Autonomous Prediction Market Oracle Interface

[zkpato]

Problem

Prediction markets produce verifiable, crowd-sourced signals (event outcomes, parametric resolutions) that downstream protocols want to consume: lending hooks, insurance triggers, DAO actions, parametric DeFi. On Stellar today there is no standard for reading those outcomes. Every consumer would have to learn each provider's contract layout, encoding, and trust model individually. That per-provider integration cost has historically been what blocks oracle composability.

[SEP-40] solves this for price feeds. There is no analogous interface for event resolutions, and the two are not interchangeable: price feeds are continuous streams keyed by asset; event resolutions are one-shot finals keyed by question.

Proposal

A minimal, read-side-only Soroban interface (PredictionMarketOracleTrait) for prediction-market platforms whose markets resolve autonomously: deterministic execution of rules committed at market creation, against inputs committed at resolution. Four methods: pmo_version, market_spec, outcome, markets (paginated discovery, MAY). Two standardized events: pm_created, pm_resolved. Provider-internal concerns (positions, liquidity, payouts, settlement) are out of scope.

Markets are identified by sha256(canonical_spec_bytes): content-addressed, tamper-evident. Resolutions carry inputs_hash + rules_hash, so any third party can fetch both, re-execute, and verify the published outcome off-chain at zero on-chain cost.

Full draft: pr pending

Key Design Choices

• Autonomous-first Stellar's value is fast deterministic settlement; a 24–72h optimistic-dispute window throws that away. Human-judgment providers can still expose outcomes via the reserved RESOLVER_ASSERTION_V1 attestation symbol, but they fall outside the verification guarantee.
• Off-chain rules + on-chain hash. Rules vary from short snippets to multi-step pipelines that consult external data; on-chain footprint is two 32-byte hashes. Tampering is detectable; expressiveness is unconstrained.
• Outcome::Invalid as a final state, distinct from None-as-unresolved. Real markets occasionally cannot be answered (source disappears, question becomes ambiguous); conflating with "unresolved" forces consumers to wait forever.
• Resolutions are immutable. Once outcome() returns Some, it MUST keep returning the same value. Consumers can cache safely.
• No dispute interface, no position tokens. Disputes are out of scope (autonomous-only). Position tokens are deliberately ceded to Gnosis CTF; consumers of outcomes don't need them.

Adoption

The reference Soroban implementation will land at github.com/fermah-labs/sep-prediction-market-oracle. The first conforming provider will be Flashcast Social (flashcast.social), whose existing autonomous-resolution pipeline (deterministic workflow executed against committed inputs, multisig resolver) is the production motivation for this SEP.

We expect organic adoption from any platform on Stellar whose markets are rule-driven rather than judgment-driven, and from Reflector-style oracle providers that want to expose discrete event outcomes alongside price feeds.