tech-log-backend/docs/runbooks/dependency-4xx-client.md

title, category, error_codes, severity, owner, last_updated, status

title	category	error_codes	severity	owner	last_updated	status
Runbook — DEPENDENCY_4XX_CLIENT (업스트림 클라이언트 오류)	PERMANENT_DEPENDENCY	DEPENDENCY_4XX_CLIENT	P2	oncall	2026-06-15	stub

Runbook: DEPENDENCY_4XX_CLIENT (runbook://dependency/4xx-client)

Symptoms

• HTTP 502 with error.code=DEPENDENCY_4XX_CLIENT
• Upstream returned 401/403/400 — credential, scope, or request format issue

Diagnosis

• Check upstream response body in logs for error detail
• Verify API credentials and scopes are valid

Action

• Rotate credentials if expired
• Fix request format if API contract changed

Escalation

• Escalate to upstream API owner if contract change is suspected

---

Stub: Phase D2 — author body after domain adoption. (feature-operational-runbook-contract D9)