Changelog

v0.4 (draft), 2026-11-14

Current draft. Order forms beyond limit and market, declared per asset class by the venue adapter.

• Intent fields: stop, stop_limit, trailing_stop; notional; order_class (simple, bracket, oto, oco, mleg); take_profit, stop_loss, legs, position_intent, replaces. Times in force add opg and cls.
• Decision payload version 4 signs asset_class and the order terms. Versions 1 to 3 are still verified; a v1–v3 payload that carries a v4 field is rejected.
• New order states: working (a group’s entry filled, exits still rest), pending_replace and terminal replaced.
• Holds are the worst case of each form (a stop at max(stop, reference) plus the collar; a bracket its entry; a long option its premium; a spread its maximum loss). A stop-market gap past the hold is settled from cash. If a bracket’s stop loss is rejected after the entry filled, the account goes reduce-only (group.unprotected).
• Mandate options_level (0 none, 1 covered calls and cash-secured puts, 2 also long calls and puts, 3 defined-risk spreads). The authorizer may cap the effective level. allow_short allows a cash-collateralized short of whole shares.
• Option contracts are OCC symbols. POST /v1/actions signs exercise or do_not_exercise for a long position. Calendar and diagonal spreads are not supported.
• A replacement (replaces) is a new decision with its own hold. Groups cannot be replaced.
• Venue adapter: Capabilities.asset_classes, and operations Replace and Act. Venue differences live in the capability declaration.
• New codes include A2M_ORDER_CLASS, A2M_NOTIONAL, A2M_OPTIONS_LEVEL, A2M_UNCOVERED, A2M_UNDEFINED_RISK, A2M_NO_POSITION, A2M_REPLACE, A2M_ACTION, A2M_ASSET_CLASS.
• MCP tools a2m_replace_order and a2m_exercise.

v0.3 (draft), 2026-11-12

• Intent field extended_hours (boolean, default false). Allowed only on a limit order with day or gtc.
• Session and calendar semantics: regular and extended sessions, holidays, and early closes. US equities extended hours are 04:00–09:30 and 16:00–20:00 Eastern Time (17:00 on early-close days).
• New codes A2M_EXTENDED_HOURS and an updated meaning for A2M_MARKET_CLOSED when both regular and extended sessions are closed.
• Decision payload version 3 adds signed extended_hours. Version 2 payloads are still verified and mean extended_hours false.
• Protect-price wording: a protective limit is used only on venues that have no native market order. Native market venues rely on pre-send checks of the signed reference price.
• Time-in-force guidance for market orders: Hyperliquid uses ioc, Alpaca uses day. The protocol default remains gtc, which a venue that does not accept it will refuse.
• Mandate instruments is an optional allowlist, on the mandate and on each limits row. Empty allows every instrument the venue lists as active.
• Order size is capped by notional only. max_order_qty is accepted from older callers and ignored.
• Venue adapter operation ListInstruments: the venue’s instrument list, which the authorizer syncs and uses to mark delisted symbols.

v0.2 (draft), 2026-11-12

• The authorizer mints client_order_id as co_ plus 32 hex characters (35 in all) and never reuses it. The same id with a different decision_id is A2M_IDEMPOTENCY (409).
• An unsupported time in force or order type is refused before send, never coerced.
• qty, limit_price and reference_price take at most 6 decimal places; more is a 400 (APEX_4011), never rounded.
• Cancel semantics: A2M_UNKNOWN (409) if the order is still in unknown; A2M_CANCEL_PENDING (409) if a cancel was sent but the venue has not confirmed it.
• Mandate limits: one row per venue and currency, set by the user per agent. Defaults are max_leverage 1 and short_collateral_ratio 1. Leverage above 1 and short collateral below 1 are not yet supported. The older flat mandate shape is still accepted when every instrument shares one quote currency.

v0.1 (draft), 2026-11-11

First public draft.

• Five objects: Intent, Mandate, Decision, ExecutionReport, Evidence.
• Decision payload version 2 (time_in_force and enforcement are signed). Version 1 payloads are still accepted until they expire.
• Order state machine with an explicit unknown state resolved only by reconciliation.
• Error codes for rule rejections and for transport errors.
• Venue adapter contract.
• MCP binding with seven tools, and OAuth discovery through protected-resource metadata.