health_check

Instructions

Implementation Reference

• src/tools/health_check.ts:26-72 (handler)

  The main handler function that probes each requested chain adapter with a trivial search query ('milch') and reports health status, latency, capabilities, and errors.

  export async function healthCheckHandler(
    registry: AdapterRegistry,
    input: HealthCheckInput,
  ): Promise<{ chains: HealthCheckResult[]; summary: { healthy: number; unhealthy: number; unregistered: number } }> {
    const all: Chain[] = ['migros', 'coop', 'aldi', 'denner', 'lidl'];
    const requested = input.chains ?? all;
    const timeout = input.timeoutMs ?? 5000;
  
    const results = await Promise.all(requested.map(async (chain): Promise<HealthCheckResult> => {
      const adapter = registry.get(chain);
      if (!adapter) return { chain, registered: false, ok: false };
      const start = Date.now();
      try {
        const r = await Promise.race([
          adapter.searchProducts({ query: TRIVIAL_QUERY, limit: 1 }),
          new Promise<never>((_, reject) => setTimeout(() => reject(new Error('timeout')), timeout)),
        ]);
        const latencyMs = Date.now() - start;
        if (r.ok) {
          return {
            chain, registered: true, ok: true, latencyMs,
            capabilities: { ...adapter.capabilities },
          };
        }
        return {
          chain, registered: true, ok: false, latencyMs,
          error: { code: r.error.code, reason: 'reason' in r.error ? r.error.reason : undefined },
          capabilities: { ...adapter.capabilities },
        };
      } catch (e) {
        const msg = e instanceof Error ? e.message : String(e);
        return {
          chain, registered: true, ok: false,
          error: { code: msg === 'timeout' ? 'timeout' : 'unavailable', reason: msg },
          capabilities: { ...adapter.capabilities },
        };
      }
    }));
  
    const summary = {
      healthy: results.filter((r) => r.ok).length,
      unhealthy: results.filter((r) => r.registered && !r.ok).length,
      unregistered: results.filter((r) => !r.registered).length,
    };
  
    return { chains: results, summary };
  }

• src/tools/health_check.ts:5-11 (schema)

  Zod schema defining the input parameters: optional chains array and optional timeout in milliseconds.

  export const healthCheckSchema = z.object({
    chains: z.array(z.enum(['migros', 'coop', 'aldi', 'denner', 'lidl', 'farmy', 'volgshop', 'ottos']))
      .optional()
      .describe('Chains to probe. Default: all configured.'),
    timeoutMs: z.number().int().positive().max(30000).optional()
      .describe('Per-chain timeout in milliseconds. Default 5000.'),
  }).describe('Probe each registered chain adapter with a trivial query and report which are healthy. Useful for diagnosing why a particular chain is missing from search/plan results.');

• src/tools/health_check.ts:15-22 (schema)

  TypeScript interface describing the result structure returned per chain.

  export interface HealthCheckResult {
    chain: Chain;
    registered: boolean;
    ok: boolean;
    latencyMs?: number;
    error?: { code: string; reason?: string };
    capabilities?: Record<string, boolean>;
  }

• src/index.ts:105-110 (registration)

  Tool registration in the TOOLS array, mapping name 'health_check' to its schema and handler.

  {
    name: 'health_check',
    description: 'Probe each registered chain adapter with a trivial query and report status, latency, and capability flags. Use this when a chain seems missing from results or when debugging adapter problems.',
    schema: healthCheckSchema,
    handler: healthCheckHandler,
  },

• scripts/probe-health-check.ts:1-11 (helper)

  Standalone probe script that runs the health check against all chains and prints results.

  import { buildRegistry } from '../src/index.js';
  import { healthCheckHandler } from '../src/tools/health_check.js';
  
  const r = buildRegistry();
  const out = await healthCheckHandler(r, {});
  for (const c of out.chains) {
    const status = !c.registered ? 'UNREGISTERED' : c.ok ? `OK ${c.latencyMs}ms` : `FAIL (${c.error?.code}: ${c.error?.reason ?? ''})`;
    console.log(`${c.chain}: ${status}`);
  }
  console.log('\nSummary:', out.summary);