smartcontractkit · aelmanaa · Mar 9, 2026 · Mar 6, 2026
@@ -53,6 +53,49 @@ Optional: copy `.env.example` to `.env`. Set `RPC_<NETWORK_ID>` (e.g. `RPC_ETHER
 - **Validation:** `isValidAddress(receiver, networkInfo(destNetworkId).family)` (shared-utils) handles all families.
 - **Pools:** Not every token is enabled on every lane. PoolInfo shows support and rate limits; unsupported lanes show "Lane Not Supported."
 
+## SDK Inspector
+
+The app includes an SDK Inspector panel (toggle via the `</>` button) that visualizes every CCIP SDK call in real time, grouped into four phases: **Setup**, **Fee Estimation**, **Transfer**, and **Tracking**. Each entry shows the method name, arguments, result, latency, and an educational annotation explaining _what_ the call does and _why_ it happens at that point in the flow.
+
+The inspector is **optional instrumentation** layered on top of the SDK calls -- it does not change the SDK's behavior or API surface. If you are reading the source code to learn how to build your own frontend, here is how to navigate it:
+
+### Reading through the inspector code
+
+SDK calls in hooks like `useTransfer.ts` are wrapped in `logSDKCall()`:
+
+```ts
+// The wrapper adds inspector instrumentation around the SDK call.
+// The actual SDK usage is always the second argument (the lambda).
+const tokenInfo = await logSDKCall(
+  { method: "chain.getTokenInfo", phase: "estimation", ... },
+  () => chain.getTokenInfo(tokenAddress)  // <-- this is the SDK call
+);
+```
+
+To extract the SDK pattern, read the lambda. The config object above it (`method`, `phase`, `displayArgs`, `annotation`) is purely for the inspector UI.
+
+### What you can ignore
+
+| File / directory                         | Purpose                                  | Needed for your app? |
+| ---------------------------------------- | ---------------------------------------- | -------------------- |
+| `src/inspector/`                         | Inspector store, annotations, re-exports | No                   |
+| `logSDKCall` / `logSDKCallSync` wrappers | Record calls to the inspector            | No                   |
+| `getAnnotation(...)`                     | Educational text for each method         | No                   |
+| `displayArgs` in hook calls              | Badge labels shown in the inspector      | No                   |
+
+### What to focus on
+
+| File                         | What it teaches                                                                                                        |
+| ---------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
+| `hooks/useTransfer.ts`       | End-to-end transfer flow: `networkInfo` → `getTokenInfo` → `getFee` → `getLaneLatency` → `generateUnsignedSendMessage` |
+| `hooks/useEVMTransfer.ts`    | EVM-specific signing: approval txs, simulation, `sendTransaction`, `getMessagesInTx`                                   |
+| `hooks/useSolanaTransfer.ts` | Solana-specific signing: `VersionedTransaction`, wallet adapter `sendTransaction`                                      |
+| `hooks/useAptosTransfer.ts`  | Aptos-specific signing: `signAndSubmitTransaction`, transaction polling                                                |
+| `hooks/useTokenPoolInfo.ts`  | Token pool discovery: registry → pool config → remote token + rate limits                                              |
+| `hooks/ChainContext.tsx`     | Lazy chain instantiation: `EVMChain.fromUrl` / `SolanaChain.fromUrl` / `AptosChain.fromUrl`                            |
+
+Every SDK call in these files follows the same pattern: strip the `logSDKCall` wrapper and you have production-ready code.
+
 ## Concepts
 
 - **Network IDs:** SDK format only (e.g. `ethereum-testnet-sepolia`, `solana-devnet`, `aptos-testnet`).

@@ -0,0 +1,5 @@
+.appBody {
+  display: flex;
+  flex: 1;
+  position: relative;
+}
@@ -3,7 +3,7 @@
  * Order: ErrorBoundary → QueryClient → Wagmi → RainbowKit → Solana → Aptos → ChainContext → TransactionHistory → App.
  */
 
-import { useMemo, useCallback, useContext } from "react";
+import { useMemo, useCallback, useContext, lazy, Suspense } from "react";
 import { QueryClientProvider } from "@tanstack/react-query";
 import { WagmiProvider } from "wagmi";
 import { RainbowKitProvider, darkTheme } from "@rainbow-me/rainbowkit";
@@ -26,6 +26,8 @@ import { NETWORKS, type FeeTokenOptionItem } from "@ccip-examples/shared-config"
 import { networkInfo, NetworkType } from "@chainlink/ccip-sdk";
 import { getWalletAddress, type WalletAddresses } from "@ccip-examples/shared-utils";
 import { ErrorBoundary, Header } from "@ccip-examples/shared-components";
+import { SDKInspectorToggle } from "@ccip-examples/shared-components/inspector";
+import { useSDKInspector } from "@ccip-examples/shared-utils/inspector";
 import { ChainContextProvider } from "./hooks/ChainContext.jsx";
 import { TransactionHistoryContext } from "./hooks/transactionHistoryTypes.js";
 import { TransactionHistoryProvider } from "./hooks/TransactionHistoryContext.jsx";
@@ -36,8 +38,16 @@ import { TransactionHistory } from "./components/transaction/TransactionHistory.
 import { useTransfer } from "./hooks/useTransfer.js";
 import "@ccip-examples/shared-components/styles/globals.css";
 import styles from "@ccip-examples/shared-components/layout/AppLayout.module.css";
+import appStyles from "./App.module.css";
 import "@rainbow-me/rainbowkit/styles.css";
 
+// Lazy load the inspector panel — zero cost when inspector is disabled
+const SDKInspectorPanel = lazy(() =>
+  import("@ccip-examples/shared-components/inspector").then((m) => ({
+    default: m.SDKInspectorPanel,
+  }))
+);
+
 const queryClient = createDefaultQueryClient();
 
 /** RPC endpoints from shared-config (no wrapper files needed). */
@@ -69,6 +79,7 @@ function AppContent() {
 
   const transfer = useTransfer();
   const addTransaction = useContext(TransactionHistoryContext).addTransaction;
+  const { enabled: inspectorEnabled } = useSDKInspector();
 
   const isConnected = Boolean(evmAddress ?? solanaAddress ?? aptosAddress);
   const isLoading = ["estimating", "sending"].includes(transfer.status);
@@ -94,9 +105,18 @@ function AppContent() {
       token: string,
       amount: string,
       receiver: string,
-      feeToken: FeeTokenOptionItem | null
+      feeToken: FeeTokenOptionItem | null,
+      remoteToken: string | null
     ) => {
-      const result = await transfer.transfer(source, dest, token, amount, receiver, feeToken);
+      const result = await transfer.transfer(
+        source,
+        dest,
+        token,
+        amount,
+        receiver,
+        feeToken,
+        remoteToken
+      );
       if (result?.messageId == null) return;
       const sender = getWalletAddress(source, walletAddresses);
       if (sender)
@@ -124,42 +144,52 @@ function AppContent() {
   return (
     <div className={styles.app}>
       <Header title="Multichain Family Bridge" subtitle="EVM, Solana, and Aptos token transfers">
+        <SDKInspectorToggle />
         <HistoryButton />
       </Header>
-      <main className={`${styles.main} ${styles.mainWide}`}>
-        <div className={styles.section}>
-          <WalletConnect />
-        </div>
-
-        {isConnected && (
-          <>
-            <BridgeForm
-              walletAddresses={walletAddresses}
-              currentChainId={chainId ?? null}
-              fee={transfer.fee}
-              feeFormatted={transfer.feeFormatted}
-              estimatedTime={transfer.estimatedTime}
-              isLoading={isLoading}
-              onEstimateFee={handleEstimateFee}
-              onTransfer={handleTransfer}
-              onSwitchChain={handleSwitchChain}
-              onClearEstimate={transfer.clearEstimate}
-              onReset={transfer.reset}
-            />
-
-            <TransactionStatusView
-              status={transfer.status}
-              error={transfer.error}
-              txHash={transfer.txHash}
-              messageId={transfer.messageId}
-              estimatedTime={transfer.estimatedTime}
-              onReset={transfer.reset}
-              lastTransferContext={transfer.lastTransferContext}
-              categorizedError={transfer.categorizedError}
-            />
-          </>
+
+      <div className={appStyles.appBody}>
+        {inspectorEnabled && (
+          <Suspense fallback={null}>
+            <SDKInspectorPanel />
+          </Suspense>
         )}
-      </main>
+
+        <main className={`${styles.main} ${styles.mainWide}`}>
+          <div className={styles.section}>
+            <WalletConnect />
+          </div>
+
+          {isConnected && (
+            <>
+              <BridgeForm
+                walletAddresses={walletAddresses}
+                currentChainId={chainId ?? null}
+                fee={transfer.fee}
+                feeFormatted={transfer.feeFormatted}
+                estimatedTime={transfer.estimatedTime}
+                isLoading={isLoading}
+                onEstimateFee={handleEstimateFee}
+                onTransfer={handleTransfer}
+                onSwitchChain={handleSwitchChain}
+                onClearEstimate={transfer.clearEstimate}
+                onReset={transfer.reset}
+              />
+
+              <TransactionStatusView
+                status={transfer.status}
+                error={transfer.error}
+                txHash={transfer.txHash}
+                messageId={transfer.messageId}
+                estimatedTime={transfer.estimatedTime}
+                onReset={transfer.reset}
+                lastTransferContext={transfer.lastTransferContext}
+                categorizedError={transfer.categorizedError}
+              />
+            </>
+          )}
+        </main>
+      </div>
 
       <TransactionHistory />
     </div>

@@ -34,6 +34,9 @@ import {
   type BalanceItem,
 } from "@ccip-examples/shared-components";
 import { useWalletBalances, useFeeTokens } from "@ccip-examples/shared-utils/hooks";
+import { inspectorStore } from "../../inspector/index.js";
+import { getAnnotation } from "../../inspector/annotations.js";
+import { serializeForDisplay } from "@ccip-examples/shared-utils/inspector";
 import { PoolInfo } from "./PoolInfo.js";
 import { useChains } from "../../hooks/useChains.js";
 import { NETWORK_TO_CHAIN_ID } from "@ccip-examples/shared-config/wagmi";
@@ -62,7 +65,8 @@ interface BridgeFormProps {
     token: string,
     amount: string,
     receiver: string,
-    feeToken: FeeTokenOptionItem | null
+    feeToken: FeeTokenOptionItem | null,
+    remoteToken: string | null
   ) => Promise<void>;
   onSwitchChain: (chainId: number) => void;
   onClearEstimate: () => void;
@@ -88,15 +92,17 @@ export function BridgeForm({
   const [receiver, setReceiver] = useState("");
   const [useSelfAsReceiver, setUseSelfAsReceiver] = useState(true);
   const [copied, setCopied] = useState(false);
+  const [poolRemoteToken, setPoolRemoteToken] = useState<string | null>(null);
 
   const { isEVM, getChain } = useChains();
 
-  /** Clear stale transfer result + fee when the user changes networks */
+  /** Clear stale transfer result + fee + inspector when the user changes source network */
   const handleSourceChange = useCallback(
     (id: string) => {
       setSourceNetworkId(id);
       onReset();
       onClearEstimate();
+      inspectorStore.clearCalls();
     },
     [onReset, onClearEstimate]
   );
@@ -127,13 +133,40 @@ export function BridgeForm({
     ? (getTokenAddress(TOKEN_SYMBOL, sourceNetworkId) ?? null)
     : null;
 
+  /** Stable callback for PoolInfo to report remoteToken changes */
+  const handleRemoteTokenResolved = useCallback((rt: string | null) => {
+    setPoolRemoteToken(rt);
+  }, []);
+
+  const recordSDKCall = useCallback(
+    (method: string, args: Record<string, string>, result?: unknown, durationMs?: number) => {
+      if (!inspectorStore.getSnapshot().enabled) return;
+      const ann = getAnnotation(method);
+      inspectorStore.addCall({
+        id: crypto.randomUUID(),
+        timestamp: Date.now(),
+        phase: "setup",
+        method,
+        displayArgs: args,
+        codeSnippet: ann.codeSnippet,
+        annotation: ann.annotation,
+        status: "success",
+        result: serializeForDisplay(result),
+        durationMs,
+      });
+    },
+    []
+  );
+
   const {
     feeTokens,
     selectedToken: feeToken,
     setSelectedToken: setFeeToken,
     isLoading: feeTokensLoading,
     error: feeTokensError,
-  } = useFeeTokens(sourceNetworkId || null, routerAddress, walletAddress, getChain);
+  } = useFeeTokens(sourceNetworkId || null, routerAddress, walletAddress, getChain, {
+    onSDKCall: recordSDKCall,
+  });
 
   const {
     token,
@@ -144,7 +177,8 @@ export function BridgeForm({
     tokenAddress,
     walletAddress ?? null,
     getChain,
-    TOKEN_SYMBOL
+    TOKEN_SYMBOL,
+    { onSDKCall: recordSDKCall, skipNative: true, skipLink: true }
   );
 
   /** Wallet address on the destination chain (for "send to myself") */
@@ -195,7 +229,15 @@ export function BridgeForm({
 
   const handleTransfer = () => {
     if (canTransfer && token)
-      void onTransfer(sourceNetworkId, destNetworkId, TOKEN_SYMBOL, amount, receiver, feeToken);
+      void onTransfer(
+        sourceNetworkId,
+        destNetworkId,
+        TOKEN_SYMBOL,
+        amount,
+        receiver,
+        feeToken,
+        poolRemoteToken
+      );
   };
 
   const handleSwitchChain = () => {
@@ -258,6 +300,7 @@ export function BridgeForm({
         tokenAddress={tokenAddress ?? undefined}
         tokenDecimals={token?.decimals}
         tokenSymbol={TOKEN_SYMBOL}
+        onRemoteTokenResolved={handleRemoteTokenResolved}
       />
 
       <div className={styles.tokenRow}>

@@ -71,6 +71,18 @@
 
 .rateLimits {
   margin-top: var(--spacing-4);
+  padding-top: var(--spacing-3);
+  border-top: 1px solid var(--color-border-light);
+}
+
+.rateLimitsLabel {
+  display: block;
+  font-size: var(--font-size-xs);
+  font-weight: 600;
+  color: var(--color-text-secondary);
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+  margin-bottom: var(--spacing-3);
 }
 
 .skeleton {