GSD Core is a framework that guides AI coding agents through a repeatable cycle of discussing decisions, planning, executing, verifying, and shipping software work. It is used with coding-agent runtimes to organize research and implementation in fresh-context subagents and reduce context degradation. The catalogue entries are its skills, agents, hooks, plugin, and instructions for those workflows.
Borrowing it
Nothing to install: this file belongs to open-gsd/gsd-core. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/open-gsd/gsd-core/next/GEMINI.mdgit clone --depth 1 https://github.com/open-gsd/gsd-coreWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/open-gsd/gsd-core/gemini-md)<a href="https://agentmods.dev/instructions/open-gsd/gsd-core/gemini-md"><img src="https://agentmods.dev/badge/instructions/open-gsd/gsd-core/gemini-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/open-gsd/gsd-core/gemini-md"><img src="https://agentmods.dev/badge/instructions/open-gsd/gsd-core/gemini-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00618 | $0.00618 |
| Opus 5.5 | $0.00247 | $0.00247 |
| Sonnet 5.5 | $0.00124 | $0.00124 |
| Haiku 4.5 | $0.00062 | $0.00062 |
Grade A, and why
gsd-core GEMINI.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GSD Core — Antigravity CLI context
Gemini CLI was sunset by Google on 2026-06-18 and is no longer served for free/Pro/Ultra tiers. Antigravity CLI is its official successor, and this file is the context Antigravity reads automatically (its
contextFileNameisGEMINI.md, inherited from the shared Gemini 3 backend).
This context gives Antigravity the operating context for GSD Core, a meta-prompting, context-engineering, and spec-driven development system for AI coding agents.
What GSD is
GSD turns a vague goal into shipped software through an explicit,
resumable workflow: explore → plan → execute → verify → ship. Work is
organised into milestones and phases under a .planning/ directory, with each
phase carrying a SPEC, a PLAN, and verification criteria. The system favours
small, atomic, test-backed commits and keeps durable context in version-tracked
files rather than in the conversation.
The slash commands (installed separately)
This file ships only the context above — not the slash commands. To install the
/gsd-*command set, agents, and hooks into~/.gemini/antigravity/, run the dedicated installer:npx @opengsd/gsd-core@latest --antigravity --globalThe commands below are available only once that installer has run.
If you have installed the gsd commands, the workflow is driven by these /gsd-*
slash commands (Antigravity registers gsd's commands under a hyphenated
namespace):
/gsd-new-project— initialise a project and gather deep context./gsd-progress— the unified situational command: check progress, advance the workflow, or dispatch a freeform intent./gsd-plan-phase <N>— produce a detailed phase plan with a verification loop./gsd-execute-phase <N>— execute a phase's plans with wave-based parallelism./gsd-verify-work— validate built features through conversational UAT./gsd-ship— open a PR, run review, and prepare for merge./gsd-help— list every available command.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago Changed · +7 tokens per session 531ed974257f
- 1mo ago First seen · 56 lines · 611 tokens per session scan A 264c71c5c9d5
gsd-core GEMINI.md is an instructions file published in the GitHub repository open-gsd/gsd-core (10,564 stars, last pushed today), licensed MIT. It adds 618 tokens to every session, about $0.0025 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).