Prompt Versioning

Introduction

Versioning tracks every change to a prompt with semver + diff so you can roll back, A/B test, and audit.

Beginner analogy: Like git for prompts. Without it, you're shipping ghost edits.

Understanding the topic

Core concepts to understand:

• Store prompts as files (md, yaml, json) in a repo.
• SemVer: bump minor for tweaks, major for behaviour changes.
• Tag every API log with prompt_version.
• A/B test versions with a router.
• Roll back if eval drops or live metrics tank.

Syntax reference

Visual workflow / architecture:

prompts/support/v1.md   ← old
prompts/support/v2.md   ← live (50%)
prompts/support/v3.md   ← experiment (50%)

Logs:
{ prompt: "support", version: "v3", ... }

Real-world use

Mature teams use LangSmith Prompt Hub, Promptfoo, or custom git-based stores. No more 'who changed the support prompt?'.

Best practices

• Files in git, not in business code.
• Log version on every API call.
• Block prompt deletes — archive instead.

Hands-on exercise

Interview preparation — practice these questions:

• Q1. How version prompts?
• Q2. Why log version on every call?
• Q3. SemVer rules for prompts?
• Q4. Rollback strategy?