diff --git a/docs/ai-agents/index.mdx b/docs/ai-agents/index.mdx
index 1ba0a37e2..2a1c1c283 100644
--- a/docs/ai-agents/index.mdx
+++ b/docs/ai-agents/index.mdx
@@ -8,6 +8,14 @@ import { WalletSetupDemo } from "/snippets/WalletSetupDemo.jsx"
 
 Base MCP gives your AI assistant direct access to your [Base Account](/base-account) (the smart wallet powering the Base App). Connect once and your assistant can check balances, send funds, swap tokens, sign messages, execute contract calls, and pay x402-enabled APIs across multiple networks. Every write action requires your approval.
 
+<Warning>
+  **Wallet compatibility:** Base MCP supports only native Base Smart Wallet accounts created through the email or passkey authentication flow. Standard Externally Owned Accounts (EOAs) cannot connect directly.
+
+  Native Base Smart Wallets are initialized with a 13-word recovery phrase and a device passkey configuration. Standard EOAs use a 12–24 word recovery phrase and do not produce the passkey configuration Base MCP expects, which results in schema errors.
+
+  Upgrading an existing EOA to a Smart Wallet does **not** resolve this: the account keeps its original recovery-phrase structure and will not generate the 13-word phrase or passkey configuration required to connect.
+</Warning>
+
 ## Demo
 
 <Visibility for="humans">