Canvas: fix A2UI v0.8 rendering

apps/macos/Sources/Clawdis/CanvasManager.swift

@@ -93,7 +93,7 @@ final class CanvasManager {
     func eval(sessionKey: String, javaScript: String) async throws -> String {
         _ = try self.show(sessionKey: sessionKey, path: nil)
         guard let controller = self.panelController else { return "" }
-        return await controller.eval(javaScript: javaScript)
+        return try await controller.eval(javaScript: javaScript)
     }
 
     func snapshot(sessionKey: String, outPath: String?) async throws -> String {

apps/macos/Sources/Clawdis/CanvasWindow.swift

@@ -171,11 +171,11 @@ final class CanvasWindowController: NSWindowController, WKNavigationDelegate, NS
         self.webView.loadFileURL(fileURL, allowingReadAccessTo: accessDir)
     }
 
-    func eval(javaScript: String) async -> String {
-        await withCheckedContinuation { cont in
+    func eval(javaScript: String) async throws -> String {
+        try await withCheckedThrowingContinuation { cont in
             self.webView.evaluateJavaScript(javaScript) { result, error in
                 if let error {
-                    cont.resume(returning: "error: \(error.localizedDescription)")
+                    cont.resume(throwing: error)
                     return
                 }
                 if let result {

apps/macos/Sources/Clawdis/ControlRequestHandler.swift

@@ -247,9 +247,12 @@ enum ControlRequestHandler {
             case .reset:
                 js = """
                 (() => {
-                  if (!globalThis.clawdisA2UI) { return "missing clawdisA2UI"; }
-                  globalThis.clawdisA2UI.reset();
-                  return "ok";
+                  try {
+                    if (!globalThis.clawdisA2UI) { return JSON.stringify({ ok: false, error: "missing clawdisA2UI" }); }
+                    return JSON.stringify(globalThis.clawdisA2UI.reset());
+                  } catch (e) {
+                    return JSON.stringify({ ok: false, error: String(e?.message ?? e), stack: e?.stack });
+                  }
                 })()
                 """
 
@@ -257,43 +260,100 @@ enum ControlRequestHandler {
                 guard let jsonl, !jsonl.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
                     return Response(ok: false, message: "missing jsonl")
                 }
-                let messages: [Any]
+                let items: [ParsedJSONLItem]
                 do {
-                    messages = try Self.parseJSONL(jsonl)
+                    items = try Self.parseJSONL(jsonl)
                 } catch {
                     return Response(ok: false, message: "invalid jsonl: \(error.localizedDescription)")
                 }
+
+                do {
+                    try Self.validateA2UIV0_8(items)
+                } catch {
+                    return Response(ok: false, message: error.localizedDescription)
+                }
+
+                let messages = items.map(\.value)
                 let data = try JSONSerialization.data(withJSONObject: messages, options: [])
                 let json = String(data: data, encoding: .utf8) ?? "[]"
                 js = """
                 (() => {
-                  if (!globalThis.clawdisA2UI) { return "missing clawdisA2UI"; }
-                  const messages = \(json);
-                  globalThis.clawdisA2UI.applyMessages(messages);
-                  return "ok";
+                  try {
+                    if (!globalThis.clawdisA2UI) { return JSON.stringify({ ok: false, error: "missing clawdisA2UI" }); }
+                    const messages = \(json);
+                    return JSON.stringify(globalThis.clawdisA2UI.applyMessages(messages));
+                  } catch (e) {
+                    return JSON.stringify({ ok: false, error: String(e?.message ?? e), stack: e?.stack });
+                  }
                 })()
                 """
             }
 
             let result = try await CanvasManager.shared.eval(sessionKey: session, javaScript: js)
-            return Response(ok: true, payload: Data(result.utf8))
+
+            let payload = Data(result.utf8)
+            if let obj = try? JSONSerialization.jsonObject(with: payload, options: []) as? [String: Any],
+               let ok = obj["ok"] as? Bool
+            {
+                let error = obj["error"] as? String
+                return Response(ok: ok, message: ok ? "" : (error ?? "A2UI error"), payload: payload)
+            }
+
+            return Response(ok: true, payload: payload)
         } catch {
             return Response(ok: false, message: error.localizedDescription)
         }
     }
 
-    private static func parseJSONL(_ text: String) throws -> [Any] {
-        var out: [Any] = []
-        for rawLine in text.split(whereSeparator: \.isNewline) {
-            let line = rawLine.trimmingCharacters(in: .whitespacesAndNewlines)
+    private struct ParsedJSONLItem {
+        let lineNumber: Int
+        let value: Any
+    }
+
+    private static func parseJSONL(_ text: String) throws -> [ParsedJSONLItem] {
+        var out: [ParsedJSONLItem] = []
+        var lineNumber = 0
+        for rawLine in text.split(omittingEmptySubsequences: false, whereSeparator: \.isNewline) {
+            lineNumber += 1
+            let line = String(rawLine).trimmingCharacters(in: .whitespacesAndNewlines)
             if line.isEmpty { continue }
             let data = Data(line.utf8)
             let obj = try JSONSerialization.jsonObject(with: data, options: [])
-            out.append(obj)
+            out.append(ParsedJSONLItem(lineNumber: lineNumber, value: obj))
         }
         return out
     }
 
+    private static func validateA2UIV0_8(_ items: [ParsedJSONLItem]) throws {
+        let allowed = Set(["beginRendering", "surfaceUpdate", "dataModelUpdate", "deleteSurface"])
+        for item in items {
+            guard let dict = item.value as? [String: Any] else {
+                throw NSError(domain: "A2UI", code: 1, userInfo: [
+                    NSLocalizedDescriptionKey: "A2UI JSONL line \(item.lineNumber): expected a JSON object",
+                ])
+            }
+
+            if dict.keys.contains("createSurface") {
+                throw NSError(domain: "A2UI", code: 2, userInfo: [
+                    NSLocalizedDescriptionKey: """
+                    A2UI JSONL line \(item.lineNumber): looks like A2UI v0.9 (`createSurface`).
+                    Canvas currently supports A2UI v0.8 server→client messages (`beginRendering`, `surfaceUpdate`, `dataModelUpdate`, `deleteSurface`).
+                    """,
+                ])
+            }
+
+            let matched = dict.keys.filter { allowed.contains($0) }
+            if matched.count != 1 {
+                let found = dict.keys.sorted().joined(separator: ", ")
+                throw NSError(domain: "A2UI", code: 3, userInfo: [
+                    NSLocalizedDescriptionKey: """
+                    A2UI JSONL line \(item.lineNumber): expected exactly one of \(allowed.sorted().joined(separator: ", ")); found: \(found)
+                    """,
+                ])
+            }
+        }
+    }
+
     private static func waitForCanvasA2UI(session: String, timeoutMs: Int) async -> Bool {
         let clock = ContinuousClock()
         let deadline = clock.now.advanced(by: .milliseconds(timeoutMs))

apps/macos/Sources/ClawdisCLI/ClawdisCLI.swift

@@ -515,7 +515,7 @@ struct ClawdisCLI {
           Canvas:
             clawdis-mac canvas show [--session <key>] [--target </...|https://...|file://...>]
               [--x <screenX> --y <screenY>] [--width <w> --height <h>]
-            clawdis-mac canvas a2ui push --jsonl <path> [--session <key>]
+            clawdis-mac canvas a2ui push --jsonl <path> [--session <key>]   # A2UI v0.8 JSONL
             clawdis-mac canvas a2ui reset [--session <key>]
             clawdis-mac canvas hide [--session <key>]
             clawdis-mac canvas eval --js <code> [--session <key>]