
+++ b/viewport/src/editor/update.rs
@@ -458,7 +458,10 @@ impl super::EditorState {
                 let line_idx = cursor.position.line;
                 if line_idx < lines.len() {
                     let line = lines[line_idx].trim();
-                    if let Some(varname) = parse_let_binding(line) {
+                    let varname = self.new_eval_interpreter()
+                        .hook_eval_binding_name(line)
+                        .or_else(|| parse_let_binding(line));
+                    if let Some(varname) = varname {
                         let insert = format!("\n/= {varname}");
                         self.content_mut().perform(text_widget::Action::Move(Motion::End));
                         self.content_mut().perform(text_widget::Action::Edit(
diff --git a/viewport/src/syntax.rs b/viewport/src/syntax.rs
index b401903..3739919 100644
--- a/viewport/src/syntax.rs
+++ b/viewport/src/syntax.rs
@@ -512,6 +512,15 @@ fn extract_paren_idents(s: &str, map: &mut HashMap<String, u8>, slot: &mut u32)
     }
 }
 
+/// highlights a single eval-output line with the given rules into (range, kind) spans.
+pub fn highlight_eval_spans(line: &str, rules: &SyntaxRules) -> Vec<(Range<usize>, u8)> {
+    let idents: HashMap<String, u8> = HashMap::new();
+    highlight_cordial(line, &idents, rules)
+        .into_iter()
+        .map(|(r, SyntaxHighlight { kind })| (r, kind))
+        .collect()
+}
+
 fn highlight_cordial(line: &str, user_idents: &HashMap<String, u8>, rules: &SyntaxRules) -> Vec<(Range<usize>, SyntaxHighlight)> {
     let bytes = line.as_bytes();
     let len = bytes.len();