fix: fix agents limit exceeded error + allow deletions in /agents (#678)

Co-authored-by: Letta <noreply@letta.com>

src/cli/helpers/errorFormatter.ts

@@ -91,6 +91,23 @@ function getResourceLimitMessage(e: APIError): string | undefined {
   return undefined;
 }
 
+/**
+ * Check if the error is an agent limit error (429 with agents-limit-exceeded)
+ */
+function isAgentLimitError(e: APIError): boolean {
+  if (e.status !== 429) return false;
+
+  const errorBody = e.error;
+  if (errorBody && typeof errorBody === "object") {
+    if ("reasons" in errorBody && Array.isArray(errorBody.reasons)) {
+      if (errorBody.reasons.includes("agents-limit-exceeded")) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 /**
  * Check if the error is a credit exhaustion error (402 with not-enough-credits)
  */
@@ -152,6 +169,18 @@ export function formatErrorDetails(
       return `You've hit your usage limit. ${resetInfo}. View usage: ${LETTA_USAGE_URL}`;
     }
 
+    // Check for agent limit error (free tier agent count limit)
+    if (isAgentLimitError(e)) {
+      const { billingTier } = getErrorContext();
+
+      if (billingTier?.toLowerCase() === "free") {
+        return `You've reached the agent limit (3) for the Free Plan. Delete agents at: ${LETTA_AGENTS_URL}\nOr upgrade to Pro for unlimited agents at: ${LETTA_USAGE_URL}`;
+      }
+
+      // Fallback for paid tiers (shouldn't normally hit this, but just in case)
+      return `You've reached your agent limit. Delete agents at: ${LETTA_AGENTS_URL}\nOr check your plan at: ${LETTA_USAGE_URL}`;
+    }
+
     // Check for resource limit error (e.g., "You have reached your limit for agents")
     const resourceLimitMsg = getResourceLimitMessage(e);
     if (resourceLimitMsg) {