Isocast API — Polymarket weather-signal feed for AI agents

# Isocast — Polymarket weather-signal API for AI agents (v1.1.0) > Agents pay per-signal bundles via x402 and get pushed (Telegram) the instant a city's > daily-high temperature crosses into a new Polymarket bucket — market URL, old/new reading, > and live odds for every bucket. 37 cities. Free to browse (cities, sample, pricing, terms); > paid signal reads settle USDC on Base. Informational data only — not financial or betting advice. ## Base URL - API: https://api.isocast.dev - This document: https://api.isocast.dev/llms.txt · Extended: /llms-full.txt · Topic: /llms/weather-signals - Discovery (JSON): https://api.isocast.dev/discovery - OpenAPI 3.1: https://api.isocast.dev/openapi.json - x402 manifest: https://api.isocast.dev/.well-known/x402 - Agent card (A2A): https://api.isocast.dev/.well-known/agent-card.json - Terms: https://isocast.dev/terms ## What a signal is When a city's observed daily-high temperature crosses out of one Polymarket temperature bucket and into another, Isocast emits ONE signal for that (city, day, transition). It carries: the Polymarket market URL + conditionId, the old and new {reading, unit, bucket}, and live YES/NO/midpoint odds for EVERY bucket (with `dead: true` on buckets the day can no longer reach), plus `bucketsAsOf` (odds freshness, ≤ ~10s) and `observedAt`. `seq` is a monotonic per-city counter; delivery is at-most-once per (city, day, bucket). See /llms/weather-signals for semantics. ## Free endpoints (no auth, no payment) | Method | Path | Description | |--------|------|-------------| | GET | /health | Liveness + payment mode (live\|mock) + OFAC status | | GET | /v1/cities | All active cities (slug, unit, bucketWidth, timezone, latestSeq). 30s cache | | GET | /v1/cities/:slug | One city + today's targetDate + Polymarket marketUrl | | GET | /v1/sample?city=SLUG | Promo signal — fixed seq-1 (never latest); synthetic fallback. `sample:true` | | GET | /v1/signals/meta?city=SLUG | Pricing + payment metadata (un

{ "openapi": "3.1.0", "info": { "title": "Isocast API", "version": "1.1.0", "summary": "Per-signal Polymarket weather-market bucket-transition signals for AI agents.", "x-guidance": "Start with GET /v1/cities to pick a city slug. Cheapest paid read: GET /v1/spot?city={slug} buys a $0.01 snapshot of the city's LATEST signal — payable by a STOCK x402 client (plain @x402/fetch, no binding nonce); it never returns history. For a running feed: POST /v1/subscribe?city={slug}&coun