Specification / Entity Kinds

11 Entity Kinds

Every participant in the agent ecosystem has a typed identity. Entity kinds determine lineage requirements, trust properties, and permitted operations.

Scroll to meet each one

hmr
01 / 12
hmr

Human Managed Resource

The root of all trust. Represents an individual human identity. Every lineage chain in OAS terminates at an HMR. Without a human root, no agent can be verified.

Lineage

Self-rooted. No parent required.

mhr
02 / 12
mhr

Multi-Human Root

Collective identity governed by multiple humans via FROST threshold signatures. Requires M-of-N signers to authorize actions. Shared control for organizations.

Lineage

Requires 2+ HMR co-signers.

enr
03 / 12
enr

Enterprise Root

Organizational identity governed by an MHR group or a single HMR. Represents a legal or operational entity such as a company, department, or project.

Lineage

Parent must be hmr or mhr.

ao
04 / 12
ao

Autonomous Organization

Self-governing entity with DID-based governance. Operates independently within delegated authority. Internal decision-making without human approval for routine operations.

Lineage

Parent must be enr or mhr.

agent
05 / 12
agent

Agent

Autonomous software agent with a cryptographic lineage proof binding it to a human root. The primary operational entity. Performs tasks, calls tools, and communicates.

Lineage

Requires AgentLineageProof2025.

agent:instance
06 / 12
agent:instance

Agent Instance

A running instance of an agent with ephemeral state. Distinguished from the agent definition to track concurrent executions. Session keys and independent lifecycle.

Lineage

Inherits from parent agent.

tool
07 / 12
tool

Tool

A callable capability exposed by an agent or service. Tools have typed input/output schemas, access policies, and usage metering. The unit of agent interaction.

Lineage

Parent must be agent or service.

skill
08 / 12
skill

Skill

A composable behavioral module attachable to agents. Defines reusable capabilities: reasoning strategies, domain knowledge, or interaction patterns. Hot-swappable.

Lineage

Parent must be agent or enr.

workflow
09 / 12
workflow

Workflow

An orchestrated sequence of agent actions with control flow, error handling, and compensation logic. Coordinates multi-agent collaboration and complex task execution.

Lineage

Parent must be agent, ao, or enr.

model
10 / 12
model

Model

An AI/ML model with full provenance tracking. Captures training data lineage, architecture, hyperparameters, and evaluation metrics. Enables reproducibility and trust scoring.

Lineage

Parent must be agent, enr, or hmr.

dataset
11 / 12
dataset

Dataset

Training or evaluation data with cryptographic lineage. Tracks origin, transformations, access policies, and usage history. Critical for model trust and compliance.

Lineage

Parent must be enr or hmr.

service
12 / 12
service

Service

A long-running infrastructure endpoint with a stable DID. Provides persistent APIs, message buses, or data stores. Uptime SLAs and health monitoring.

Lineage

Parent must be enr or ao.

Trust Hierarchy

hmr mhr enr ao agent agent:instance

Every chain terminates at a human root. Tools, skills, workflows, models, datasets, and services attach to entities within the chain.