# Rex3 This page is an informative summary of the Rex3 specification. For the full normative definition, see the Rex3 spec in the mega-evm repository. ## Summary Rex3 addresses two issues with [oracle](/spec/system-contracts/oracle.md) [gas detention](/spec/megaevm/gas-detention.md) and fixes a gap in [keyless deploy](/spec/system-contracts/keyless-deploy.md) resource accounting. The oracle access [compute gas](/spec/reference/glossary.md#compute-gas) cap is increased from 1M to **20M**, matching the block environment cap. The 1M cap was too restrictive for legitimate use cases, causing frequent `VolatileDataAccessOutOfGas` halts in contracts that need meaningful computation after reading oracle data. Oracle detention is also changed from CALL-based to **SLOAD-based** triggering — simply calling the oracle contract without reading its storage no longer activates gas detention. Finally, the keyless deploy sandbox overhead (100K gas) is now properly tracked as compute gas. ## What Changed ### Oracle Access Compute Gas Limit Increase #### Previous behavior * Oracle access (triggered by CALL or STATICCALL to the oracle address) caps compute gas at 1,000,000 (1M). #### New behavior * Oracle storage reads (SLOAD from the oracle contract) cap compute gas at 20,000,000 (20M). * The block environment access cap remains at 20M (unchanged). * When both block environment and oracle storage are accessed, neither is more restrictive than the other. ### Oracle Gas Detention Triggers on SLOAD #### Previous behavior * CALL or STATICCALL to the oracle contract address triggers gas detention. * Any CALL or STATICCALL to the oracle triggers detention even without reading storage. #### New behavior * SLOAD from the oracle contract's storage triggers gas detention. * CALL to the oracle contract address alone does not trigger gas detention — only an SLOAD from the oracle's storage triggers it. * The SLOAD-based trigger is caller-agnostic: any SLOAD reading the oracle contract's storage triggers detention regardless of call depth. * DELEGATECALL to the oracle does not trigger detention — SLOAD in a DELEGATECALL context reads the caller's storage, not the oracle's. * Transactions from `MEGA_SYSTEM_ADDRESS` are exempted from oracle gas detention (unchanged, but the exemption now checks the transaction sender rather than the call-frame-level caller). ### Keyless Deploy Compute Gas Tracking #### Previous behavior * The 100K overhead gas for keyless deploy sandbox execution is deducted from call frame gas but not recorded as compute gas. * Keyless deploy transactions do not count the overhead toward the per-transaction compute gas limit. #### New behavior * The 100K keyless deploy overhead is recorded as compute gas. * If recording the overhead causes the compute gas limit to be exceeded, execution halts. ## Developer Impact **Contracts that read oracle data can now perform more computation.** The oracle access cap increased from 1M to 20M, providing 20× more post-access compute budget. Contracts that previously hit `VolatileDataAccessOutOfGas` after oracle reads should no longer encounter this issue. **Simply calling the oracle no longer triggers detention.** Only actual SLOAD reads from oracle storage activate the cap. Contracts that call the oracle contract for hint operations or other non-storage-reading functionality are no longer penalized. **The gas detention cap is still absolute in Rex3.** Transactions that have consumed more than 20M compute gas before an oracle SLOAD will halt immediately. Rex4 changes this to a relative cap — see the [Rex4 upgrade page](/spec/network-upgrades/rex4.md). ## Safety and Compatibility All pre-Rex3 behavior is unchanged. The shift from CALL-based to SLOAD-based oracle detection more accurately captures actual oracle data access. DELEGATECALL to the oracle is excluded because SLOAD in a DELEGATECALL context reads the caller's storage, not the oracle's — this is consistent with Rex2 behavior. The [`MEGA_SYSTEM_ADDRESS`](/spec/system-contracts/system-tx.md) exemption now checks `TxEnv.caller` (the transaction sender) rather than the call-frame-level caller, meaning the entire transaction from the system address is exempted regardless of call depth. ## References * [mega-evm repository](https://github.com/megaeth-labs/mega-evm) * [Gas Detention](/spec/megaevm/gas-detention.md) — background on the gas detention mechanism * [Oracle Service](/spec/system-contracts/oracle.md) — oracle contract documentation --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.megaeth.com/spec/network-upgrades/rex3.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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