go-ultimate

A single, opinionated AI agent skill for writing the best Go programs — synthesized from four general-Go skills, four agent/MCP donors (one donor contributes two documents), the Google and Uber style guides, and a repository/production-practice donor. Routes any Go task (CLI, library, backend service, MCP server, AI agent) to the right architecture, conventions, and review checklist. Highly opinionated; overrides generic Go style and lint guidance on conflicts.

Status: v0.11.0. Designed for Claude Code, Codex, Cursor, Grok Build, GitHub Copilot CLI, OpenCode, and any harness that reads the Agent Skills SKILL.md format. MIT licensed.

What's inside

The skill lives under skills/go-ultimate/ and is structured for progressive disclosure:

Path	Purpose
skills/go-ultimate/SKILL.md	The skill itself — when it applies, the non-negotiable principles, the project-type decision tree, conflict precedence.
skills/go-ultimate/references/	Deep dives loaded on demand: architecture.md, engineering-policy.md, modern-go.md, testing.md, code-review.md, libraries.md, project-layouts.md, wiring-and-runtime.md, modular-monolith.md, production-readiness.md, repo-and-ci.md, mcp-server.md, agents.md.
skills/go-ultimate/assets/	Scaffolded project templates per type: cli-simple, cli-cobra, library, game, mcp-server, webservice (all build, vet and test -race green), plus ci/ workflows.
skills/go-ultimate/scripts/	goversion/main.go (detects the project's go.mod version) and check-source-versions.sh + source-versions.json (drift checker for upstream donor sources).
skills/go-ultimate/evals/	Example prompts and expected behaviors for catching skill drift.

Install

go-ultimate ships a plugin manifest per harness (see the repo root), so the same skill installs natively on each. Install via the Djarvur marketplace (Djarvur/cc-mplace), which indexes go-ultimate for every supported host. Once installed, it auto-triggers on any Go task (mentions of Go, Golang, go.mod, a Go package, MCP server, or AI agent).

Claude Code

claude plugin marketplace add Djarvur/cc-mplace
claude plugin install go-ultimate

Codex

codex plugin marketplace add Djarvur/cc-mplace
codex plugin add go-ultimate@djarvur-plugin-marketplace

Invoke with $go-ultimate:go-ultimate.

Cursor

agent plugin marketplace add https://github.com/Djarvur/cc-mplace.git

Then install go-ultimate from the Cursor marketplace UI.

Grok Build

grok plugin install 'Djarvur/cc-mplace#go-ultimate' --trust

GitHub Copilot CLI

copilot plugin marketplace add Djarvur/cc-mplace
copilot plugin install go-ultimate@djarvur-plugin-marketplace

OpenCode

OpenCode consumes skills as files rather than a marketplace bundle. Copy the skill into your project (or globally below ~/.config/opencode/):

src="$(mktemp -d)"
git clone --depth 1 https://github.com/Djarvur/go-ultimate.git "$src"
mkdir -p .opencode
cp -R "$src/skills/go-ultimate" .opencode/skills/
rm -rf "$src"

Invoke via OpenCode's skill tool; the SKILL.md documents <skill-dir> resolution.

ZCode

Copy or symlink skills/go-ultimate/ into ~/.zcode/skills/. ZCode also recognizes the .claude-plugin/ manifest.

Manual / unsupported harness

Clone and point your harness at the skill directory:

git clone https://github.com/Djarvur/go-ultimate.git

The SKILL.md documents <skill-dir> resolution per harness.

How it works

When triggered, the skill:

1. Detects the project's Go version (go run <skill-dir>/scripts/goversion/main.go <project>) and gates feature usage on it.
2. Routes the project through a decision tree — script / CLI / library / backend service / MCP server / AI agent — and loads the matching reference.
3. Applies nine non-negotiable principles (modern version-gated Go, no pkg/, context-first, thin adapters, concurrency hygiene, etc.).
4. Resolves conflicts via an explicit precedence ladder (architecture → modern-go → engineering-policy → libraries → code-review → mcp-server → agents → production-readiness → repo-and-ci).

See the SKILL.md for the full opinionated rule set.

Donor sources

The skill synthesizes thirteen upstream sources. Full attribution and the live pins used to detect upstream drift are in skills/go-ultimate/scripts/source-versions.json. Summary:

General Go: teetsh-org/claude-skills#golang-code-review, JetBrains/go-modern-guidelines#use-modern-go, powerman/skills#go-bounded-context-hexagonal (v0.6.0), powerman/skills#go-engineering-policy (v0.0.5).

Style guides: google/styleguide#go (CC-BY-3.0), uber-go/guide (Apache-2.0).

Repository / production practice: metalagman/agent-skills#go-senior-developer, #go-oss-maintainer, #golangci-lint-strict.

Agent / MCP: cloudwego/eino#orchestration-design-principles, cloudwego/eino#adk-0.1, modelcontextprotocol/go-sdk (v1.6.1), philschmid.de#mcp-best-practices, modelcontextprotocol.info#docs/best-practices.

Originally also sourced from danicat/skills#go-best-practices and danicat/skills#go-project-setup; both were deleted upstream on 2026-07-21. Their distilled content is now owned and maintained by this skill (project-setup boilerplates under assets/, best-practices material folded into references/engineering-policy.md and references/code-review.md).

metalagman/agent-skills ships no LICENSE file, so its text is all-rights-reserved by default. Nothing is copied from it verbatim — the rules were extracted and rewritten, with the donor credited in each affected reference. Its bulk style-guide documents are derivatives of the Google and Uber guides, which this skill pins and attributes directly from upstream instead. Its tool-specific playbooks (go-fx, go-goose, go-options-gen, go-adk) are deliberately not folded in: they are version-fragile, they contradict this skill's defaults (hand-written wiring over Fx, Resolvable Config Struct over options-gen), and an always-on skill should not carry per-library tutorials.

Checking for upstream drift

bash skills/go-ultimate/scripts/check-source-versions.sh

Exit 0 = no drift, 1 = a donor changed since the pin was recorded, 2 = fetch failure. Refresh the pin in source-versions.json whenever you fold a change back into the skill.

License

MIT — see LICENSE.