Constraint: PR #283 review requested TDD fixes for Kakao Local distance sorting, Mobility toll avoidance, lint coverage, and coord2region routing coverage.
Rejected: Relying on upstream Kakao validation for sort=distance | it spends quota and returns a proxy/upstream error instead of local bad_request.
Rejected: Document-only toll avoidance correction | the skill already promises the behavior and Kakao Mobility exposes an explicit avoid option.
Confidence: high
Scope-risk: narrow
Directive: Preserve server-side KAKAO_REST_API_KEY injection only; never accept or forward caller apiKey query values.
Tested: node --test packages/k-skill-proxy/test/server.test.js; npm test --workspace k-skill-proxy; npm run lint --workspace k-skill-proxy; node --test scripts/skill-docs.test.js; bash scripts/validate-skills.sh; manual Fastify inject smoke for sort=distance and avoid forwarding; npm run ci through lint/typecheck until local Python pyexpat failure.
Not-tested: Full npm run ci completion due local Python 3.14 pyexpat ImportError during pip install.