Crosswire — Polymarket & Kalshi Arbitrage
REMOTE · API.CROSSWIRE-API.COM · SCANNED SEP 25
Cross-venue Polymarket+Kalshi arbitrage: resolution mismatch, void risk & settlement divergence.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security57
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 2 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability61
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 953 tokens (~476/item across 2 items; 2 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 2 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 3 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
How do I install the Crosswire — Polymarket & Kalshi Arbitrage MCP server?
Crosswire — Polymarket & Kalshi Arbitrage is a hosted endpoint at https://api.crosswire-api.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · api.crosswire-api.com
claude mcp add --transport http com-crosswire-api-crosswire-polymarket-kalshi-ar 'https://api.crosswire-api.com/mcp'
{
"mcpServers": {
"com-crosswire-api-crosswire-polymarket-kalshi-ar": {
"url": "https://api.crosswire-api.com/mcp"
}
}
} {
"servers": {
"com-crosswire-api-crosswire-polymarket-kalshi-ar": {
"type": "http",
"url": "https://api.crosswire-api.com/mcp"
}
}
} [mcp_servers.com-crosswire-api-crosswire-polymarket-kalshi-ar] url = "https://api.crosswire-api.com/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"com-crosswire-api-crosswire-polymarket-kalshi-ar": {
"type": "remote",
"url": "https://api.crosswire-api.com/mcp",
"enabled": true
}
}
} openclaw mcp add com-crosswire-api-crosswire-polymarket-kalshi-ar --url 'https://api.crosswire-api.com/mcp' --transport streamable-http
mcp_servers:
com-crosswire-api-crosswire-polymarket-kalshi-ar:
url: "https://api.crosswire-api.com/mcp" {
"McpServers": {
"com-crosswire-api-crosswire-polymarket-kalshi-ar": {
"Transport": "http",
"Url": "https://api.crosswire-api.com/mcp"
}
}
} assistant mcp add com-crosswire-api-crosswire-polymarket-kalshi-ar -t streamable-http -u 'https://api.crosswire-api.com/mcp'
{
"mcpServers": {
"com-crosswire-api-crosswire-polymarket-kalshi-ar": {
"type": "http",
"url": "https://api.crosswire-api.com/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 25 Sept 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 26 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Aug 26 0
- Stability: 0.97 → pass security
- 15 Aug 26 0
- Server version: 0.6.0 → 0.6.1 functional
- 11 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 7 Aug 26 0
- The server no longer declares the “experimental” capability functional
- 31 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 30 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 25 Sept 2026 · Probed https://api.crosswire-api.com/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=api.crosswire-api.com | CN=YE1,O=Let's Encrypt,C=US | 10 Aug 2026 | 8 Nov 2026 | ECDSA 256 | ECDSA-SHA384 | 6157d8375c617e5c65b8b5db84325541271 |
| SANs: api.crosswire-api.com | ||||||
| CN=YE1,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 5ddd70dd31f801c85c186a7a04b80afe |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of api.crosswire-api.com. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| com. | present | 19718 | 13 | Verified |
| crosswire-api.com. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://api.crosswire-api.com/mcp | Verified | 200 | |
| http (plaintext) | http://api.crosswire-api.com/mcp | HTTPS enforced | 301 | https://api.crosswire-api.com/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
check_resolution_risk ~612
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.
| Name | Type | Req | Description |
|---|---|---|---|
| api_key | – | – | 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 v… |
| canonical_event_id | – | – | 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 f… |
| market_a | – | – | 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 | – | – | Second leg of the pair to audit (the other venue). |
| mode | string | – | 'advisory' (default) or 'strict'. |
| notional_usd | – | – | Intended position size in USD. Optional; sizes the thin-liquidity check against live top-of-book depth. |
Structured output declared, but exposes no named fields.
No examples provided.
list_covered_events ~163
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 present but exposes no named parameters.
Structured output declared, but exposes no named fields.
No examples provided.
What is the Crosswire — Polymarket & Kalshi Arbitrage MCP server?
Crosswire — Polymarket & Kalshi Arbitrage is an MCP server listed in the public MCP registry as com.crosswire-api/crosswire-polymarket-kalshi-arbitrage. Cross-venue Polymarket+Kalshi arbitrage: resolution mismatch, void risk & settlement divergence. This page covers its hosted endpoint (https://api.crosswire-api.com/mcp).
Is the Crosswire — Polymarket & Kalshi Arbitrage MCP server safe to use?
Crosswire — Polymarket & Kalshi Arbitrage scores 76 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Crosswire — Polymarket & Kalshi Arbitrage MCP server expose?
Crosswire — Polymarket & Kalshi Arbitrage exposes 2 tools: check_resolution_risk, list_covered_events. Their descriptions and schemas cost roughly 775 tokens of context every time the server is loaded.
Does the Crosswire — Polymarket & Kalshi Arbitrage MCP server require authentication?
No. We connected to Crosswire — Polymarket & Kalshi Arbitrage without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Crosswire — Polymarket & Kalshi Arbitrage MCP server still maintained?
Crosswire — Polymarket & Kalshi Arbitrage is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.