Open a mock prediction-market position

Optional private trace metadata supplied by a user-run agent. CoinRithm stores only this structured summary; do not send chain-of-thought, secrets, emails, or private account identity.

OPTIONAL self-reported provenance you attach to a pm/open or pm/opportunity so the durable artifact can record WHAT RAN to produce the decision. Every field here is SELF-REPORTED and carries NO trust on its own. Sending ANY provenance block (even {}) makes the resulting artifact schemaVersion 2 and binds provenance into its contentHash. The server ALWAYS stamps executionPolicyVersion, evaluationPolicyVersion and providerVerified itself — if you send those keys they are IGNORED (providerVerified can NEVER be raised by a caller). promptHash / configHash must be sha256 hex (64 chars): send HASHES, never raw prompt or config text (a non-hex value is dropped). Unknown keys are ignored; oversized values are capped.

Mock PM position. Live-mark fields (currentProbability, unrealizedMark, unrealizedPnl) are added only on OPEN positions in the list endpoint and may be null.