Description

Quick reference for terms and abbreviations used in ERC-8004 Offchain Standards

Abbreviations

A

A2A - Agent-to-Agent Protocol
Communication protocol enabling direct agent-to-agent interactions and collaborations.
Specification

Arweave (AR) - Permanent decentralized storage network
Uses ar:// URI scheme

C

CAIP - Chain Agnostic Improvement Proposal
Standards for blockchain-agnostic identifiers

CAIP-2 - Blockchain ID format (namespace:chainId)
Example: eip155:1 for Ethereum Mainnet

CAIP-10 - Account address format (namespace:chainId:address)
Example: eip155:1:0x742d35...

CID - Content Identifier
Unique hash-based identifier used in IPFS
Example: bafkreiabc... (CIDv1)

E

EIP - Ethereum Improvement Proposal
Process for proposing standards to Ethereum ecosystem

ERC - Ethereum Request for Comments
Standards track within EIP process (e.g., ERC-20, ERC-721, ERC-8004)

ERC-8004 - Trustless Agents Standard
NFT-based standard for AI agent identity, reputation, and validation

G

Groth16 - Type of zkSNARK proof system
Widely used zero-knowledge proof construction, efficient verification

I

IANA - Internet Assigned Numbers Authority
Organization that maintains official MIME type registry

IPFS - InterPlanetary File System
Content-addressed, peer-to-peer file system
Uses ipfs:// URI scheme

ISO 8601 - International date and time format standard
Example: 2025-12-21T14:30:00Z

J

JSON - JavaScript Object Notation
Text-based data format used for all offchain metadata

K

Keccak-256 - Cryptographic hash function
Used for content hashing in Ethereum (produces bytes32 output)

M

MCP - Model Context Protocol
Protocol for AI agents to expose tools, prompts, and resources
Specification

MIME Type - Multipurpose Internet Mail Extensions
Standard for indicating file type (e.g., application/json, image/png)

N

NFT - Non-Fungible Token
Unique token standard (ERC-721), used for agent identity in ERC-8004

O

OASF - Open Agent Skills Framework
Taxonomy for categorizing agent capabilities and domains.
Specification

OASF Domain - High-level field of operation
Categories like finance_and_business, healthcare_and_medicine, technology_and_engineering.
See: OASF Domain Taxonomy

OASF Skill - Specific capability an agent possesses
Hierarchical paths like analytical_skills/data_analysis, communication_skills/content_creation.
See: OASF Skills Taxonomy

P

PLONK - Type of zkSNARK proof system
More flexible than Groth16, supports universal setup

R

RFC 2119 - Key words for requirement levels
Defines MUST, SHOULD, MAY, etc. for specification documents

S

SemVer - Semantic Versioning
Version numbering scheme (MAJOR.MINOR.PATCH)

STARK - Scalable Transparent Argument of Knowledge
Type of zero-knowledge proof, post-quantum secure

T

TEE - Trusted Execution Environment
Hardware-based secure computation (e.g., Intel SGX, ARM TrustZone)

U

URI - Uniform Resource Identifier
Generic identifier for resources (includes URLs)
Schemes: https://, ipfs://, ar://, data:

URL - Uniform Resource Locator
Subset of URI using http:// or https:// schemes

UTC - Coordinated Universal Time
Standard time zone (offset +00:00), required for all timestamps

X

x402 - Payment protocol for AI agents
Protocol for agent payment proofs referenced in feedback records

Z

zkML - Zero-Knowledge Machine Learning
Techniques for proving ML model execution without revealing model weights

zkSNARK - Zero-Knowledge Succinct Non-Interactive Argument of Knowledge
Cryptographic proof system enabling verification without revealing inputs
Types include Groth16, PLONK, STARK, Halo2

Key Terms

AgentURI

Offchain metadata URI referenced by ERC-8004 Identity Registry NFTs. Points to JSON containing agent identity, endpoints, and capabilities.

See: Agent Metadata Standard

Attachment Pattern

Standardized schema for including evidence files in feedback and validation records. Defines fields like name, uri, mimeType, size.

See: Attachment Pattern Standard

Base Sepolia

Ethereum Layer 2 testnet (chainId: 84532). Used extensively in 8004scan production data.

Compatibility Levels

Three-level system for classifying offchain data formats:

• Level 1: ERC-8004 Standard (recommended)
• Level 2: Known Custom Formats (recognized)
• Level 3: Unknown Formats (stored as-is)

See: Validation Standard - Format Compatibility

Data URI

URI scheme for embedding data inline: data:[mediatype][;base64],<data>

Example: data:application/json;base64,eyJuYW1lI...

Feedback Authorization

Two-step process for creating feedback:

1. Client requests permission via agent endpoint
2. Agent provides signature (feedbackAuth) authorizing feedback

See: Feedback Standard

Identity Registry

ERC-8004 smart contract managing agent NFTs and metadata URIs. Core component for agent registration.

Normative vs Non-normative

Normative: Defines requirements (MUST/SHOULD/MAY)
Non-normative: Provides informative guidance, examples, or rationale

Marked with: > **Non-normative**: ...

Offchain Data

JSON metadata stored off-blockchain (IPFS, HTTPS) and referenced by URIs in smart contracts.

Contrasts with onchain data: data stored directly in contract state.

Parse Status

Classification of how well offchain data conforms to standards:

• success - Perfect compliance
• warning - Minor issues, still usable
• known_custom - Recognized custom format
• unknown - Unrecognized format

Reputation Registry

ERC-8004 smart contract managing feedback records and reputation scores for agents.

Validation Registry

ERC-8004 smart contract managing validation requests and responses (proofs, attestations).

Validation Type

Category of validation method:

• crypto-economic - Economic incentive based
• tee-attestation - Hardware-secured proof
• zkml-proof - Zero-knowledge ML proof

See: Validation Standard

Protocol References

MCP (Model Context Protocol)

Current Version: 2025-06-18
Specification: https://modelcontextprotocol.io/

Standard for AI agents to expose:

• Tools: Callable functions
• Prompts: Pre-defined prompt templates
• Resources: Data sources and context

A2A (Agent-to-Agent)

Current Version: 0.3.0
Specification: https://a2a.to/

Protocol for agent discovery, capability negotiation, and communication.

OASF (Open Agent Skills Framework)

Current Version: v0.8.0
Repository: https://github.com/agntcy/oasf/

Hierarchical taxonomy for agent:

• Skills: What agents can do (e.g., analytical_skills/data_analysis)
• Domains: What fields they operate in (e.g., finance_and_business)

x402

Payment protocol for AI agents. Enables proof of payment in feedback records.

Fields:

• fromAddress, toAddress (CAIP-10)
• txHash, amount, currency
• protocol: "x402"

Chain Identifiers

Common chain IDs using CAIP-2 format:

Blockchain	CAIP-2 Format	Chain ID
Ethereum Mainnet	eip155:1	1
Sepolia Testnet	eip155:11155111	11155111
Base Mainnet	eip155:8453	8453
Base Sepolia	eip155:84532	84532
Polygon PoS	eip155:137	137
Arbitrum One	eip155:42161	42161
Optimism	eip155:10	10

MIME Types

Common MIME types used in attachment patterns:

File Type	MIME Type
JSON	application/json
PDF	application/pdf
PNG	image/png
JPEG	image/jpeg
SVG	image/svg+xml
Plain Text	text/plain
CSV	text/csv
MP4 Video	video/mp4
ZIP Archive	application/zip

Custom formats: application/x-<format> (e.g., application/x-groth16-proof)

External References

• EIP-8004: https://eips.ethereum.org/EIPS/eip-8004
• RFC 2119: https://www.rfc-editor.org/rfc/rfc2119
• CAIP-2: https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-2.md
• CAIP-10: https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-10.md
• ISO 8601: https://www.iso.org/iso-8601-date-and-time-format.html