diff --git a/handlers/anthropic.go b/handlers/anthropic.go
index 7dc9711..2fc02a9 100644
--- a/handlers/anthropic.go
+++ b/handlers/anthropic.go
@@ -299,6 +299,9 @@ func handleStreaming(
 	}
 
 	// Stream the SSE response
+	// Capture values before SetBodyStreamWriter — the callback runs in a
+	// separate goroutine where fiber.Ctx is no longer valid.
+	clientIP := c.IP()
 	transformer := transform.NewStreamTransformer("", "")
 	c.Set("Content-Type", "text/event-stream")
 	c.Set("Cache-Control", "no-cache")
@@ -320,17 +323,17 @@ func handleStreaming(
 			event := transformer.TransformChunk(chunk)
 			if event != "" {
 				if _, err := w.WriteString(event); err != nil {
-					logger.Warn("[ANTHROPIC] Stream write error [IP: %s]: %v", c.IP(), err)
+					logger.Warn("[ANTHROPIC] Stream write error [IP: %s]: %v", clientIP, err)
 					return
 				}
 				if err := w.Flush(); err != nil {
-					logger.Warn("[ANTHROPIC] Stream flush error [IP: %s]: %v", c.IP(), err)
+					logger.Warn("[ANTHROPIC] Stream flush error [IP: %s]: %v", clientIP, err)
 					return
 				}
 			}
 		}
 		if err := scanner.Err(); err != nil {
-			logger.Warn("[ANTHROPIC] Stream scan error [IP: %s]: %v", c.IP(), err)
+			logger.Warn("[ANTHROPIC] Stream scan error [IP: %s]: %v", clientIP, err)
 			return
 		}
 		// Ensure final events are sent