Handle Ollama offline gracefully with retry and 503 response

src/clients/retry.js

@@ -10,7 +10,7 @@ const DEFAULT_CONFIG = {
   backoffMultiplier: 2,
   jitterFactor: 0.1, // 10% jitter
   retryableStatuses: [429, 500, 502, 503, 504],
-  retryableErrors: ['ECONNRESET', 'ETIMEDOUT', 'ENOTFOUND', 'ENETUNREACH'],
+  retryableErrors: ['ECONNRESET', 'ETIMEDOUT', 'ENOTFOUND', 'ENETUNREACH', 'ECONNREFUSED'],
 };
 
 /**
@@ -44,6 +44,11 @@ function isRetryable(error, response, config) {
     return true;
   }
 
+  // Check nested cause (Node undici wraps connection errors as TypeError)
+  if (error && error.cause?.code && config.retryableErrors.includes(error.cause.code)) {
+    return true;
+  }
+
   // Check for network errors
   if (error && (error.name === 'FetchError' || error.name === 'AbortError')) {
     return true;

src/orchestrator/index.js

@@ -1694,7 +1694,33 @@ IMPORTANT TOOL USAGE RULES:
     });
   }
 
-  const databricksResponse = await invokeModel(cleanPayload);
+  let databricksResponse;
+  try {
+    databricksResponse = await invokeModel(cleanPayload);
+  } catch (modelError) {
+    const isConnectionError = modelError.cause?.code === 'ECONNREFUSED'
+      || modelError.message?.includes('fetch failed')
+      || modelError.code === 'ECONNREFUSED';
+    if (isConnectionError) {
+      logger.error(`Provider ${providerType} is unreachable (connection refused). Is it running?`);
+      return {
+        response: {
+          status: 503,
+          body: {
+            error: {
+              type: "provider_unreachable",
+              message: `Provider ${providerType} is unreachable. Is the service running?`,
+            },
+          },
+          terminationReason: "provider_unreachable",
+        },
+        steps,
+        durationMs: Date.now() - start,
+        terminationReason: "provider_unreachable",
+      };
+    }
+    throw modelError;
+  }
 
   // Extract and log actual token usage
   const actualUsage = databricksResponse.ok && config.tokenTracking?.enabled !== false