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Satsuma Engineering · day

Sunday, 4 October 2026

The system

First experiment run locally end to end: 10 of 10 swaps on a second chain

Satsuma pairs language models, which make its decisions, with a blockchain of its own that holds its funds and the limits it has to act within. Experiment 01 tested that pairing on a common task: keep a token holding balanced 50/50 by trading on an exchange on another chain, tangerine, which is a version of Satsuma started from a different initial state. Both chains ran locally, connected by a message bridge with an official Uniswap v2 build as the exchange. A person approved the limits once, and after that no person approved anything.

The recorded run lasted 19.6 minutes. All 10 of 10 swaps executed on tangerine, with a median round trip of 16.2 seconds. Two requests outside the approved limits were refused and none of them executed. Both failures that came up were reconciled, and the holding ended inside its target range at 48.1% tUSD. At the end, the final state was read from both chains and agreed with the recorded objective, the records of the approved limits, and the balances.

The bridge moves messages, not money. "Yes, but a message bridge, not a token bridge: no funds cross chains." The process that carries messages between the chains vouches for nothing: "In ISMP the relayer attests to nothing. It only delivers proofs that the destination verifies for itself, which is why it can delay a message but not forge one."

A swap service was chosen over a pay-per-use AI service as the scenario, because trading is the more familiar case. The run was written up as an article with a replay, a video and a short primer on swaps and automated exchanges, in a new Experiments section on this site. Biological wording was replaced with plain terms, and the language model is named as what it is. At the end of the session the article sat in an unmerged pull request, and its layout on phones had not been checked.

Running the same thing on the live chain still needs a newer node release and a Solidity entry point for the message bridge.

commits
  • Experiment 01: ISMP peering and a contract surface for itThe chain
  • Experiment 01: Satsuma trades on tangerineThe system
  • Experiment 01: recorded runs, on-chain verification, replay and video recorderThe system
  • Replay: name the language model plainly; re-rendered mediaThe system
explored
  • Pay-per-use AI inference as the demo scenario, dropped in favour of a more common trading action
decided
  • The scenario is a swap: keeping a holding balanced 50/50 on an exchange on tangerine
  • The two chains are connected by a message bridge with direct peering, and no tokens cross chains
  • For this experiment the limits are approved once by a person and no trade needs approval
  • Plain technical terms, no biological wording; the language model is named directly
  • Tests run locally, with tangerine as a version of Satsuma started from a different initial state
open
  • The article is in an unmerged pull request
  • Layout on phones and video playback have not been checked
  • Running this on Satsuma itself needs a newer node release and a Solidity entry point for the message bridge