diff --git a/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/AgentClaudeCodeChatModelBuilder.java b/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/AgentClaudeCodeChatModelBuilder.java
index 0acc89b8..e9e184a9 100644
--- a/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/AgentClaudeCodeChatModelBuilder.java
+++ b/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/AgentClaudeCodeChatModelBuilder.java
@@ -97,12 +97,18 @@ public class AgentClaudeCodeChatModelBuilder implements ChatModelBuilder {
         //    sampling-params handling, thinking-budget mapping, prompt cache.
         AnthropicChatOptions options = anthropicBuilder.buildAnthropicOptions(model);
 
-        return AnthropicChatModel.builder()
+        AnthropicChatModel raw = AnthropicChatModel.builder()
                 .anthropicApi(api)
                 .defaultOptions(options)
                 .retryTemplate(retry)
                 .observationRegistry(observationRegistryProvider.getIfAvailable(() -> ObservationRegistry.NOOP))
                 .build();
+
+        // 4) Wrap with the OAuth identity decorator. Anthropic's edge rate-limits /
+        //    5xxs requests that don't claim Claude Code identity in the system
+        //    prompt — symptom: 429 rate_limit_error with body "Error" on quiet
+        //    accounts. See ClaudeCodeIdentityChatModelDecorator javadoc.
+        return new ClaudeCodeIdentityChatModelDecorator(raw);
     }
 
     /**
diff --git a/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/ClaudeCodeIdentityChatModelDecorator.java b/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/ClaudeCodeIdentityChatModelDecorator.java
new file mode 100644
index 00000000..5c90f095
--- /dev/null
+++ b/mateclaw-server/src/main/java/vip/mate/agent/chatmodel/ClaudeCodeIdentityChatModelDecorator.java
@@ -0,0 +1,134 @@
+package vip.mate.agent.chatmodel;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.ai.chat.messages.Message;
+import org.springframework.ai.chat.messages.SystemMessage;
+import org.springframework.ai.chat.model.ChatModel;
+import org.springframework.ai.chat.model.ChatResponse;
+import org.springframework.ai.chat.prompt.ChatOptions;
+import org.springframework.ai.chat.prompt.Prompt;
+import reactor.core.publisher.Flux;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * RFC-062: Claude Code OAuth identity transform applied to every Anthropic
+ * request when the underlying auth is a Claude Code OAuth token.
+ *
+ * <p>Anthropic's OAuth edge enforces an anti-abuse path that rate-limits
+ * (and intermittently 5xxs) requests whose system prompt does NOT claim
+ * Claude Code identity. Symptoms include:
+ *
+ * <ul>
+ *   <li>HTTP 429 with {@code rate_limit_error} on quiet accounts that haven't
+ *       come close to their token budget — the give-away is a body of just
+ *       {@code {"type":"error","error":{"type":"rate_limit_error","message":"Error"}}}
+ *       (genuine quota exhaustion includes a descriptive message).</li>
+ *   <li>Sporadic 500s on the first call after a long idle period.</li>
+ * </ul>
+ *
+ * <p>Reference: hermes-agent {@code anthropic_adapter._build_anthropic_messages_request}
+ * lines 1571-1607 — applies the same transforms unconditionally on
+ * {@code is_oauth=True} requests.
+ *
+ * <h2>Transforms applied per call</h2>
+ * <ol>
+ *   <li>Prepend {@code "You are Claude Code, Anthropic's official CLI for Claude."}
+ *       to the system prompt. If no system message is present we insert one.</li>
+ *   <li>Scrub MateClaw branding from system text — replace
+ *       {@code "MateClaw"} → {@code "Claude Code"} and a few common variants —
+ *       so server-side content filters don't fire on the spoofed identity.</li>
+ * </ol>
+ *
+ * <p><b>Tool-name {@code mcp_} prefix</b> (hermes lines 1593-1607) is a
+ * separate concern: it requires bidirectional rewriting (out + back) and
+ * touches Spring AI's tool-callback layer. Deferred to a follow-up — current
+ * symptom is rate-limit on memory analysis (which uses no tools).
+ */
+@Slf4j
+public class ClaudeCodeIdentityChatModelDecorator implements ChatModel {
+
+    /** Magic identity prefix Anthropic's OAuth edge requires in the system prompt. */
+    static final String CLAUDE_CODE_SYSTEM_PREFIX =
+            "You are Claude Code, Anthropic's official CLI for Claude.";
+
+    private final ChatModel delegate;
+
+    public ClaudeCodeIdentityChatModelDecorator(ChatModel delegate) {
+        this.delegate = delegate;
+    }
+
+    @Override
+    public ChatResponse call(Prompt prompt) {
+        return delegate.call(transform(prompt));
+    }
+
+    @Override
+    public Flux<ChatResponse> stream(Prompt prompt) {
+        return delegate.stream(transform(prompt));
+    }
+
+    @Override
+    public ChatOptions getDefaultOptions() {
+        return delegate.getDefaultOptions();
+    }
+
+    /**
+     * Build a new {@link Prompt} with the OAuth identity transforms applied.
+     * Package-private for unit tests.
+     */
+    Prompt transform(Prompt original) {
+        if (original == null) {
+            return null;
+        }
+        List<Message> source = original.getInstructions();
+        List<Message> rewritten = new ArrayList<>(source.size() + 1);
+
+        boolean systemSeen = false;
+        for (Message msg : source) {
+            if (msg instanceof SystemMessage sm && !systemSeen) {
+                // Only mutate the FIRST system message — multiple system messages
+                // are rare in practice but preserve the second-onward verbatim.
+                rewritten.add(new SystemMessage(prependIdentity(sanitizeBranding(sm.getText()))));
+                systemSeen = true;
+            } else {
+                rewritten.add(msg);
+            }
+        }
+        if (!systemSeen) {
+            // No system message at all → insert one with just the identity prefix.
+            rewritten.add(0, new SystemMessage(CLAUDE_CODE_SYSTEM_PREFIX));
+        }
+        return new Prompt(rewritten, original.getOptions());
+    }
+
+    private static String prependIdentity(String existingSystem) {
+        if (existingSystem == null || existingSystem.isBlank()) {
+            return CLAUDE_CODE_SYSTEM_PREFIX;
+        }
+        if (existingSystem.startsWith(CLAUDE_CODE_SYSTEM_PREFIX)) {
+            // Already prefixed (defensive — protects against double-wrapping
+            // if a caller invokes the decorator twice).
+            return existingSystem;
+        }
+        return CLAUDE_CODE_SYSTEM_PREFIX + "\n\n" + existingSystem;
+    }
+
+    /**
+     * Replace MateClaw / agent-specific branding tokens with their Claude Code
+     * equivalents. Same idea as hermes-agent's
+     * {@code text.replace("Hermes Agent", "Claude Code")} chain — Anthropic's
+     * server-side filter flags requests where the spoofed identity contradicts
+     * itself ("You are Claude Code … built by MateClaw").
+     */
+    static String sanitizeBranding(String text) {
+        if (text == null || text.isEmpty()) {
+            return text;
+        }
+        return text
+                .replace("MateClaw", "Claude Code")
+                .replace("mateclaw", "claude-code")
+                .replace("Mate Claw", "Claude Code");
+    }
+}