diff --git a/client.go b/client.go
index d5f29c8..1a7af1c 100644
--- a/client.go
+++ b/client.go
@@ -144,7 +144,7 @@ func (a *APIClient) Do(req *http.Request, result any) error {
 
 		// Server errors are retryable.
 		if resp.StatusCode >= 500 {
-			lastErr = coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, string(data)), nil)
+			lastErr = coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, truncateBody(data, maxErrBodyLen)), nil)
 			if attempt < attempts-1 {
 				a.backoff(attempt, req)
 			}
@@ -153,7 +153,7 @@ func (a *APIClient) Do(req *http.Request, result any) error {
 
 		// Client errors (4xx, except 429 handled above) are not retried.
 		if resp.StatusCode >= 400 {
-			return coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, string(data)), nil)
+			return coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, truncateBody(data, maxErrBodyLen)), nil)
 		}
 
 		// Success — decode if requested.
@@ -228,7 +228,7 @@ func (a *APIClient) DoRaw(req *http.Request) ([]byte, error) {
 		}
 
 		if resp.StatusCode >= 500 {
-			lastErr = coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, string(data)), nil)
+			lastErr = coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, truncateBody(data, maxErrBodyLen)), nil)
 			if attempt < attempts-1 {
 				a.backoff(attempt, req)
 			}
@@ -236,7 +236,7 @@ func (a *APIClient) DoRaw(req *http.Request) ([]byte, error) {
 		}
 
 		if resp.StatusCode >= 400 {
-			return nil, coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, string(data)), nil)
+			return nil, coreerr.E(a.prefix, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, truncateBody(data, maxErrBodyLen)), nil)
 		}
 
 		return data, nil
@@ -261,6 +261,17 @@ func (a *APIClient) backoff(attempt int, req *http.Request) {
 	}
 }
 
+// maxErrBodyLen is the maximum number of bytes from a response body included in error messages.
+const maxErrBodyLen = 256
+
+// truncateBody limits response body length in error messages to prevent sensitive data leakage.
+func truncateBody(data []byte, max int) string {
+	if len(data) <= max {
+		return string(data)
+	}
+	return string(data[:max]) + "...(truncated)"
+}
+
 // parseRetryAfter interprets the Retry-After header value.
 // Supports seconds (integer) format. Falls back to 1 second.
 func parseRetryAfter(val string) time.Duration {
diff --git a/cmd/monitor/cmd_monitor.go b/cmd/monitor/cmd_monitor.go
index 7b144bf..482fb84 100644
--- a/cmd/monitor/cmd_monitor.go
+++ b/cmd/monitor/cmd_monitor.go
@@ -210,7 +210,7 @@ func resolveRepos() ([]string, error) {
 func fetchRepoFindings(repoFullName string) ([]Finding, []string) {
 	var findings []Finding
 	var errs []string
-	repoName := strings.Split(repoFullName, "/")[1]
+	repoName := repoShortName(repoFullName)
 
 	// Fetch code scanning alerts
 	codeFindings, err := fetchCodeScanningAlerts(repoFullName)
@@ -264,7 +264,7 @@ func fetchCodeScanningAlerts(repoFullName string) ([]Finding, error) {
 		return nil, log.E("monitor.fetchCodeScanning", "failed to parse response", err)
 	}
 
-	repoName := strings.Split(repoFullName, "/")[1]
+	repoName := repoShortName(repoFullName)
 	var findings []Finding
 	for _, alert := range alerts {
 		if alert.State != "open" {
@@ -318,7 +318,7 @@ func fetchDependabotAlerts(repoFullName string) ([]Finding, error) {
 		return nil, log.E("monitor.fetchDependabot", "failed to parse response", err)
 	}
 
-	repoName := strings.Split(repoFullName, "/")[1]
+	repoName := repoShortName(repoFullName)
 	var findings []Finding
 	for _, alert := range alerts {
 		if alert.State != "open" {
@@ -369,7 +369,7 @@ func fetchSecretScanningAlerts(repoFullName string) ([]Finding, error) {
 		return nil, log.E("monitor.fetchSecretScanning", "failed to parse response", err)
 	}
 
-	repoName := strings.Split(repoFullName, "/")[1]
+	repoName := repoShortName(repoFullName)
 	var findings []Finding
 	for _, alert := range alerts {
 		if alert.State != "open" {
@@ -530,6 +530,15 @@ func outputTable(findings []Finding) error {
 	return nil
 }
 
+// repoShortName extracts the repo name from "org/repo" format.
+// Returns the full string if no "/" is present.
+func repoShortName(fullName string) string {
+	if i := strings.LastIndex(fullName, "/"); i >= 0 {
+		return fullName[i+1:]
+	}
+	return fullName
+}
+
 // truncate truncates a string to max runes (Unicode-safe)
 func truncate(s string, max int) string {
 	runes := []rune(s)