board: a tag in the prose is coloured where it sits, not printed twice

A tagged note was showing its tag twice — once where it was typed, once as a
chip — and the duplicate was the loud copy. Now the chip row carries only what
the body cannot say (a tag lifted off its own line, a label from the picker),
and a `#tag` left mid-sentence is tinted in place.

Which characters are a tag is asked of the CORE, the way the card already asks
it which lines are checklist items: `extract_tag_spans` keeps the spans
`extract_tags` throws away, and `body_tags` hands them to Kotlin. Offsets are
UTF-16 code units, because `AnnotatedString` and JS both index that way and a
char index lands mid-token the first time somebody writes an emoji. The web
keeps its own matcher in markdown.ts, mirroring `line_tags` case for case.

The inline ink is its own table, one Tailwind step deeper than the chip's. A
chip brings its own -100 fill and reads against that alone; inline text sits on
whatever the card is, including a gray-tagged card at neutral-200 — where the
chip's -700 measured 3.98 (green), 4.11 (orange) and 4.34 (teal), under the 4.5
body text needs. At -800/-300 every hue lands 5.63-12.01 light and 7.20-10.84
dark across every palette and generated fill.

Chips now carry the `#` on every surface. The via_tag branch that used to
decide it is gone from the card, and Android's row said no hash at all.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/thoughtsync/ui/EditorChrome.kt

@@ -336,7 +336,10 @@ fun EditorLabelRow(
                 modifier = Modifier.padding(vertical = 2.dp),
             ) {
                 Text(
-                    text = label.name,
+                    // `#` on every chip, matching the card. This row still shows the
+                    // tags the BODY owns as well — it is the control surface, and the
+                    // "from tag" hint beside one is what says why it has no cross.
+                    text = "#${label.name}",
                     style = MaterialTheme.typography.labelLarge,
                     color = tint.chipForeground(dark),
                     modifier =

android/app/src/main/java/com/fabledsword/thoughtsync/ui/NoteCard.kt

@@ -22,7 +22,11 @@ import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.shadow
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.buildAnnotatedString
 import androidx.compose.ui.text.font.FontStyle
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -30,6 +34,7 @@ import com.fabledsword.thoughtsync.R
 import com.fabledsword.thoughtsync.core.BodyItem
 import com.fabledsword.thoughtsync.core.Note
 import com.fabledsword.thoughtsync.core.NoteLabel
+import com.fabledsword.thoughtsync.core.bodyTags
 import com.fabledsword.thoughtsync.core.checklistItems
 
 @Composable
@@ -67,8 +72,16 @@ fun NoteCard(
         // note's NAME (M13 steps 3 and 4) and a chip floated next to it would compete
         // with the thing that identifies the note. A row of its own costs one line and
         // only on notes that have tags at all.
-        if (note.labels.isNotEmpty()) {
-            LabelChips(labels = note.labels)
+        //
+        // ONLY the labels whose text is not still in the note. `via_tag` means exactly
+        // "backed by body text" since M311, so a chip for one printed the same tag
+        // twice — once where it was typed, once up here — and the card was carrying
+        // furniture for information it was already showing. A tag left in prose is
+        // tinted in place instead; see [tintTags]. What reaches this row is what the
+        // body cannot say: a tag lifted off its own line, and a label added by hand.
+        val chips = note.labels.filterNot { it.viaTag }
+        if (chips.isNotEmpty()) {
+            LabelChips(labels = chips)
             Spacer(Modifier.height(8.dp))
         }
 
@@ -129,13 +142,13 @@ private fun NoteBody(
             val found = itemAtLine[n]
             when {
                 found != null ->
-                    ChecklistRow(found.second) { onToggleItem(found.first, !found.second.checked) }
+                    ChecklistRow(note, found.second) { onToggleItem(found.first, !found.second.checked) }
                 // Kept as a gap rather than dropped: it is the paragraph break
                 // somebody typed, and the card reads as a wall without it.
                 line.isBlank() -> Spacer(Modifier.height(4.dp))
                 else ->
                     Text(
-                        text = line,
+                        text = tintTags(line, note),
                         style = MaterialTheme.typography.bodyMedium,
                         maxLines = MAX_WRAPPED_LINES,
                         overflow = TextOverflow.Ellipsis,
@@ -163,6 +176,7 @@ private fun NoteBody(
  */
 @Composable
 private fun ChecklistRow(
+    note: Note,
     item: BodyItem,
     onToggle: () -> Unit,
 ) {
@@ -176,7 +190,7 @@ private fun ChecklistRow(
                     .padding(end = 6.dp),
         )
         Text(
-            text = item.text,
+            text = tintTags(item.text, note),
             style = MaterialTheme.typography.bodyMedium,
             textDecoration = if (item.checked) TextDecoration.LineThrough else null,
             color =
@@ -191,6 +205,58 @@ private fun ChecklistRow(
     }
 }
 
+/**
+ * One string of a note's own words, with every `#tag` in it drawn in that tag's colour.
+ *
+ * This is what replaced the chip for a tag still living in the prose. The card used to
+ * print such a tag twice — once where it was typed and once in the row above — and the
+ * duplicate was the loud copy, which made a tagged note read as "tag, then some text
+ * that happens to start with the same word". Colouring it in place says the same thing
+ * with no furniture, and says it more honestly: the token you can see IS the text you
+ * would delete to remove the tag.
+ *
+ * WHICH characters are a tag is asked of the core, exactly as [NoteBody] asks it which
+ * lines are checklist items. The grammar already exists three times (Rust, Python,
+ * TypeScript); a fourth in Compose would be a fourth thing to disagree — and this one
+ * would fail silently, as the wrong characters tinted rather than an error anywhere.
+ * The core's offsets are UTF-16 code units for this call site specifically, which is
+ * the only unit `addStyle` can take.
+ *
+ * Called per rendered STRING rather than once per body so a checklist item's text can
+ * be handled with no arithmetic: an item is a line minus a `- [ ] ` prefix of a length
+ * nothing carries, and shifting spans by a guessed prefix is the kind of off-by-one
+ * that shows up only on the one note that had a tag in a list.
+ */
+@Composable
+private fun tintTags(
+    text: String,
+    note: Note,
+): AnnotatedString {
+    val dark = isSystemInDarkTheme()
+    return remember(text, note.labels, dark) {
+        val spans = bodyTags(text)
+        if (spans.isEmpty()) {
+            AnnotatedString(text)
+        } else {
+            // A tag the note does not carry as a label yet — just typed, not yet
+            // derived — still gets a colour: `labelTint` falls back to deriving one
+            // from the name, which is what the chip would have shown anyway.
+            val picked = note.labels.associate { it.name.lowercase() to it.color }
+            buildAnnotatedString {
+                append(text)
+                spans.forEach { tag ->
+                    val tint = labelTint(tag.name, picked[tag.name.lowercase()].orEmpty())
+                    addStyle(
+                        SpanStyle(color = tint.tagInk(dark), fontWeight = FontWeight.Medium),
+                        tag.start.toInt(),
+                        tag.end.toInt(),
+                    )
+                }
+            }
+        }
+    }
+}
+
 @Composable
 private fun LabelChips(labels: List<NoteLabel>) {
     val dark = isSystemInDarkTheme()
@@ -200,7 +266,11 @@ private fun LabelChips(labels: List<NoteLabel>) {
         labels.take(MAX_LABEL_CHIPS).forEach { label ->
             val tint = labelTintFor(label.name, label.color)
             Text(
-                text = label.name,
+                // The `#` is carried on every chip, because everything that reaches
+                // this row is a tag — a tag lifted off its own line, or one attached
+                // through the picker — and the hash is how you would type either. It
+                // also keeps a lifted chip reading as the `#todo` somebody wrote.
+                text = "#${label.name}",
                 style = MaterialTheme.typography.labelSmall,
                 color = tint.chipForeground(dark),
                 maxLines = 1,

android/app/src/main/java/com/fabledsword/thoughtsync/ui/NoteTint.kt

@@ -34,6 +34,20 @@ data class NoteTint(
     val lightChipForeground: Color,
     val darkChipBackground: Color,
     val darkChipForeground: Color,
+    /**
+     * The colour a `#tag` is drawn in when it is left in the prose — see [tagInk].
+     *
+     * A SEPARATE value from [lightChipForeground] rather than a reuse of it, and the
+     * difference is not cosmetic. A chip brings its own `-100` fill, so its text only
+     * ever has to read against that one colour. Inline text sits on whatever the card
+     * happens to be, which includes the gray-tagged card at `neutral-200` — and there
+     * the chip's `-700` measured 3.98 (green), 4.11 (orange) and 4.34 (teal), all
+     * under the 4.5 body text needs. One step deeper puts every hue between 5.63 and
+     * 12.01 in light and 7.20 and 10.84 in dark, across every fill in the palette and
+     * every generated fill, so it is one rule rather than three exceptions.
+     */
+    val lightTagInk: Color,
+    val darkTagInk: Color,
     /**
      * False only for `default`, which is the ABSENCE of a colour rather than one of
      * them. A tint can be drawn at the chosen weight (see [chosenBackground]);
@@ -81,6 +95,16 @@ data class NoteTint(
 
     fun chipForeground(dark: Boolean): Color = if (dark) darkChipForeground else lightChipForeground
 
+    /**
+     * The colour for a `#tag` still sitting in the note's own words.
+     *
+     * A tag whose text is in the body is no longer repeated as a chip (the card was
+     * printing every tag twice — once where it was typed, once at the top). It is
+     * tinted in place instead, which is both less furniture and a more honest card:
+     * the thing you see IS the thing you would delete to remove the tag.
+     */
+    fun tagInk(dark: Boolean): Color = if (dark) darkTagInk else lightTagInk
+
     /**
      * A hairline edge for a chip, in its own text colour at low alpha.
      *
@@ -128,6 +152,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF525252),
                 darkChipBackground = Color(0x1AFFFFFF),
                 darkChipForeground = Color(0xFFD4D4D4),
+                lightTagInk = Color(0xFF404040),
+                darkTagInk = Color(0xFFD4D4D4),
                 tintable = false,
             ),
         "red" to
@@ -141,6 +167,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFFB91C1C),
                 darkChipBackground = Color(0x80450A0A),
                 darkChipForeground = Color(0xFFFCA5A5),
+                lightTagInk = Color(0xFF991B1B),
+                darkTagInk = Color(0xFFFCA5A5),
             ),
         "orange" to
             NoteTint(
@@ -153,6 +181,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFFC2410C),
                 darkChipBackground = Color(0x80431407),
                 darkChipForeground = Color(0xFFFDBA74),
+                lightTagInk = Color(0xFF9A3412),
+                darkTagInk = Color(0xFFFDBA74),
             ),
         "yellow" to
             NoteTint(
@@ -165,6 +195,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF92400E),
                 darkChipBackground = Color(0x80451A03),
                 darkChipForeground = Color(0xFFFCD34D),
+                lightTagInk = Color(0xFF92400E),
+                darkTagInk = Color(0xFFFCD34D),
             ),
         "green" to
             NoteTint(
@@ -177,6 +209,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF15803D),
                 darkChipBackground = Color(0x80052E16),
                 darkChipForeground = Color(0xFF86EFAC),
+                lightTagInk = Color(0xFF166534),
+                darkTagInk = Color(0xFF86EFAC),
             ),
         "teal" to
             NoteTint(
@@ -189,6 +223,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF0F766E),
                 darkChipBackground = Color(0x80042F2E),
                 darkChipForeground = Color(0xFF5EEAD4),
+                lightTagInk = Color(0xFF115E59),
+                darkTagInk = Color(0xFF5EEAD4),
             ),
         "blue" to
             NoteTint(
@@ -201,6 +237,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF1D4ED8),
                 darkChipBackground = Color(0x80172554),
                 darkChipForeground = Color(0xFF93C5FD),
+                lightTagInk = Color(0xFF1E40AF),
+                darkTagInk = Color(0xFF93C5FD),
             ),
         "purple" to
             NoteTint(
@@ -213,6 +251,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF7E22CE),
                 darkChipBackground = Color(0x803B0764),
                 darkChipForeground = Color(0xFFD8B4FE),
+                lightTagInk = Color(0xFF6B21A8),
+                darkTagInk = Color(0xFFD8B4FE),
             ),
         "pink" to
             NoteTint(
@@ -225,6 +265,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFFBE185D),
                 darkChipBackground = Color(0x80500724),
                 darkChipForeground = Color(0xFFF9A8D4),
+                lightTagInk = Color(0xFF9D174D),
+                darkTagInk = Color(0xFFF9A8D4),
             ),
         "gray" to
             NoteTint(
@@ -237,6 +279,8 @@ val NOTE_TINTS: Map<String, NoteTint> =
                 lightChipForeground = Color(0xFF404040),
                 darkChipBackground = Color(0xFF404040),
                 darkChipForeground = Color(0xFFE5E5E5),
+                lightTagInk = Color(0xFF262626),
+                darkTagInk = Color(0xFFE5E5E5),
             ),
     )
 
@@ -321,4 +365,17 @@ private fun firstLabelColor(note: Note): String {
 fun labelTintFor(
     name: String,
     color: String,
-): NoteTint = noteTint(resolvedLabelColor(name, color, NOTE_TINTS.keys))
+): NoteTint = labelTint(name, color)
+
+/**
+ * [labelTintFor] with no composable context, for a caller building its value inside
+ * `remember` — where a `@Composable` call is not allowed. The card's inline tag
+ * colours are computed there, once per body rather than once per recomposition.
+ *
+ * One implementation, two entry points: the composable one delegates here rather than
+ * repeating the lookup, so the chip and the inline token cannot resolve differently.
+ */
+fun labelTint(
+    name: String,
+    color: String,
+): NoteTint = NOTE_TINTS[resolvedLabelColor(name, color, NOTE_TINTS.keys)] ?: NOTE_TINTS.getValue("default")

android/ffi/src/lib.rs

@@ -43,8 +43,8 @@ use thoughtsync_core::sync::blobs::BlobStore;
 use thoughtsync_core::sync::{client, compat, engine, push, state};
 
 use models::{
-    patch_from, BodyItem, ClientUpdate, Identity, Label, Note, NoteDraft, NoteEdit, NoteQuery,
-    ProbeResult, RevokeOutcome, SyncOutcome, SyncStatus,
+    patch_from, BodyItem, BodyTag, ClientUpdate, Identity, Label, Note, NoteDraft, NoteEdit,
+    NoteQuery, ProbeResult, RevokeOutcome, SyncOutcome, SyncStatus,
 };
 
 uniffi::setup_scaffolding!();
@@ -530,6 +530,21 @@ pub fn checklist_items(body: String) -> Vec<BodyItem> {
         .collect()
 }
 
+/// Every `#tag` in a body, with the line and the UTF-16 span each one occupies — so
+/// a card can colour the tag where it was typed instead of printing it twice.
+///
+/// The same argument as `checklist_items` above, and the same answer: the grammar for
+/// what a `#tag` is already exists in Rust, Python and TypeScript. Matching it a
+/// fourth time in Compose would be a fourth place for a tag to change shape when it
+/// syncs — and this one would fail silently, as the wrong characters tinted.
+#[uniffi::export]
+pub fn body_tags(body: String) -> Vec<BodyTag> {
+    local::derive::extract_tag_spans(&body)
+        .into_iter()
+        .map(BodyTag::from)
+        .collect()
+}
+
 /// Helpers, deliberately NOT exported — uniffi only binds what an `#[uniffi::export]`
 /// block names, so these stay Rust-side.
 impl ThoughtSync {

android/ffi/src/models.rs

@@ -76,6 +76,36 @@ impl From<thoughtsync_core::local::derive::DerivedItem> for BodyItem {
     }
 }
 
+/// One `#tag` and where it sits in a note's body.
+///
+/// Mirrors `derive::DerivedTag`. The card colours the tag where it was typed rather
+/// than repeating it as a chip, so it needs the SPAN — and the offsets are UTF-16
+/// code units precisely because Kotlin's `AnnotatedString` counts that way.
+#[derive(Debug, Clone, uniffi::Record)]
+pub struct BodyTag {
+    pub line: u32,
+    pub start: u32,
+    pub end: u32,
+    pub name: String,
+}
+
+impl From<thoughtsync_core::local::derive::DerivedTag> for BodyTag {
+    fn from(t: thoughtsync_core::local::derive::DerivedTag) -> Self {
+        let thoughtsync_core::local::derive::DerivedTag {
+            line,
+            start,
+            end,
+            name,
+        } = t;
+        BodyTag {
+            line,
+            start,
+            end,
+            name,
+        }
+    }
+}
+
 /// An Android build the linked server is offering, already judged to be newer.
 ///
 /// A mirror rather than a re-export of `client::ClientRelease`, for the same