Settlement infrastructure for the agent economy. Mist is how AI agents pay each other and vendors on-chain without paying one transaction per payment: a Delegated Spend Authority (DSA) authorization primitive plus an optimistic batch-settlement aggregator. Every line is written to survive published benchmarks.
简体中文文档：README.zh-CN.md
Upstream x402 settles one payment as one EIP-3009 transaction. We measured what that actually costs on Base — with the real USDC bytecode and mainnet receipts, all commands and logs published:
- 61,105–90,053 gas per payment (warm/fresh payee) — 1,000 payments burn 15–23% of an entire 400M-gas Base block
- Mist replaces that with one settlement transaction per batch: ≈ (246,000 + 78,958 × R) / N per payment — at N=1,000, R=1 that is 325 gas, 188× cheaper
- Honest negative result included: with all-unique recipients, batching is ~30% more expensive than direct — batching wins when recipients repeat (N/R > ~5), which is exactly merchant traffic
Full ledger: docs/articles/02-x402-gas-ledger-en.md
Deployed and exercised against Base mainnet (chain_id 8453, native ETH mode):
| Contract | Address |
|---|---|
| DSA | 0x0fF07b282C9c51720885F0a9B3bA8a6458b41385 |
| RevocationRegistry | 0x6e5c690ee2e76Cf920BE22e2583A9B7d0390d79F |
| OperatorRegistry | 0x278Fa3ff77d02b6caa981340Ca6f0CC5543bC57c |
| BatchSettler #1 (retired) | 0x247148601909395834e836CEa01B101D187E28a1 |
BatchSettler #2 (releaseBond) |
0xa3397ce4fDE01810F8540A25363A88D5e57f4166 |
Instance #1 is retired — it predates the challenge-path refund fix and releaseBond;
do not settle against it. Instance #2 is the live one.
Mainnet rehearsal (epoch 0, BatchSettler #2): commit escrows an operator-chosen bond
(0.0005 ETH), settle funds a 5-intent batch netting to 1000 wei, then a 6-hour
challenge window runs before claim and releaseBond return the funds — commit tx
0x2ed64056…66a8,
settle tx 0x621045df…1434.
The full life cycle closed on 2026-09-02: the window passed with zero challenges,
claim tx 0x189e72c8…20f3e0
paid the 1,000-wei net 74 s after unlock, and releaseBond tx
0x33b51686…e0afe1
returned the bond in full — the settler contract is drained.
The bond is escrowed, not burned: honest settlement returns it in full via releaseBond
(BatchSettler.sol:405). The contracts are open source and permissionless — anyone can
deploy their own BatchSettler and self-register as operator.
- 488,738 payments/s in-process aggregator ingest (signature verify → nonce → budget, all cores) — PoC report with reproduction command
- Hot path is allocation-free,
std-only HTTP/1.1 gateway and facilitator - CI runs a performance gate on every push (zero-allocation benchmarks, automatic re-test on suspected regression)
Mist ships an x402 adapter: the mist-v1 scheme, an EIP-3009 bridge that routes
standard x402 clients through the full DSA gate (no protocol layer bypassed), a
facilitator reference implementation, and both v1 and v2 wire formats. An entry in the
upstream x402 third-party extensions list is in review.
git clone https://github.com/changshenhan/mist.git && cd mist
bash scripts/verify.sh # full gate: fmt/clippy/test/bench/contracts/noir
cd contracts/rust-smoke && cargo run --release --bin m1_demo # 100k intents -> net settlement demo (needs foundry)Developer docs: docs/developers/quickstart.md
(5-minute walkthrough) and docs/developers/integration.md
(agent / framework / vendor).
Measured-engineering pieces live in docs/articles/: the
x402 gas ledger, a Barretenberg msgpack reverse-engineering, the pricing one-pager, the
mainnet settlement life cycle, and the position paper
why machine commerce does not need a new chain.
core/ DSA primitives + budget ledger (mist-core)
aggregator/ settlement kernel: ingest / commitment lattice / WAL / netting (mist-aggregator)
gateway/ multi-tenant network ingest gateway, std-only HTTP/1.1 (mist-gateway)
sdk/ agent integration: authorize / pay / attest + x402 fetch interception (mist-sdk)
facilitator/ x402 merchant reference implementation, fail-closed (mist-facilitator)
mcp-server/ MCP stdio server: 6 tools, keyless, real ZK proofs (mist-mcp)
monitor/ Prometheus /metrics + /healthz (mist-monitor)
bench/ benchmark base + allocation gate + CI gate (mist-bench)
contracts/ Solidity: DSA / RevocationRegistry / BatchSettler + rust-smoke
circuits/ Noir ZK circuits (intent_hash binding + revocation non-membership)
demos/ three-framework demos (LangChain / AutoGen / Eliza)
poc-delivery/ delivery proof via TLSNotary MPC-TLS (separate workspace)
- Contracts are live and exercised on mainnet; the epoch-0 rehearsal ran its full
life cycle end to end (commit → settle → 6 h window → claim →
releaseBond, bond returned, contract drained). - Internally audited (slither + a 130-test invariant/fuzz suite); an external audit is planned — no audit tag has been issued yet.
- ZK path: Noir circuits with real Barretenberg proving in CI; the production prover integration is separate (see TECH_SPEC).
- Single-operator deployment so far; multi-operator governance is designed (§6.17) and partially landed (P2 series), not yet exercised with multiple live operators.
Elastic License 2.0 — free for personal, internal, and research use; commercial
hosting/white-label settlement requires a license. See THIRD_PARTY.md for dependency
licenses.