implements PLN-0074

discussion/index.ndjson

@@ -1,5 +1,5 @@
 {"type":"meta","next_id":{"DSC":35,"AGD":38,"DEC":35,"PLN":75,"LSN":47,"CLSN":1}}
-{"type":"discussion","id":"DSC-0034","status":"in_progress","ticket":"frontend-semantic-host-projection-flexibility","title":"Frontend semantic vocabulary flexibility and declarative host projection","created_at":"2026-05-06","updated_at":"2026-05-06","tags":["compiler","compiler-general","frontend","semantics","vscode","host-projection","lsp"],"agendas":[{"id":"AGD-0037","file":"AGD-0037-frontend-semantic-host-projection-flexibility.md","status":"accepted","created_at":"2026-05-06","updated_at":"2026-05-06"}],"decisions":[{"id":"DEC-0034","file":"DEC-0034-frontend-semantic-host-projection-flexibility.md","status":"accepted","created_at":"2026-05-06","updated_at":"2026-05-06","ref_agenda":"AGD-0037"}],"plans":[{"id":"PLN-0072","file":"PLN-0072-frontend-semantic-host-projection-contract.md","status":"done","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0034"]},{"id":"PLN-0073","file":"PLN-0073-lsp-semantic-host-projection-transport.md","status":"done","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0034"]},{"id":"PLN-0074","file":"PLN-0074-vscode-semantic-host-projection-adapter.md","status":"open","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0034"]}],"lessons":[]}
+{"type":"discussion","id":"DSC-0034","status":"in_progress","ticket":"frontend-semantic-host-projection-flexibility","title":"Frontend semantic vocabulary flexibility and declarative host projection","created_at":"2026-05-06","updated_at":"2026-05-06","tags":["compiler","compiler-general","frontend","semantics","vscode","host-projection","lsp"],"agendas":[{"id":"AGD-0037","file":"AGD-0037-frontend-semantic-host-projection-flexibility.md","status":"accepted","created_at":"2026-05-06","updated_at":"2026-05-06"}],"decisions":[{"id":"DEC-0034","file":"DEC-0034-frontend-semantic-host-projection-flexibility.md","status":"accepted","created_at":"2026-05-06","updated_at":"2026-05-06","ref_agenda":"AGD-0037"}],"plans":[{"id":"PLN-0072","file":"PLN-0072-frontend-semantic-host-projection-contract.md","status":"done","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0034"]},{"id":"PLN-0073","file":"PLN-0073-lsp-semantic-host-projection-transport.md","status":"done","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0034"]},{"id":"PLN-0074","file":"PLN-0074-vscode-semantic-host-projection-adapter.md","status":"done","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0034"]}],"lessons":[]}
 {"type":"discussion","id":"DSC-0033","status":"in_progress","ticket":"frontend-visual-theme-spec-and-css-retirement","title":"Frontend visual theme spec and retirement of host-consumed semantic CSS","created_at":"2026-05-06","updated_at":"2026-05-06","tags":["compiler","compiler-general","frontend","presentation","theming","studio","vscode","lsp","pbs"],"agendas":[{"id":"AGD-0036","file":"AGD-0036-frontend-visual-theme-spec-and-css-retirement.md","status":"accepted","created_at":"2026-05-06","updated_at":"2026-05-06"}],"decisions":[{"id":"DEC-0033","file":"DEC-0033-frontend-visual-theme-spec-and-css-retirement.md","status":"accepted","created_at":"2026-05-06","updated_at":"2026-05-06","ref_agenda":"AGD-0036"}],"plans":[{"id":"PLN-0068","file":"PLN-0068-frontend-visual-contract-and-pbs-migration.md","status":"open","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0033"]},{"id":"PLN-0069","file":"PLN-0069-lsp-visual-theme-transport-and-selection.md","status":"open","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0033"]},{"id":"PLN-0070","file":"PLN-0070-studio-visual-theme-adapter-and-css-retirement.md","status":"open","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0033"]},{"id":"PLN-0071","file":"PLN-0071-vscode-dynamic-theme-translation-adapter.md","status":"open","created_at":"2026-05-06","updated_at":"2026-05-06","ref_decisions":["DEC-0033"]}],"lessons":[]}
 {"type":"discussion","id":"DSC-0032","status":"in_progress","ticket":"studio-new-lsp-api-and-v1-boundary","title":"Novo boundary entre lsp-api, lsp-v1 e a extensao VS Code","created_at":"2026-05-05","updated_at":"2026-05-05","tags":["studio","lsp","vscode","protocol","api","boundary"],"agendas":[{"id":"AGD-0035","file":"AGD-0035-studio-new-lsp-api-and-v1-boundary.md","status":"accepted","created_at":"2026-05-05","updated_at":"2026-05-05"}],"decisions":[{"id":"DEC-0032","file":"DEC-0032-studio-new-lsp-api-and-v1-boundary.md","status":"accepted","created_at":"2026-05-05","updated_at":"2026-05-05","ref_agenda":"AGD-0035"}],"plans":[{"id":"PLN-0065","file":"PLN-0065-lsp-boundary-and-module-scaffolding.md","status":"done","created_at":"2026-05-05","updated_at":"2026-05-05","ref_decisions":["DEC-0032"]},{"id":"PLN-0066","file":"PLN-0066-project-scoped-lsp-server-lifecycle-in-studio.md","status":"done","created_at":"2026-05-05","updated_at":"2026-05-05","ref_decisions":["DEC-0032"]},{"id":"PLN-0067","file":"PLN-0067-compiler-backed-dumb-lsp-server-baseline.md","status":"done","created_at":"2026-05-05","updated_at":"2026-05-05","ref_decisions":["DEC-0032"]}],"lessons":[]}
 {"type":"discussion","id":"DSC-0031","status":"in_progress","ticket":"studio-editor-workspace-cleanup","title":"Limpeza completa do Workspace Editor do Studio e remoção dos acoplamentos legados","created_at":"2026-05-05","updated_at":"2026-05-05","tags":["studio","editor","cleanup","vfs","lsp","migration"],"agendas":[{"id":"AGD-0034","file":"AGD-0034-vscode-editor-migration-feasibility.md","status":"accepted","created_at":"2026-05-05","updated_at":"2026-05-05"}],"decisions":[{"id":"DEC-0031","file":"DEC-0031-studio-editor-workspace-cleanup.md","status":"in_progress","created_at":"2026-05-05","updated_at":"2026-05-05","ref_agenda":"AGD-0034"}],"plans":[{"id":"PLN-0062","file":"PLN-0062-shell-session-and-state-cleanup-after-editor-removal.md","status":"done","created_at":"2026-05-05","updated_at":"2026-05-05","ref_decisions":["DEC-0031"]},{"id":"PLN-0063","file":"PLN-0063-legacy-lsp-and-vfs-module-removal-with-runtime-preservation.md","status":"done","created_at":"2026-05-05","updated_at":"2026-05-05","ref_decisions":["DEC-0031"]},{"id":"PLN-0064","file":"PLN-0064-normative-test-and-lesson-cleanup-for-editor-stack-removal.md","status":"done","created_at":"2026-05-05","updated_at":"2026-05-05","ref_decisions":["DEC-0031"]}],"lessons":[]}

discussion/workflow/plans/PLN-0074-vscode-semantic-host-projection-adapter.md

@@ -2,9 +2,9 @@
 id: PLN-0074
 ticket: frontend-semantic-host-projection-flexibility
 title: VS Code Semantic Host Projection Adapter
-status: open
+status: done
 created: 2026-05-06
-completed:
+completed: 2026-05-06
 tags: [vscode, extension, frontend, semantics, host-projection, adapter]
 ---
 

tools/vscode-extension/out/extension.js

@@ -45,6 +45,7 @@ let reconnectContext;
 let stoppingClient = false;
 let lastAppliedThemeSignature;
 const RECONNECT_DELAY_MS = 2000;
+const VSCODE_HOST_ID = "vscode";
 function activate(context) {
     reconnectContext = context;
     output = vscode.window.createOutputChannel("Prometeu LSP");
@@ -207,21 +208,30 @@ function clearReconnectTimer() {
     reconnectTimer = undefined;
 }
 async function applyPrometeuVisualTheme(initializeResult) {
-    const payload = extractPrometeuVisualThemesPayload(initializeResult);
+    const visualThemesPayload = extractPrometeuVisualThemesPayload(initializeResult);
-    if (!payload) {
+    if (!visualThemesPayload) {
         output.appendLine("Prometeu visual theme payload not present in initialize result.");
         return;
     }
-    const activeTheme = payload.visualThemes.find((theme) => theme.themeId === payload.activeVisualThemeId);
+    const semanticProjectionPayload = extractPrometeuSemanticHostProjectionsPayload(initializeResult);
+    const vscodeProjection = selectHostProjection(semanticProjectionPayload, VSCODE_HOST_ID);
+    if (!semanticProjectionPayload) {
+        output.appendLine("Prometeu semantic host projection payload not present in initialize result.");
+    }
+    else if (!vscodeProjection) {
+        output.appendLine("Prometeu semantic host projection payload does not declare a vscode projection.");
+    }
+    const activeTheme = visualThemesPayload.visualThemes.find((theme) => theme.themeId === visualThemesPayload.activeVisualThemeId);
     if (!activeTheme) {
-        output.appendLine(`Prometeu visual theme '${payload.activeVisualThemeId}' was not declared by the server.`);
+        output.appendLine(`Prometeu visual theme '${visualThemesPayload.activeVisualThemeId}' was not declared by the server.`);
         return;
     }
     const themeSignature = JSON.stringify({
-        languageId: payload.frontendLanguageId,
+        languageId: visualThemesPayload.frontendLanguageId,
         themeId: activeTheme.themeId,
         editorPalette: activeTheme.editorPalette,
-        tokenStyles: activeTheme.tokenStyles
+        tokenStyles: activeTheme.tokenStyles,
+        semanticProjection: vscodeProjection ?? null
     });
     if (themeSignature === lastAppliedThemeSignature) {
         output.appendLine(`Prometeu visual theme '${activeTheme.themeId}' is already applied.`);
@@ -234,7 +244,7 @@ async function applyPrometeuVisualTheme(initializeResult) {
     const existingSemanticCustomizations = configuration.get("editor.semanticTokenColorCustomizations") ?? {};
     const semanticRules = {
         ...(readObject(existingSemanticCustomizations.rules)),
-        ...buildSemanticTokenRules(payload.frontendLanguageId, activeTheme)
+        ...buildSemanticTokenRules(visualThemesPayload.frontendLanguageId, activeTheme, vscodeProjection)
     };
     await configuration.update("editor.semanticTokenColorCustomizations", {
         ...existingSemanticCustomizations,
@@ -249,7 +259,7 @@ async function applyPrometeuVisualTheme(initializeResult) {
         "editorLineNumber.foreground": activeTheme.editorPalette.lineNumberForeground
     }, configurationTarget);
     lastAppliedThemeSignature = themeSignature;
-    output.appendLine(`Applied Prometeu visual theme '${activeTheme.themeId}' for language '${payload.frontendLanguageId}'.`);
+    output.appendLine(`Applied Prometeu visual theme '${activeTheme.themeId}' for language '${visualThemesPayload.frontendLanguageId}'.`);
 }
 function extractPrometeuVisualThemesPayload(initializeResult) {
     if (!initializeResult || typeof initializeResult !== "object") {
@@ -266,27 +276,63 @@ function extractPrometeuVisualThemesPayload(initializeResult) {
     }
     return payload;
 }
-function buildSemanticTokenRules(languageId, theme) {
+function extractPrometeuSemanticHostProjectionsPayload(initializeResult) {
+    if (!initializeResult || typeof initializeResult !== "object") {
+        return undefined;
+    }
+    const capabilities = readObject(initializeResult.capabilities);
+    const experimental = readObject(capabilities.experimental);
+    const payload = readObject(experimental.prometeuSemanticHostProjections);
+    if (typeof payload.frontendLanguageId !== "string" || !Array.isArray(payload.semanticKeys) || !Array.isArray(payload.hostProjections)) {
+        return undefined;
+    }
+    return payload;
+}
+function selectHostProjection(payload, hostId) {
+    if (!payload) {
+        return undefined;
+    }
+    return payload.hostProjections.find((projection) => projection.hostId === hostId);
+}
+function buildSemanticTokenRules(languageId, theme, hostProjection) {
     const rules = {};
+    const projectionBySemanticKey = new Map((hostProjection?.tokenProjections ?? []).map((projection) => [projection.semanticKey, projection]));
     for (const tokenStyle of theme.tokenStyles) {
-        const selector = `${tokenStyle.semanticKey}:${languageId}`;
+        const styleValue = !tokenStyle.italic && !tokenStyle.bold && !tokenStyle.underline
-        if (!tokenStyle.italic && !tokenStyle.bold && !tokenStyle.underline) {
+            ? tokenStyle.foreground
-            rules[selector] = tokenStyle.foreground;
+            : {
+                foreground: tokenStyle.foreground,
+                ...(tokenStyle.italic ? { italic: true } : {}),
+                ...(tokenStyle.bold ? { bold: true } : {}),
+                ...(tokenStyle.underline ? { underline: true } : {})
+            };
+        rules[`${tokenStyle.semanticKey}:${languageId}`] = styleValue;
+        const projection = projectionBySemanticKey.get(tokenStyle.semanticKey);
+        if (!projection) {
             continue;
         }
-        rules[selector] = {
+        const projectedSelector = buildSemanticSelector(languageId, projection.hostTokenType, projection.hostTokenModifiers);
-            foreground: tokenStyle.foreground,
+        if (!(projectedSelector in rules)) {
-            ...(tokenStyle.italic ? { italic: true } : {}),
+            rules[projectedSelector] = styleValue;
-            ...(tokenStyle.bold ? { bold: true } : {}),
+        }
-            ...(tokenStyle.underline ? { underline: true } : {})
+        const fallbackSelector = buildSemanticSelector(languageId, projection.fallbackTokenType, projection.fallbackTokenModifiers);
-        };
+        if (!(fallbackSelector in rules)) {
+            rules[fallbackSelector] = styleValue;
+        }
     }
     return rules;
 }
+function buildSemanticSelector(languageId, tokenType, modifiers) {
+    const normalizedModifiers = [...modifiers].sort();
+    if (normalizedModifiers.length === 0) {
+        return `${tokenType}:${languageId}`;
+    }
+    return `${tokenType}.${normalizedModifiers.join(".")}:${languageId}`;
+}
 function readObject(value) {
     if (!value || typeof value !== "object" || Array.isArray(value)) {
         return {};
     }
     return value;
 }
-//# sourceMappingURL=extension.js.map
+//# sourceMappingURL=extension.js.map

tools/vscode-extension/package.json

@@ -53,100 +53,6 @@
         }
       }
     },
-    "semanticTokenTypes": [
-      {
-        "id": "pbs-comment",
-        "description": "PBS comment token"
-      },
-      {
-        "id": "pbs-string",
-        "description": "PBS string token"
-      },
-      {
-        "id": "pbs-number",
-        "description": "PBS number token"
-      },
-      {
-        "id": "pbs-literal",
-        "description": "PBS literal token"
-      },
-      {
-        "id": "pbs-lifecycle",
-        "description": "PBS lifecycle token"
-      },
-      {
-        "id": "pbs-keyword",
-        "description": "PBS keyword token"
-      },
-      {
-        "id": "pbs-operator",
-        "description": "PBS operator token"
-      },
-      {
-        "id": "pbs-punctuation",
-        "description": "PBS punctuation token"
-      },
-      {
-        "id": "pbs-function",
-        "description": "PBS function token"
-      },
-      {
-        "id": "pbs-method",
-        "description": "PBS method token"
-      },
-      {
-        "id": "pbs-constructor",
-        "description": "PBS constructor token"
-      },
-      {
-        "id": "pbs-struct",
-        "description": "PBS struct token"
-      },
-      {
-        "id": "pbs-contract",
-        "description": "PBS contract token"
-      },
-      {
-        "id": "pbs-host",
-        "description": "PBS host token"
-      },
-      {
-        "id": "pbs-builtin-type",
-        "description": "PBS builtin type token"
-      },
-      {
-        "id": "pbs-service",
-        "description": "PBS service token"
-      },
-      {
-        "id": "pbs-error",
-        "description": "PBS error token"
-      },
-      {
-        "id": "pbs-enum",
-        "description": "PBS enum token"
-      },
-      {
-        "id": "pbs-callback",
-        "description": "PBS callback token"
-      },
-      {
-        "id": "pbs-global",
-        "description": "PBS global token"
-      },
-      {
-        "id": "pbs-const",
-        "description": "PBS const token"
-      },
-      {
-        "id": "pbs-implements",
-        "description": "PBS implements token"
-      },
-      {
-        "id": "pbs-identifier",
-        "description": "PBS identifier token"
-      }
-    ],
     "configurationDefaults": {
       "editor.semanticHighlighting.enabled": true
     }

tools/vscode-extension/src/extension.ts

@@ -51,6 +51,27 @@ type PrometeuVisualThemesPayload = {
     visualThemes: PrometeuVisualTheme[];
 };
 
+type PrometeuSemanticHostProjectionEntry = {
+    semanticKey: string;
+    hostTokenType: string;
+    hostTokenModifiers: string[];
+    fallbackTokenType: string;
+    fallbackTokenModifiers: string[];
+};
+
+type PrometeuSemanticHostProjection = {
+    hostId: string;
+    tokenProjections: PrometeuSemanticHostProjectionEntry[];
+};
+
+type PrometeuSemanticHostProjectionsPayload = {
+    frontendLanguageId: string;
+    semanticKeys: string[];
+    hostProjections: PrometeuSemanticHostProjection[];
+};
+
+const VSCODE_HOST_ID = "vscode";
+
 export function activate(context: vscode.ExtensionContext): void {
     reconnectContext = context;
     output = vscode.window.createOutputChannel("Prometeu LSP");
@@ -255,23 +276,31 @@ function clearReconnectTimer(): void {
 }
 
 async function applyPrometeuVisualTheme(initializeResult: unknown): Promise<void> {
-    const payload = extractPrometeuVisualThemesPayload(initializeResult);
+    const visualThemesPayload = extractPrometeuVisualThemesPayload(initializeResult);
-    if (!payload) {
+    if (!visualThemesPayload) {
         output.appendLine("Prometeu visual theme payload not present in initialize result.");
         return;
     }
+    const semanticProjectionPayload = extractPrometeuSemanticHostProjectionsPayload(initializeResult);
+    const vscodeProjection = selectHostProjection(semanticProjectionPayload, VSCODE_HOST_ID);
+    if (!semanticProjectionPayload) {
+        output.appendLine("Prometeu semantic host projection payload not present in initialize result.");
+    } else if (!vscodeProjection) {
+        output.appendLine("Prometeu semantic host projection payload does not declare a vscode projection.");
+    }
 
-    const activeTheme = payload.visualThemes.find((theme) => theme.themeId === payload.activeVisualThemeId);
+    const activeTheme = visualThemesPayload.visualThemes.find((theme) => theme.themeId === visualThemesPayload.activeVisualThemeId);
     if (!activeTheme) {
-        output.appendLine(`Prometeu visual theme '${payload.activeVisualThemeId}' was not declared by the server.`);
+        output.appendLine(`Prometeu visual theme '${visualThemesPayload.activeVisualThemeId}' was not declared by the server.`);
         return;
     }
 
     const themeSignature = JSON.stringify({
-        languageId: payload.frontendLanguageId,
+        languageId: visualThemesPayload.frontendLanguageId,
         themeId: activeTheme.themeId,
         editorPalette: activeTheme.editorPalette,
-        tokenStyles: activeTheme.tokenStyles
+        tokenStyles: activeTheme.tokenStyles,
+        semanticProjection: vscodeProjection ?? null
     });
     if (themeSignature === lastAppliedThemeSignature) {
         output.appendLine(`Prometeu visual theme '${activeTheme.themeId}' is already applied.`);
@@ -286,7 +315,7 @@ async function applyPrometeuVisualTheme(initializeResult: unknown): Promise<void
     const existingSemanticCustomizations = configuration.get<Record<string, unknown>>("editor.semanticTokenColorCustomizations") ?? {};
     const semanticRules = {
         ...(readObject(existingSemanticCustomizations.rules)),
-        ...buildSemanticTokenRules(payload.frontendLanguageId, activeTheme)
+        ...buildSemanticTokenRules(visualThemesPayload.frontendLanguageId, activeTheme, vscodeProjection)
     };
 
     await configuration.update(
@@ -312,7 +341,7 @@ async function applyPrometeuVisualTheme(initializeResult: unknown): Promise<void
     );
 
     lastAppliedThemeSignature = themeSignature;
-    output.appendLine(`Applied Prometeu visual theme '${activeTheme.themeId}' for language '${payload.frontendLanguageId}'.`);
+    output.appendLine(`Applied Prometeu visual theme '${activeTheme.themeId}' for language '${visualThemesPayload.frontendLanguageId}'.`);
 }
 
 function extractPrometeuVisualThemesPayload(initializeResult: unknown): PrometeuVisualThemesPayload | undefined {
@@ -334,27 +363,82 @@ function extractPrometeuVisualThemesPayload(initializeResult: unknown): Prometeu
     return payload as unknown as PrometeuVisualThemesPayload;
 }
 
+function extractPrometeuSemanticHostProjectionsPayload(initializeResult: unknown): PrometeuSemanticHostProjectionsPayload | undefined {
+    if (!initializeResult || typeof initializeResult !== "object") {
+        return undefined;
+    }
+
+    const capabilities = readObject((initializeResult as { capabilities?: unknown }).capabilities);
+    const experimental = readObject(capabilities.experimental);
+    const payload = readObject(experimental.prometeuSemanticHostProjections);
+
+    if (typeof payload.frontendLanguageId !== "string" || !Array.isArray(payload.semanticKeys) || !Array.isArray(payload.hostProjections)) {
+        return undefined;
+    }
+
+    return payload as unknown as PrometeuSemanticHostProjectionsPayload;
+}
+
+function selectHostProjection(
+    payload: PrometeuSemanticHostProjectionsPayload | undefined,
+    hostId: string
+): PrometeuSemanticHostProjection | undefined {
+    if (!payload) {
+        return undefined;
+    }
+    return payload.hostProjections.find((projection) => projection.hostId === hostId);
+}
+
 function buildSemanticTokenRules(
     languageId: string,
-    theme: PrometeuVisualTheme
+    theme: PrometeuVisualTheme,
+    hostProjection: PrometeuSemanticHostProjection | undefined
 ): Record<string, string | { foreground: string; italic?: boolean; bold?: boolean; underline?: boolean }> {
     const rules: Record<string, string | { foreground: string; italic?: boolean; bold?: boolean; underline?: boolean }> = {};
+    const projectionBySemanticKey = new Map<string, PrometeuSemanticHostProjectionEntry>(
+        (hostProjection?.tokenProjections ?? []).map((projection) => [projection.semanticKey, projection])
+    );
     for (const tokenStyle of theme.tokenStyles) {
-        const selector = `${tokenStyle.semanticKey}:${languageId}`;
+        const styleValue = !tokenStyle.italic && !tokenStyle.bold && !tokenStyle.underline
-        if (!tokenStyle.italic && !tokenStyle.bold && !tokenStyle.underline) {
+            ? tokenStyle.foreground
-            rules[selector] = tokenStyle.foreground;
+            : {
+                foreground: tokenStyle.foreground,
+                ...(tokenStyle.italic ? { italic: true } : {}),
+                ...(tokenStyle.bold ? { bold: true } : {}),
+                ...(tokenStyle.underline ? { underline: true } : {})
+            };
+        rules[`${tokenStyle.semanticKey}:${languageId}`] = styleValue;
+
+        const projection = projectionBySemanticKey.get(tokenStyle.semanticKey);
+        if (!projection) {
             continue;
         }
-        rules[selector] = {
+
-            foreground: tokenStyle.foreground,
+        const projectedSelector = buildSemanticSelector(languageId, projection.hostTokenType, projection.hostTokenModifiers);
-            ...(tokenStyle.italic ? { italic: true } : {}),
+        if (!(projectedSelector in rules)) {
-            ...(tokenStyle.bold ? { bold: true } : {}),
+            rules[projectedSelector] = styleValue;
-            ...(tokenStyle.underline ? { underline: true } : {})
+        }
-        };
+
+        const fallbackSelector = buildSemanticSelector(languageId, projection.fallbackTokenType, projection.fallbackTokenModifiers);
+        if (!(fallbackSelector in rules)) {
+            rules[fallbackSelector] = styleValue;
+        }
     }
     return rules;
 }
 
+function buildSemanticSelector(
+    languageId: string,
+    tokenType: string,
+    modifiers: string[]
+): string {
+    const normalizedModifiers = [...modifiers].sort();
+    if (normalizedModifiers.length === 0) {
+        return `${tokenType}:${languageId}`;
+    }
+    return `${tokenType}.${normalizedModifiers.join(".")}:${languageId}`;
+}
+
 function readObject(value: unknown): Record<string, unknown> {
     if (!value || typeof value !== "object" || Array.isArray(value)) {
         return {};