[jxom]

Adds a genesis option to Instance.tempo and prool/testcontainers' Instance.tempo. It receives the dumped genesis of the selected chain, after hardfork applies, and returns the genesis that the node starts from. Without chain, it starts from the dev chain, as hardfork does.

Tempo's dev genesis has no field for some settings that only a genesis sets, such as configurableAccountRecoveryFactory (TIP-1107), which no published image sets yet. Today a caller sets one by running dump-genesis in its own container and starting a generic one from the edited file.

Instance.tempo({
  genesis: (genesis) => ({
    ...genesis,
    config: { ...genesis.config, configurableAccountRecoveryFactory: '0x7171717171717171717171717171717171717171' },
  }),
})

• prepareGenesis in src/internal/tempoGenesis.ts applies hardfork, then genesis. Both instances use it.
• The process instance keeps a changed genesis's data in tempo.<port>.genesis-<digest>, keyed by the SHA-256 of the final genesis, so a node never reuses data from another genesis. hardfork alone keeps its current folder.
• genesis is not passed to the node as a flag.

Validation: pnpm check:types and pnpm check pass. A new testcontainers test sets config.chainId to 1338 and reads 0x53a from eth_chainId, and behavior: selects hardfork still passes. The process instance is not covered locally, since it needs a tempo binary.

---

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commit: febf7fe

[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-23T06:07:47.017432Z	ba03ca1	PR opened

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