diff --git a/backend/internal/auth/codex_api.go b/backend/internal/auth/codex_api.go
index 99a0cf5..d3aa358 100644
--- a/backend/internal/auth/codex_api.go
+++ b/backend/internal/auth/codex_api.go
@@ -232,6 +232,7 @@ func (c *CodexAPIAuth) getConfig() []interface{} {
 
 // solvePow 解决 PoW 挑战
 func (c *CodexAPIAuth) solvePow(seed, difficulty string, cfg []interface{}, maxIterations int) string {
+	startTime := time.Now()
 	seedBytes := []byte(seed)
 
 	for i := 0; i < maxIterations; i++ {
@@ -246,6 +247,8 @@ func (c *CodexAPIAuth) solvePow(seed, difficulty string, cfg []interface{}, maxI
 		hexHash := fmt.Sprintf("%08x", h)
 
 		if hexHash[:len(difficulty)] <= difficulty {
+			elapsed := time.Since(startTime).Seconds()
+			c.logStep(StepNavigate, "[PoW] Solved in %.2fs (iteration %d, difficulty=%s)", elapsed, i, difficulty)
 			return encoded + "~S"
 		}
 	}
@@ -328,6 +331,7 @@ func (c *CodexAPIAuth) callSentinelReq(flow string) bool {
 		if required, ok := powReq["required"].(bool); ok && required {
 			seed, _ := powReq["seed"].(string)
 			difficulty, _ := powReq["difficulty"].(string)
+			c.logStep(StepNavigate, "[Sentinel] flow=%s, PoW required, difficulty=%s", flow, difficulty)
 			config := c.getConfig()
 			solved := c.solvePow(seed, difficulty, config, 5000000)
 			if solved != "" {
@@ -337,9 +341,11 @@ func (c *CodexAPIAuth) callSentinelReq(flow string) bool {
 				return false
 			}
 		} else {
+			c.logStep(StepNavigate, "[Sentinel] flow=%s, PoW not required", flow)
 			c.solvedPow = initToken
 		}
 	} else {
+		c.logStep(StepNavigate, "[Sentinel] flow=%s, no PoW in response", flow)
 		c.solvedPow = initToken
 	}