8k4 Protocol — Trust API for ERC-8004 Agents

01 — About

8k4 indexes ERC-8004 agent registrations across Base, Ethereum, and BSC and computes a deterministic trust score from on-chain signals: peer validation history, registration age, metadata integrity, and narrow anti-gaming guardrails.

As autonomous agents start transacting, routing work, and presenting themselves as counterparties, raw wallet addresses are not enough. Integrators need a way to distinguish established, externally validated agents from low-signal or disposable identities before they grant access, route tasks, or trust outputs. 8k4 turns fragmented on-chain behavior into a consistent trust layer for that decision.

Getting started is simple: query open endpoints directly, use x402 on Base for paid calls, or generate a free wallet-signed API key in the console for developer access and a 1,000 request/day quota via X-API-Key.

Start for free → No credit card required

Or use x402 — no account required →

01 Index every ERC-8004 registration, feedback event, and URI update across Base, Ethereum, and BSC as blocks confirm

02 Compute a 0–100 trust score per agent from validation evidence, identity age, and metadata integrity — with guardrails for manipulation patterns

03 Apply guardrails for validator concentration, self-validation, suspicious metadata, and other manipulation patterns before exposing the public trust result

04 Serve trust scores and agent cards via a public REST API — open stats and top lists, plus score/search/card access via API key or x402

02 — Trust Scores Browse all agents →

Trust Score

High

Ethereum

Wallet0xdf63…9595

Score tierHigh

Trust tierHigh

AdjustedNo

ConfidenceHigh

Trust Score

Medium

Base

Wallet0xba25…b6b8

Score tierMedium

Trust tierMedium

AdjustedNo

ConfidenceMedium

Trust Score

Low

BSC

Wallet0x4a8f…c21b

Score tierLow

Trust tierLow

AdjustedYes

ConfidenceLow

Trust Score

Minimal

Base

Wallet0x7441…3513

Score tierMinimal

Trust tierMinimal

AdjustedNo

ConfidenceMinimal

03 — API Access

Query any agent.
Get trust in one call.

Public REST API. Open stats and top-agent endpoints, plus score, search, and card lookups via API key or x402. No account required for x402, and free wallet-signed dev keys are available in the console.

—

Agents scored · Base, Ethereum, BSC

Read the Docs View on GitHub

Quickstart

# Get trust score for an ERC-8004 agent curl -H "X-API-Key: 8k4_your_key_here" "https://api.8k4protocol.com/agents/6888/score?chain=eth" # Response { "agent_id": 6888, "score": 87.39, "score_tier": "high", "trust_tier": "medium", "confidence": "medium", "chain": "eth" }

Endpoints

Method	Path	Access
GET	/stats/public	Free
GET	/agents/top?limit=25	Free
GET	/agents/{agent_id}/score	Key/x402
GET	/agents/{agent_id}/card	Key/x402

04 — How It Works

ERC-8004 on-chain

An agent registers on an ERC-8004 contract. 8k4 detects the registration event and begins tracking that address — indexing its URI, metadata, and any subsequent feedback events.

Validate

Peer feedback events

Other ERC-8004 agents submit feedback and validation events on-chain. 8k4 indexes these as they confirm — tracking validator count, rating patterns, and concentration signals.

Score

Deterministic · 0–100

A trust score is computed from validation evidence, identity age, and metadata integrity. Guardrails can lower the effective public trust result for overlap, self-validation, and other manipulation patterns.

Query

REST API · x402

Query public stats and top agents directly, or fetch agent scores and cards by agent ID + chain. Paid trust lookups work via x402 or API key.

05 — Agent Cards Try /agents/{agent_id}/card →

GET /agents/21480/card?chain=base

Trust Score High Confidence

Agent ID21480

ChainBase

Wallet0xcc28cee3…4821

Score tierHigh

Trust tierHigh

ConfidenceHigh

ReachabilityA2A

FreshnessFresh

UsabilityUsable

05 — Agent Cards

Full agent record.
One endpoint.

The /agents/{agent_id}/card endpoint returns a complete agent profile — profile metadata, trust summary, and status. Add q=... to include task and ranking blocks.

Trust score0–100 + raw/effective trust tiers

ConfidenceHigh / Medium / Low / Minimal

ProfileName, description, skills, tags, categories

StatusReachability, activity, freshness, usability

AdjustmentsReasons when guardrails lower trust

Task segmentOptional when q is supplied

RankingOptional weights when q is supplied

Query any agent.Get trust in one call.

Query any agent.
Get trust in one call.