feat: 5 defensive hardenings

- ConversationWindowManager: cap reserve token at 50% of effective max
  to prevent negative historyBudget on small-context models (8K/16K)
- common.security.SecretEquals: new constant-time comparison utility
  (MessageDigest.isEqual wrapper) for secrets/tokens/signatures
- WeixinChannelAdapter: migrate context_token comparison to SecretEquals
- FeishuChannelAdapter: fail-fast on empty encrypt_key when connection_mode=webhook
- TelegramChannelAdapter: sanitize attachment captions — strip control bytes
  (\p{Cc} except \t\r\n) + format chars (\p{Cf}) + 4096 char cap
- AgentGraphBuilder: fallback Anthropic max_tokens to 4096 on null/0/negative

Tests: SecretEqualsTest (5) + TelegramCaptionSanitizeTest (5) — all green.

mateclaw-server/src/main/java/vip/mate/agent/AgentGraphBuilder.java

@@ -991,9 +991,16 @@ public class AgentGraphBuilder {
             } else if (runtimeModel.getTopP() != null) {
                 builder.topP(runtimeModel.getTopP());
             }
-            if (runtimeModel.getMaxTokens() != null) {
-                builder.maxTokens(runtimeModel.getMaxTokens());
+            // RFC-025 Change 5: 非正值 maxTokens 会被 Anthropic API 直接拒绝；本地提前拦截
+            // 并 fallback 到 4096，避免错误信息在运行时才暴露、也防止坏配置透传
+            Integer configuredMax = runtimeModel.getMaxTokens();
+            if (configuredMax != null && configuredMax > 0) {
+                builder.maxTokens(configuredMax);
             } else {
+                if (configuredMax != null) {
+                    log.warn("Ignoring non-positive Anthropic maxTokens={} for model {}; falling back to 4096",
+                            configuredMax, runtimeModel.getModelName());
+                }
                 builder.maxTokens(4096);
             }
         }

mateclaw-server/src/main/java/vip/mate/agent/context/ConversationWindowManager.java

@@ -141,6 +141,16 @@ public class ConversationWindowManager {
 
         // 可用于历史的 token 预算 = max - system - currentMsg - 安全余量
         int reservedTokens = systemTokens + currentMsgTokens + (int) (effectiveMax * 0.05);
+        // RFC-025 Change 1: reserve 硬封顶到 effectiveMax 的 50%。
+        // 小上下文模型（Ollama 16K、本地 8K）下，systemTokens + currentMsgTokens 很容易
+        // 接近或超过 effectiveMax，不封顶会让 historyBudget 变负数导致死循环压缩
+        // （压缩目标比压缩前还大 → 压缩后又触发压缩）。
+        int reservedCap = Math.max(1024, effectiveMax / 2);
+        if (reservedTokens > reservedCap) {
+            log.warn("[ConversationWindow] 预留 token {} 超过上下文窗口 50% {}，封顶至 {}",
+                    reservedTokens, effectiveMax, reservedCap);
+            reservedTokens = reservedCap;
+        }
         int historyBudget = effectiveMax - reservedTokens;
 
         // 尾部保护 token 预算：阈值的 20%（与 Hermes 一致）

mateclaw-server/src/main/java/vip/mate/channel/feishu/FeishuChannelAdapter.java

@@ -110,7 +110,17 @@ public class FeishuChannelAdapter extends AbstractChannelAdapter {
         if ("websocket".equals(connectionMode)) {
             startWebSocket(appId, appSecret);
         } else {
-            log.info("[feishu] Webhook mode, waiting for callbacks at /api/v1/channels/webhook/feishu");
+            // RFC-025 Change 3: webhook 模式下 encrypt_key 必须配置，否则 fail-fast 拒绝启动；
+            // 没有加密密钥 + 无签名校验 = 任何人可伪造 webhook 请求触发 agent 消息
+            String encryptKey = getConfigString("encrypt_key", null);
+            if (encryptKey == null || encryptKey.isBlank()) {
+                throw new IllegalStateException(
+                        "Feishu channel in webhook mode requires encrypt_key in configJson " +
+                        "(fail-closed to prevent unauthenticated webhook abuse). " +
+                        "Configure encrypt_key on the Feishu Event Subscriptions page and mirror " +
+                        "it in this channel's configJson, or switch connection_mode to websocket.");
+            }
+            log.info("[feishu] Webhook mode (encrypt_key configured), waiting for callbacks at /api/v1/channels/webhook/feishu");
         }
 
         log.info("[feishu] Feishu channel initialized: appId={}, mode={}, domain={}",

mateclaw-server/src/main/java/vip/mate/channel/telegram/TelegramChannelAdapter.java

@@ -393,7 +393,10 @@ public class TelegramChannelAdapter extends AbstractChannelAdapter {
         // 构建 contentParts
         List<MessageContentPart> contentParts = new ArrayList<>();
         String textContent = (String) message.get("text");
-        String caption = (String) message.get("caption");
+        // RFC-025 Change 4: caption 净化 — .epub / .mobi 等附件的二进制元数据会被
+        // 某些 Telegram Bot API 版本塞进 caption，非 UTF-8 字节序列直接进 LLM prompt
+        // 会让 token 数爆涨、成本不可控
+        String caption = sanitizeInboundText((String) message.get("caption"));
         boolean hasVoice = message.get("voice") != null;
 
         if (textContent != null && !textContent.isBlank()) {
@@ -716,4 +719,26 @@ public class TelegramChannelAdapter extends AbstractChannelAdapter {
     public String getChannelType() {
         return CHANNEL_TYPE;
     }
+
+    /** RFC-025 Change 4 入站文本净化上限（防止 caption 含超长二进制撑爆 prompt）。 */
+    private static final int INBOUND_TEXT_MAX = 4096;
+
+    /**
+     * 净化入站文本（caption / text 可选复用）：
+     * <ul>
+     *   <li>剥掉控制字符与非可打印字节，保留常见空白、中日韩文字</li>
+     *   <li>硬封顶 {@value #INBOUND_TEXT_MAX} 字符，超出追加 truncation 标记</li>
+     * </ul>
+     * <p>RFC-025 Change 4：应对 .epub / .mobi 等附件把二进制元数据塞到 caption 的场景。</p>
+     */
+    static String sanitizeInboundText(String raw) {
+        if (raw == null || raw.isEmpty()) return raw;
+        // 策略：剥掉控制字符（\p{Cc}）但保留 \t \r \n；再剥零宽/BIDI 等格式字符（\p{Cf}）。
+        // 其它所有 Unicode 可见字符（含 CJK 全角标点、emoji、西欧字母、阿拉伯数字等）均保留。
+        // 相比白名单法：对全角 / 异域文字 / 新 emoji 都零误杀；仅打掉真正会爆 token 的控制字节。
+        String cleaned = raw.replaceAll("[\\p{Cc}&&[^\\t\\r\\n]]", "")
+                .replaceAll("\\p{Cf}", "");
+        if (cleaned.length() <= INBOUND_TEXT_MAX) return cleaned;
+        return cleaned.substring(0, INBOUND_TEXT_MAX) + " ...[truncated]";
+    }
 }

mateclaw-server/src/main/java/vip/mate/channel/weixin/WeixinChannelAdapter.java

@@ -8,6 +8,7 @@ import vip.mate.channel.ChannelMessageRouter;
 import vip.mate.channel.ExponentialBackoff;
 import vip.mate.channel.model.ChannelEntity;
 import vip.mate.channel.weixin.error.TokenExpiredException;
+import vip.mate.common.security.SecretEquals;
 import vip.mate.workspace.conversation.model.MessageContentPart;
 
 import java.io.IOException;
@@ -563,7 +564,8 @@ public class WeixinChannelAdapter extends AbstractChannelAdapter {
         if (!fromUserId.isBlank() && !contextToken.isBlank()) {
             String prev = userContextTokens.put(fromUserId, contextToken);
             // token 变更时才持久化（减少 I/O）
-            if (!contextToken.equals(prev)) {
+            // RFC-025 Change 2: 常数时间比较，作为秘钥类字符串比较的模板统一
+            if (!SecretEquals.equals(contextToken, prev)) {
                 saveContextTokens();
             }
         }

mateclaw-server/src/main/java/vip/mate/common/security/SecretEquals.java

@@ -0,0 +1,45 @@
+package vip.mate.common.security;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+
+/**
+ * 常数时间字符串比较工具（RFC-025 Change 2）。
+ *
+ * <p>用于比较秘钥 / 签名 / 会话 token 等敏感字符串，避免 {@link String#equals} 的字符级短路
+ * 特征被 timing 攻击利用推断前缀。</p>
+ *
+ * <p>实现层统一 UTF-8 编码到 {@code byte[]} 后调用 {@link MessageDigest#isEqual(byte[], byte[])}
+ * ——该方法在 JDK 6+ 即保证线性时间不短路（即使长度不等也是返回 false 而非抛异常）。
+ * null 被视为空数组，与非 null / 非空比较结果为 false。</p>
+ *
+ * <p>使用场景：
+ * <ul>
+ *   <li>webhook 签名比对</li>
+ *   <li>MCP / HTTP bearer 校验</li>
+ *   <li>会话 token / context_token 比较</li>
+ *   <li>后续 RFC（sanitizer / skill hub 签名）中复用</li>
+ * </ul></p>
+ */
+public final class SecretEquals {
+
+    private SecretEquals() {}
+
+    /**
+     * 常数时间比较两个字符串（视为 UTF-8 字节数组）。
+     *
+     * @return true 当且仅当两者非 null 且字节内容相等；任一为 null 且另一非空视为不等
+     */
+    public static boolean equals(String a, String b) {
+        byte[] ba = (a == null) ? new byte[0] : a.getBytes(StandardCharsets.UTF_8);
+        byte[] bb = (b == null) ? new byte[0] : b.getBytes(StandardCharsets.UTF_8);
+        return MessageDigest.isEqual(ba, bb);
+    }
+
+    /** 字节数组版本：调用方已自行编码时可直接使用。 */
+    public static boolean equals(byte[] a, byte[] b) {
+        if (a == null) a = new byte[0];
+        if (b == null) b = new byte[0];
+        return MessageDigest.isEqual(a, b);
+    }
+}

mateclaw-server/src/test/java/vip/mate/channel/telegram/TelegramCaptionSanitizeTest.java

@@ -0,0 +1,63 @@
+package vip.mate.channel.telegram;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/** RFC-025 Change 4：入站 caption / text 净化单测。 */
+class TelegramCaptionSanitizeTest {
+
+    @Test
+    @DisplayName("空 / null 直接原样返回")
+    void emptyInputs() {
+        assertNull(TelegramChannelAdapter.sanitizeInboundText(null));
+        assertEquals("", TelegramChannelAdapter.sanitizeInboundText(""));
+    }
+
+    @Test
+    @DisplayName("纯文本 / 中文 / emoji 不应被误杀")
+    void preservesNormalText() {
+        assertEquals("Hello world", TelegramChannelAdapter.sanitizeInboundText("Hello world"));
+        assertEquals("你好，世界", TelegramChannelAdapter.sanitizeInboundText("你好，世界"));
+        assertEquals("日本語テスト", TelegramChannelAdapter.sanitizeInboundText("日本語テスト"));
+        assertEquals("한국어", TelegramChannelAdapter.sanitizeInboundText("한국어"));
+    }
+
+    @Test
+    @DisplayName("控制字符 / ZWSP / 非可打印字节被剥掉")
+    void stripsNonPrintable() {
+        // \u0000 NUL, \u0007 BEL, \u200B ZWSP
+        String dirty = "a\u0000b\u0007c\u200Bd";
+        String clean = TelegramChannelAdapter.sanitizeInboundText(dirty);
+        assertEquals("abcd", clean, "got: " + clean);
+    }
+
+    @Test
+    @DisplayName("超长字符串被截断到 4096 + truncation 标记")
+    void longInputTruncated() {
+        String huge = "x".repeat(5000);
+        String result = TelegramChannelAdapter.sanitizeInboundText(huge);
+        assertTrue(result.length() <= 4096 + 20, "expected ≤ 4116 chars, got " + result.length());
+        assertTrue(result.endsWith("...[truncated]"));
+    }
+
+    @Test
+    @DisplayName("模拟 .epub caption 泄露二进制 → 净化后可控大小")
+    void simulatedEpubBinaryCaption() {
+        // 构造类似 .epub 元数据：混合 UTF-8 文本 + 非可打印字节
+        StringBuilder dirty = new StringBuilder();
+        dirty.append("Book Title\u0000PK\u0003\u0004");   // ZIP 魔数 + 文件头
+        for (int i = 0; i < 1000; i++) {
+            dirty.append((char) (i % 32));   // 大量控制字符
+        }
+        dirty.append(" author:Foo");
+        String clean = TelegramChannelAdapter.sanitizeInboundText(dirty.toString());
+        // 净化结果不含任何控制字符
+        assertFalse(clean.matches(".*[\\x00-\\x1F].*"),
+                "cleaned should have no control bytes: " + clean);
+        // 但保留了实际文本
+        assertTrue(clean.contains("Book Title"));
+        assertTrue(clean.contains("author:Foo"));
+    }
+}

mateclaw-server/src/test/java/vip/mate/common/security/SecretEqualsTest.java

@@ -0,0 +1,50 @@
+package vip.mate.common.security;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/** RFC-025 Change 2 常数时间秘钥比较的正确性测试（不测 timing，测正确性）。 */
+class SecretEqualsTest {
+
+    @Test
+    @DisplayName("相等字符串返回 true")
+    void equalStringsMatch() {
+        assertTrue(SecretEquals.equals("abc123", "abc123"));
+        assertTrue(SecretEquals.equals("", ""));
+    }
+
+    @Test
+    @DisplayName("不等字符串返回 false，含不同长度、前缀差异、后缀差异")
+    void unequalReturnsFalse() {
+        assertFalse(SecretEquals.equals("abc123", "abc124"));
+        assertFalse(SecretEquals.equals("abc", "abcd"));
+        assertFalse(SecretEquals.equals("xabc", "yabc"));
+    }
+
+    @Test
+    @DisplayName("null 视为空数组，任一 null 与非空字符串比较返回 false")
+    void nullSafety() {
+        assertTrue(SecretEquals.equals((String) null, (String) null));
+        assertTrue(SecretEquals.equals((String) null, ""));
+        assertFalse(SecretEquals.equals((String) null, "x"));
+        assertFalse(SecretEquals.equals("x", (String) null));
+    }
+
+    @Test
+    @DisplayName("UTF-8 编码一致性：中文等值字符串返回 true")
+    void utf8ConsistencyForCjk() {
+        assertTrue(SecretEquals.equals("秘钥", "秘钥"));
+        assertFalse(SecretEquals.equals("秘钥", "秘密"));
+    }
+
+    @Test
+    @DisplayName("字节数组版本与字符串版本结果一致")
+    void byteArrayOverloadConsistent() {
+        assertTrue(SecretEquals.equals(new byte[]{1, 2, 3}, new byte[]{1, 2, 3}));
+        assertFalse(SecretEquals.equals(new byte[]{1, 2, 3}, new byte[]{1, 2, 4}));
+        assertFalse(SecretEquals.equals(new byte[]{1, 2, 3}, new byte[]{1, 2, 3, 4}));
+        assertTrue(SecretEquals.equals((byte[]) null, (byte[]) null));
+    }
+}