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JustHandled Agent Utility Gateway

Official registry AI and agents

Thirty-two guarded agent utilities and maintained-data lookups over USDC x402.

Source code Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package @justhandledlabs/agent-client
Claude Code 
claude mcp add justhandled-agent-utility-gateway -e 'JH_EVM_PRIVATE_KEY=<your jh_evm_private_key>' -- npx -y @justhandledlabs/agent-client@0.11.1
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "justhandled-agent-utility-gateway": {
            "command": "npx",
            "args": [
                "-y",
                "@justhandledlabs/agent-client@0.11.1"
            ],
            "env": {
                "JH_EVM_PRIVATE_KEY": "<your jh_evm_private_key>"
            }
        }
    }
}

Environment variables

  • JH_EVM_PRIVATE_KEY required secret Private key for a dedicated Base wallet funded with USDC. Never use a primary wallet.

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. JustHandled Agent Client
  2. Inspect without a wallet
  3. Execute one paid utility
  4. MCP configuration
  5. Security model
  6. Development

JustHandled Agent Client

A guarded CLI, JavaScript client, and local MCP server for the JustHandled Agent Utility Gateway. The package exposes thirty-two preflights, maintained-data lookups, and evidence products. Twenty-two products cost $0.05 USDC; ten evidence-heavy or maintained-data products cost $0.25, including the live Chicago Contract Change Packet. Every paid call returns a versioned evidence receipt.

The client fails closed before signing. It accepts only the pinned JustHandled gateway, Base mainnet, canonical Base USDC, the exact per-product price, and the published merchant receiver. Customer inputs and complete customer results are not persisted by the gateway; maintained public-source snapshots are labeled in the receipt.

Inspect without a wallet

npx --package @justhandledlabs/agent-client justhandled-agent catalog
npx --package @justhandledlabs/agent-client justhandled-agent preview filename-portability-preflight --json '{"paths":["CON.txt"]}'
npx --package @justhandledlabs/agent-client justhandled-agent preview agent-run-evidence-pack --file agent-run-evidence-pack.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview agent-distribution-readiness-pack --file agent-distribution-readiness-pack.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview community-rule-credibility-preflight --file community-rule-credibility-preflight.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview qualified-demand-ledger --file qualified-demand-ledger.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview channel-fit-evidence-matrix --file channel-fit-evidence-matrix.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview proof-to-channel-evidence-packet --file proof-to-channel-evidence-packet.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview channel-experiment-postmortem --file channel-experiment-postmortem.sample.json
npx --package @justhandledlabs/agent-client justhandled-agent preview chicago-contract-change-packet --file chicago-contract-change-packet.sample.json

Preview performs an unpaid request and validates the returned x402 terms. It does not sign or spend.

The catalog includes API-response contract drift, webhook contract and replay, and policy-change evidence products. Packaged example inputs are available in examples/.

Machine-readable products, exact payment terms, and free deterministic fixtures are available from the gateway's product catalog, OpenAPI document, and sandbox index.

Execute one paid utility

Use a dedicated low-balance Base wallet. Never provide a primary wallet key.

export JH_EVM_PRIVATE_KEY=0x...
npx --package @justhandledlabs/agent-client justhandled-agent call filename-portability-preflight --json '{"paths":["CON.txt"]}'

PowerShell:

$env:JH_EVM_PRIVATE_KEY = "0x..."
npx.cmd --package @justhandledlabs/agent-client justhandled-agent call filename-portability-preflight --json '{"paths":["CON.txt"]}'

MCP configuration

{
  "mcpServers": {
    "justhandled": {
      "command": "npx",
      "args": ["-y", "@justhandledlabs/agent-client"],
      "env": {
        "JH_EVM_PRIVATE_KEY": "0xDEDICATED_LOW_BALANCE_WALLET_KEY"
      }
    }
  }
}

The MCP server exposes a free catalog tool plus one paid tool per gateway utility. Missing wallet configuration produces an error instead of a payment attempt.

The package declares the official MCP Registry identity io.github.justhandledlabs/agent-gateway. Registry identity is discovery metadata only: installing or listing the server does not spend funds, and paid execution still requires a dedicated wallet plus the client's exact-term checks.

Security model

  • Price, chain, asset, receiver, and gateway origin are pinned in code.
  • The ten $0.25 products' 250,000-base-unit price is pinned separately from 50,000-base-unit checks.
  • Every execution starts with an unpaid 402 preview.
  • A mismatched term aborts before signing.
  • The package never prints the private key.
  • The gateway does not persist customer inputs or complete customer results. Maintained-data products may retain normalized public-source snapshots and disclose that state in the receipt.
  • Treat all crypto transfers as irreversible and fund only a dedicated wallet.

Development

npm install
npm run check

The gateway implementation is intentionally not included in this client repository.

Frequently asked questions

What is JustHandled Agent Utility Gateway?

Thirty-two guarded agent utilities and maintained-data lookups over USDC x402.

How do I install JustHandled Agent Utility Gateway?

It runs on your machine. In Claude Code: claude mcp add justhandled-agent-utility-gateway -e 'JH_EVM_PRIVATE_KEY=<your jh_evm_private_key>' -- npx -y @justhandledlabs/agent-client@0.11.1. For other clients, paste the JSON configuration from this page into their MCP settings.

Does JustHandled Agent Utility Gateway need an API key?

Yes. It expects JH_EVM_PRIVATE_KEY, which you set in its configuration.

Is JustHandled Agent Utility Gateway open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains JustHandled Agent Utility Gateway?

It is published by justhandledlabs. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.