Crosswire — Polymarket & Kalshi Arbitrage MCP Server

by crosswire-api Your server? Claim it

answering

Crosswire — Polymarket & Kalshi Arbitrage is answering right now. Last checked 7 min ago. It exposes 2 tools. Last commit 21 Jun 2026.

Cross-venue Polymarket+Kalshi arbitrage: resolution mismatch, void risk & settlement divergence.

Uptime history 48 days of history

48 days agonow

100.0%

Uptime 24h

92 of 92 checks

Tools

read from the server

416 ms

Response time

average over 24h

Stars

last commit 21 Jun 2026

What changed 1

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 14 August 2026. No other catalogue keeps this.

14 Aug a tool changed version

Nothing serious here today

Today is the operative word: we check Crosswire — Polymarket & Kalshi Arbitrage every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 7 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add crosswire-polymarket-kalshi-arbitrage --transport http https://api.crosswire-api.com/mcp

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "crosswire-polymarket-kalshi-arbitrage": {
      "url": "https://api.crosswire-api.com/mcp"
    }
  }
}

~/.codex/config.toml

[mcp_servers.crosswire-polymarket-kalshi-arbitrage]
url = "https://api.crosswire-api.com/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "crosswire-polymarket-kalshi-arbitrage": {
      "url": "https://api.crosswire-api.com/mcp"
    }
  }
}

.vscode/mcp.json

{
  "mcpServers": {
    "crosswire-polymarket-kalshi-arbitrage": {
      "url": "https://api.crosswire-api.com/mcp"
    }
  }
}

Available tools 2

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

covered

list_covered_events

Free discovery of everything check_resolution_risk can audit across both inventories — the free World Cup football pairs and the metered crypto oracle-divergence pairs (the 'crypto:' namespace is the paid surface: $0.02 USDC per call after 3 free calls/day). Returns the covered canonical events, their per-outcome pair ids (…#home / #draw / #away for football), the Polymarket conditionIds and Kalshi tickers with outcome labels for each pair, match dates, the frozen ruleset_sha pinning the identity graph, the coverage kickoff cutoff, and snapshot freshness. Use a returned pair_id (or a pair's two market ids) as input to check_resolution_risk.

resolution

check_resolution_risk

Pre-trade safety check for cross-venue event markets (crypto oracle-divergence pairs, metered; World Cup football, free). Flags resolution mismatches, void-rule divergence, scope differences (e.g. 90-minute vs extra-time; matched vs differing strike), settlement-source and -timing gaps, stale data, and thin liquidity between the two Polymarket and Kalshi legs BEFORE you execute both. Returns a machine-readable verdict — execution_verdict: safe / caution / block — inside a full Fungibility & Settlement Audit Object (FSAO) with structured findings, top-level divergence flags, venue rule overrides, fee-adjusted spread, and verdict reasons. Identify the pair by EITHER canonical_event_id (a live pair id from list_covered_events — the metered 'crypto:' inventory rolls daily, so fetch a current id there rather than reusing an old one; the free 'wc26:' World Cup pairs are stable) OR market_a + market_b (one Polymarket conditionId + one Kalshi ticker, order-insensitive). If the pair is not covered, returns a non-error coverage reply (covered: false) naming the covered inventories (free World Cup football + metered crypto pairs) and the coverage cutoff instead of an FSAO.

Endpoints

URL	Transport	State	Latency	Checked
https://api.crosswire-api.com/mcp	streamable-http	answering	495 ms	7 min ago

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Crosswire — Polymarket & Kalshi Arbitrage — questions

Answers built from our own checks of this server.

What can Crosswire — Polymarket & Kalshi Arbitrage do?

It exposes 2 tools, read directly from the server on our last check. Among them: check_resolution_risk, list_covered_events. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is Crosswire — Polymarket & Kalshi Arbitrage working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 416 ms. The bar chart above shows every period we have measured.

How do I connect Crosswire — Polymarket & Kalshi Arbitrage?

Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does Crosswire — Polymarket & Kalshi Arbitrage need an API key?

No. Crosswire — Polymarket & Kalshi Arbitrage completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 2 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is Crosswire — Polymarket & Kalshi Arbitrage?

It answers our handshake in 416 ms on average, which is faster than 36% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.

Is Crosswire — Polymarket & Kalshi Arbitrage open source?

Yes — it is published under the MIT licence and 1 stars on GitHub. The source link is on this page, so you can read exactly what it does with your data before you connect it.