Skill: backend/integration-adapter

Purpose

Integrate with an external service via a dedicated adapter that enforces:

• timeouts
• retry policy
• idempotency where applicable
• error mapping into shared taxonomy
• observability (logs/metrics/traces) consistent with repo standards

This skill prevents “HTTP calls sprinkled everywhere.”

---

Inputs

• External API/service name + base URL (or SDK)
• Required operations (list)
• Auth mechanism (token, key, oauth) WITHOUT secrets
• Expected failure cases (timeouts, rate limits, invalid responses)
• Repo profile (preferred): <repo>/REPO_PROFILE.json

---

Outputs

• Adapter module with a narrow interface
• Retry/timeout configuration
• Error mapping to shared taxonomy
• Contract tests or mocks (preferred)
• Minimal observability instrumentation

---

Non-goals

• Implementing domain rules (use backend/domain-logic-module)
• Building orchestration/jobs (use backend/job-worker-orchestration)
• Storing secrets in code

---

Workflow

1. Create adapter boundary:
   • ExternalServiceClient or module functions
2. Implement calls with:
   • explicit timeouts
   • bounded retries (with backoff) where safe
   • idempotency keys when supported/needed
3. Normalize errors:
   • map external errors to internal taxonomy
4. Add contract tests/mocks:
   • validate request construction
   • validate response parsing and error handling
5. Add basic observability:
   • correlation id propagation if present
6. Run validations per profile.

---

Checks

• Adapter is the only place external calls exist for this integration

• Timeouts are explicit

• Retry policy is bounded and safe (no infinite loops)

• If retries, backoff, rate limiting, or multi-step external workflows are introduced,

• recommend system/state-machine-mapper to model external interaction states explicitly.

• Errors map to internal taxonomy

• Tests cover:

  • success
  • timeout or retry scenario
  • bad response parsing

---

Failure modes

• Retry safety unclear → default to no retry and document why.
• Rate limits encountered → add backoff and respect headers if available.
• External contract unstable → increase mocking/contract tests and tighten parsing.
• Retry/backoff logic added without explicit state modeling →
  require system/state-machine-mapper before shipping.

---

Telemetry

Log:

• skill: backend/integration-adapter
• service: <name>
• retries: none | bounded
• timeout