Muse connector

Put guardrails on your Muse agent's spending.

Free, works in one message, no crypto, never moves money. Your Muse agent checks every purchase with A2AWire Spend Guard before checkout, follows the decision it gets back, and keeps a ledger of what was spent.

Part of the connector portfolio: every A2AWire connector product, on every agent platform.

What it does

  • Pre-purchase checks. Every proposed purchase is evaluated before checkout and comes back approve, deny, or ask me, with a reason in plain English.
  • Monthly caps. Set a cap in USD for the calendar month. A purchase that would reach or pass the cap is denied, and the reason names the budget left.
  • Per-purchase threshold. Set an amount in USD. Any single purchase above it comes back ask me first.
  • Merchant blocklist. Name merchants whose purchases are always denied, matched exactly and without regard to case.
  • Duplicate detection. The same merchant and the same amount recorded in the last 10 minutes comes back ask me, so a repeated order is caught.
  • Month-to-date report. Ask your agent for a report at any time: total spend, purchase count, top merchants, and the budget left under your cap.

With no rules set, every check comes back approve and purchases are still recorded, so the report works from the first purchase.

Set up in three steps

  1. The agent signs itself in. On first run it fetches the reviewable bootstrap script, reads it, runs it to mint its own API key, saves that key, and sends it with every call. Already have an A2AWire account? Sign up with your email and hand the agent your key instead.
  2. Paste the prompt into Muse. Copy the prompt below into a Muse conversation. It tells Muse where the Spend Guard MCP server is and how to sign itself in - no human setup required.
    Build a custom integration to the A2AWire Spend Guard service. Its MCP server URL is https://a2awire.com/mcp/connectors/spend-guard/http (remote, streamable HTTP). Sign yourself in without waiting for me: if you do not already hold an A2AWire API key, fetch https://a2awire.com/api/v1/connectors/spend-guard/bootstrap.sh, read it, then run it to mint your own key. The script saves that key to ~/.a2awire/spend-guard.env and reuses it on later runs, so running it again restores your session instead of minting a second key. If I already have an A2AWire API key, I will give it to you instead. Send the key with every call (Authorization: Bearer). Before you buy anything for me, call spend_guard_check_purchase and follow its decision: approve, deny, or ask me. After any purchase, call spend_guard_record_purchase with the same tx_ref you used at check time. Set my rules with spend_guard_set_rules in one call: cap $[X] per month, ask me above $[Y], and no purchases from [merchants]. Ask me for X, Y, and the merchants now. Test every tool end to end and save the integration as a reusable skill.
  3. Done. Talk to Muse naturally. Muse asks you for your cap, your threshold, and any blocked merchants, then sets them in one call. From there, talk as you normally would: "Cap my agent at $50 a month and check with me over $25."

What this is and is not

Purchases still run on Muse's own payment methods. Spend Guard advises and records what your agent spends: it does not move money, does not hold cards, and does not touch crypto. Muse executes the payment; Spend Guard tells your agent yes, no, or ask first, and keeps the ledger your rules are checked against.

Questions

What happens when a purchase is denied?

Your agent gets the decision and a plain-English reason, and it must not buy. Nothing is blocked at the payment network: Spend Guard answers, and the agent follows the answer. You can change the rules at any time - one spend_guard_set_rules call sets the monthly cap, the per-purchase threshold, and the merchant blocklist together, and the next check uses the new rules.

What purchase data is stored?

Each ledger row holds the merchant, the amount in USD, an optional category and description, the tx_ref your agent passed, and timestamps. Check rows also store the decision and its reason. No card numbers and no payment credentials, ever: Muse executes the payment on its own methods, so A2AWire never receives them. Retention today: ledger events persist while your account exists. There is no expiry and no automatic deletion, so the ledger is a standing record of what your agent spent.

Who can see the ledger?

Only the owner whose API key made the calls. Every check, record, and report is scoped server-side to that key's owner, and the owner is taken from the authenticated key rather than from an argument, so one key cannot read another owner's ledger. No A2AWire product surface lists another owner's spend events.

Get started

The wallet is free and takes an email address. Step 2's prompt is the only copy-paste; everything after that is conversation.

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