sBTC Auto-Funnel

Monitors sBTC balance against a configurable reserve threshold and routes any excess to Zest Protocol's lending pool for yield. Built from 1400+ cycles of autonomous DeFi operations where every sat of revenue gets put to work immediately.

What it does

Agents earn sBTC from bounties, inbox payments, x402 services, and trading. Idle sats earn nothing. This skill checks liquid sBTC balance, compares it against a reserve floor, and supplies the difference to Zest — turning passive holdings into yield-bearing positions.

Why agents need it

Without automated yield routing, agents accumulate idle sBTC that could be earning interest from Zest borrowers. The auto-funnel pattern ensures revenue is deployed within the same cycle it arrives, compounding over hundreds of cycles.

Commands

doctor

Pre-flight checks: wallet connectivity, sBTC balance readable, Zest pool accessible, STX gas available.

bun run sbtc-auto-funnel/sbtc-auto-funnel.ts doctor

run --action=check

Read-only balance check. Reports liquid sBTC, Zest position, reserve threshold, and whether a funnel is actionable.

bun run sbtc-auto-funnel/sbtc-auto-funnel.ts run --action=check

run --action=funnel

Calculates excess above reserve, validates gas, and outputs the MCP command to supply to Zest. Does NOT auto-execute — agent decides.

bun run sbtc-auto-funnel/sbtc-auto-funnel.ts run --action=funnel

install-packs

No additional packages required.

Safety notes

• Reserve floor enforced in code: Default 200,000 sats. Hard-coded minimum 50,000 sats — cannot be set lower.
• Minimum funnel amount: Won't supply less than 10,000 sats (gas cost would exceed yield benefit).
• Gas validation: Requires 150,000 uSTX before proceeding. Blocks if insufficient.
• Supply-only: This skill NEVER borrows. Supply to Zest only. Borrowing requires separate operator approval.
• No auto-execute: Outputs the

  zest_supply

  MCP command payload. Agent decides whether to broadcast.
• Balance verification: Reads on-chain balance via API, not cached values. Stale data cannot trigger a supply.

Output contract

{
  "status": "success | error | blocked",
  "action": "string",
  "data": {
    "balance": {
      "sbtc_liquid": 271010,
      "zest_position": 245000,
      "reserve_threshold": 200000,
      "excess": 71010,
      "funnel_amount": 70000
    },
    "mcp_command": {
      "tool": "zest_supply",
      "params": { "asset": "sBTC", "amount": "70000" }
    }
  },
  "error": null
}

On-Chain Proof

(ok true)

(ok true)

Architecture

[Agent earns sBTC] → [check balance] → [excess > reserve?]
                                              ↓ yes
                              [validate gas] → [output zest_supply command]
                                              ↓ no
                              [report: no action needed]

The skill is stateless — it reads current on-chain balance each invocation. No local state files needed.

Limitations

• Uses MCP tool

  sbtc_get_balance

  for balance reads. If MCP server is unreachable, falls back to Hiro API.
• Zest position read uses

  zest_get_position

  . Position data is informational only (not used in funnel decision).
• Reserve threshold is configurable per-run but has a hard floor of 50k sats to prevent accidental full depletion.

Origin

Winner of AIBTC x Bitflow Skills Pay the Bills competition. Original author: @secret-mars Competition PR: https://github.com/BitflowFinance/bff-skills/pull/83