fix(tui): tighten fence indent and sparse spillover detection

codex-rs/tui/src/markdown_render.rs

@@ -1426,7 +1426,25 @@ where
     }
 
     fn looks_like_html_content(text: &str) -> bool {
-        text.contains('<') && text.contains('>')
+        let bytes = text.as_bytes();
+        for idx in 0..bytes.len() {
+            if bytes[idx] != b'<' {
+                continue;
+            }
+
+            let mut tag_start = idx + 1;
+            if tag_start < bytes.len() && (bytes[tag_start] == b'/' || bytes[tag_start] == b'!') {
+                tag_start += 1;
+            }
+
+            if tag_start < bytes.len()
+                && bytes[tag_start].is_ascii_alphabetic()
+                && bytes[tag_start + 1..].contains(&b'>')
+            {
+                return true;
+            }
+        }
+        false
     }
 
     fn looks_like_html_label_line(text: &str) -> bool {

codex-rs/tui/src/markdown_render_tests.rs

@@ -1542,6 +1542,28 @@ fn table_spillover_prose_wraps_in_narrow_width() {
     );
 }
 
+#[test]
+fn table_keeps_sparse_comparison_row_inside_grid() {
+    let md = "| A | B | C |\n|---|---|---|\n| x < y > z | | |\n";
+    let text = render_markdown_text(md);
+    let lines: Vec<String> = text
+        .lines
+        .iter()
+        .map(|line| line.spans.iter().map(|span| span.content.clone()).collect())
+        .collect();
+
+    assert!(
+        lines
+            .iter()
+            .any(|line| line.contains("│ x < y > z") && line.ends_with('│')),
+        "expected sparse comparison row to remain inside table grid: {lines:?}"
+    );
+    assert!(
+        !lines.iter().any(|line| line.trim() == "x < y > z"),
+        "did not expect sparse comparison row to spill outside table: {lines:?}"
+    );
+}
+
 #[test]
 fn table_keeps_sparse_rows_with_empty_trailing_cells() {
     let md = "| A | B | C |\n|---|---|---|\n| a | | |\n";

codex-rs/tui/src/streaming/controller.rs

@@ -616,7 +616,15 @@ fn parse_lines_with_fence_state(source: &str) -> Vec<ParsedLine<'_>> {
             },
         });
 
-        let trimmed = raw_line.trim_start();
+        let leading_spaces = raw_line
+            .as_bytes()
+            .iter()
+            .take_while(|byte| **byte == b' ')
+            .count();
+        if leading_spaces > 3 {
+            continue;
+        }
+        let trimmed = &raw_line[leading_spaces..];
         if let Some((marker, len)) = parse_fence_marker(trimmed) {
             if !in_fence {
                 in_fence = true;
@@ -1391,6 +1399,15 @@ mod tests {
         );
     }
 
+    #[test]
+    fn table_holdback_state_treats_indented_fence_text_as_plain_content() {
+        let source = "    ```sh\n| Key | Description |\n| --- | --- |\n";
+        assert!(
+            matches!(table_holdback_state(source), TableHoldbackState::Confirmed),
+            "indented fence-like text should not open a fence and should not block table detection",
+        );
+    }
+
     // -----------------------------------------------------------------------
     // source_bytes_for_rendered_count — prefix-stability tests
     // -----------------------------------------------------------------------