Document EIP-3009 and Permit2 policy patterns

[andrewkmin]

Summary

• harden the Permit2 policy examples by pinning the EIP-712 encoding, chain, verifying contract, primary type, spender, and token constraints
• replace the incompatible numeric range example with decimal-string equality that matches normal Ethers and bigint-based Viem serialization
• document that standard Permit2 signature-transfer payloads do not commit the eventual recipient
• expand the EIP-3009 example to pin the complete USDC domain, signer, recipient, and exact amount
• list Permit2 in the Ethers and Viem example catalog

Why

The previous examples matched only the domain name and primary type, which left important domain and message fields unconstrained. The previous Permit2 amount-cap example also compared a serialized decimal string as a number, so it did not model the current policy evaluator behavior.

These examples make the enforceable boundary explicit and call out the recipient, nonce-history, relative-time, and cumulative-limit behavior that must be enforced elsewhere.

Validation

• parsed all JSON code blocks in features/policies/examples/ethereum.mdx
• validated the primary Permit2 and EIP-3009 conditions with mono's ConditionValidator
• git diff --check

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
turnkey-docs	🟢 Ready	View Preview	Jul 31, 2026, 4:51 AM

💡 Tip: Enable Workflows to automatically generate PRs for you.

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
turnkey-docs	🟡 Building	–	Jul 31, 2026, 4:49 AM

💡 Tip: Enable Workflows to automatically generate PRs for you.