Ephyr

Ephyr is an access broker that replaces static credentials with a single Model Context Protocol (MCP) endpoint, giving multi-agent systems cryptographically bounded, ephemeral access to infrastructure

ROUND 1 DEADLINE

VOTING CLOSES THURSDAY, MARCH 26

Ephyr is live in Round 1 right now. Voting closes Thursday, March 26, so if you're backing this project, send people into the matchup before the round locks.

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Share URL

https://agentmadness.ai/entries/ephyr

Builder

Ben Spanswick

Build Type

Vibe-Coded Experience

Lifecycle

Working prototype

Consensus Score

82.8

Region

REGION 3

Seed

11

Current Matchup

REGION 3 Round 1 • Round 1

Opponent

Volntir

Project Link

https://www.ephyr.ai

Demo Link

https://www.ephyr.ai

CATEGORIES

Other

Go Deeper

Ephyr represents a step-change in multi-agent security. It is the first open-source implementation of the Delegation Capability Token (DCT) architecture, proposed in a February 2026 Google DeepMind paper. 

It solves the complex problem of agent-to-agent delegation by using HMAC-chained macaroon tokens and an effective envelope reducer, making it cryptographically impossible for a delegated sub-agent to escalate its privileges. 

It features zero standing backend credentials, instantly cascades task revocations down a whole tree of agents using "epoch watermark revocation", and operates incredibly lean with zero external databases or container runtimes.

Stack Used

Core Backend: Go (Golang 1.24+)
Protocols & Frameworks: Model Context Protocol (MCP 2025-03-26) , JSON-RPC 2.0 over Streamable HTTP, WebSockets
Frontend Dashboard: React 18 SPA
Infrastructure / Security Tools: OpenSSH (ephemeral certificates), systemd (sandboxing), nftables (network isolation), Ed25519 cryptography, and purely stdlib-based Macaroons