diff --git a/internal/channel/adapters/discord/discord.go b/internal/channel/adapters/discord/discord.go
index c1a3044d..80e00473 100644
--- a/internal/channel/adapters/discord/discord.go
+++ b/internal/channel/adapters/discord/discord.go
@@ -108,6 +108,7 @@ func (*DiscordAdapter) Descriptor() channel.Descriptor {
 }
 
 func (a *DiscordAdapter) getOrCreateSession(token, configID string) (*discordgo.Session, error) {
+	channel.SetIMErrorSecrets("discord:"+configID, token)
 	a.mu.RLock()
 	session, ok := a.sessions[token]
 	a.mu.RUnlock()
diff --git a/internal/channel/adapters/discord/stream.go b/internal/channel/adapters/discord/stream.go
index 9e56e521..5193a9dc 100644
--- a/internal/channel/adapters/discord/stream.go
+++ b/internal/channel/adapters/discord/stream.go
@@ -76,7 +76,7 @@ func (s *discordOutboundStream) Push(ctx context.Context, event channel.StreamEv
 		return nil
 
 	case channel.StreamEventError:
-		errText := strings.TrimSpace(event.Error)
+		errText := channel.RedactIMErrorText(strings.TrimSpace(event.Error))
 		if errText == "" {
 			return nil
 		}
diff --git a/internal/channel/adapters/discord/stream_test.go b/internal/channel/adapters/discord/stream_test.go
new file mode 100644
index 00000000..dae64546
--- /dev/null
+++ b/internal/channel/adapters/discord/stream_test.go
@@ -0,0 +1,74 @@
+package discord
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/bwmarrin/discordgo"
+
+	"github.com/memohai/memoh/internal/channel"
+)
+
+type roundTripFunc func(*http.Request) (*http.Response, error)
+
+func (f roundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) { return f(req) }
+
+func TestDiscordOutboundStream_PushErrorEventRedactsSecrets(t *testing.T) {
+	channel.ResetIMErrorSecretsForTest()
+	t.Cleanup(channel.ResetIMErrorSecretsForTest)
+
+	const token = "discord-token-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	channel.SetIMErrorSecrets("test", token)
+	prefixHalf := token[:len(token)/2]
+
+	var sentBody string
+	session, err := discordgo.New("Bot test")
+	if err != nil {
+		t.Fatalf("create session: %v", err)
+	}
+	session.Client = &http.Client{
+		Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+			body, _ := io.ReadAll(req.Body)
+			sentBody = string(body)
+			resp := &http.Response{
+				StatusCode: http.StatusOK,
+				Body:       io.NopCloser(strings.NewReader(`{"id":"msg-1","channel_id":"ch-1"}`)),
+				Header:     http.Header{"Content-Type": []string{"application/json"}},
+			}
+			return resp, nil
+		}),
+	}
+
+	stream := &discordOutboundStream{
+		adapter: &DiscordAdapter{},
+		target:  "ch-1",
+		session: session,
+	}
+
+	err = stream.Push(context.Background(), channel.StreamEvent{
+		Type:  channel.StreamEventError,
+		Error: "request failed: " + prefixHalf,
+	})
+	if err != nil {
+		t.Fatalf("push error event: %v", err)
+	}
+
+	var payload map[string]any
+	if err := json.Unmarshal([]byte(sentBody), &payload); err != nil {
+		t.Fatalf("decode sent body: %v (body=%q)", err, sentBody)
+	}
+	content, _ := payload["content"].(string)
+	if strings.Contains(content, prefixHalf) {
+		t.Fatalf("expected prefix half to be redacted, got %q", content)
+	}
+	if !strings.Contains(content, "Error: ") {
+		t.Fatalf("expected error prefix, got %q", content)
+	}
+	if !strings.Contains(content, strings.Repeat("*", len(prefixHalf))) {
+		t.Fatalf("expected redaction mask, got %q", content)
+	}
+}
diff --git a/internal/channel/adapters/feishu/config.go b/internal/channel/adapters/feishu/config.go
index 7a0e87df..d96bec75 100644
--- a/internal/channel/adapters/feishu/config.go
+++ b/internal/channel/adapters/feishu/config.go
@@ -192,3 +192,12 @@ func (c Config) openBaseURL() string {
 	}
 	return lark.FeishuBaseUrl
 }
+
+func (c Config) registerIMErrorSecrets() {
+	channel.SetIMErrorSecrets("feishu:"+c.AppID, c.AppSecret, c.EncryptKey, c.VerificationToken)
+}
+
+func (c Config) newClient() *lark.Client {
+	c.registerIMErrorSecrets()
+	return lark.NewClient(c.AppID, c.AppSecret, lark.WithOpenBaseUrl(c.openBaseURL()))
+}
diff --git a/internal/channel/adapters/feishu/directory.go b/internal/channel/adapters/feishu/directory.go
index bfcbe084..b4023091 100644
--- a/internal/channel/adapters/feishu/directory.go
+++ b/internal/channel/adapters/feishu/directory.go
@@ -34,7 +34,7 @@ func (*FeishuAdapter) ListPeers(ctx context.Context, cfg channel.ChannelConfig,
 	if err != nil {
 		return nil, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 	pageSize := directoryLimit(query.Limit)
 	req := larkcontact.NewListUserReqBuilder().
 		UserIdType(larkcontact.UserIdTypeOpenId).
@@ -66,7 +66,7 @@ func (*FeishuAdapter) ListGroups(ctx context.Context, cfg channel.ChannelConfig,
 	if err != nil {
 		return nil, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 	pageSize := directoryLimit(query.Limit)
 	var items []*larkim.ListChat
 	if strings.TrimSpace(query.Query) != "" {
@@ -115,7 +115,7 @@ func (*FeishuAdapter) ListGroupMembers(ctx context.Context, cfg channel.ChannelC
 	if chatID == "" {
 		return nil, errors.New("feishu list group members: empty group id")
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 	pageSize := directoryLimit(query.Limit)
 	req := larkim.NewGetChatMembersReqBuilder().
 		ChatId(chatID).
@@ -146,7 +146,7 @@ func (a *FeishuAdapter) ResolveEntry(ctx context.Context, cfg channel.ChannelCon
 	if err != nil {
 		return channel.DirectoryEntry{}, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 	input = strings.TrimSpace(input)
 	switch kind {
 	case channel.DirectoryEntryUser:
diff --git a/internal/channel/adapters/feishu/feishu.go b/internal/channel/adapters/feishu/feishu.go
index 833df38a..035e1b97 100644
--- a/internal/channel/adapters/feishu/feishu.go
+++ b/internal/channel/adapters/feishu/feishu.go
@@ -227,7 +227,7 @@ func (*FeishuAdapter) processingReactionGateway(cfg channel.ChannelConfig) (proc
 	if err != nil {
 		return nil, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 	gateway := &larkProcessingReactionGateway{api: client.Im.MessageReaction}
 	return gateway, nil
 }
@@ -291,7 +291,7 @@ func (*FeishuAdapter) DiscoverSelf(ctx context.Context, credentials map[string]a
 	if err != nil {
 		return nil, "", err
 	}
-	client := lark.NewClient(cfg.AppID, cfg.AppSecret, lark.WithOpenBaseUrl(cfg.openBaseURL()))
+	client := cfg.newClient()
 	resp, err := client.Get(ctx, "/open-apis/bot/v3/info", nil, larkcore.AccessTokenTypeTenant)
 	if err != nil {
 		return nil, "", fmt.Errorf("feishu discover self: %w", err)
@@ -466,6 +466,7 @@ func (a *FeishuAdapter) Connect(ctx context.Context, cfg channel.ChannelConfig,
 		eventDispatcher.OnP2MessageReactionDeletedV1(func(_ context.Context, _ *larkim.P2MessageReactionDeletedV1) error {
 			return nil
 		})
+		feishuCfg.registerIMErrorSecrets()
 		return larkws.NewClient(
 			feishuCfg.AppID,
 			feishuCfg.AppSecret,
@@ -526,7 +527,7 @@ func (a *FeishuAdapter) Send(ctx context.Context, cfg channel.ChannelConfig, msg
 		return err
 	}
 
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 
 	if len(msg.Message.Attachments) > 0 {
 		for _, att := range msg.Message.Attachments {
@@ -603,7 +604,7 @@ func (a *FeishuAdapter) OpenStream(ctx context.Context, cfg channel.ChannelConfi
 	if err != nil {
 		return nil, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 	select {
 	case <-ctx.Done():
 		return nil, ctx.Err()
@@ -855,7 +856,7 @@ func (*FeishuAdapter) ResolveAttachment(ctx context.Context, cfg channel.Channel
 	if err != nil {
 		return channel.AttachmentPayload{}, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 
 	resourceType := "file"
 	if isFeishuImageAttachment(attachment) {
diff --git a/internal/channel/adapters/feishu/sender_profile.go b/internal/channel/adapters/feishu/sender_profile.go
index 057a9eb4..c76133d7 100644
--- a/internal/channel/adapters/feishu/sender_profile.go
+++ b/internal/channel/adapters/feishu/sender_profile.go
@@ -75,7 +75,7 @@ func (*FeishuAdapter) lookupSenderProfile(ctx context.Context, cfg channel.Chann
 	if err != nil {
 		return feishuSenderProfile{}, err
 	}
-	client := lark.NewClient(feishuCfg.AppID, feishuCfg.AppSecret, lark.WithOpenBaseUrl(feishuCfg.openBaseURL()))
+	client := feishuCfg.newClient()
 
 	var lastErr error
 	chatID = strings.TrimSpace(chatID)
diff --git a/internal/channel/adapters/feishu/stream.go b/internal/channel/adapters/feishu/stream.go
index 3e93e6df..28bceeb4 100644
--- a/internal/channel/adapters/feishu/stream.go
+++ b/internal/channel/adapters/feishu/stream.go
@@ -133,7 +133,7 @@ func (s *feishuOutboundStream) Push(ctx context.Context, event channel.StreamEve
 		}
 		return nil
 	case channel.StreamEventError:
-		errText := strings.TrimSpace(event.Error)
+		errText := channel.RedactIMErrorText(strings.TrimSpace(event.Error))
 		if errText == "" {
 			return nil
 		}
diff --git a/internal/channel/adapters/qq/client.go b/internal/channel/adapters/qq/client.go
index d61d358d..86ae92c3 100644
--- a/internal/channel/adapters/qq/client.go
+++ b/internal/channel/adapters/qq/client.go
@@ -13,6 +13,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/memohai/memoh/internal/channel"
 )
 
 type qqClient struct {
@@ -105,6 +107,7 @@ func (c *qqClient) accessToken(ctx context.Context) (string, error) {
 	}
 	c.token = token
 	c.expiresAt = time.Now().Add(time.Duration(expiresIn) * time.Second)
+	channel.SetIMErrorSecrets("qq-token:"+c.appID, c.clientSecret, c.token)
 	return c.token, nil
 }
 
diff --git a/internal/channel/adapters/qq/qq.go b/internal/channel/adapters/qq/qq.go
index 07787df9..cd99a4e2 100644
--- a/internal/channel/adapters/qq/qq.go
+++ b/internal/channel/adapters/qq/qq.go
@@ -224,6 +224,7 @@ func (*QQAdapter) ProcessingFailed(context.Context, channel.ChannelConfig, chann
 }
 
 func (a *QQAdapter) getOrCreateClient(cfg channel.ChannelConfig, parsed Config) *qqClient {
+	channel.SetIMErrorSecrets("qq:"+parsed.AppID, parsed.AppSecret)
 	a.mu.Lock()
 	defer a.mu.Unlock()
 
diff --git a/internal/channel/adapters/qq/stream.go b/internal/channel/adapters/qq/stream.go
index 9677f55f..24bfb9e6 100644
--- a/internal/channel/adapters/qq/stream.go
+++ b/internal/channel/adapters/qq/stream.go
@@ -3,6 +3,7 @@ package qq
 import (
 	"context"
 	"errors"
+	"fmt"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -23,6 +24,11 @@ type qqOutboundStream struct {
 }
 
 func (a *QQAdapter) OpenStream(_ context.Context, cfg channel.ChannelConfig, target string, opts channel.StreamOptions) (channel.OutboundStream, error) {
+	parsed, err := parseConfig(cfg.Credentials)
+	if err != nil {
+		return nil, fmt.Errorf("qq open stream: %w", err)
+	}
+	channel.SetIMErrorSecrets("qq:"+parsed.AppID, parsed.AppSecret)
 	return &qqOutboundStream{
 		target: target,
 		reply:  opts.Reply,
@@ -80,7 +86,7 @@ func (s *qqOutboundStream) Push(ctx context.Context, event channel.StreamEvent)
 		s.mu.Unlock()
 		return nil
 	case channel.StreamEventError:
-		errText := strings.TrimSpace(event.Error)
+		errText := channel.RedactIMErrorText(strings.TrimSpace(event.Error))
 		if errText == "" {
 			return nil
 		}
diff --git a/internal/channel/adapters/qq/stream_test.go b/internal/channel/adapters/qq/stream_test.go
index 57d0ad97..487964d0 100644
--- a/internal/channel/adapters/qq/stream_test.go
+++ b/internal/channel/adapters/qq/stream_test.go
@@ -2,6 +2,7 @@ package qq
 
 import (
 	"context"
+	"strings"
 	"testing"
 
 	"github.com/memohai/memoh/internal/channel"
@@ -169,3 +170,32 @@ func TestQQOutboundStreamRejectsAfterClose(t *testing.T) {
 		t.Fatal("expected closed error")
 	}
 }
+
+func TestQQOutboundStreamErrorRedactsRegisteredTokenFragments(t *testing.T) {
+	channel.ResetIMErrorSecretsForTest()
+	t.Cleanup(channel.ResetIMErrorSecretsForTest)
+
+	const token = "qq-token-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	channel.SetIMErrorSecrets("test", token)
+	prefixHalf := token[:len(token)/2]
+
+	var sent []channel.OutboundMessage
+	stream := &qqOutboundStream{
+		target: "c2c:user-openid",
+		send: func(_ context.Context, msg channel.OutboundMessage) error {
+			sent = append(sent, msg)
+			return nil
+		},
+	}
+
+	err := stream.Push(context.Background(), channel.StreamEvent{Type: channel.StreamEventError, Error: "failed: " + prefixHalf})
+	if err != nil {
+		t.Fatalf("push error: %v", err)
+	}
+	if len(sent) != 1 {
+		t.Fatalf("expected one outbound message, got %d", len(sent))
+	}
+	if got := sent[0].Message.PlainText(); strings.Contains(got, prefixHalf) {
+		t.Fatalf("expected redacted token fragment, got %q", got)
+	}
+}
diff --git a/internal/channel/adapters/telegram/stream.go b/internal/channel/adapters/telegram/stream.go
index e97d911e..d278fdff 100644
--- a/internal/channel/adapters/telegram/stream.go
+++ b/internal/channel/adapters/telegram/stream.go
@@ -439,7 +439,7 @@ func (s *telegramOutboundStream) pushFinal(ctx context.Context, event channel.St
 }
 
 func (s *telegramOutboundStream) pushError(ctx context.Context, event channel.StreamEvent) error {
-	errText := strings.TrimSpace(event.Error)
+	errText := channel.RedactIMErrorText(strings.TrimSpace(event.Error))
 	if errText == "" {
 		return nil
 	}
diff --git a/internal/channel/adapters/telegram/stream_test.go b/internal/channel/adapters/telegram/stream_test.go
index 5121ec01..f2c49659 100644
--- a/internal/channel/adapters/telegram/stream_test.go
+++ b/internal/channel/adapters/telegram/stream_test.go
@@ -105,6 +105,56 @@ func TestTelegramOutboundStream_PushErrorEventEmptyNoOp(t *testing.T) {
 	}
 }
 
+func TestTelegramOutboundStream_PushErrorEventRedactsRegisteredTokenFragments(t *testing.T) {
+	channel.ResetIMErrorSecretsForTest()
+	t.Cleanup(channel.ResetIMErrorSecretsForTest)
+
+	const botToken = "123456:ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	var sentText string
+
+	adapter := NewTelegramAdapter(nil)
+	stream, err := adapter.OpenStream(context.Background(), channel.ChannelConfig{
+		ID:          "cfg-1",
+		Credentials: map[string]any{"botToken": botToken},
+	}, "12345", channel.StreamOptions{Metadata: map[string]any{"conversation_type": "private"}})
+	if err != nil {
+		t.Fatalf("open stream: %v", err)
+	}
+	s, ok := stream.(*telegramOutboundStream)
+	if !ok {
+		t.Fatalf("unexpected stream type %T", stream)
+	}
+
+	origGetBot := getOrCreateBotForTest
+	origSendText := sendTextForTest
+	getOrCreateBotForTest = func(_ *TelegramAdapter, _, _ string) (*tgbotapi.BotAPI, error) {
+		return &tgbotapi.BotAPI{Token: botToken}, nil
+	}
+	sendTextForTest = func(_ *tgbotapi.BotAPI, _ string, text string, _ int, _ string) (int64, int, error) {
+		sentText = text
+		return 1, 1, nil
+	}
+	defer func() {
+		getOrCreateBotForTest = origGetBot
+		sendTextForTest = origSendText
+	}()
+
+	prefixHalf := botToken[:len(botToken)/2]
+	err = s.Push(context.Background(), channel.StreamEvent{Type: channel.StreamEventError, Error: "request failed: " + prefixHalf})
+	if err != nil {
+		t.Fatalf("push error event: %v", err)
+	}
+	if strings.Contains(sentText, prefixHalf) {
+		t.Fatalf("expected prefix half to be redacted, got %q", sentText)
+	}
+	if !strings.Contains(sentText, "Error: ") {
+		t.Fatalf("expected error prefix, got %q", sentText)
+	}
+	if !strings.Contains(sentText, strings.Repeat("*", len(prefixHalf))) {
+		t.Fatalf("expected redaction mask, got %q", sentText)
+	}
+}
+
 func TestTelegramOutboundStream_CloseContextCanceled(t *testing.T) {
 	t.Parallel()
 
diff --git a/internal/channel/adapters/telegram/telegram.go b/internal/channel/adapters/telegram/telegram.go
index dc1165ba..ea857d09 100644
--- a/internal/channel/adapters/telegram/telegram.go
+++ b/internal/channel/adapters/telegram/telegram.go
@@ -82,6 +82,7 @@ func (a *TelegramAdapter) SetAssetOpener(opener assetOpener) {
 var getOrCreateBotForTest func(a *TelegramAdapter, token, configID string) (*tgbotapi.BotAPI, error)
 
 func (a *TelegramAdapter) getOrCreateBot(cfg Config, configID string) (*tgbotapi.BotAPI, error) {
+	channel.SetIMErrorSecrets("telegram:"+configID, cfg.BotToken)
 	if getOrCreateBotForTest != nil {
 		return getOrCreateBotForTest(a, cfg.BotToken, configID)
 	}
@@ -644,6 +645,11 @@ func (a *TelegramAdapter) OpenStream(ctx context.Context, cfg channel.ChannelCon
 	if target == "" {
 		return nil, errors.New("telegram target is required")
 	}
+	telegramCfg, err := parseConfig(cfg.Credentials)
+	if err != nil {
+		return nil, fmt.Errorf("telegram open stream: %w", err)
+	}
+	channel.SetIMErrorSecrets("telegram:"+cfg.ID, telegramCfg.BotToken)
 	select {
 	case <-ctx.Done():
 		return nil, ctx.Err()
diff --git a/internal/channel/error_redaction.go b/internal/channel/error_redaction.go
new file mode 100644
index 00000000..420ebd64
--- /dev/null
+++ b/internal/channel/error_redaction.go
@@ -0,0 +1,125 @@
+package channel
+
+import (
+	"net/url"
+	"slices"
+	"sort"
+	"strings"
+	"sync"
+	"unicode/utf8"
+)
+
+var imErrorRedactionRegistry = struct {
+	mu     sync.RWMutex
+	groups map[string][]string // key → variants
+	cache  []string            // deduplicated, sorted longest-first
+}{
+	groups: map[string][]string{},
+}
+
+// SetIMErrorSecrets associates a set of secrets with the given key.
+// Calling again with the same key replaces the previous secrets,
+// so rotating credentials (e.g. access tokens) are handled naturally
+// without explicit unregistration.
+//
+// The key should identify the credential scope, e.g. "qq-token:<appID>"
+// or "telegram:<configID>". For multiple instances of the same adapter,
+// include a stable instance identifier in the key.
+//
+// This is intentionally scoped to IM error rendering only: logs and
+// normal outbound messages keep their original text so operators can
+// debug issues and user content is not mutated.
+func SetIMErrorSecrets(key string, secrets ...string) {
+	var variants []string
+	for _, secret := range secrets {
+		variants = append(variants, imErrorRedactionVariants(secret)...)
+	}
+
+	imErrorRedactionRegistry.mu.Lock()
+	defer imErrorRedactionRegistry.mu.Unlock()
+
+	if len(variants) == 0 {
+		if _, exists := imErrorRedactionRegistry.groups[key]; !exists {
+			return
+		}
+		delete(imErrorRedactionRegistry.groups, key)
+	} else {
+		if slices.Equal(imErrorRedactionRegistry.groups[key], variants) {
+			return
+		}
+		imErrorRedactionRegistry.groups[key] = variants
+	}
+	imErrorRedactionRegistry.cache = rebuildSecretCache(imErrorRedactionRegistry.groups)
+}
+
+// RedactIMErrorText masks registered secrets from error text that is about to
+// be rendered back into an IM conversation.
+func RedactIMErrorText(text string) string {
+	if strings.TrimSpace(text) == "" {
+		return text
+	}
+
+	imErrorRedactionRegistry.mu.RLock()
+	cache := imErrorRedactionRegistry.cache
+	imErrorRedactionRegistry.mu.RUnlock()
+
+	result := text
+	for _, secret := range cache {
+		result = strings.ReplaceAll(result, secret, strings.Repeat("*", utf8.RuneCountInString(secret)))
+	}
+	return result
+}
+
+func imErrorRedactionVariants(secret string) []string {
+	secret = strings.TrimSpace(secret)
+	if secret == "" {
+		return nil
+	}
+
+	variants := []string{secret}
+	runes := []rune(secret)
+	half := len(runes) / 2
+	if half > 5 {
+		variants = append(variants, string(runes[:half]), string(runes[len(runes)-half:]))
+	}
+	if encoded := url.QueryEscape(secret); encoded != secret {
+		variants = append(variants, encoded)
+	}
+	return variants
+}
+
+func rebuildSecretCache(groups map[string][]string) []string {
+	seen := make(map[string]struct{})
+	var all []string
+	for _, variants := range groups {
+		for _, v := range variants {
+			if _, ok := seen[v]; ok {
+				continue
+			}
+			seen[v] = struct{}{}
+			all = append(all, v)
+		}
+	}
+	sort.Slice(all, func(i, j int) bool {
+		li := utf8.RuneCountInString(all[i])
+		lj := utf8.RuneCountInString(all[j])
+		if li == lj {
+			return all[i] < all[j]
+		}
+		return li > lj
+	})
+	return all
+}
+
+func resetIMErrorSecretsForTest() {
+	imErrorRedactionRegistry.mu.Lock()
+	defer imErrorRedactionRegistry.mu.Unlock()
+	imErrorRedactionRegistry.groups = map[string][]string{}
+	imErrorRedactionRegistry.cache = nil
+}
+
+// ResetIMErrorSecretsForTest clears the IM error redaction registry.
+// It is intended for tests in other packages that need deterministic state.
+func ResetIMErrorSecretsForTest() {
+	resetIMErrorSecretsForTest()
+}
diff --git a/internal/channel/error_redaction_test.go b/internal/channel/error_redaction_test.go
new file mode 100644
index 00000000..cd95d7f1
--- /dev/null
+++ b/internal/channel/error_redaction_test.go
@@ -0,0 +1,126 @@
+package channel
+
+import (
+	"net/url"
+	"strings"
+	"testing"
+	"unicode/utf8"
+)
+
+func TestRedactIMErrorText_RedactsFullSecretAndBothHalves(t *testing.T) {
+	resetIMErrorSecretsForTest()
+	t.Cleanup(resetIMErrorSecretsForTest)
+
+	const secret = "123456:ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	SetIMErrorSecrets("test", secret)
+
+	runes := []rune(secret)
+	half := len(runes) / 2
+	prefixHalf := string(runes[:half])
+	suffixHalf := string(runes[len(runes)-half:])
+
+	input := strings.Join([]string{
+		"full=" + secret,
+		"prefix=" + prefixHalf,
+		"suffix=" + suffixHalf,
+	}, " ")
+
+	got := RedactIMErrorText(input)
+	if strings.Contains(got, secret) {
+		t.Fatalf("full secret should be redacted: %q", got)
+	}
+	if strings.Contains(got, prefixHalf) {
+		t.Fatalf("prefix half should be redacted: %q", got)
+	}
+	if strings.Contains(got, suffixHalf) {
+		t.Fatalf("suffix half should be redacted: %q", got)
+	}
+	if !strings.Contains(got, strings.Repeat("*", utf8.RuneCountInString(secret))) {
+		t.Fatalf("full secret mask missing: %q", got)
+	}
+}
+
+func TestRedactIMErrorText_DoesNotRegisterShortHalfFragments(t *testing.T) {
+	resetIMErrorSecretsForTest()
+	t.Cleanup(resetIMErrorSecretsForTest)
+
+	const secret = "ABCDEFGHIJ"
+	SetIMErrorSecrets("test", secret)
+
+	runes := []rune(secret)
+	shortHalf := string(runes[:len(runes)/2])
+
+	got := RedactIMErrorText("partial=" + shortHalf)
+	if got != "partial="+shortHalf {
+		t.Fatalf("short half fragment should not be redacted: %q", got)
+	}
+
+	got = RedactIMErrorText("full=" + secret)
+	if strings.Contains(got, secret) {
+		t.Fatalf("full secret should still be redacted: %q", got)
+	}
+}
+
+func TestRedactIMErrorText_RedactsURLEncodedVariant(t *testing.T) {
+	resetIMErrorSecretsForTest()
+	t.Cleanup(resetIMErrorSecretsForTest)
+
+	const secret = "123456:ABC+DEF/GHI=JKL"
+	SetIMErrorSecrets("test", secret)
+
+	encoded := url.QueryEscape(secret)
+	if encoded == secret {
+		t.Fatal("test secret must differ when URL-encoded")
+	}
+
+	got := RedactIMErrorText("url=" + encoded)
+	if strings.Contains(got, encoded) {
+		t.Fatalf("URL-encoded secret should be redacted: %q", got)
+	}
+}
+
+func TestSetIMErrorSecrets_ReplacesOnSameKey(t *testing.T) {
+	resetIMErrorSecretsForTest()
+	t.Cleanup(resetIMErrorSecretsForTest)
+
+	const oldToken = "old-rotating-token-ABCDEFGHIJKLMNO"
+	const newToken = "new-rotating-token-XYZXYZXYZXYZXYZ"
+
+	SetIMErrorSecrets("qq-token:app1", oldToken)
+
+	got := RedactIMErrorText("err: " + oldToken)
+	if strings.Contains(got, oldToken) {
+		t.Fatalf("old token should be redacted: %q", got)
+	}
+
+	// Simulate token rotation: same key, new value
+	SetIMErrorSecrets("qq-token:app1", newToken)
+
+	got = RedactIMErrorText("err: " + oldToken)
+	if !strings.Contains(got, oldToken) {
+		t.Fatalf("old token should no longer be redacted after replacement: %q", got)
+	}
+	got = RedactIMErrorText("err: " + newToken)
+	if strings.Contains(got, newToken) {
+		t.Fatalf("new token should be redacted: %q", got)
+	}
+}
+
+func TestSetIMErrorSecrets_IndependentKeys(t *testing.T) {
+	resetIMErrorSecretsForTest()
+	t.Cleanup(resetIMErrorSecretsForTest)
+
+	const secretA = "secret-AAAAAAAAAAAAAAAA"
+	const secretB = "secret-BBBBBBBBBBBBBBBB"
+
+	SetIMErrorSecrets("key-a", secretA)
+	SetIMErrorSecrets("key-b", secretB)
+
+	// Replacing key-a should not affect key-b
+	SetIMErrorSecrets("key-a", "secret-CCCCCCCCCCCCCCCC")
+
+	got := RedactIMErrorText("err: " + secretB)
+	if strings.Contains(got, secretB) {
+		t.Fatalf("secretB should still be redacted: %q", got)
+	}
+}
diff --git a/internal/mcp/providers/web/provider.go b/internal/mcp/providers/web/provider.go
index 8bf400e9..ea4ce4aa 100644
--- a/internal/mcp/providers/web/provider.go
+++ b/internal/mcp/providers/web/provider.go
@@ -21,6 +21,8 @@ import (
 	"strings"
 	"time"
 
+	"github.com/memohai/memoh/internal/channel"
+	"github.com/memohai/memoh/internal/db/sqlc"
 	mcpgw "github.com/memohai/memoh/internal/mcp"
 	"github.com/memohai/memoh/internal/searchproviders"
 	"github.com/memohai/memoh/internal/settings"
@@ -87,6 +89,7 @@ func (p *Executor) CallTool(ctx context.Context, session mcpgw.ToolSessionContex
 	if err != nil {
 		return mcpgw.BuildToolErrorResult(err.Error()), nil
 	}
+	registerSearchProviderSecrets(provider)
 
 	switch toolName {
 	case toolWebSearch:
@@ -1145,3 +1148,19 @@ func firstNonEmpty(values ...string) string {
 	}
 	return ""
 }
+
+// searchProviderSecretFields are config keys known to hold credentials.
+var searchProviderSecretFields = []string{"api_key", "secret_id", "secret_key"}
+
+func registerSearchProviderSecrets(provider sqlc.SearchProvider) {
+	cfg := parseConfig(provider.Config)
+	var secrets []string
+	for _, key := range searchProviderSecretFields {
+		if v := stringValue(cfg[key]); v != "" {
+			secrets = append(secrets, v)
+		}
+	}
+	if len(secrets) > 0 {
+		channel.SetIMErrorSecrets("search:"+provider.ID.String(), secrets...)
+	}
+}
diff --git a/internal/models/models.go b/internal/models/models.go
index 59152398..388cbbda 100644
--- a/internal/models/models.go
+++ b/internal/models/models.go
@@ -12,6 +12,7 @@ import (
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgtype"
 
+	"github.com/memohai/memoh/internal/channel"
 	"github.com/memohai/memoh/internal/db"
 	"github.com/memohai/memoh/internal/db/sqlc"
 )
@@ -487,7 +488,14 @@ func FetchProviderByID(ctx context.Context, queries *sqlc.Queries, providerID st
 	if err != nil {
 		return sqlc.LlmProvider{}, err
 	}
-	return queries.GetLlmProviderByID(ctx, parsed)
+	provider, err := queries.GetLlmProviderByID(ctx, parsed)
+	if err != nil {
+		return sqlc.LlmProvider{}, err
+	}
+	if strings.TrimSpace(provider.ApiKey) != "" {
+		channel.SetIMErrorSecrets("llm-provider:"+providerID, provider.ApiKey)
+	}
+	return provider, nil
 }
 
 func intToInt4(value int, name string) (pgtype.Int4, error) {