handoff-protocols

Handoff Protocols

A handoff is the moment one agent passes work to another — or to a human. It's where multi-agent systems most commonly fail. A dropped handoff means lost context, repeated work, or abandoned tasks.

Anatomy of a Handoff

Every handoff has:

• Trigger: What causes the handoff? (task completion, scope boundary, failure, user request)
• Source: Who is handing off?
• Destination: Who is receiving?
• Payload: What information transfers? (context, partial results, user state, instructions)
• Acknowledgment: How does the source know the destination received the handoff?
• User experience: What does the user see during the handoff?

Handoff Types

• Sequential: Agent A finishes, passes results to Agent B who continues. Like a relay race.
• Parallel fan-out: One agent distributes subtasks to multiple agents simultaneously.
• Parallel fan-in: Multiple agents' results converge back to one agent for synthesis.
• Escalation: An agent can't handle the task and passes up to a more capable agent or human.
• Fallback: The primary agent fails and a backup takes over.
• Human handoff: AI passes work to a human for review, decision, or completion.

Context Transfer

The most common handoff failure is context loss. Design what transfers:

• Full context: Everything the source agent knew. Safe but potentially overwhelming.
• Summarised context: Key information distilled. Efficient but risks losing important nuance.
• Structured context: Predefined fields that must be populated. Consistent but rigid.
• Incremental context: Only what's new since the last handoff. Efficient for ongoing collaborations.

Designing for the User

The user's experience of handoffs matters:

• Invisible handoff: The user doesn't know agents changed. The experience feels seamless.
• Transparent handoff: The user is told a new agent is taking over and why.
• Participatory handoff: The user confirms the handoff or provides additional context.
• User-initiated handoff: The user explicitly requests a different agent or a human.

Handoff Anti-Patterns

• The black hole: Work is handed off but never picked up
• The echo chamber: Agents hand work back and forth without progress
• The context cliff: Critical information is lost in the handoff
• The jarring transition: The user's experience changes dramatically at the handoff point
• The silent redirect: The user doesn't know they've been handed off and gets confused by changes

Design Artefacts

• Handoff protocol specifications (trigger, source, destination, payload, acknowledgment)
• Context transfer templates
• Handoff sequence diagrams
• User experience specifications for each handoff type
• Handoff failure mode analysis