Summary
Builds and maintains a persistent feature-to-file concept map so Claude doesn't re-explore your codebase every session. Exposes a Map-Reduce workflow through MCP tools: mason_init walks you through setup, generate_snapshot_batch processes files in chunks, and reduce_snapshot merges them into a unified catalog stored in .mason/snapshot.json. After init, get_snapshot returns instant feature lookups, get_impact traces change ripples through co-change history and references, and export_to_confluence syncs the map to wiki pages. Benchmarks show 36% average token savings on architecture questions. Designed for large codebases where architectural context gets rebuilt from scratch every conversation. Works across Cursor, Windsurf, and any MCP-compatible client.
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Your agents are creating tech debt. Mason helps you prevent it.
Remember why decisions were made · Catch outdated guidance · Find what else needs updating
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 setup --host codex
# For Claude Code, use --host claude.
Setup connects MCP, hooks, and project instructions. 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 the reason with Mason. Later tasks can retrieve it. Proposals and accepted decisions stay distinct.
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
Documentation
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Fastest browser for AI agents to run web automation tasks, always free.
Download Free life-time →Notes, actions and memory. Without a meeting bot. First month 100% off.
Download for free →belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
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