The zipcode-search docs were directionally correct, but they left a few practical failure modes underexplained for real operator use. This update makes the retry order explicit, adds guidance for temp-file based parsing in wrapped shells, and documents the benign curl (23) case when downstream readers close early.
Constraint: Keep the change docs-first without adding runtime code or dependencies
Constraint: The official ePost endpoint remains intermittently flaky, so guidance must focus on stable operator behavior rather than pretending transport is deterministic
Rejected: Replace the docs example with a larger shell wrapper script | too heavy for a small skill-doc improvement
Rejected: Ignore curl (23) and here-doc issues as user error | repeated operator confusion is worth documenting
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: If the zipcode-search example changes again, keep the retry order and shell-wrapper caveats aligned between the skill doc, feature doc, and regression test
Tested: node --check scripts/skill-docs.test.js
Tested: node --test scripts/skill-docs.test.js
Tested: npm run ci
Tested: npx --yes skills add . --list
Not-tested: Live ePost requests for this doc-only follow-up
Broaden the root regression suite to cover the roadmap/source/feature-doc surface and replace the fragile urllib example with a curl-backed, timeout-bounded snippet that matches the verified live query path.
Constraint: The ePost endpoint resets the shipped urllib transport on current local python3 toolchains
Constraint: Must keep the fix doc-only with no new dependencies
Rejected: Keep urllib and add a warning only | the published example would still fail as written
Confidence: high
Scope-risk: narrow
Directive: If the ePost markup or transport requirements change, update both docs and scripts/skill-docs.test.js together
Tested: node --test scripts/skill-docs.test.js
Tested: npx --yes skills add . --list
Tested: python3 /tmp/zipcode_live_check.py
Tested: npm run ci
Not-tested: Alternative HTTP clients beyond the curl-backed path
Issue #3 asks for a low-friction way to turn a known Korean address into a postal code. This change adds a dedicated zipcode-search skill, wires it into repo docs, and protects the new discovery/documentation surface with a root-level regression test that now runs under npm test/ci.
Constraint: Must use the official ePost postal search page and avoid new dependencies
Rejected: Data.go.kr key-based postal API | unnecessary setup for a simple lookup skill
Confidence: high
Scope-risk: narrow
Directive: Keep the zipcode-search extraction logic aligned with the official ePost HTML fields unless a more stable public API replaces it
Tested: node --test scripts/skill-docs.test.js
Tested: npm run ci
Tested: npx --yes skills add . --list
Tested: python3 live query against the ePost endpoint for 세종대로 209
Not-tested: Broader address variants beyond the verified ePost query example
