AI coding tools forget.
decidex fixes that.

decidex extracts engineering decisions from your git history and surfaces them in Claude Code, Cursor, Copilot, and Windsurf — so your AI tools know what you've already decided, and why.

$ npm install -g decidex

or npx decidex generate — no install needed

How it works

git log ── your commit history

↓

Claude API ── classifies decisions, extracts rationale

↓

.decisions/ ── plain markdown, committed to git

↓

CLAUDE.md · Cursor rules · Copilot instructions · Windsurf

Decisions in action

$ decidex generate

✓ Loaded 11 commits (2024-09-01 → 2026-03-21)

✓ Classified 8 decisions — 8 new, 0 unchanged

✓ Skipped 2 commits (too short to classify)

✓ Updated CLAUDE.md

Decisions captured:

packages/core/ · ClassifierInterface injectable for testing

packages/core/ · atomicWrite() temp in same dir, then rename

packages/cli/ · Batch 500 commits per API call, retry once

packages/mcp/ · MCP server: get_decisions + get_stats via stdio

(repo-wide) · tsc -b for monorepo, respects ref ordering

(repo-wide) · Skip commits with subject+body < 20 chars

CLAUDE.md — managed section

## Engineering Decisions

## (managed by decidex)

- ClassifierInterface is injectable for testing.

ClaudeAPIClassifier in prod, mockClassifier() in tests.

- atomicWrite() writes to a temp file in the same

directory as target, then renames. Guarantees

same-filesystem move — no cross-device copy.

- 500 commits per API batch. Retry once on failure.

Collect all results before writing anything.

- tsc -b for monorepo build. Respects project

reference ordering: core → cli → mcp.

What it does

Incremental

Only new commits classified. Fast after first run.

Multi-tool

Cursor rules. Copilot instructions. Windsurf. One command.

MCP server

Claude Code queries decisions for the file you're editing.

Local mode

Ollama. No API key. Runs on your machine.

Secret scanning

Pre-commit hook blocks accidental secrets in .decisions/.

Manual capture

Decisions not in git: decidex capture "No Passport.js"

decisions captured

areas covered

AI tools supported

forgotten decisions

Get started

Install

$ npm install -g decidex

Set your API key

$ export ANTHROPIC_API_KEY=sk-ant-...

Wire up hooks and MCP (once per repo)

$ decidex init

Classify your git history