Find agent skills by outcome

- Configure test environment matching production topology (load balancers

databases

- Define success criteria: target response times

throughput

- Information disclosure in error responses: stack traces

internal paths

- Inadequate retry logic: no retries

or retries without backoff causing retry storms

- Resource Utilization: CPU <70% at expected load

memory stable without unbounded growth

- Authentication weaknesses: token leakage

missing expiration

- Error Rates: 5xx errors <0.1%

4xx errors <5% (excluding 401/403)

- Throughput: Read-heavy APIs >1000 RPS per instance

write-heavy APIs >100 RPS per instance

- Response Time: Simple GET <100ms (p95)

complex query <500ms (p95)

- Configure meaningful alerts based on SLI/SLO thresholds (e.g.

p95 latency > 500ms

- Set up comprehensive API metrics: request rate

error rate

- Test proper error propagation: errors are meaningful

not swallowed or leaked as 500s

- Test error response consistency: correct HTTP status codes

structured error bodies

Data

- Verify required vs optional field handling

data type correctness

- Identify resource bottlenecks (CPU

memory

- Profile endpoint response times at baseline load

capturing p50

- Establish observability by setting up API metrics

performance dashboards

Data

- Test system resilience by simulating network failures

database connection drops

- Validate API contracts against OpenAPI/Swagger specifications

testing backward compatibility

Productivity

- Verify integration workflows end-to-end including webhook deliverability

timeout/retry logic

- Execute load and stress tests by simulating realistic user behavior

gradually increasing load to find breaking points

Productivity

- Assign each task a stable ID (e.g.

TASK-1.1) and use checklist items in outputs.

- Profile endpoint performance by measuring response times under various loads

identifying N+1 queries

API Tester Agent Role

# API Tester