From 8ab322038b0d0f099b73ef65b0e3f706f34c430b Mon Sep 17 00:00:00 2001
From: Shekhar Vaidya <shekhar.vaidya2@hotmail.com>
Date: Wed, 8 Jul 2026 12:29:59 +0530
Subject: [PATCH] feat(telemetry): capture error message on failed CLI runs

Failure telemetry only recorded success=false with no context. Adds
a truncated error string (150 chars, CLI-side) forwarded to a new
msdl:telemetry:errors Redis hash so failure causes are diagnosable
from /metrics instead of guessed at.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 backend/main.go |  5 +++++
 cli/main.go     | 15 +++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/backend/main.go b/backend/main.go
index 5e716cd..df2edc3 100644
--- a/backend/main.go
+++ b/backend/main.go
@@ -579,6 +579,7 @@ type telemetryPayload struct {
 	Platform  string `json:"platform"`
 	Version   string `json:"version"`
 	Success   bool   `json:"success"`
+	Error     string `json:"error"`
 }
 
 // --- Evalcenter helpers ---
@@ -1662,6 +1663,9 @@ func handleTelemetry(w http.ResponseWriter, r *http.Request) {
 			result = "failed"
 		}
 		rdb.HIncrBy(ctx, "msdl:telemetry:results", result, 1)
+		if !p.Success && p.Error != "" && len(p.Error) <= 200 {
+			rdb.HIncrBy(ctx, "msdl:telemetry:errors", p.Error, 1)
+		}
 	}
 
 	w.WriteHeader(http.StatusOK)
@@ -1695,6 +1699,7 @@ func loadTelemetryFromRedis() map[string]map[string]string {
 		"msdl:telemetry:versions",
 		"msdl:telemetry:products",
 		"msdl:telemetry:results",
+		"msdl:telemetry:errors",
 	}
 	out := make(map[string]map[string]string, len(keys))
 	for _, k := range keys {
diff --git a/cli/main.go b/cli/main.go
index 3fcfb78..2528bb7 100644
--- a/cli/main.go
+++ b/cli/main.go
@@ -87,6 +87,20 @@ type cliTelemetryPayload struct {
 	Platform  string `json:"platform"`
 	Version   string `json:"version"`
 	Success   bool   `json:"success"`
+	Error     string `json:"error,omitempty"`
+}
+
+// truncateError caps an error string for telemetry (avoids leaking huge bodies,
+// keeps Redis field values small).
+func truncateError(err error) string {
+	if err == nil {
+		return ""
+	}
+	s := err.Error()
+	if len(s) > 150 {
+		s = s[:150]
+	}
+	return s
 }
 
 // sendTelemetry posts a single telemetry event. Fire-and-forget: all errors
@@ -243,6 +257,7 @@ More info: https://msdl.tech-latest.com/cli`)
 			Platform:  runtime.GOOS,
 			Version:   Version,
 			Success:   err == nil,
+			Error:     truncateError(err),
 		})
 	}