Crosswire — Polymarket & Kalshi Arbitrage

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

Should I use this

Quality & Safety

A
Description quality
100%
Schema completeness
52%
Naming quality
100%
Poisoning risk
100%
Permission match
100%
Protocol compliance
100%

Based on automated analysis of tool definitions and protocol compliance.

Context Cost

~1,382Tokens (tool definitions)
~5.2 KBTypical response size
Moderate attention impact (1.08% of 128k context)

This is the approximate number of tokens consumed each time the server's tools are loaded into a model's context. Higher counts reduce the attention available for other tasks.

Install

One-Click Install

Add this to your `claude_desktop_config.json` file:

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

Remote endpoints

https://api.crosswire-api.com/mcpstreamable-http

What it can do

Tool inventory

Tools (2)

🟢 Read-only🟡 Write🔴 Delete⚪ Unknown
🟢check_resolution_risk(market_a, market_b, canonical_event_id, notional_usd, mode, ...)

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.

Input Schema

{
  "type": "object",
  "properties": {
    "market_a": {
      "anyOf": [
        {
          "description": "One outcome leg on one venue (mirrors the REST `AuditRequest` refs).",
          "properties": {
            "venue": {
              "enum": [
                "polymarket",
                "kalshi"
              ],
              "type": "string",
              "description": "The venue: 'polymarket' or 'kalshi'."
            },
            "market_id": {
              "description": "Venue-native market id: Polymarket conditionId (0x… hex) or Kalshi market ticker (e.g. 'KXWCGAME-26JUN11MEXRSA-MEX').",
              "type": "string"
            },
            "outcome": {
              "anyOf": [
                {
                  "type": "string"
                },
                {
                  "type": "null"
                }
              ],
              "default": null,
              "description": "Venue-native outcome label. Optional — pair matching uses only (venue, market_id); when omitted the venue's binary book key ('Yes' on Polymarket, 'yes' on Kalshi) is assumed."
            },
            "side": {
              "anyOf": [
                {
                  "type": "string"
                },
                {
                  "type": "null"
                }
              ],
              "default": null,
              "description": "'yes' | 'no' if applicable. Optional, informational."
            }
          },
          "required": [
            "venue",
            "market_id"
          ],
          "type": "object"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "First leg of the pair to audit (either venue; order does not matter). Provide market_a AND market_b together, or use canonical_event_id instead."
    },
    "market_b": {
      "anyOf": [
        {
          "description": "One outcome leg on one venue (mirrors the REST `AuditRequest` refs).",
          "properties": {
            "venue": {
              "enum": [
                "polymarket",
                "kalshi"
              ],
              "type": "string",
              "description": "The venue: 'polymarket' or 'kalshi'."
            },
            "market_id": {
              "description": "Venue-native market id: Polymarket conditionId (0x… hex) or Kalshi market ticker (e.g. 'KXWCGAME-26JUN11MEXRSA-MEX').",
              "type": "string"
            },
            "outcome": {
              "anyOf": [
                {
                  "type": "string"
                },
                {
                  "type": "null"
                }
              ],
              "default": null,
              "description": "Venue-native outcome label. Optional — pair matching uses only (venue, market_id); when omitted the venue's binary book key ('Yes' on Polymarket, 'yes' on Kalshi) is assumed."
            },
            "side": {
              "anyOf": [
                {
                  "type": "string"
                },
                {
                  "type": "null"
                }
              ],
              "default": null,
              "description": "'yes' | 'no' if applicable. Optional, informational."
            }
          },
          "required": [
            "venue",
            "market_id"
          ],
          "type": "object"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Second leg of the pair to audit (the other venue)."
    },
    "canonical_event_id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "A covered pair id — the outcome-suffixed canonical id. Two namespaces: the metered crypto oracle-divergence inventory (shape 'crypto:btc-above:<date>:strike-<n>#above' — $0.02 USDC per call after 3 free calls/day; the daily pair rolls, so fetch a current id from list_covered_events rather than reusing an old one) and the free World Cup football pairs (shape 'wc26:match:<TEAMS>:<date>:result#home|#draw|#away'; the suffix selects the outcome leg-pair). A bare event id without the suffix is ambiguous and only accepted when market_a + market_b are also given to select the leg. Always get live pair ids from list_covered_events."
    },
    "notional_usd": {
      "anyOf": [
        {
          "type": "number"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Intended position size in USD. Optional; sizes the thin-liquidity check against live top-of-book depth."
    },
    "mode": {
      "default": "advisory",
      "description": "'advisory' (default) or 'strict'.",
      "type": "string"
    },
    "api_key": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Crosswire API key (cw_…). Optional. Free for the World Cup graph and the first calls/day on metered crypto pairs; beyond that, metered crypto calls draw down this key's prepaid USDC balance (top up via the x402 /v1/credits/topup endpoint)."
    }
  },
  "additionalProperties": false
}

Output Schema

{
  "type": "object",
  "additionalProperties": true
}
🟢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.

Input Schema

{
  "type": "object",
  "properties": {},
  "additionalProperties": false
}

Output Schema

{
  "type": "object",
  "additionalProperties": true
}

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Evidence

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