Send Allow

More from yellowgram: OSS tools.

Status: public MIT · npm [email protected] · no Polar

Non-custodial JSON-RPC middleware that gates eth_sendRawTransaction with an address allowlist and optional native spend caps (maxNativeWei). Signing stays outside the proxy. No simulation — for sim-before-send use L2 Send Guard (l2-send-guard) as a complementary layer.

Charter: no key custody · no Soft* · no Coinbase-plugin claim · no mainnet SLA — CHARTER.md

Supported surface (0.1.0)

| | | | --- | --- | | Is | A JSON-RPC proxy in front of your existing RPC | | Submit | Signed eth_sendRawTransaction (and Sync). eth_sendTransaction is refused (-32081) | | Policy | Deny if to not allowlisted and/or native value exceeds per-address / global caps → -32083 | | Undecodable | Default fail-open (forward). Optional fail_closed. Definite policy misses never fail-open | | Not | Simulation, key custody, hosted SaaS, mainnet SLA, a Coinbase / CDP plugin |

Pin

# from this tree (package not assumed published)
npm ci && npm test && npm run build

npm name: [email protected]. Imports: send-allow, send-allow/sdk. CLI: send-allow.

Quick start

cp policy.agent.example.json policy.json
# replace 0x1111… / 0x2222… placeholders
npm run policy:check -- ./policy.json   # must print OK

cp .env.example .env
# set SEND_ALLOW_UPSTREAM_RPC + SEND_ALLOW_POLICY_FILE=./policy.json

npm run build && npm start
# http://127.0.0.1:8546/health

SEND_ALLOW_HOST defaults to 127.0.0.1. Binding 0.0.0.0 without an ACL turns the proxy into an unauthenticated raw-tx forwarder.

Fail-open vs fail-closed

| Case | Behavior | | --- | --- | | to not allowlisted | fail-closed -32083 DESTINATION_NOT_ALLOWLISTED | | value over cap | fail-closed -32083 OVER_CAP | | contract create (no to) | fail-closed unless allowContractCreation | | raw undecodable | fail-open forward by default (SEND_ALLOW_UNDECODABLE_MODE=fail_open) |

P0 = fail-closed on every definite policy miss. See CHARTER.md.

Error codes

| Code | Meaning | | --- | --- | | -32081 | eth_sendTransaction refused — no key custody | | -32083 | policy_denied — allowlist / cap / (optional) undecodable fail-closed |

Codes align with L2 Send Guard where semantics match so agent halt helpers stay portable.

Prove it offline

npm ci
npm test
npm run build
npm run demo:offline

Details: docs/DEMO.md.

Agent / viem wiring

import { http } from "viem";
import { viemHttpArgs, isPolicyDeniedError } from "send-allow/sdk";

const transport = http(
  ...viemHttpArgs({ proxyUrl: "http://127.0.0.1:8546" })
);

Stub (does not import @coinbase/agentkit; not a Coinbase plugin): examples/agentkit-viem.ts.

Complementary: L2 Send Guard

| | Send Allow | L2 Send Guard | | --- | --- | --- | | Allowlist + native caps | yes (this package) | optional Layer 2 | | Simulate before send | no | yes (Layer 1) | | Fail-open | undecodable only (default) | uncertain sim (when GUARD_MODE=open) |

Stack them if you want both fences. This README does not sell a bundle or a hosted tier.

License

MIT — LICENSE.