Hermes Tempo Payments

Standalone Hermes plugin for onboarding a Tempo Wallet and giving Hermes agents a payment-aware HTTP tool backed by the official Tempo Wallet CLI.

What it does

• hermes tempo setup connects a Tempo Wallet using Tempo's passkey authorization flow.
• hermes tempo setup --no-browser supports a Hermes host running on a remote machine.
• hermes tempo setup --install can explicitly run Tempo's official installer when the CLI is missing.
• tempo_wallet_status lets the agent inspect the connected wallet without spending.
• tempo_request lets the agent call paid HTTP endpoints through tempo request.
• Agent requests default to mode="preview", which maps to tempo request --dry-run and does not pay.
• mode="pay" is required before the agent may let Tempo Wallet satisfy a compatible payment challenge.

Protocol note: MPP vs x402

Tempo Wallet's current CLI handles HTTP 402 Payment Required using Machine Payments Protocol (MPP). It is not a generic implementation of Coinbase's x402 wire protocol. An endpoint that only supports x402 and does not advertise a compatible MPP challenge will not become payable merely by installing this plugin.

The integration intentionally says "MPP" and "HTTP 402" in its tool descriptions so Hermes does not overstate interoperability.

Security model

This plugin never reads or stores a root private key. Wallet authorization is delegated to the official Tempo Wallet CLI. Tempo's wallet flow uses passkey authorization and stores a restricted access/session key locally for subsequent signing.

tempo_request also enforces these guardrails before invoking Tempo:

• HTTPS is required for remote endpoints.
• Plain HTTP is only accepted for loopback development addresses.
• URLs with embedded credentials are rejected.
• Payment is preview-only unless mode="pay" is explicitly selected.
• Command output and errors are bounded before they are returned to the Hermes model context.
• Subprocesses use argument arrays and never invoke a shell.

Wallet-side spending limits remain the hard boundary. Only fund or authorize an amount you are prepared for the agent to spend.

Install

This repository is structured as a Hermes standalone plugin because Hermes' contribution guidelines require third-party product integrations to ship outside core.

After publishing this directory to GitHub:

hermes plugins install wundercorp/hermes-tempo-pay --enable

For a local checkout during development, use the plugin install mechanism supported by your Hermes build or copy/symlink the directory under ~/.hermes/plugins/tempo_payments and enable the plugin.

Onboard a wallet

If Tempo Wallet is already installed:

hermes tempo setup

If Hermes runs on a remote host:

hermes tempo setup --no-browser

If Tempo Wallet is not installed and you want the plugin to execute Tempo's official installer explicitly:

hermes tempo setup --install

Install + remote-host login:

hermes tempo setup --install --no-browser

Fund after connecting:

hermes tempo fund

Preview and pay from the CLI

Preview only:

hermes tempo request https://example.mpp.tempo.xyz/v1/resource

Allow payment:

hermes tempo request --pay https://example.mpp.tempo.xyz/v1/resource

POST JSON while still previewing:

hermes tempo request -X POST --json '{"input":"hello"}' https://service.mpp.tempo.xyz/v1/stream

Agent tool

A normal first call should look conceptually like:

{
  "url": "https://example.mpp.tempo.xyz/v1/resource",
  "mode": "preview"
}

After inspecting the preview, the agent can make a separate call with:

{
  "url": "https://example.mpp.tempo.xyz/v1/resource",
  "mode": "pay"
}

For a POST:

{
  "url": "https://service.mpp.tempo.xyz/v1/stream",
  "method": "POST",
  "json_body": {
    "input": "hello"
  },
  "payment_intent": "session",
  "mode": "preview"
}

Development

Run the standalone tests against a Hermes checkout:

PYTHONPATH=/path/to/hermes-agent python -m pytest -q --import-mode=importlib tests