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.
npx skills add circlefin/skills --skill bridge-tokensgit clone --depth 1 https://github.com/circlefin/skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/circlefin/skills/bridge-tokens)<a href="https://agentmods.dev/skills/circlefin/skills/bridge-tokens"><img src="https://agentmods.dev/badge/skills/circlefin/skills/bridge-tokens/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/circlefin/skills/bridge-tokens"><img src="https://agentmods.dev/badge/skills/circlefin/skills/bridge-tokens.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00186 | $0.04306 |
| Opus 5.5 | $0.00074 | $0.01722 |
| Sonnet 5.5 | $0.00037 | $0.00861 |
| Haiku 4.5 | $0.00019 | $0.00431 |
Grade A, and why
bridge-tokens scanned grade A with 0 findings 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 9d 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 256 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Overview
This skill bridges tokens across chains with Circle's App Kit or Bridge Kit. USDC moves over Crosschain Transfer Protocol (CCTP) -- burn on the source chain, mint on the destination. CCTPx tokens use a registry alias (such as wETH, cirBTC, or EURC) or a registry-listed token ID. Both run through the same kit.bridge() call -- pass the alias or token ID directly as token and the SDK routes it automatically; there is no protocol to choose. App Kit (@circle-fin/app-kit) is Circle's all-inclusive SDK covering bridge, swap, and send in one package; standalone Bridge Kit (@circle-fin/bridge-kit) ships the same bridge API in a lighter package. Recommend App Kit unless the user wants bridge-only functionality. Bridge operations need no kit key.
Both SDKs run in browser and server applications. Use browser wallet provider adapters in client code and keep private keys plus Circle Wallets credentials on the server. App Kit >=1.11.0 and Bridge Kit >=1.12.2 bundle for browsers without consumer-provided Node or Buffer polyfills. CCTPx tokens require App Kit or Bridge Kit >=1.15.0; browser apps bridging CCTPx tokens need App Kit >=1.15.2 or Bridge Kit >=1.15.1.
Supported tokens & routes
Pass a registry alias or token ID directly as token in kit.bridge() and kit.estimateBridge() (App Kit) / kit.estimate() (Bridge Kit); do not wrap it in a provider-selector object. The SDK routes it to the correct protocol automatically. Only USDC supports Solana; every CCTPx route is EVM-to-EVM. Aliases are case-sensitive ("wETH", not "WETH"), and a token ID is a bytes32 hex string (0x followed by 64 hex characters).
| Token selector | Supported chains |
|---|---|
USDC |
All CCTP-supported chains (EVM + Solana) -- see supported chains |
EURC |
Ethereum, Base, and Arc on mainnet, plus eligible testnet routes |
wETH |
Ethereum <-> Arc on mainnet, plus eligible testnet routes |
cirBTC |
Ethereum <-> Arc on mainnet, plus eligible testnet routes |
| Registry-listed token ID | Any EVM route where the CCTPx registry lists that token on both endpoint domains |
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 9d ago First seen · 256 lines · 186 tokens per session scan A ad12b1597a85
bridge-tokens is a skill published in the GitHub repository circlefin/skills (155 stars, last pushed 2d ago), licensed Apache-2.0. It adds 186 tokens to every session and 4,306 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-10.
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