2 files changed, 31 insertions, 1 deletions
diff --git a/internal/retry/backoff.go b/internal/retry/backoff.go
index b91abc4..a372b37 100644
--- a/internal/retry/backoff.go
+++ b/internal/retry/backoff.go
@@ -17,6 +17,12 @@ const maxBackoffDelay = 5 * time.Minute
 
 // IsRateLimitError returns true if err looks like a transient rate-limit
 // (e.g. HTTP 429, "too many requests", "overloaded") that is worth retrying.
+//
+// Patterns are additive across providers: the original set matches
+// OpenAI-compatible error text (internal/llm); "rate_limit_error",
+// "overloaded_error", and "529" additionally match Anthropic's Messages API
+// error shape (HTTP 429 with error.type "rate_limit_error", or HTTP 529
+// with error.type "overloaded_error" — see internal/provider/anthropic).
 func IsRateLimitError(err error) bool {
 	if err == nil {
 		return false
@@ -25,7 +31,10 @@ func IsRateLimitError(err error) bool {
 	return strings.Contains(msg, "rate limit") ||
 		strings.Contains(msg, "too many requests") ||
 		strings.Contains(msg, "429") ||
-		strings.Contains(msg, "overloaded")
+		strings.Contains(msg, "overloaded") ||
+		strings.Contains(msg, "rate_limit_error") ||
+		strings.Contains(msg, "overloaded_error") ||
+		strings.Contains(msg, "529")
 }
 
 // ParseRetryAfter extracts a Retry-After duration from an error message.
diff --git a/internal/retry/backoff_test.go b/internal/retry/backoff_test.go
index a963fc2..d605f29 100644
--- a/internal/retry/backoff_test.go
+++ b/internal/retry/backoff_test.go
@@ -38,6 +38,27 @@ func TestIsRateLimitError_Overloaded(t *testing.T) {
 	}
 }
 
+func TestIsRateLimitError_AnthropicRateLimitError(t *testing.T) {
+	err := errors.New(`anthropic: http 429 rate_limit_error: Number of requests has exceeded your rate limit.`)
+	if !IsRateLimitError(err) {
+		t.Error("want true for Anthropic 'rate_limit_error' shape, got false")
+	}
+}
+
+func TestIsRateLimitError_AnthropicOverloadedError(t *testing.T) {
+	err := errors.New(`anthropic: http 529 overloaded_error: Overloaded`)
+	if !IsRateLimitError(err) {
+		t.Error("want true for Anthropic 'overloaded_error' shape (HTTP 529), got false")
+	}
+}
+
+func TestIsRateLimitError_HTTP529(t *testing.T) {
+	err := errors.New("anthropic: http 529 unexpected_error: service unavailable")
+	if !IsRateLimitError(err) {
+		t.Error("want true for '529', got false")
+	}
+}
+
 func TestIsRateLimitError_NonRateLimitError(t *testing.T) {
 	err := errors.New("claude exited with error: exit status 1")
 	if IsRateLimitError(err) {