Elephant-Goldfish is an open-source plugin from Google that makes an AI coding assistant write a plan before it writes any code. It is for developers using Claude Code, Codex or Google’s Antigravity. One long AI session, the Elephant, keeps the whole project in memory, interviews the developer and drafts a design document that names every file to change. It writes no code. Then fresh AI sessions, the Goldfish, read only that document and the code it points to. Like a new hire handed only the written instructions, they cannot fill gaps from the earlier chat. The review has five stages, including a check where a Goldfish must explain the plan back and a critique where several hunt for holes in it. A person approves the design before coding starts.
In the project’s example, a developer adds webhook delivery, where one program sends automatic messages to another. What should happen when a message fails, or when the same event arrives twice? The developer settles those questions in the document before any code exists. Google says thousands of its employees use the plugin every day. The project’s FAQ says a small, well-understood change may not repay the extra time. An open issue reports that reviewers in Codex and Antigravity still receive the project’s standing-instructions file (AGENTS.md), which Claude Code reviewers do not. Dave Rensin, whose essay the method grew from, says that, anecdotally, about 30% of the critic Goldfish’s suggestions are highly valuable, enough to make the method worthwhile.
Read More: Superpowers and mattpocock/skills: Cross-Platform Agent Skills Frameworks, a set of agent skills that adds brainstorming and implementation-plan phases before coding agents write code
Sources:
- Introducing the Elephant-Goldfish Model plugin (Google Open Source Blog)
- Elephant-Goldfish Model: install steps, webhook example and five review stages (GitHub)
- Setup guide: supported coding tools and how reviewers are isolated (GitHub)
- FAQ: when the workflow pays off and when it does not (GitHub)
- Elephants, Goldfish, and the New Golden Age of Software Engineering (Dave Rensin, Medium)
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Citation
@misc{kabui2026,
author = {{Kabui, Charles}},
title = {Elephant-Goldfish: {Google’s} {Plugin} {Where} {Fresh} {AI}
{Reviewers} {Test} a {Coding} {Plan}},
date = {2026-11-12},
url = {https://toknow.ai/posts/google-elephant-goldfish-plugin-ai-coding-design-review/},
langid = {en-GB}
}