Agent cards: shareable brain QR on the flip side

- Backend brainhub: AgentBrain gains resourceUrl
  (https://clawbrainhub.com/brains/{owner}/{name}); set in parse_brain + fake.
- Mobile: AgentMeta gains brainUrl (carried from the pulled brain's resourceUrl).
- AgentBackTemplate: under Special capabilities, a "Share brain link" toggle
  reveals a QR (+ the URL) that anyone can scan to open the brain on
  ClawBrainHub.
- Gate green: mobile 28, backend brainhub tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

cardclaws-backend/crates/cardclaws-api/src/brainhub.rs

@@ -10,6 +10,8 @@ const DEFAULT_BASE: &str = "https://clawbrainhub.com/api/v1";
 /// Reference brains the registry always ships — handy picks even when the user
 /// hasn't published their own yet.
 const REFERENCE_OWNER: &str = "redclawsystems";
+/// Public web base for a shareable brain link.
+const WEB_BASE: &str = "https://clawbrainhub.com/brains";
 
 /// A brain as shown in the picker list.
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -34,6 +36,8 @@ pub struct AgentBrain {
     pub skills: Vec<String>,
     pub tools: Vec<String>,
     pub capabilities: Vec<String>,
+    /// Public ClawBrainHub URL to access this brain (shareable via QR).
+    pub resource_url: String,
 }
 
 #[derive(Debug)]
@@ -226,6 +230,7 @@ fn parse_brain(owner: &str, name: &str, version: &str, json: &serde_json::Value)
         skills,
         tools,
         capabilities,
+        resource_url: format!("{WEB_BASE}/{owner}/{name}"),
     }
 }
 
@@ -311,6 +316,7 @@ impl BrainHubClient for FakeBrainHubClient {
             skills: vec!["Web Search".into(), "Code".into()],
             tools: vec![],
             capabilities: vec!["Writing".into(), "Analysis".into()],
+            resource_url: format!("{WEB_BASE}/{owner}/{name}"),
         })
     }
 }

cardclaws-mobile/app/demo.tsx

@@ -193,6 +193,7 @@ export default function CardEditorScreen() {
           skills: b.skills.map((s) => ({ name: s, level: 4 })),
           tools: b.tools,
           capabilities: b.capabilities,
+          brainUrl: b.resourceUrl,
         });
         setShowing(false);
         draft.setPendingAgentBrain(null);

cardclaws-mobile/src/api/brainhub.ts

@@ -20,6 +20,8 @@ export interface AgentBrain {
   skills: string[];
   tools: string[];
   capabilities: string[];
+  /** Public ClawBrainHub URL to access this brain (shareable via QR). */
+  resourceUrl: string;
 }
 
 export async function listBrains(): Promise<BrainSummary[]> {

cardclaws-mobile/src/components/card/AgentBackTemplate.tsx

@@ -2,8 +2,10 @@
 // skill bars, tools, and special capabilities (trading-card style).
 
 import { MaterialCommunityIcons } from "@expo/vector-icons";
-import { ScrollView, StyleSheet, Text, View } from "react-native";
+import { useState } from "react";
+import { Pressable, ScrollView, StyleSheet, Switch, Text, View } from "react-native";
 import { AgentMeta } from "../../stores/localCardsStore";
+import { QRCodeView } from "./QRCodeView";
 
 export function AgentBackTemplate({
   name,
@@ -14,6 +16,7 @@ export function AgentBackTemplate({
   title: string;
   agent: AgentMeta;
 }) {
+  const [showQr, setShowQr] = useState(false);
   return (
     <View style={styles.root}>
       <View style={styles.header}>
@@ -72,6 +75,33 @@ export function AgentBackTemplate({
             ))}
           </>
         )}
+
+        {!!agent.brainUrl && (
+          <View style={styles.shareBlock}>
+            <Pressable style={styles.shareRow} onPress={() => setShowQr((v) => !v)}>
+              <View style={{ flex: 1 }}>
+                <Text style={styles.section}>Share brain link</Text>
+                <Text style={styles.shareHint}>QR to access this brain on ClawBrainHub</Text>
+              </View>
+              <Switch
+                value={showQr}
+                onValueChange={setShowQr}
+                trackColor={{ true: "#ff3b30", false: "#3a3a44" }}
+                thumbColor="#ffffff"
+              />
+            </Pressable>
+            {showQr && (
+              <View style={styles.qrWrap}>
+                <View style={styles.qrCard}>
+                  <QRCodeView value={agent.brainUrl} size={150} />
+                </View>
+                <Text style={styles.qrUrl} numberOfLines={1}>
+                  {agent.brainUrl}
+                </Text>
+              </View>
+            )}
+          </View>
+        )}
       </ScrollView>
     </View>
   );
@@ -110,4 +140,16 @@ const styles = StyleSheet.create({
   chipText: { color: "#f5f5f7", fontSize: 13, fontWeight: "600" },
   capRow: { flexDirection: "row", alignItems: "center", gap: 8 },
   capText: { color: "#e0e0e4", fontSize: 14, flex: 1 },
+  shareBlock: {
+    marginTop: 16,
+    paddingTop: 14,
+    borderTopWidth: StyleSheet.hairlineWidth,
+    borderTopColor: "#2a2a30",
+  },
+  shareRow: { flexDirection: "row", alignItems: "center", gap: 12 },
+  shareHint: { color: "#9a9aa0", fontSize: 12, marginTop: 2 },
+  qrWrap: { alignItems: "center", marginTop: 14, gap: 8 },
+  qrCard: { backgroundColor: "#ffffff", padding: 12, borderRadius: 14 },
+  qrUrl: { color: "#9a9aa0", fontSize: 11 },
 });
+

cardclaws-mobile/src/stores/localCardsStore.ts

@@ -42,6 +42,8 @@ export interface AgentMeta {
   skills: AgentSkill[];
   tools: string[];
   capabilities: string[];
+  /** ClawBrainHub URL to access the brain (shared via the flip-side QR). */
+  brainUrl?: string;
 }
 
 export interface LocalCard {