bridging

A guide for moving assets between Ethereum’s main network and supported L2 networks, which are connected networks designed to process transactions separately. It covers canonical bridges operated by those networks and faster third-party routes.

In plain words
What is it for?
Use it to check bridge destinations, compare routes and round-trip timing, and decide whether to move assets between Ethereum, Arbitrum One, Robinhood Chain, and Base.
Why use it?
It addresses the risk of sending funds through fake contracts and the time and capital locked during bridge transfers, especially withdrawals.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/obolnetwork/obol-stack/bridging
Any agent
npx skills add ObolNetwork/obol-stack --skill bridging
Clone the repo
git clone --depth 1 https://github.com/ObolNetwork/obol-stack

Made for: Claude Code, Codex.

Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,707 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00128 $0.04707
Opus 5 $0.00064 $0.02354
Sonnet 5 $0.00026 $0.00941
Haiku 4.5 $0.00013 $0.00471

Measured 2d ago against content hash d2bb398626c9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bridging scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

metadata: { "openclaw": { "emoji": "🌉", "requires": { "bins": ["cast", "python3", "curl"] } } }
internal/embed/skills/bridging/SKILL.md · 329 lines

How it starts

The opening of the file, as written. The whole thing — 329 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bridging

Move value between Ethereum L1 and the L2s the Stack touches: Arbitrum One (42161), Robinhood Chain (4663, Arbitrum Nitro), and Base (8453, OP Stack). Bridging is the highest-stakes routine operation an agent can do — fake bridge contracts are a top drain vector, and canonical withdrawals lock capital for a week. This skill is about doing it safely and, just as often, about recognising when NOT to do it at all.

Signing goes through the agent's remote-signer (ethereum-local-wallet skill); reads go through eRPC (ethereum-networks skill). All bridge addresses come from the addresses skill references — every one was verified on-chain (eth_getCode + eth_call) on 2026-07-10.

Iron rules — no exceptions:

  1. Verify every bridge contract address before sending. It must appear in addresses/references/bridges.md or addresses/references/robinhood-chain.md, AND return real bytecode on-chain right now (rpc.sh code <addr>0x means EOA, abort; the inspect skill's contract.py check <addr> gives a fuller verdict: proxy, verified source, labels). Fake bridge contracts are a top drain vector. Never use a bridge address from web search, a DM, a chat log, or your own memory.
  2. Confirm with the user before bridging — state the amount, the exact route, the expected time BOTH directions (getting back matters), and the total cost including destination-side claim gas. Never bridge autonomously.
  3. First bridge on any new route = small test amount. Confirm arrival before sending the real amount.
  4. Never bridge the whole treasury. Keep gas plus working capital on the origin chain — you may need to act there while funds are in flight.
  5. Canonical withdrawals are a 7-DAY CAPITAL LOCKUP plus a separate L1 claim transaction (L1 gas). Treat withdrawn funds as illiquid until claimed. Any plan that assumes those funds are usable sooner is wrong.
  6. Bridged ERC-20 addresses DIFFER per chain. Resolve the destination token via the gateway router's calculateL2TokenAddress(l1Token) — never reuse the L1 address, never trust an explorer search result by token name (Robinhood Chain's explorer is full of scam "USDC").
  7. Ensure destination-chain ETH for gas BEFORE bridging ERC-20s — or bridge ETH first. Tokens you can't move are tokens you don't have.

Read the full file on GitHub · 329 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 329 lines · 128 tokens per session scan A d2bb398626c9

Subscribe to this mod's changes

bridging is a skill published in the GitHub repository ObolNetwork/obol-stack (11 stars, last pushed 3d ago), licensed Apache-2.0. It adds 128 tokens to every session and 4,707 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.