Arc Market MCP

An MCP server that reads live market state on Arc — Circle's L1 (chainId 5042) — through the BABA Capital Arc Data API.

Circle publishes an Arc MCP, but it serves documentation. This one reads chain state:

• arc_launchpads — launchpad concentration (HHI), pools created, v3 vs v4 launch counts, distinct deployer callers, and per-launchpad share / graduations / dead-on-arrival.

• arc_lp_apr — realised range-APR for LP pools from the latest scan (filter by pair / venue / range).

• arc_rpc_consensus — how many of Arc's four public RPCs agree this block, before you trust a figure.

• arc_token_screen — a launched token's USDC pool, fee, recent swap count, why that pool was selected, and the simulated round trip.

• arc_token_sellsim — a simulated round trip: buy, then sell, against current chain state, reporting the round-trip fraction recovered. Not a heuristic — an actual simulation.

• arc_pool_decoy — for one v4 poolId: its fee, the fee cap applied, and which rule placed it (selected, fee above the cap, untraded, or less traded than the selected pool).

• arc_rpc_consensus, arc_health, arc_agent_card — trust, liveness, and identity.

BridgeCheck — is this Circle's bridge contract, and where will the USDC land?

• bridgecheck — on Arc, Base, Ethereum or HyperEVM: give an address, a mined transaction, or an unsigned transaction (to + data). MATCH only when the address is the one Circle publishes for that chain and its live code, EIP-1967 implementation and admin equal the values pinned from Circle's pages (read on two RPCs). Circle's proxy code is generic, so the same code at another address is NO_MATCH. Also decodes the destination chain, mint recipient (same as you / different), destination caller, max fee and approval size, and says in plain words what happened, e.g. "The contract you're calling is not Circle's. The burn inside is Circle's. Recipient: same as you." Other statuses: IMPLEMENTATION_CHANGED, ADMIN_CHANGED, NOT_DECODED, NO_DATA. Every answer lists what it did not check.

Agent Directory — who is actually on Arc

337 agents (crawl of 2026-09-29 12:47 UTC) are registered in the ERC-8004 registry on Arc and nothing else lets you see who they are. Circle builds the rails; this is the phone book.

• arc_agents_list — every registered agent: agentId, owner, agentURI, host, name, skills, validation status, and how concentrated its host and owner are.

• arc_agent_get — one agent in full, including the raw card as served and a validation report giving the evidence for every flag, so you can check the directory rather than trust it.

• arc_agents_search — "find me an Arc agent that does X and that I can pay."

• arc_agents_stats — the registry's shape in one call.

Two things worth knowing, both measured rather than assumed:

• x402=true is much narrower than payment=true. Most of this registry prices in USDC via ERC-8183 settlement, which is not x402. Each match carries the exact key and value that prove it.

• The registry is concentrated. The largest host holds 115 of 337 ids (34.1%) and the largest owner holds 100 (29.7%). The directory publishes those counts and lets you draw the conclusion — it attaches no label or rating to any agent, because a directory that editorialises is worth nothing.

A card that will not resolve is listed as UNRESOLVED, never quietly dropped; a partial crawl comes back NO_DATA with coverage naming the ids it could not reach. BABA Capital operates agentIds 135 and 136; they are listed on the same terms as everyone else and get no ranking advantage.

Honesty model (read this)

Every data route returns one envelope:

{ "chain": "arc", "chainId": 5042, "asof": "…", "head": 123, "status": "OK|NO_DATA|REFUSED",
  "coverage": {…}, "rpc_consensus": true, "data": {…}, "warnings": [], "source": "…", "version": "…" }

• NO_DATA is never a zero. A missing or partial reading returns status: "NO_DATA", not an empty success. Absence of a signal is stated, never disguised as a value of the signal.

• REFUSED means the API declined (e.g. fewer than 2 of 4 RPCs agreed). The reading was not cross-checked; weigh it accordingly.

• This server passes the envelope through unchanged. It never unwraps data and hides the status.

This is a read-only client. It holds no private key, signs nothing, and moves no funds. This is a software tool that reports chain reads. A passing sell-simulation is a snapshot at one block, not a guarantee.

Related MCP server: @arcnow/mcp

Install

Runs over stdio via npx — no global install needed.

npx arc-market-mcp

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "arc-market": {
      "command": "npx",
      "args": ["-y", "arc-market-mcp"]
    }
  }
}

Configuration

Pricing

The Arc Data API's free tier is 20 calls/day/IP. Paid calls settle in USDC over Circle Gateway x402 on Arc (eip155:5042). This package is the reader; payment, when required, is negotiated by the API's 402 response. The reader never holds funds or keys.

Identity (ERC-8004)

BABA Capital's Arc agents publish ERC-8004 agent-cards at https://babacapital.app/.well-known/agents/ — baba-arc-data and baba-arc-yield. Fetch one with arc_agent_card. agentId is null until on-chain registration completes.

Build from source

npm install
npm run build
npm test
node dist/index.js

Provenance

This repository is standalone. Its git history begins on 2026-09-17; it shares no history with any other BABA Capital repository.

License

MIT © 2026 BABA Capital