How do I install Mason?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does Mason need an API key?

No required environment variable is listed on this record.

When was Mason last checked?

Last checked 2026-11-08. Engineering decisions, change impact, documentation audits, and CI evidence for coding assistants.

Mason MCP server

Power your agent

Add this server

The publisher's own command. Not a PlugMCP endpoint.

Add to Cursor Add to VS Code Run on PlugMCP

Host a copy with our keys and logs.

Local command

npx -y [email protected]

Claude Code has no install link for a local command. Copy the command below and run it in a terminal.

shClaude Code

1claude mcp add com.adrianczuczka-mason -- npx -y mason-context@0.24.0

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "com.adrianczuczka-mason": {4      "command": "npx",5      "args": [6        "-y",7        "[email protected]"8      ]9    }10  }11}

claude_desktop_config.json

Local · npmPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Run on PlugMCP

Host a copy with our keys and logs.

A new server you create. It is not this listing's official endpoint. Use the publisher install when you want their URL and their credentials.

Launch

Server facts

Local

Transport: stdio
Version: 0.24.0
Last checked

Tools

No tool list yet. Remote servers get one after the first health check.

FAQ

Questions

Mason

Preserve why your code was built this way.

Record the reason · Review the lesson · Surface applicable guidance · Reconsider it as code changes

Mason preserves reviewed engineering reasoning with your repository, so future maintainers and coding agents can retrieve the evidence behind consequential decisions. Record workarounds, rejected approaches and constraints while their reasons are available; revisit them when the underlying code changes.

Get started

Install on macOS or Linux:

curl -fsSL https://github.com/adrianczuczka/mason/releases/latest/download/install.sh | sh

Windows PowerShell:

irm https://github.com/adrianczuczka/mason/releases/latest/download/install.ps1 | iex

No Node or npm required. Git is required. The installer configures PATH for Bash, Zsh, and Windows. Platform details · npm installation

New standard standalone installs update automatically in the background. Updates activate on a future MCP launch after existing Mason MCP servers exit. Run mason updates to inspect or change this preference. Existing installations require one manual upgrade and mason updates enable. Update controls

Run this in your Git repository (open a new terminal if the installer asks):

mason init --host codex    # Maintainer: prepare shared configuration for review/commit
mason setup --host codex   # Each developer: activate locally
# For Claude Code, use --host claude.

If the repository already has compatible Mason configuration, run only mason setup. Initialization prepares MCP, hooks and project instructions; setup leaves shared files untouched. Review your host's trust settings, start a new session, and give your agent a normal task.

Check that Mason is being used:

mason status

Setup uses your installed mason command—no project launch scripts or runtime copies. Status distinguishes configuration from observed use. Setup and upgrades · Disconnect a project · Other MCP clients

Try a check without setup

mason audit --dir .
mason review --dir . --base origin/main

The audit checks claims in README and agent instruction files throughout the repository. The review checks committed changes against your chosen base. Both are read-only and need no model calls.

What Mason catches

As your project grows…	Mason helps by…
Instructions fall behind the code.	Flagging missing paths, incorrect workspace counts, and missing npm scripts.
A patch misses a related update.	Surfacing references, related tests, and files that historically change together.
Old decisions lose their context.	Retrieving recorded rationale and review status, and flagging changes to the code they apply to.
A repair gets interrupted.	Retaining the original findings and verifying them through the final documentation commit.

After resolving an incident or settling a constraint, ask your agent to record a sourced proposal with Mason. Review it before accepting it as project guidance. Later tasks can retrieve the operative accepted revision while proposed replacements remain distinct, and changes to referenced code can prompt inspection, revision or retirement.

Mason complements tests, linters, and code review. Findings are evidence to inspect; unavailable checks stay explicit.

Evidence so far

Earlier read-only decision-retrieval evaluations scored 9.0/10 with Mason vs 7.0/10 without. The initial ten-task patch comparison tied at 10/10 for both. Improved patch outcomes remain to be demonstrated. Results, methodology, and limitations

Maintained notes also succeeded in the reuse trials. Recent hook experiments verified supported file delivery, with additional context cost and no demonstrated correctness gain; direct delivery for ordinary Bash workflows remains open. The current focus is useful preservation and reuse of engineering reasoning during ordinary work, with capture and maintenance effort that feels worthwhile. Preventing repeat mistakes is one intended benefit; comparative superiority remains unestablished. Positioning and validation plan · Current evidence

Documentation

Development

For development, use Node 20 (20.19+), Node 22 (22.13+), or Node 24+. After npm ci, run npm run format to format TypeScript sources, tests, and tooling configs. CI checks formatting with npm run format:check and runs npm run lint, npm run typecheck, and the test suite. Run npm test locally to check behavior.

ESLint uses the recommended TypeScript rules plus type-aware checks for unhandled promises, misused async callbacks, and invalid awaits. Prettier handles formatting. Test fixtures and generated outputs are excluded from formatting and linting. Production sources also reject explicit any and unsafe assignments, property access, calls, arguments, and returns. External data is validated before use. Test doubles keep the more permissive rules.

Add this server

Host a copy with our keys and logs.

Server facts

Tools

Questions

How do I install Mason?

Does Mason need an API key?

What transport does Mason use?

When was Mason last checked?

Documentation

Mason

Preserve why your code was built this way.

Get started

Try a check without setup

What Mason catches

Evidence so far

Documentation

Development