# Archcore

> Archcore is a git-native context layer for AI coding agents. Archcore keeps specs, architecture, decisions, rules, and plans in Git, and makes the right project context available to AI coding agents as they work. Agents access project context through MCP. Supported hosts also receive context through hooks. Installation and updates send limited analytics; see the privacy policy for details and opt-out options.

## Main pages

- [Home](https://archcore.ai/): what Archcore is and how to install Archcore
- [Plugin](https://archcore.ai/plugin/): /archcore slash commands, skills, and guardrails for Claude Code, Cursor, Codex CLI, and GitHub Copilot CLI
- [CLI](https://archcore.ai/cli/): single cross-platform binary that scaffolds .archcore/, runs a local MCP server, and connects eight AI coding agents over MCP, with session hooks on five supported hosts
- [How to use](https://archcore.ai/how-to-use/): one feature through init, plan, document, and review, with prompts and slash-command shortcuts
- [Privacy policy](https://archcore.ai/privacy/): local-first data practices

## Reference

- [Context Engineering for AI Coding Agents](https://archcore.ai/context-engineering/): the five properties of engineered context (explicit, structured, selective, versioned, portable), how it differs from prompt engineering and RAG, and what belongs in project context
- [Spec-Driven Development for AI Coding Agents](https://archcore.ai/spec-driven-development/): what a spec is and is not, EARS and BCP 14 clause form, the idea to PRD to spec to plan track, and how specs stay connected after the merge
- [Project Context for AI Coding Agents](https://archcore.ai/project-context/): what belongs in project context, how it differs from agent memory and retrieval, and the three ways persistence usually fails
- [Why Project Context Belongs in Git](https://archcore.ai/git-native-context/): reviewable, versioned, branch-aware, portable, team-owned, and what the alternatives give up
- [MCP for AI Coding Agent Context](https://archcore.ai/mcp/): why a protocol rather than a file, what a context server should expose, local stdio, and how MCP and hooks divide the work

## Agent integrations

- [Claude Code](https://archcore.ai/claude-code/): production plugin host, full hook set, compared with CLAUDE.md and Claude Code memory
- [Cursor](https://archcore.ai/cursor/): plugin on Cursor 2.5+, MCP setup, compared with .cursor/rules and the removed Memories feature
- [Codex CLI](https://archcore.ai/codex/): plugin on 0.117+, hooks behind the experimental flag and unavailable on Windows, compared with AGENTS.md
- [GitHub Copilot](https://archcore.ai/github-copilot/): two required install steps and why (github/copilot-cli#4234), no pre-write injection, compared with custom instructions
- [Gemini CLI](https://archcore.ai/gemini-cli/): CLI path with the full hook set, no plugin needed, one context across several agents

## Comparisons and migration

- [AI agent memory vs project context](https://archcore.ai/learn/agent-memory-vs-project-context/): what each one holds, what memory is the wrong instrument for, and the two questions that settle any case
- [Context engineering vs prompt engineering](https://archcore.ai/learn/context-engineering-vs-prompt-engineering/): where the leverage moved on coding agents, and the test for which kind of problem you have
- [Spec-driven development vs context engineering](https://archcore.ai/learn/spec-driven-development-vs-context-engineering/): intent versus understanding, the collapse in both directions, and where the two practices meet

## Concepts and explainers

- [What Is Harness Engineering?](https://archcore.ai/learn/harness-engineering/): the guides-and-sensors taxonomy, how harness engineering nests inside context engineering rather than superseding it, where loop engineering ends, and which half of the harness belongs to your project
- [What Is Repo Memory?](https://archcore.ai/learn/repo-memory/): project context stored as versioned files in the repository, compared with cloud agent memory, vector retrieval, and flat instruction files
- [MCP server for project context](https://archcore.ai/blog/mcp-server-project-context/): exposing repository context to coding agents over MCP
- [Claude Code memory](https://archcore.ai/blog/claude-code-memory/): CLAUDE.md limits and what belongs in structured project context instead
- [Cursor Memories removed](https://archcore.ai/blog/cursor-memories-removed/): what changed in Cursor and what to use instead
- [All explainers](https://archcore.ai/learn/) and [all guides](https://archcore.ai/blog/)

## Documentation

- [Docs home](https://docs.archcore.ai/): full documentation
- [Start here](https://docs.archcore.ai/start/install/): install and first steps
- [Project context](https://docs.archcore.ai/concepts/project-context/): document types, relations, and the context model
- [CLI reference](https://docs.archcore.ai/cli/commands/): command syntax and options
- [Commands and examples](https://docs.archcore.ai/guides/commands/): use Archcore in your agent
- [Connect your agent](https://docs.archcore.ai/guides/connect-your-agent/): MCP, lifecycle hooks, and instructions

## Source

- [GitHub organization](https://github.com/archcore-ai): open-source CLI and plugin repositories