diff --git a/tracker_doctor.go b/tracker_doctor.go
index 42ab4cd..3e7ca2d 100644
--- a/tracker_doctor.go
+++ b/tracker_doctor.go
@@ -320,7 +320,7 @@ func probeProvider(p providerDef, key string) (bool, string) {
 		if isAuthError(msg) {
 			return false, "invalid or expired API key"
 		}
-		return false, trimErrMsg(msg, 80)
+		return false, trimErrMsg(sanitizeProviderError(msg), 80)
 	}
 	return true, ""
 }
@@ -342,6 +342,26 @@ func trimErrMsg(msg string, maxLen int) string {
 	return msg[:maxLen] + "..."
 }
 
+var providerErrorSanitizers = []struct {
+	re   *regexp.Regexp
+	repl string
+}{
+	{regexp.MustCompile(`(?i)\bBearer\s+[A-Za-z0-9._~+/=-]+\b`), "Bearer [REDACTED]"},
+	{regexp.MustCompile(`\bsk-ant-[A-Za-z0-9_-]+\b`), "[REDACTED_API_KEY]"},
+	{regexp.MustCompile(`\bsk-[A-Za-z0-9_-]{8,}\b`), "[REDACTED_API_KEY]"},
+	{regexp.MustCompile(`\bAIza[0-9A-Za-z_-]{20,}\b`), "[REDACTED_API_KEY]"},
+	{regexp.MustCompile(`(?i)\b(request[-_ ]?id)\s*[:=]\s*[A-Za-z0-9._-]+\b`), "$1=[REDACTED]"},
+	{regexp.MustCompile(`\breq_[A-Za-z0-9_-]+\b`), "req_[REDACTED]"},
+}
+
+func sanitizeProviderError(msg string) string {
+	sanitized := msg
+	for _, rule := range providerErrorSanitizers {
+		sanitized = rule.re.ReplaceAllString(sanitized, rule.repl)
+	}
+	return sanitized
+}
+
 // checkDippinLib verifies the dippin binary is installed. The full "dippin
 // <ver> at <path>" string goes into the details so the CLI can print a
 // per-item line; the composite summary carries the shorter "dippin <ver>"
diff --git a/tracker_doctor_test.go b/tracker_doctor_test.go
index 71d1569..d7717d3 100644
--- a/tracker_doctor_test.go
+++ b/tracker_doctor_test.go
@@ -3,9 +3,13 @@
 package tracker
 
 import (
+	"context"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
+
+	"github.com/2389-research/tracker/llm"
 )
 
 func TestDoctor_NoProbe_KeyPresent(t *testing.T) {
@@ -76,3 +80,60 @@ func TestDoctor_PipelineFileValidation(t *testing.T) {
 		t.Fatal("Pipeline File check missing when PipelineFile set")
 	}
 }
+
+type doctorProbeTestAdapter struct {
+	completeErr error
+}
+
+func (a *doctorProbeTestAdapter) Name() string { return "test" }
+
+func (a *doctorProbeTestAdapter) Complete(_ context.Context, _ *llm.Request) (*llm.Response, error) {
+	return nil, a.completeErr
+}
+
+func (a *doctorProbeTestAdapter) Stream(_ context.Context, _ *llm.Request) <-chan llm.StreamEvent {
+	ch := make(chan llm.StreamEvent)
+	close(ch)
+	return ch
+}
+
+func (a *doctorProbeTestAdapter) Close() error { return nil }
+
+func TestSanitizeProviderError_RedactsSensitiveTokens(t *testing.T) {
+	in := "request failed: Authorization: Bearer verySecretToken request-id=req_abc123 key=sk-ant-supersecret AIzaSyA1234567890123456789012345"
+	got := sanitizeProviderError(in)
+
+	for _, secret := range []string{
+		"verySecretToken",
+		"req_abc123",
+		"sk-ant-supersecret",
+		"AIzaSyA1234567890123456789012345",
+	} {
+		if strings.Contains(got, secret) {
+			t.Fatalf("sanitized message still contains secret %q: %q", secret, got)
+		}
+	}
+}
+
+func TestProbeProvider_SanitizesNonAuthError(t *testing.T) {
+	secret := "sk-1234567890SECRET"
+	ok, msg := probeProvider(providerDef{
+		name:         "OpenAI",
+		defaultModel: "gpt-4.1-mini",
+		buildAdapter: func(_ string) (llm.ProviderAdapter, error) {
+			return &doctorProbeTestAdapter{
+				completeErr: &llm.ProviderError{
+					SDKError: llm.SDKError{Msg: "boom Bearer topsecret " + secret + " req_abc123"},
+					Provider: "openai",
+				},
+			}, nil
+		},
+	}, "test-key")
+
+	if ok {
+		t.Fatal("expected auth probe to fail")
+	}
+	if strings.Contains(msg, "topsecret") || strings.Contains(msg, secret) || strings.Contains(msg, "req_abc123") {
+		t.Fatalf("probe message not sanitized: %q", msg)
+	}
+}