Check Versions

Check Versions / 先测炉温，再铸剑

> The API you remember and the API that's installed are not the same API until you've checked. > 你记得的 API 和实际装着的 API,在你查证之前不是同一个 API。

The discipline / 纪律

1. Verify the version first — run the version-check command, confirm the actual runtime/library version.

先确认版本:执行版本检查命令,确认实际运行时/库版本。

1. Then read the docs — confirm how the feature actually behaves in that version.

再查文档:用官方文档确认该版本下特性的实际行为。

1. Then write code — built on the confirmed version and docs.

后写代码:基于已确认的版本和文档开发。

Forbidden: writing code that depends on a specific language feature based on a version assumption from training data. 绝对禁止: 基于训练数据里的版本假设,直接写依赖特定特性的代码。

When this triggers / 触发时机

• About to use any concrete language / runtime / SDK / framework API.
• You suspect "I remember it's written like this" but aren't sure.
• A version-sensitive error (ESM/CJS, Python 3.x behavior diffs, deprecated Node APIs).
• Porting a snippet across projects.

Done criterion (verifiable) / 完成判据（可验证）

✅ You pasted the actual version-check command and its output (e.g. node -v → v18.20.4) and cited the docs section/URL for that version — not just "I checked". ⚠️ You couldn't verify the version — say so, and mark the code as needing a version check. ❌ You wrote API-dependent code from memory with no version check. Stop and verify.

Worked examples / 实战反例

Real before/after cases for this discipline live in [EXAMPLES.md](./EXAMPLES.md) — read them before you act. 本纪律的真实 before/after 反例见 [EXAMPLES.md](./EXAMPLES.md) —— 动手前先对照。

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: yli769227-jpg
• Source: yli769227-jpg/agent-discipline
• License: MIT

Install and usage instructions live in the source repository linked above.