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Open Protocol

A2H — Agent-to-Human
Interaction Protocol

A2A defined how agents talk to agents. MCP defined how agents use tools. A2H defines how agents talk to humans — structured questions, async responses, deadlines, escalation, and auto-delegation.

Agent Agent  A2A
Agent Tool  MCP
Agent Human  A2H
6
Response Types
4
Availability States
13
Interactive Demos
7
Framework Integrations

Why A2H?

Every real AI agent deployment reaches a point where an agent needs a human — an approval, a decision, clarification, a review. Today this is handled with ad-hoc Slack bots, custom UIs, and email triggers. There is no standard. A2H is that standard.

📋

Structured Questions

Choice, approval, text, number, confirm, form — not free text. Agents ask the right question in the right format.

Async Responses

Deadlines measured in hours, not milliseconds. Humans respond when ready via dashboard, Slack, email, or SMS.

🔄

Auto-Delegation

Rules that auto-respond to routine requests. “Under $500? Auto-approve.” No human action needed.

📨

Escalation Chains

Timeout-based promotion to the next human. Sarah doesn’t respond in 10 minutes? Auto-escalate to Tom.

🟢

State-Aware Routing

Available, busy, away, offline — plus custom states. In a call? Queue it. On vacation? Reroute to delegate.

🔌

Pluggable Architecture

Custom channels (Slack, Teams, email), custom storage (Postgres, Redis), and integrations with 7 AI frameworks.

6 Response Types

Every interaction between agent and human maps to one of six structured types.

🔘
Choice
Pick from options
Approval
Approve / Reject
📝
Text
Free-text input
🔢
Number
Numeric input
👍
Confirm
Yes / No
📄
Form
Multi-field input

The Collaboration Stack

┌─────────────────────────────────────────────────────────────┐ │ THE COLLABORATION STACK │ │ │ │ ┌─────────┐ A2A ┌─────────┐ MCP ┌───────┐ │ │ │ Agent │◄──────────►│ Agent │─────────►│ Tool │ │ │ └────┬────┘ └─────────┘ └───────┘ │ │ │ │ │ │ A2H (this protocol) │ │ │ structured questions │ │ │ async responses │ │ │ deadlines + escalation │ │ │ auto-delegation │ │ ▼ │ │ ┌─────────┐ │ │ │ Human │ responds via dashboard / Slack / email │ │ └─────────┘ │ └─────────────────────────────────────────────────────────────┘

Interactive Demos

13 fully interactive HTML demos showing A2H in action across real-world scenarios. Each demo simulates the full agent-human interaction flow with live UI.

Core

A2H Protocol Demo

The foundational demo — all 6 response types, escalation chains, auto-delegation, and state-aware routing in a single interactive experience.

All response typesEscalationDelegation
Industry

Call Center

Live call routing with agent availability states, queue management, CSAT tracking, and escalation to supervisors.

State routingQueueCSAT
Trust & Safety

Content Moderation

AI flags content, humans make the final call. Priority queues, confidence scores, and policy-based auto-actions.

ApprovalPriority queueAuto-action
Engineering

AI Code Review

AI reviews PRs, flags security issues, and escalates critical findings to senior engineers for approval.

Severity tiersEscalationApproval
SRE

Incident Response

War room simulation with real-time metrics, automated runbooks, and escalation chains from on-call to VP Engineering.

War roomRunbooksEscalation
Finance

Expense Approval

Tiered approval workflows with auto-delegation rules. Under $500? Auto-approved. Over $10K? CFO escalation.

Auto-delegationTiered approval
HR

Hiring Pipeline

AI screens candidates, hiring managers make decisions. Structured forms for feedback, interview scheduling, and offers.

FormChoiceApproval
Compliance

Compliance Review

Regulatory checks with AI pre-screening, human sign-off, and audit trails for SOX/GDPR requirements.

Audit trailSign-offEscalation
Legal

Legal Review

Contract analysis with AI clause extraction, risk scoring, and attorney approval workflows.

Risk scoringApprovalClauses
Marketing

Marketing Approval

Campaign and creative approval with brand compliance checks, A/B variant selection, and budget sign-off.

ChoiceBrand checkBudget
Healthcare

Patient Care

Clinical decision support with AI triage, physician confirmation, and medication approval chains.

ConfirmPriorityEscalation
Real Estate

Real Estate

Property matching with client preference forms, showing scheduling, and offer approval workflows.

FormMatchingApproval
Operations

Supply Chain

Inventory and procurement decisions with demand forecasting, reorder approvals, and supplier selection.

NumberChoiceAuto-delegation
View on GitHub — Apache 2.0