Wallet or vault: which MON a trade is allowed to spend

An entry spends one pile of MON. The screen shows three candidates and people add them. The pay chip is the connected wallet: native MON, WMON, and USDCm. The vault line, when you are armed, is a different contract. The trading key is a third address and it is for gas, not for the size of the trade. If the chip says 640 MON and the vault holds 0, the trade has to come from the wallet. Sending it to the vault produces the revert you can quote from memory: the vault only holds 0 MON. Nothing was signed. No gas was spent. And nothing was bought.

What the two errors mean

“The vault only holds 0 MON” means the transaction was built against the vault and the simulation refused it. That is the simulator doing its job. The fix is not a higher gas limit. The fix is to spend the wallet, which has the coin, or to put MON into the vault first if you truly want the agent to trade it.

“No quote” means the quoter did not answer in time and the desk refused to invent an output. For a wallet entry the pool price is already on the card. The desk now uses that price when the quoter is silent, and only fails when it cannot see the pool at all. A missing quote is no longer a reason to do nothing when slot0 is on the screen.

Arming a vault does not fill it. An empty vault cannot buy. The wallet can.

When the vault is the right payer

Use the vault when its MON balance covers the size and you want the position kept inside it, so the agent can exit later without a popup. Check the vault’s MON on the card, not the wallet chip. If it covers the size, the entry is a desk-key transaction: no wallet popup, a gas limit of 550,000, and a minimum output at 99 percent of the expected tokens. The position is booked to the vault address. My money shows it with the other trades. Closing it is the key’s job, not a second approval of the token in your wallet.

When the wallet is the right payer

Use the wallet when the chip is where the money is. You will sign. Native MON is sent as value with the swap, and the router wraps it. WMON and USDCm need an approval the first time. The output tokens land in the wallet. The fill is stored against your address. A later close sells from that address. Do not then look for the tokens in the vault. They are not there, and a vault close of a wallet fill will not find them.

A thirty-second decision

Read the chip. Read the vault’s MON if a vault is armed. If only one of them covers the size, that one pays. If both do, pick the vault when you want the agent to be able to leave the trade, and the wallet when you want the tokens in the address you already use everywhere else. If neither covers the size, do not sign. The button will tell you. Getting MON onto the chain is a separate job, and a searched “bridge” in an ad is not part of it.