# Cx Programming

> Apply non-obvious Python, TypeScript, Go or Rust guidance at typing, validation, async/concurrency, resource, error, FFI or toolchain boundaries. Use when language-specific failure modes matter; do not load for routine syntax or when project conventions already decide the approach.

- Skill: `bongsuchoi/cx-programming` (Agent Skill, multi-file: 27 files)
- Install (CLI): `npx skillmds@latest add bongsuchoi/cx-programming`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bongsuchoi/cx-programming/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: BongSuCHOI (https://skillmd.com/u/bongsuchoi)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/bongsuchoi/cx-programming

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# Programming

Load only the language card needed for the current decision. Project conventions and dependencies win.

## Priority

1. Follow the nearest project `AGENTS.md`, manifest, architecture and style.
2. Reuse existing dependencies and patterns.
3. Load only the reference needed for the current failure mode.
4. Prefer the smallest implementation that satisfies observable behavior.

## Reference routing

- Python: `references/python/README.md`
- TypeScript: `references/typescript/README.md`
- Go: `references/go/README.md`
- Rust: `references/rust/README.md`

Reference recommendations are decision support, not reasons to replace an established stack or upgrade dependencies.

## Implementation and verification

- Inspect call sites and trust boundaries before changing behavior.
- Use strict types where they reduce material invalid states; avoid ceremony that adds no safety.
- Add or update tests when behavior changes or regression risk warrants it.
- Follow project verification first; otherwise run the closest relevant test, typecheck, lint or build.
- Do not repeat equivalent verification.

For behavior-preserving refactors, state the behavior that must remain unchanged, trace affected callers and boundaries, and use characterization coverage only when risk justifies it. Preview syntax-aware bulk rewrites and inspect the resulting diff. Do not combine a refactor with dependency upgrades or unrelated cleanup.

## Helper

`scripts/python/new-script.py` creates a no-overwrite PEP 723 script skeleton. Run it with `uv run --isolated`. If the default `uv` cache fails specifically with a sandbox permission error, retry once with `UV_CACHE_DIR=/tmp/codex-uv-cache`; do not relabel package resolution, network, script, or target failures as cache failures. If `uv` is missing, state why it is needed and propose the exact installation command. Preserve normal helper failures as execution errors.

Use `ast-grep` only when syntax-aware matching materially improves on `rg`. If it is missing, continue safely when practical or propose the exact installation command and wait for approval.