feat(heartbeat): add provider error-rate spike check

src/automation/heartbeat.test.ts

@@ -13,6 +13,8 @@ function makeConfig(overrides?: Partial<HeartbeatConfig>): HeartbeatConfig {
     disk_threshold_mb: 100,
     process_memory_threshold_mb: 1500,
     backup_failure_threshold: 1,
+    provider_error_rate_threshold: 0.5,
+    provider_error_min_calls: 5,
     ...overrides,
   };
 }
@@ -37,6 +39,7 @@ function makeDeps(overrides?: Partial<HeartbeatDeps>): HeartbeatDeps {
       hasRun: false,
       consecutiveFailures: 0,
     }),
+    getModelCalls: () => [],
     ...overrides,
   };
 }
@@ -513,4 +516,41 @@ describe('HeartbeatMonitor', () => {
       expect(check.message).toContain('minio unavailable');
     });
   });
+
+  describe('provider_errors check', () => {
+    it('passes when no model calls are recorded', async () => {
+      const deps = makeDeps({
+        config: makeConfig({ checks: ['provider_errors'] }),
+        getModelCalls: () => [],
+      });
+      monitor = new HeartbeatMonitor(deps);
+
+      const result = await monitor.runChecks();
+      const check = result.checks.find((c) => c.name === 'provider_errors');
+      if (!check) {throw new Error('Expected provider_errors check result');}
+      expect(check.healthy).toBe(true);
+      expect(check.message).toContain('No model calls');
+    });
+
+    it('fails when a provider error rate breaches threshold', async () => {
+      const deps = makeDeps({
+        config: makeConfig({ checks: ['provider_errors'], provider_error_min_calls: 4, provider_error_rate_threshold: 0.5 }),
+        getModelCalls: () => [
+          { provider: 'openai', error: 'rate limited' },
+          { provider: 'openai', error: 'timeout' },
+          { provider: 'openai' },
+          { provider: 'openai' },
+          { provider: 'anthropic' },
+          { provider: 'anthropic' },
+        ],
+      });
+      monitor = new HeartbeatMonitor(deps);
+
+      const result = await monitor.runChecks();
+      const check = result.checks.find((c) => c.name === 'provider_errors');
+      if (!check) {throw new Error('Expected provider_errors check result');}
+      expect(check.healthy).toBe(false);
+      expect(check.message).toContain('openai');
+    });
+  });
 });