arcforge

arcforge

arcforge is a minimal, composable skill toolkit for Claude Code, Codex, Gemini CLI, and OpenCode. It gives agents lightweight routing, structured SDD artifacts, and eval-backed quality gates without turning every task into a mandatory workflow.

Why arcforge

AI coding agents are powerful but uneven. Left to their defaults, they skip design, ignore review, and lose context across sessions. Heavy always-on process creates a different failure mode: the agent follows workflow ceremony when a direct answer or isolated eval would be better.

arcforge solves this with a small composable toolkit. Skills are available in the session, but they are selected when useful: design when intent is unclear, structured specs when artifacts matter, TDD/debugging/review when implementation risk is present, and verification before completion claims.

The outcome: your agent has disciplined workflows when the task justifies them, while preserving direct execution, harness isolation, and small-task speed when a workflow would be overhead.

How it works

ArcForge is split into three layers:

1. Core toolkit — a small promoted surface for routing, design, specs, planning, TDD, debugging, verification, and eval.
2. Optional workflows — recipes for SDD, bugfixes, skill authoring, and multi-agent work. These are opt-in by task fit, not global laws.
3. Harness/eval layer — tests that verify both activation and non-activation behavior, including instruction-strength regressions.

When your coding agent starts a session, arcforge's hooks inject a minimal bootstrap: ArcForge is available, ARCFORGE_ROOT is set, and agents should prefer the smallest useful workflow. Specific skills are read or invoked on demand.

Once a design is approved, ArcForge can build a clear implementation plan and then execute tasks with a two-stage review (spec compliance, then code quality). For larger work, it can create parallel git worktrees so epics can run in isolation.

Skills are tools, not laws. You can enter through arc-using for routing help or call any skill directly when you already know the needed workflow.

Installation

Note: Installation differs by platform. Claude Code has a built-in plugin system. Codex and OpenCode require manual setup.

Claude Code (Plugin Marketplace)

Register the marketplace:

/plugin marketplace add GregoryHo/arcforge

Install the plugin:

/plugin install arcforge@arcforge-dev

Verify Installation

Check that commands appear:

/help

# Should see:
# /arcforge:arc-brainstorming - Design exploration
# /arcforge:arc-writing-tasks - Break epics or features into executable tasks
# /arcforge:arc-executing-tasks - Execute tasks with checkpoints

Every skill is directly invocable by name — /arcforge:arc-<name> (e.g. /arcforge:arc-tdd, /arcforge:arc-debugging). Unsure where to start? Invoke /arcforge:arc-using for routing help.

Codex

Tell Codex:

Fetch and follow instructions from https://github.com/GregoryHo/arcforge/blob/main/.codex/INSTALL.md

Detailed docs: docs/README.codex.md

Gemini CLI

Tell Gemini CLI:

Fetch and follow instructions from https://github.com/GregoryHo/arcforge/blob/main/.gemini/INSTALL.md

Detailed docs: docs/README.gemini.md

OpenCode

Tell OpenCode:

Clone https://github.com/GregoryHo/arcforge to ~/.agents/arcforge, then create directory ~/.config/opencode/skills, then symlink ~/.agents/arcforge/skills to ~/.config/opencode/skills/arcforge, then create directory ~/.config/opencode/plugins, then symlink ~/.agents/arcforge/.opencode/plugins/arcforge.js to ~/.config/opencode/plugins/arcforge.js, then restart opencode.

Detailed docs: docs/README.opencode.md

Quick Start: Common Commands

These are the most frequently used commands:

Command	Purpose	When to Use
/arcforge:arc-using	Routing help + skill index	When unsure which skill or workflow applies
/arcforge:arc-brainstorming	Design exploration	When starting new work or clarifying requirements
/arcforge:arc-writing-tasks	Break down into tasks	When you have a clear spec and need executable steps
/arcforge:arc-executing-tasks	Run task list	When tasks are ready and you want to implement
/arcforge:arc-journaling	Session journaling	At end of session to capture reflections
/arcforge:arc-reflecting	Analyze patterns	After 5+ journal entries to summarize learnings

How Skills Compose