Overview
MCode Stack is an open-source library of agent skills that MiniMax released under the MIT licence on October 28, 2026. It contains the workflows the MiniMax Code team uses every day to build MiniMax Code. The repository is explicit that this is not a prompt collection or a list of best practices.
There are two stacks today, ronny and jiachen, holding 17 SKILL.md files and five checklists. Ronny's stack, from the R and D lead, covers task splitting, context cost, long-session hygiene and independent review. Jiachen's two skills find the loops where a person is acting as a manual step for agents and turn each into a fix, and turn source material into Xiaohongshu image posts and vertical video.
There are three ways to install: copy a single skill directory into ~/.agents/skills, copy a whole stack as a local plugin, or add the repository as a plugin marketplace and install, update or uninstall from there. Because the format is the common SKILL.md, most of the skills also work in Claude Code.
Key Features
- Workflows actually in use: The repository states plainly that this is not a prompt collection. It records how the team keeps AI-written code at a high bar, when a task should go to a subagent, how long to wait on a long command and how to keep sessions from going dull.
- 17 skills grouped by moment: Planning uses subagent-split-check, engineering-small-prs and engineering-change-descriptions. Context and tools use tool-budget-audit and context-tax-audit. Long sessions use long-session-check, handoff-doc and long-command-check. Review uses independent-review.
- One skill per article: Each skill pairs with an entry in the MCode Engineering Notes column. The article explains the idea and the repository makes it runnable, so the guidance has something to execute.
- Installable as a marketplace: A .claude-plugin/marketplace.json at the root lets MiniMax Code desktop add MiniMax-AI/mcode-stack through Add marketplace, and Claude Code do the same with /plugin marketplace add.
- CI keeps versions visible: scripts/check.mjs verifies that marketplace entries match stack directories one to one, and CI requires a plugin.json version bump for any changed stack so updates reach installed copies.
- Contribute your own stack: templates/stack-template takes a copy, a WORKFLOW.md describes how you work with the agent, at least one skill you really use gets added, and scripts/check.mjs validates the result before a pull request.
Use Cases
- Adding engineering constraints to an agent, starting with independent-review and subagent-split-check.
- Projects where tool definitions eat the context window, measured first with tool-budget-audit.
- Long sessions that drift, where long-session-check decides between compaction, writing to disk and restarting.
- Hand-offs between sessions, using handoff-doc so a fresh one can pick up the work.
- Repeated manual steps, where lifting-loops finds the person acting as a manual step and turns it into a rule, script or scheduled task.
- Content teams converting material into image posts and vertical video through making-content.
Pros
- Content comes from the team's own daily use rather than a demo repository.
- 17 skills grouped by workflow, installable individually or as a stack.
- MIT licensed, with the six engineering skills under CC-BY 3.0 from Google Engineering Practices.
- The SKILL.md format means the same skills run in Claude Code.
- The repository doubles as a plugin marketplace with update support.
- CI enforces version bumps so installed copies stay current.
Pricing
MIT licensed and free to use or modify. The six engineering series skills adapt material from Google Engineering Practices and remain under CC-BY 3.0, with terms in stacks/ronny/NOTICE.md. Cloning the repository is all that is required; there are no server costs.
Summary
What matters here is not the skill count but the record of how a company building a coding agent constrains its agents day to day. Splitting work, controlling context, managing long sessions and reviewing independently are habits everyone nods at in an article and almost nobody executes. Turning them into installable skills is what makes them run. Start with independent-review and long-command-check, where the difference shows up immediately.
Version History
- MCode Stack open-sourced: 17 skills from the MiniMax Code team (2026-10-28): MiniMax open-sourced MCode Stack under the MIT licence with two stacks, ronny and jiachen, containing 17 SKILL.md files and five checklists. Ronny's 15 skills cover task splitting, context cost, long sessions, long commands and independent review. A .claude-plugin/marketplace.json makes the repository installable as a plugin marketplace, also usable from Claude Code, and scripts/check.mjs enforces marketplace entries and version bumps in CI. Six engineering skills adapt Google Engineering Practices material under CC-BY 3.0.