hive-mcp-auction

Inbound reverse Dutch auction agent — Hive Civilization

When a Hive shim hits its rate-limit headroom, the next request gets a 402 with a Dutch descent envelope: starting price 5x standard asking, dropping 5% every 30s until claimed or floor. First agent to settle at the current price wins the slot. Pure protocol — no DMs, no spam. Inbound only.

Council provenance: Ad-hoc, user-promoted 2026-04-27 (Tier A position 2, symmetric sibling to HiveBarter). Barter discovers what others will sell for; auction discovers what others will pay for ours.

What this is

hive-mcp-auction is a Model Context Protocol server that runs the inbound side of the 402 payment surface. When hivemorph's rate-limiter detects a shim's current usage exceeds its headroom (default 80% of cap), it signs an internal auction_open request, this service publishes the descent curve, and the next 402 envelope on that shim carries an auction block alongside the standard accepts[]. Agents who don't want to play pay normal asking and queue. Agents who want the slot now claim at the current curve price.

• Protocol: MCP 2024-11-05 over Streamable-HTTP / JSON-RPC 2.0
• Transport: POST /mcp
• Discovery: GET /.well-known/mcp.json
• Health: GET /health
• Settlement: USDC on Base L2 — real rails, no mock, no simulated
• Brand gold: Pantone 1245 C / #C08D23

Tools

REST endpoints

Dutch descent math

start_price = asking_usd * 5.0          (5x asking)
floor_price = asking_usd * 0.5          (50% of asking)
drop_pct    = 0.05                      (5% per tick)
interval_s  = 30                        (one tick per 30s)

current_price(t) = max(
  floor_price,
  start_price * (1 - drop_pct) ** floor((t - opened_at) / interval_s)
)

After ~28 ticks (~14 min) the auction reaches floor. If no claim by then, the auction expires and the slot returns to the standard 402 flow. The function is pure. Same arguments give the same number to the cent. No RNG, no DB read, no clock skew tolerance baked in. The public envelope alone is provably fair.

402 envelope extension

Standard hivemorph 402 envelope plus an auction block:

{
  "x402_version": 1,
  "ask": "0.05",
  "accepts": [...],
  "auction": {
    "id": "auct_abc123",
    "type": "dutch",
    "asking_usd": "0.05",
    "current_price_usd": "0.2375",
    "start_price_usd": "0.25",
    "floor_price_usd": "0.025",
    "drop_pct": 0.05,
    "interval_s": 30,
    "opened_at": "2026-04-27T20:30:00Z",
    "expires_at": "2026-04-27T20:44:00Z",
    "claim_url": "https://hive-mcp-auction.onrender.com/v1/auction/claim",
    "subscribe_url": "https://hive-mcp-auction.onrender.com/v1/auction/curve?id=auct_abc123",
    "policy": "first-claim-wins"
  }
}

The standard accepts[] block stays. Agents who don't want to play pay normal asking and get queued. Auction is opt-in via claim_url.

Claim flow (race-safe, first-claim-wins)

POST /v1/auction/claim
{
  "auction_id": "auct_abc123",
  "claim_at_price_usd": "0.2375",
  "idempotency_key": "{caller-uuid}",
  "tx_hash": "0x..."
}

→ 200 { winner: true, slot_token: "...", expires_in_s: 60 }
→ 409 { winner: false, reason: "already_claimed" }
→ 410 { winner: false, reason: "auction_expired" }
→ 422 { winner: false, reason: "price_mismatch", current_price_usd: "..." }

Race-safety is enforced by an atomic SQLite UPDATE auctions SET state='claimed' WHERE id=? AND state='open'. The first UPDATE that touches a row wins. Tx verification is async — slot_token is issued provisionally and the on-chain Transfer is verified against the wallet via Base RPC.

Risk controls

All caps fail-closed. Configurable via env; missing or invalid env always falls back to the stricter default.

Configuration

HMAC signing (for hivemorph)

Hivemorph signs each /v1/auction/open request:

ts   = Date.now().toString()
body = JSON.stringify(payload)
sig  = HMAC_SHA256(AUCTION_OPEN_HMAC_KEY, `${ts}.${body}`)

Headers:
  Content-Type: application/json
  X-Hive-Timestamp: ${ts}
  X-Hive-Signature: ${sig.hex}

Server rejects requests where |now - ts| > 5min or the signature does not match in constant time. Both shims must hold the same AUCTION_OPEN_HMAC_KEY.

Run locally

git clone https://github.com/srotzin/hive-mcp-auction.git
cd hive-mcp-auction
npm install
npm start
# server up on http://localhost:3000/mcp
curl http://localhost:3000/health
curl http://localhost:3000/.well-known/mcp.json
curl http://localhost:3000/v1/auction/today

Connect from an MCP client

Claude Desktop / Cursor / Manus — add to your mcp.json:

{
  "mcpServers": {
    "hive_mcp_auction": {
      "command": "npx",
      "args": ["-y", "mcp-remote@latest", "https://hive-mcp-auction.onrender.com/mcp"]
    }
  }
}

Why Dutch (not Vickrey, not English)

• Dutch (Shape α — this repo): deterministic clock-driven price, first-claim-wins, no judgment, no late-bid manipulation, agents reveal urgency by claim timing.
• Vickrey (Shape β): requires trusted bid-window timing; late-bid attacks need defending; agents must trust we read sealed bids honestly.
• English (Shape γ): highest revenue per auction but blocks the slot for the full window even with one bidder. Works for unique assets, not fungible compute.

Dutch is the only one where the math is provably fair from the public envelope alone. Shapes β and γ are explicitly out of scope for v1; revisit once Shape α produces clean telemetry.

Hive Civilization

Part of the Hive Civilization — sovereign DID, USDC settlement, agent-to-agent rails. Companion shims include hive-mcp-barter (the symmetric outbound sibling), hive-mcp-evaluator, hive-mcp-compute-grid, hive-mcp-depin, hive-mcp-agent-storage, hive-mcp-agent-kyc, and hive-mcp-trade.

License

MIT (c) 2026 Steve Rotzin / Hive Civilization