The problem

You use Cursor at work, Claude Code in the terminal, Copilot in
pull requests, and three CLI agents on CI. Each one wants its own instruction
file. So you maintain four copies of the same rules, they drift, and no agent
knows what the others did yesterday.

The idea

Keep the rules once, in .syncytium/, and transpile them into every
tool's native format.

.syncytium/          canonical, human-authored, git-tracked
  rules/*.md         code style, security, testing, architecture, …
  memory/decisions.md  ADRs — why the project is the way it is
  HANDOFF.md         live agent baton: who has it, what's next
        │
        │  syncytium sync
        ▼
CLAUDE.md   AGENTS.md   GEMINI.md   AGENT.md   CONVENTIONS.md
.cursorrules   .clinerules   .roomodes   .windsurfrules   .traerules
.cursor/rules/*.mdc          .gemini/antigravity/rules/*.md
.github/copilot-instructions.md + .github/instructions/*.instructions.md

Every generated file carries a banner saying where it came from, and
syncytium diff --check fails your CI if any of them drift. syncytium clean
removes only banner-tagged files — your hand-written rules are never touched.

Quick start

npx syncytium init          # scaffold .syncytium/ (stack auto-detected)
npx syncytium sync          # generate every bridge file
npx syncytium graph         # open the 3D knowledge graph in your browser

Requires Node.js 22.6+. No global install needed; npx works.

What you get

Commands

Run syncytium --help for the full list.

Context

Rules & decisions

syncytium rules [query]                       # search the catalog
syncytium rule add --title "..." --body "..." # add a canonical rule
syncytium rule show <id>                      # inspect one
syncytium rule update <id> --body-file x.md   # edit in place
syncytium rule remove <id>                    # delete + prune generated files

syncytium adr list                            # architectural decisions
syncytium adr add --title "..." --context "..." \
                  --decision "..." --consequences "..."
syncytium adr show ADR-006
syncytium adr remove ADR-006

Multi-agent coordination

syncytium lock acquire --agent "Cursor" --goal "Refactor auth"
syncytium lock heartbeat --agent "Cursor"    # extend the lease
syncytium lock status
syncytium lock release --agent "Cursor"

syncytium handoff -i                          # interactive wizard
syncytium handoff --from "Cursor" --to "Claude" \
  -s ready_for_review -g "Ship v1" -d "…" -t "…"
syncytium log -n 20                           # baton audit trail

Guards

syncytium hook install      # block commits on drift
syncytium hook install --auto-sync   # or just re-sync on every commit
syncytium ci                # .github/workflows/syncytium.yml drift gate
syncytium ci --force        # regenerate an existing workflow

Knowledge graph

syncytium graph                        # 3D WebGL cosmos + vault explorer
syncytium graph --category ide         # isolate IDE adapters
syncytium graph --compact              # hide file and tag nodes
syncytium graph --no-open --port 4000

The server binds to 127.0.0.1 and rejects non-loopback Host headers
(DNS-rebinding guard). It refuses to serve .env*, *.pem, *.key, .git/**
and other in-root secrets.

MCP

{
  "mcpServers": {
    "syncytium": {
      "command": "npx",
      "args": ["-y", "syncytium-mcp"],
      "cwd": "${workspaceFolder}"
    }
  }
}

Or syncytium mcp if you already have the CLI installed. Tools include
syncytium_get_context, syncytium_handoff, syncytium_create_rule,
syncytium_update_rule, syncytium_remove_rule, syncytium_record_decision,
syncytium_sync, syncytium_diff, syncytium_doctor, syncytium_validate,
syncytium_lock_acquire/release/status, syncytium_get_graph and more.
Every input is zod-validated; every output is summarised rather than dumped.

.syncytiumignore

Excludes generated targets from both sync and diff. Full gitignore syntax,
including **, ?, directory-only patterns and ! negation:

# Don't manage these tools
.cursorrules
.github/instructions/

# Except this one
!.github/instructions/keep.md

Custom adapters

Declare any tool in syncytium.config.json — no code required:

{
  "customAdapters": [
    {
      "id": "zed",
      "name": "Zed",
      "targetFile": ".rules/zed.md",
      "includeHandoff": true,
      "includeArchitecture": true
    }
  ],
  "enabledAdapters": ["cursor", "claude", "zed"]
}

Library usage

import { SyncytiumEngine } from 'syncytium-md';

const engine = new SyncytiumEngine(process.cwd());
await engine.sync();
const { hasDrift, summary } = await engine.diff();
const graph = await engine.getKnowledgeGraph({ category: 'ide' });

Development

npm install
npm run verify      # typecheck -> build -> 114 tests

See CONTRIBUTING.md and
.syncytium/architecture.md.

License

MIT © Miraç Birben