bridge

ChainGPT Bridge Skill

You move funds between EVM mainnets via Across Protocol v3. Intent-based — once the deposit lands on the origin chain, a relayer (Across calls them "fillers") provides the destination liquidity within seconds. Fees: capital + relay gas + LP, all returned in the quote.

Tools

Tool	Purpose
chaingpt_bridge_quote	Fees + estimated fill time + SpokePool addresses
chaingpt_bridge_build_deposit_tx	Unsigned depositV3 tx (refuses mainnet w/o ack)
chaingpt_bridge_status	Track a deposit by origin-chain tx hash

The mandatory pipeline

chaingpt_bridge_quote
       │  (surface fees + fill time to user)
       ▼
chaingpt_dex_approve_tx token=<inputToken> spender=<spokePoolAddress from quote> acknowledgeMainnet=true
       │  (skip if inputToken is native — ETH/MATIC/etc.)
[user signs the approval]
       │
       ▼
chaingpt_bridge_build_deposit_tx (requires acknowledgeMainnet=true)
[user signs the deposit on the ORIGIN chain]
       │  (~seconds later)
       ▼
chaingpt_bridge_status depositTxHash=<hash>
       │  (returns destination fill tx hash once relayer fills)
       ▼
chaingpt_onchain_tx hash=<destination fill hash> chain=<destination>

Supported networks

Ethereum · Base · Arbitrum · Optimism · Polygon · BSC · Avalanche · Blast · Linea · Scroll. Any pair of these can be bridged.

Key behavior

• Fee math: input − relay_fee − lp_fee = output. The quote returns the exact outputAmount needed to keep the relayer profitable. Don't modify it.
• Native vs ERC-20: native bridging (ETH→ETH on a different chain) is value-bearing; the deposit tx must include value: inputAmount. ERC-20 sets value: 0 and uses the prior approval.
• Exclusivity: each quote names an exclusiveRelayer for the first exclusivityDeadline seconds. Other relayers can fill after.
• Fill deadline: defaults to 4 hours. If unfilled by then, the depositor can be refunded.

What this skill does NOT do

• Bridge to/from Solana, Sui, Aptos, or any non-EVM chain. Across is EVM-only.
• Bridge tokens that don't exist on both chains (e.g., a Base-native memecoin to Ethereum). The output token must already be deployed on the destination.
• Refund stuck deposits. After fillDeadline, the user has to call requestSlowFillV3 separately — not yet a tool in this plugin.

Credit accounting

All bridge tools cost 0 ChainGPT credits — Across is free. Credit funnel comes from upstream chaingpt_intel_token (the user typically wants to research the destination token before bridging) or chaingpt_audit_contract (for unfamiliar destination contracts).

Reference

• Across v3 docs: https://docs.across.to
• SpokePool ABI: this skill uses depositV3(depositor, recipient, inputToken, outputToken, inputAmount, outputAmount, destinationChainId, exclusiveRelayer, quoteTimestamp, fillDeadline, exclusivityDeadline, message)