HandoffKit

Reliable handoffs for AI agent systems.

HandoffKit is a Go reference implementation for coordinating LLM agents with explicit message passing instead of shared coordination scratchpads. It includes mailboxes, select-style waits, routed handoffs, joins/quorums, pub/sub, budgets, supervision, dead letters, corpus-backed compaction, and message-level tracing.

"Do not communicate by sharing memory; instead, share memory by communicating." (Rob Pike)

Read the full blog post here: HandoffKit: coordinate agents by passing messages, not sharing memory.

• Interfaces: sketch/
• Runtime primitives: runtime/
• LLM-backed agents: llm/
• Examples: examples/
• Design notes: docs/

Integration status:

Surface	Status	Setup	Notes
OpenAI SDK LLM agents	Supported API path	OPENAI_API_KEY	Uses the official OpenAI Go SDK.
Codex plugin / skills	Supported Codex extension path	codex plugin marketplace add dyngai/handoffkit, then install HandoffKit from /plugins	Provides the handoffkit and handoffkit-scaffold skills inside Codex.
Codex transport LLM agents	Local / unsupported	codex login	Reverse-engineered ChatGPT-session transport used for demos and experiments; it can change or break without notice.

Core Idea

Treat each agent as an actor: private state, an addressable mailbox, and a single-owner run loop. Move work by sending messages. Ownership transfers with the message, so the sender stops touching the task after handoff.

Use message passing for control flow, and a shared Corpus of referenced knowledge. Its default merge is last-write-wins for single-writer keys; use a merge policy that is associative, commutative, and idempotent when multiple agents write the same key.

Why it helps:

• Select waits on peer messages, interrupts, budgets, cancellation, and timeouts in one place.
• Single-owner handoff avoids shared-scratchpad races.
• Unbuffered mailboxes provide natural backpressure.
• Tracer gives a complete message-level record.

What Is Included

Primitive	Purpose
ChanMailbox	Channel-backed inbox; unbuffered mailboxes provide rendezvous/backpressure.
Selector	reflect.Select over messages, deadlines, budgets, and cancellation.
Router	Point-to-point delivery by address.
Broker	Broadcast one event to every subscriber.
JoinAgent / QuorumAgent	Fan-in barriers.
Budget	Selectable resource ceiling.
Nursery	Structured concurrency and topology guard.
MemCorpus / Compactor	Shared referenced knowledge plus bounded handoff summaries.
WithDeadLetters	Capture undeliverable messages.
RunTraced / Tracer	Message-level observability.

How It Compares

Ranked by overall similarity (language, the actor/message-passing model, and the LLM-agent domain together), the closest repos are: