bep-protocol

name	bep-protocol
description	P2P file synchronization via BEP protocol. Use when working with syncthing-rust BEP messages, TCP+TLS transport, NAT traversal, or the MCP Bridge. Covers Rust↔Go interop, handshake flow, and cross-instance verification extensions.

BEP Protocol Skill

Quick Commands

cargo test --workspace              # 255+ tests
cargo clippy --workspace            # 0 warnings

Status

• Version: v0.2.8 Alpha
• Tests: 309+ passed, 0 clippy warnings
• Transports: TCP+TLS ✅ / HTTP CONNECT ⚠️（代码完整，主流程未接入） / SOCKS5 ⚠️（同上） / DERP（自研协议，非 Syncthing 官方 Relay） / UPnP ⚠️（无自动续约） / NAT-PMP ❌ / PCP ❌

BEP Messages

Core message types for Go interop:

Message	Direction	Notes
Hello	bidirectional	Device ID + name + capabilities
ClusterConfig	bidirectional	Folders + devices; WireFolder.label is String (not repeated string)
Index	bidirectional	File metadata updates
Request / Response	bidirectional	Block-level file transfer

MCP Bridge

• Process: syncthing-mcp-bridge (standalone)
• Protocol: hand-written JSON-RPC 2.0 (~200 LOC), zero third-party MCP SDK deps
• Tools: 11 tools + 3 resources
• Path: Kimi/Claude ← MCP stdio ← Bridge ← REST API → syncthing-rust

Current Blocker

• 跨网络互联: 无 Tailscale 时无法与隔离网络中的节点建立连接；Global Discovery + 官方 Relay Protocol 完全空白
• ManagerBlockSource 缺陷: Pull 方向向任意已连接设备请求块，非目标定向
• Next step: 实现 Global Discovery 客户端 + 官方 Relay Protocol XDR 编解码

Cross-Project Interfaces

• clarity: clarity-wire event bus → syncthing-rust P2P gateway → cross-instance verification
• devbase: .syncdone marker format aligned; boundary map versions synced via P2P then written to devbase OpLog

Tech Selection Framework

All selections weighted across 7 dimensions: SDK maturity, dev efficiency, distribution cost, stack consistency, maintenance cost, dependency risk, type safety. High-necessity features must score high on stack consistency + dependency risk.