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Polymarket–Kalshi Spread

polymarket_kalshi_spread
Read-onlyIdempotent

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 — BOTH modes run the identical token-overlap matcher, so the same disclosures apply to both. 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 is a sentence and compatibility_codes[] the machine-readable form; BOTH can be non-empty on returned pairs, so read them even when matched_pairs>0. Codes: event_subject_mismatch (the two event titles share no subject words — probably not the same question), temporal_mismatch (they resolve in different months), temporal_alignment_unknown (the resolution month could not be parsed on one or both sides — NOT the same as confirmed-aligned; check each event's close/strike date yourself), non_equivalent_bet_shapes, no_candidate_pairs, unclassified_legs_excluded, pairing_unverified (set in EITHER mode whenever pairs are returned: the legs were matched by keyword and word overlap, not a shared resolution source). Each entry in top_spreads_pp carries its own flags[] (temporal_mismatch, temporal_alignment_unknown, event_subject_mismatch, low_token_overlap). A leg whose metric_type or match_subtype is "unknown" is NEVER paired — those comparisons land in spread.skipped_unclassified and, when the wording lined up, in spread.low_confidence_pairs[] for inspection only. temporal_alignment{polymarket_month,kalshi_month,aligned} tells you whether the two events resolve in the same calendar period, in EITHER mode; null means it could not be computed (see temporal_alignment_unknown), not that the two sides align. spread.fees_note is a standing disclosure: Kalshi charges per-contract trading fees, Polymarket does not, and this tool does not model Kalshi's fee schedule — every spread_pp is gross, not a net tradeable edge. 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.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
topicNoPre-mapped: fed | btc | cpi | gdp | sp500 | recession | next_pope | next_uk_pm | next_israel_pm | 2028_president
kalshi_event_tickerNoExplicit Kalshi event ticker, e.g. "KXFED-26OCT". Overrides the topic-mapped Kalshi side.
polymarket_event_slugNoExplicit Polymarket event slug, e.g. "fed-decision-in-june-825". Overrides the topic-mapped Polymarket side.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. Changed1 schema field changed
    • addedInput schema / examples
      Added value: +[
      +  {
      +    "topic": "fed"
      +  },
      +  {
      +    "topic": "btc"
      +  }
      +]
  2. Added

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark this read-only and idempotent, and the description adds extensive behavioral context beyond them: compatibility_warning and codes semantics, gross vs. net fee disclosure, the rule that unknown metric_type/match_subtype legs are never paired, the precise meaning of null in temporal_alignment, and skipped-leg counters. Nothing contradicts the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is long and dense, but it is organized into labeled sections (TWO MODES, RESPONSE, SAFETY FIELDS, Codes, counters) and every sentence carries non-obvious operational detail. It is front-loaded with the core purpose. Slightly verbose, though justified by the tool's complexity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description fully carries the burden of explaining return values—and it does: leg prices, top_spreads_pp, compatibility codes, per-entry flags, temporal_alignment, fees_note, skipped counters, and failure semantics. It also warns about the gap between pre-mapped shortcuts and actual tradable spreads. For a tool this complex, nothing needed for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Input schema covers all three parameters with descriptions and examples, so the baseline is 3. The description adds genuine extra semantics: the override relationship between explicit ticker/slug and topic, the fact both modes run the same token-overlap matcher, and the full list of topic shortcut values. That elevates it above a purely schema-driven understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific function: computing the cross-venue spread between Kalshi and Polymarket for the same resolving question. It distinguishes itself from sibling tools by naming both venues and the 2-25pp participant-pool gap, and its two explicit modes (topic shortcuts vs. custom ticker/slug) clarify the exact resource it acts on.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Clear context is given for when to use each mode: topic shortcuts for 10 pre-mapped macros, explicit ticker/slug for custom pairings. It also warns that most pre-mapped topics return compatibility warnings today, which is useful steering. No exclusion or comparison against sibling tools like polymarket_arbitrage, so it falls short of fully explicit alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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TDQS

A3.6/5.0
Disambiguation2/5

The StackExchange tools are distinct, but the dominating data-lookup cluster is highly ambiguous: ask_pipeworx, ask_pipeworx_beta (explicitly identical today), ask_pipeworx_grounded, deep_research, and validate_claim all route into the same underlying tool catalog. The polymorpharket tools also overlap heavily, making selection between bet_research, polymarket_edges, polymarket_arbitrage, and fill-risk checks genuinely hard.

Naming Consistency2/5

The names are all snake_case but otherwise follow no consistent pattern: bare verbs (remember, forget, subscribe), prefixed names (pipeworx_feedback, stack_get_user), composite domain names (ask_pipeworx, generate_llms_txt), and generic verbs (resolve_entity, validate_claim, search_within). The StackExchange subset itself is split between stack_get_user/stack_tags and search_questions/get_answers.

Tool Count2/5

36 tools is already in the 'too many' range for one server, and the mismatch with the server name is severe: only 5 of 36 tools relate to StackExchange. The rest form a broad Pipeworx/prediction-market data platform that would itself be oversized for a focused purpose.

Completeness2/5

For a StackExchange-focused server, the surface has core read operations but lacks question-detail-by-ID, comments, related questions, or any write/community actions, and the 31 unrelated tools do not fill that gap. For the broader apparent Pipeworx platform coverage is broad, but the set has no single coherent domain against which completeness can be meaningfully judged.