TAP — Trustless Agents Plus

One canonical identity. One aggregated reputation score. Across every chain.

TAP extends ERC-8004 with cross-chain identity unification and reputation aggregation for on-chain AI agents. It lives on Push Chain and works with existing ERC-8004 agents on any supported chain — no migration required.

The Problem

An ERC-8004 agent on 3 chains has 3 separate token IDs, 3 separate reputation scores, and zero on-chain proof they belong to the same entity.

ERC-8004 Agent vs TAP Agent

How TAP Fixes It

	ERC-8004	TAP (Trustless Agents Plus)
Identity	Per-chain token ID, no cross-chain link	One canonical ID across all chains, linked via EIP-712 bindings
Reputation	Per-chain score, no aggregation	Aggregated score (0-10,000 bps) combining quality, volume, diversity
Transferability	Transferable ERC-721	Soulbound (non-transferable)
Cross-chain proof	Off-chain registrations[] array (self-asserted)	On-chain binding with cryptographic proof (ECDSA / ERC-1271)
Slashing	None	Persistent cross-chain slash penalties
Multi-chain reads	Query each chain separately	canonicalOwnerFromBinding() resolves any per-chain ID to canonical owner

Architecture

Per-chain ERC-8004 registries            Push Chain (Settlement)
+------------------+                    +---------------------------+
| Ethereum         | --bind (EIP-712)-> |        TAPRegistry        |
| boundAgentId=17  |                    |   canonical soulbound ID  |
+------------------+                    |   UEA-anchored, 7-digit   |
| Base             | --bind (EIP-712)-> |                           |
| boundAgentId=42  |                    +---------------------------+
+------------------+                    |   TAPReputationRegistry   |
| BSC              | --bind (EIP-712)-> |   aggregated score (bps)  |
| boundAgentId=8   |                    |   per-chain breakdowns    |
+------------------+                    +---------------------------+

TAPRegistry — Canonical identity layer. Agents register once via their UEA (Universal Executor Account) on Push Chain. agentId is deterministic: uint256(uint160(ueaAddress)) % 10_000_000. Per-chain ERC-8004 identities are linked via bind() with EIP-712 signed proofs. Owner-level dedup ensures the same wallet on different source chains resolves to one identity.

TAPReputationRegistry — Cross-chain reputation aggregator. Authorized reporters submit per-chain reputation snapshots validated against TAPRegistry bindings. Score formula: (baseScore * volumeMultiplier / 10000) + diversityBonus - slashPenalty, output in [0, 10,000] bps.

Quick Start

Build a TAP agent in minutes with the CLI scaffolding tool:

npx create-8004-tap-agent

See create-8004-TAP-agent for the full CLI reference — scaffold, register, bind, and query TAP profiles from any supported chain.

Supported Chains

TAP agents can register and bind from any of these chains. Agents pay gas in their native token — Push Chain's fee abstraction handles the rest.

EVM Chains (Testnet)

Chain	Chain ID	CAIP-2	ERC-8004 IdentityRegistry	Push Gateway
Ethereum Sepolia	11155111	eip155:11155111	0x8004A818BFB912233c491871b3d84c89A494BD9e	0x05bD7a3D18324c1F7e216f7fBF2b15985aE5281A
Base Sepolia	84532	eip155:84532	0x8004A818BFB912233c491871b3d84c89A494BD9e	0xFD4fef1F43aFEc8b5bcdEEc47f35a1431479aC16
BNB Testnet	97	eip155:97	0x8004A818BFB912233c491871b3d84c89A494BD9e	0x44aFFC61983F4348DdddB886349eb992C061EaC0

Push Chain (Settlement)

Chain	Chain ID	RPC
Push Chain Donut (testnet)	42101	https://evm.donut.rpc.push.org/

Deployed Contracts

Push Chain Donut Testnet (Chain ID: 42101)

Contract	Proxy Address	Explorer
TAPRegistry	0xa2B09263a7a41567D5F53b7d9F7CA1c6cc046CE2	View
TAPReputationRegistry	0x591A56D98A14e8A88722F794981F00CabB328a91	View

Full address book (implementations, proxy admins, roles): docs/addresses/tap_address_book.md

Build and Test

forge build                    # compile
forge test                     # all tests (unit, binding, fuzz, integration)
forge test -vv                 # verbose output
forge test --gas-report        # with gas reporting
forge fmt                      # format

Integration tests auto-skip unless run against Push Chain Donut testnet:

forge test --match-path test/TAPRegistry.integration.t.sol \
    --fork-url $PUSH_CHAIN_RPC -vv

Deploy

# TAPRegistry
DEPLOYER_KEY=0x... forge script script/deploy/Deploy.s.sol \
    --rpc-url $PUSH_CHAIN_RPC --broadcast

# TAPReputationRegistry (requires existing TAPRegistry proxy)
TAP_REGISTRY_PROXY=0x... INITIAL_REPORTER=0x... INITIAL_SLASHER=0x... \
    forge script script/deploy/DeployReputation.s.sol \
    --rpc-url $PUSH_CHAIN_RPC --broadcast

Documentation

Document	Description
docs/TAPRegistry.md	Full TAPRegistry spec — registration, binding, storage, function reference
docs/TAPReputationRegistry.md	Reputation aggregation — scoring formula, slashing, reporter model
docs/addresses/tap_address_book.md	TAP contract addresses and deployment history
docs/addresses/ext_address_book.md	External dependencies — UEA Factory, ERC-8004 registries, gateways

Repository Layout

src/
  TAPRegistry.sol                  # Canonical identity (registration, binding, soulbound ERC-721)
  TAPReputationRegistry.sol        # Cross-chain reputation aggregation and scoring
  interfaces/
    ITAPRegistry.sol               # TAPRegistry interface
    ITAPReputationRegistry.sol     # TAPReputationRegistry interface
    IUEAFactory.sol                # Push Chain UEA Factory interface
  libraries/
    Types.sol                      # Shared types (UniversalAccountId)
    RegistryErrors.sol             # Custom errors for TAPRegistry
    ReputationErrors.sol           # Custom errors for TAPReputationRegistry
test/                              # Unit, binding, fuzz, integration tests
script/
  deploy/                          # Deployment scripts
  upgrade/                         # Upgrade scripts
  demo-track-1/                    # Direct Push Chain demo scripts
  demo-track-1_a/                  # Cross-chain via Universal Gateway demo scripts

License

MIT