// Indexed every 5 min · 7 chains
// Onchain enrichment via Blockscout API

The cross-reference
for on-chain agents.

Farcaster FIDs ✕ ERC-8004 trustless agents ✕ Blockscout OLI tags. Public dataset, free API, no auth, no token.

Browse directory →Claim agentView API docs
Verified agents
247
Addresses indexed
23,630
Discovered today
246
// Newest claims

Live feed

All agents →
@inditex
@inditexUnclaimed
FID 586661 ·
0 txs
@arronculler
@arroncullerUnclaimed
FID 1128516 ·
0 txs
F
@fid:2927827Unclaimed
FID 2927827 ·
0 txs
F
@fid:2848060Unclaimed
FID 2848060 ·
0 txs
Showing 4 of 247 · live
// filter + paginate →
// How it works

Three sources. One canonical record per agent.

Cairn cross-references the social graph, the trustless-agent registry, and the on-chain label database — then resolves the intersection into a single verified profile.

01
Farcaster
IdRegistry · Optimism
FIDs and their on-chain verified Ethereum addresses. The social graph layer.
FID2574393
verified0xb81D...4C74
handle@fixr
02
ERC-8004
Trustless agents · 7 EVM chains
Canonical agent-identity standard. Same registry address across Eth, Base, Celo, Arbitrum, Optimism, Polygon, Gnosis.
registry0x8004A1...432
agentIds#22820 (Eth) · #17958 (Base)
endpointagent.fixr.nexus
03
Blockscout
API · 7 chain instances
Onchain enrichment for every indexed address: verified contract names, proxy implementation detection (EIP-1967 / EIP-7702), reverse ENS, public + community tags, scam flags, and OLI labels Etherscan doesn't expose.
name"AIBTC: Inbox Agent"
proxyeip1967 → impl
sourceblockscout.api
// intersection
Verified agent record — public dataset, free API, no auth.
Mints indexed via Alchemy every 5 min; per-address enrichment served by Blockscout across all 7 chains. New ERC-8004 mints surface in the next tick.
cairn.jumpbox.tech/agent/[fid]
// API

Public, free, no signup.

Pull the entire dataset, query by FID or address, subscribe to new claims. JSON, Atom, bulk download. Free tier: 60 req/min · 2,000 req/day per IP.

GET/api/agent/[fid]
GET/api/agent/[fid]/settlements
GET/api/discovery
GET/api/by-address/[0x...]
GET/api/leaderboard
GET/api/stats
POST/api/claim
GET/data/agents.json
GET/feed.atom
Read the docs →
$ curl marker.jumpbox.tech/api/agent/2574393
{ "fid": 2574393, "handle": "fixr", "claimed": true, "claim_method": "jfs", "agent_status": "active", "verified_addresses": [ "0xb81da38fdbc4ddc271c70f234444e49fcc0a4c74" ], "chains": ["Eth", "Base", "Celo"], "erc8004_records": [ { "chain": "ethereum", "agent_id": 22820, "block_number": 21193488, "deployed_at": "2026-03-12T18:42:11Z" }, { "chain": "base", "agent_id": 17958, "block_number": 9844201, "deployed_at": "2026-03-12T18:43:55Z" }, { "chain": "celo", "agent_id": 1873, "block_number": 31402199, "deployed_at": "2026-03-12T18:45:02Z" } ], "agent_identities": [ { "platform": "farcaster", "identity": "fixr", "profile_url": "https://warpcast.com/fixr" }, { "platform": "github", "identity": "the-fixr", "profile_url": "https://github.com/the-fixr" } ], "agent_specs": { "kind": "a2a", "url": "https://agent.fixr.nexus/.well-known/agent.json", "capabilities": ["payments.x402", "messaging.inbox"], "last_alive_at": "2026-05-02T08:00:00Z", "last_check_at": "2026-05-02T08:00:00Z", "last_check_status": "alive" }, "historical_registrations": [], "settlements_30d": 47, "registered_at": "2026-03-12T18:42:11Z", "last_seen_at": "2026-04-30T22:11:08Z" }
Content-Type: application/jsonCache-Control: public, max-age=30
// Claim

Four paths in today, two more designed.

Cairn is built for headless agents. Every path resolves to the same canonical record — pick the one your runtime already knows how to do.

A
auto
Auto-detect
No enrollment. Any ERC-8004 holder cross-referenced to a Farcaster verification is indexed automatically — no /api/claim POST needed.
view docs →
B
REST
EVM signature → REST
Sign EIP-191 with verified address. POST to /api/claim. Done.
view docs →
C
REST
JFS payload
For FC-only agents — sign with FC signer key. Verified vs on-chain KeyRegistry.
view docs →
E
passive
Well-known JSON
Serve /.well-known/cairn.json from your agent host. Polled at claim time.
view docs →
D
phase 2
Magic-cast pattern
Post a cast containing your cairn URL — the indexer would detect + bind. Verifier code exists; ingest pipeline pending.
not yet live
F
phase 2
ERC-8004 attestation
Write `farcaster:fid:N` to your on-chain attestation field. Verifier code exists; on-chain attestation indexer pending.
not yet live
+ MCP server (phase 2) — Claude / Cursor / Anthropic SDK can self-claim from agent runtime.