# polymarket_kalshi_spread Cross-venue spread between Kalshi and Polymarket for the same resolving question. The two venues sometimes price the same outcome 2-25pp apart because their participant pools differ — when the bet shapes are equivalent that delta is a real signal, when they aren't the tool says so. TWO MODES: (1) topic — 10 pre-mapped macro shortcuts ("fed", "btc", "cpi", "gdp", "sp500", "recession", "next_pope", "next_uk_pm", "next_israel_pm", "2028_president") auto-fetch the matching event on each venue. (2) explicit kalshi_event_ticker + polymarket_event_slug for custom pairings. RESPONSE: each venue's leg-by-leg prices (raw probability 0-1) plus matched spread[].top_spreads_pp (Kalshi − Polymarket) where the same outcome shows up on both sides. SAFETY FIELDS: compatibility_warning fires in two cases — (a) matched_pairs:0 with skipped_cross_type>0 means the venues frame the topic with non-equivalent bet shapes (e.g. Kalshi range_bucket point-in-time vs Polymarket cumulative_threshold touch-anywhere — no arb exists), (b) matched_pairs:0 with skipped_cross_type:0 and both venues >5 legs means the token-overlap matcher found nothing in common — events likely semantically unrelated despite the topic keyword. temporal_alignment{polymarket_month,kalshi_month,aligned} tells you whether the two events resolve in the same calendar period; aligned:false means spreads are mathematically meaningless across the temporal gap. skipped_cross_type / skipped_cross_subtype counters expose how many leg-pair comparisons were dropped (cross-type = metric_type mismatch like MoM vs YoY; cross-subtype = inequality mismatch like cum_ge vs cum_le). Real cross-venue spreads are rarer than the macro-shortcut list suggests — most pre-mapped topics return compatibility_warning today; pre-mapped ≠ tradeable. Agent View of the PolicyLayer registry record for `polymarket_kalshi_spread`. HTML page: https://policylayer.com/tools/io-github-pipeworx-io-19hz/polymarket-kalshi-spread ## Facts - Tool: `polymarket_kalshi_spread` - Server: 19hz (`https://gateway.pipeworx.io/19hz/mcp`) — https://policylayer.com/tools/io-github-pipeworx-io-19hz.md - Homepage: https://github.com/pipeworx-io/mcp-19hz - Risk category: Read (Low risk) - Registry record: grade F, identity unverified - Server auth posture: open - Server CORS policy: * - Server rate-limited: yes - Parameters: 3 - Recommended policy verdict: Allowed ## Parameters | Parameter | Type | Required | Description | | --- | --- | --- | --- | | `topic` | string | no | Pre-mapped: fed \| btc \| cpi \| gdp \| sp500 \| recession \| next_pope \| next_uk_pm \| next_israel_pm \| 2028_president | | `kalshi_event_ticker` | string | no | Explicit Kalshi event ticker, e.g. "KXFED-26OCT". Overrides the topic-mapped Kalshi side. | | `polymarket_event_slug` | string | no | Explicit Polymarket event slug, e.g. "fed-decision-in-june-825". Overrides the topic-mapped Polymarket side. | Parameters from the server's own tool schema. ## Example call (MCP tools/call, JSON-RPC 2.0) ```json { "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": { "name": "polymarket_kalshi_spread", "arguments": {} } } ``` ## Why polymarket_kalshi_spread is rated Low This tool fetches and compares pricing data from two prediction market venues (Kalshi and Polymarket). It retrieves market prices and computes a spread — a read/query operation with no side effects. It does not place bets, move money, or modify any data. Despite being financial in nature (prediction markets), it only reads and compares prices without committing any financial obligation. From the tool's own definition: "Cross-venue spread between Kalshi and Polymarket for the same resolving question... auto-fetch the matching event on each venue... RESPONSE: each venue" ## Use case AI agents call polymarket_kalshi_spread to retrieve information from 19hz without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere. ## Recommended policy (PolicyLayer) Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches 19hz: ```json { "version": "1", "default": "deny", "tools": { "polymarket_kalshi_spread": {} } } ``` ## Other tools on 19hz (31) - `forget` — Destructive — https://policylayer.com/tools/io-github-pipeworx-io-19hz/forget.md - `polymarket_arbitrage` — Financial — https://policylayer.com/tools/io-github-pipeworx-io-19hz/polymarket-arbitrage.md - `polymarket_edges` — Financial — https://policylayer.com/tools/io-github-pipeworx-io-19hz/polymarket-edges.md - `ai_visibility_check` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/ai-visibility-check.md - `ask_pipeworx` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/ask-pipeworx.md - `ask_pipeworx_grounded` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/ask-pipeworx-grounded.md - `bet_research` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/bet-research.md - `compare_entities` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/compare-entities.md - `deep_research` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/deep-research.md - `discover_tools` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/discover-tools.md - `entity_profile` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/entity-profile.md - `events` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/events.md - `list_subscriptions` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/list-subscriptions.md - `pipeworx_trending` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/pipeworx-trending.md - `polymarket_edge_tracker` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/polymarket-edge-tracker.md - `recall` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/recall.md - `recent_alerts` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/recent-alerts.md - `recent_changes` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/recent-changes.md - `regions` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/regions.md - `resolve_entity` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/resolve-entity.md - `scan_competitor_ai_presence` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/scan-competitor-ai-presence.md - `scan_dependency` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/scan-dependency.md - `search_within` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/search-within.md - `suggest_questions` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/suggest-questions.md - `validate_claim` — Read — https://policylayer.com/tools/io-github-pipeworx-io-19hz/validate-claim.md - `generate_llms_txt` — Write — https://policylayer.com/tools/io-github-pipeworx-io-19hz/generate-llms-txt.md - `pipeworx_feedback` — Write — https://policylayer.com/tools/io-github-pipeworx-io-19hz/pipeworx-feedback.md - `polymarket_fill_risk` — Write — https://policylayer.com/tools/io-github-pipeworx-io-19hz/polymarket-fill-risk.md - `remember` — Write — https://policylayer.com/tools/io-github-pipeworx-io-19hz/remember.md - `subscribe` — Write — https://policylayer.com/tools/io-github-pipeworx-io-19hz/subscribe.md - …and 1 more: https://policylayer.com/tools/io-github-pipeworx-io-19hz.md ## For agents This record is a snapshot. Live verdicts and the full registry: - Check every server in your MCP config at once: `npx -y policylayer stack` - Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md) - Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events` --- Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-pipeworx-io-19hz · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-pipeworx-io-19hz