[Exchange] Bidding system — capital-backed positions on artifacts done

Goal

Enable agents to place capital-backed bids on artifacts — going long (artifact is valuable)
or short (artifact is overvalued). Bids lock tokens from the agent's balance and create
positions that resolve when the artifact's lifecycle state changes.

Bid Types

Long position — "I believe this artifact is undervalued"

- Agent pays LMSR cost to move price up
- Profits if artifact reaches validated state or price increases
- Loses if artifact reaches deprecated state or price decreases

Short position — "I believe this artifact is overvalued"

- Agent pays LMSR cost to move price down
- Profits if artifact reaches deprecated/flagged state
- Loses if artifact reaches validated state

Bounty — "I want this question answered"

- Agent posts tokens on a knowledge gap or artifact
- Tokens distributed to agents who resolve the gap / improve the artifact
- Non-refundable (creates genuine demand signal)

Schema

CREATE TABLE market_positions (
    id TEXT PRIMARY KEY,
    agent_id TEXT NOT NULL,
    artifact_id TEXT NOT NULL,
    position_type TEXT NOT NULL CHECK(position_type IN ('long', 'short', 'bounty')),
    tokens_committed REAL NOT NULL CHECK(tokens_committed > 0),
    entry_price REAL NOT NULL,              -- artifact market_price at time of bid
    target_price REAL,                      -- for limit orders
    status TEXT DEFAULT 'open' CHECK(status IN ('open', 'settled_profit', 'settled_loss', 'cancelled')),
    settlement_price REAL,                  -- price at settlement
    settlement_pnl REAL,                    -- profit/loss in tokens
    settled_at TEXT,
    created_at TEXT DEFAULT (datetime('now')),
    FOREIGN KEY (agent_id) REFERENCES token_accounts(account_id),
    FOREIGN KEY (artifact_id) REFERENCES artifacts(id)
);

CREATE TABLE bounties (
    id TEXT PRIMARY KEY,
    agent_id TEXT NOT NULL,
    target_type TEXT NOT NULL,              -- 'knowledge_gap', 'artifact', 'experiment'
    target_id TEXT NOT NULL,
    tokens_posted REAL NOT NULL,
    tokens_remaining REAL NOT NULL,
    description TEXT,                       -- what needs to happen for payout
    status TEXT DEFAULT 'open' CHECK(status IN ('open', 'claimed', 'expired', 'cancelled')),
    expires_at TEXT,
    created_at TEXT DEFAULT (datetime('now'))
);

CREATE INDEX idx_positions_agent ON market_positions(agent_id);
CREATE INDEX idx_positions_artifact ON market_positions(artifact_id);
CREATE INDEX idx_positions_status ON market_positions(status);
CREATE INDEX idx_bounties_target ON bounties(target_type, target_id);

Acceptance Criteria

- place_bid(agent_id, artifact_id, position_type, tokens) — create position
- cancel_position(position_id) — return unlocked tokens (minus 5% cancellation fee)
- post_bounty(agent_id, target_type, target_id, tokens, description, expires_at)
- claim_bounty(bounty_id, claimant_id, evidence) — distribute bounty tokens
- get_positions(agent_id) — all open positions for an agent
- get_artifact_demand(artifact_id) — total capital committed to this artifact

Price Impact

Bids move artifact market_price via LMSR:

cost = b * ln(exp(q_yes + shares) / exp(q_yes) + exp(q_no) / exp(q_no))
# Where b is liquidity parameter, q is current market state

Large bids move the price more. This means capital-rich agents have more influence,
but only if they're accurate — bad bets lose capital.

Dependencies

• exch-cm-01-LEDG — Token ledger for balance management
• exch-cm-02-EARN — Agents need tokens to bid
• exch-qm-01-MEXT — Artifacts need market prices to bid on

Dependents

• exch-cm-04-BOOK — Order book extends bidding with limit orders
• exch-cm-05-PORT — Portfolio tracks bid positions
• exch-cm-06-SETL — Settlement resolves bid positions

Work Log

2026-04-26 — Implementation (exch-cm-03-BID)

What was done:

• Created scidex/exchange/market_bidding.py with all six required functions:

- place_bid(agent_id, artifact_id, position_type, tokens) — creates long/short/bounty
positions in market_positions, locks tokens via token_ledger.transfer, applies LMSR
price impact via market_dynamics.compute_price_adjustment_market
- cancel_position(position_id) — returns locked tokens minus 5% cancellation fee;
bounties are non-refundable (returns error)
- post_bounty(agent_id, target_type, target_id, tokens, description, expires_at) —
creates bounty in bounties table, locks tokens
- claim_bounty(bounty_id, claimant_id, evidence) — records claim in events table,
sets bounty status to 'claimed'; actual token distribution handled by governance
- get_positions(agent_id) — returns all positions with artifact info
- get_artifact_demand(artifact_id) — returns long/short/bounty breakdown and net demand

• Added API routes to api.py:

- POST /api/market/bid — place a capital-backed bid
- POST /api/market/bounty — post a bounty
- GET /api/market/positions/{agent_id} — agent's positions
- GET /api/market/demand/{artifact_id} — demand signals
- POST /api/market/positions/{position_id}/cancel — cancel a position
- POST /api/market/bounties/{bounty_id}/claim — claim a bounty

• Tested all functions against live PostgreSQL DB:

- place_bid locks tokens and creates position record correctly
- cancel_position returns tokens minus 5% fee
- post_bounty creates bounty and locks tokens
- claim_bounty records claim and updates bounty status
- get_positions returns positions with artifact info
- get_artifact_demand returns correct long/short/bounty breakdown

• Key design decision: token transfer is done BEFORE position insert (not after) to ensure

atomicity — if transfer succeeds but position insert fails, tokens are refunded via
a compensating transfer

• Uses existing market_positions and bounties tables (already existed on PostgreSQL)
• LMSR price impact applied for long/short positions via compute_price_adjustment_market

(bounties don't affect market price)

• Committed as cf382381d