Google AI Releases Elephant-Goldfish Model Plugin for Spec-First Coding

Google has open-sourced the Elephant-Goldfish Model (EGM) plugin, a design-and-review layer for AI coding agents. The Elephant-Goldfish Model plugin makes an agent write a specification before it writes code. Fresh subagents with no conversation history then attack that spec. Google says thousands of its engineers use it. It is quite simple: catch wrong assumptions in a Markdown file, not in a pull request.

TL;DR

• Size: 7 skills, 9 reviewer personas, 6 brainstorm lenses, 5 review stages. No model weights; your agent supplies the LLM.
• Runs on: any harness that can spawn fresh subagents: Antigravity, Claude Code 2.1.271+, Claude Cowork, Codex, ChatGPT. Uses your existing model quota.
• Performance: no accuracy benchmark published. Evidence is adoption and end-to-end harness test runs.
• Best: Codex 0.163.0 completed 15 native fresh-context reviewers in order. 2 live tests passed in 573.13s.
• Worst: the Claude Cowork run stopped after stages 5 to 7 on a usage limit. Issue #237 reports AGENTS.md leaking into Codex reviewers.
• Bottom line: best thing, forced independent review before code. Worst thing, heavy token use and unverified isolation on some hosts.

What is Google’s Elephant-Goldfish Model plugin?

EGM is an Apache 2.0 plugin of skills, reviewer personas and document standards. It is not a new language model. The method comes from Dave Rensin’s essay on elephants and goldfish. The Google Open Source blog frames it as a fix for AI “slop” and session context collapse. The README states it is not an officially supported Google product.

How does the Elephant-Goldfish workflow work?

The Elephant is a long session holding project context and earlier decisions. It drafts the spec and writes no code. Each Goldfish is a stateless subagent. It reads only the draft and the files it references. You resolve trade-offs and approve the design.

The core loop has 3 commands:

• /egm-brainstorm clarifies the idea, then runs a 6-lens Goldfish swarm. Lenses cover YAGNI, token cost, UX, migration, observability and tech debt. Output: concepts_brief.md.
• /egm-draft turns the brief into a design doc under docs/designs/, section by section.
• /egm-review runs the Goldfish review.

/egm-drift-report later compares code with the spec. The docs recommend running it weekly.

What happens in the 5-stage Goldfish review?

The review skill runs 5 sequential stages:

1. Initial Zoom Out: checks the whole document at a high level.
2. Comprehension Test: a Goldfish paraphrases the design. A wrong paraphrase means the doc is ambiguous.
3. Critic Review: design, structural and style reviewers hunt gaps and edge cases.
4. Intermediate Zoom Out: rechecks architecture after fixes.
5. Implementation Readiness: checks file paths, data structures and signatures.

Each stage allows at most 1 re-audit. Findings are ranked Blocker, Major or Nit. If a host has no subagent tool, EGM stops. A same-context review is not a Goldfish review.