Prompt Diff

git diff tells you what lines changed. Prompt Diff tells you what behaviors changed.

Compare two versions of any system prompt, SKILL.md, or AGENTS.md and get a structured behavioral changelog — which instructions were added, which were removed, which were softened or hardened, and whether any contradictions were introduced.

No external API. Works on any text-based prompt file. Outputs a commit-ready changelog.

Trigger Phrases

• "diff these prompts", "compare prompt versions", "what changed in my prompt"
• "what changed in AGENTS.md", "prompt changelog", "system prompt diff"
• "what instructions did I add", "did I introduce any contradictions"
• "compare v1 and v2 of this skill", "summarize prompt changes"
• "/prompt-diff"