A2B STANDARD CONTRACT

Declare what agents can do in existing business systems.

ACC gives APIs a common way to describe agent-visible operations, acting subjects, risk levels, approval intent, rate limits, sensitive fields, examples, and audit metadata.

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Release history and compatibility notes

ACC controls reach. The business system controls authority.

capability declaration x-agent-capability

Business API Existing System Orders, refunds, staff, inventory

ACC Capability Contract scope, risk, subject, approval

Runtime Compatible Runtime policy, governance, audit, trace

x-agent-capability:
  version: 1
  enabled: true
  scope: refund.create
  subject:
    required: true
  risk:
    level: high
  approval:
    required: true

ACC is not a chatbot framework, workflow product, or runtime. It is a portable declaration contract that different gateways, SDKs, control planes, and agent runtimes can implement.

WHERE ACC FITS

A portable declaration layer, not another all-in-one platform.

ACC complements interface descriptions, transport protocols, runtime controls, policy engines, workflows, and business authorization. It gives those systems a common way to understand the governance meaning of an agent-visible business operation.

Explore the ecosystem landscape and FAQ

Agent applications Orchestration and user intent Agent frameworks, assistants, workflows

Interface and transport Describe, discover, and invoke OpenAPI, MCP, A2A

ACC Declare operation-level governance meaning scope, risk, subject, approval, audit, execution

Runtime enforcement Evaluate and enforce local policy Gateways, control planes, runtime hooks, policy components

Business authority Make the final decision and effect Identity, authorization, workflow, data integrity

SPECIFICATION

One contract, multiple implementation styles.

ACC keeps capability metadata next to the API contract, while authorization and final business decisions stay inside the business system.

Capability Scope

Declare what operation an agent may see and which scenario may use it.

Acting Subject

Mark operations that require a real user, employee, tenant, or business actor.

Risk and Approval

Expose risk level and human approval intent without replacing business authority.

Audit Metadata

Preserve examples, sensitive fields, confirmation rules, and extension metadata.

EXAMPLES

Attach ACC to OpenAPI.

The first ACC binding is the OpenAPI extension field. It is readable by humans, verifiable by tools, and portable across control planes.

openapi.yaml

paths:
  /refunds:
    post:
      x-agent-capability:
        version: 1
        enabled: true
        scope: refund.create
        risk:
          level: high
        approval:
          required: true
          when:
            - param: amount
              op: ">"
              value: 1000
        subject:
          required: true

IMPLEMENTER ECOSYSTEM

Build independently. Register with evidence.

ACC can be implemented by control planes, API gateways, SDK generators, MCP gateways, policy engines, and audit tools. No implementation defines the standard or receives privileged compatibility status.

Open registration Self-assessment + evidence

Choose a Parser, Generator, Runtime, or Policy Component profile. Publish supported fields, limitations, tests, and a dated self-assessment, then submit the implementation to the neutral public registry. Read the implementer path.