safe-transactions

Aave transaction preparation

Every tool named below comes from Aave's MCP server, https://mcp.aave.com. If get_markets is not available, add it first: claude mcp add --transport http aave https://mcp.aave.com (Claude Code), codex mcp add aave --url https://mcp.aave.com (Codex), or point any other MCP client at the URL.

Non-custodial: every tool here returns an unsigned transaction for the user's own wallet to sign. Say what a prepared transaction will do once signed, and that nothing has been sent.

The chain is discover → inspect → simulate → build, then hand over unsigned.

Steps

1. Discover — get_markets with symbols, and user set to the sender, in this session even when a market looks familiar: selectors (v4 reserveId; v3 market + token + chainId) are deployment-specific and cannot be recalled. The user rows say what this wallet can actually supply or borrow before anything is built.
2. Inspect — get_user_summary for what the wallet already owes and how much room it has, and get_reserve_details where the reserve's own parameters bear on the action. A borrow or a withdraw sized without this is a guess.
3. Simulate — preview_action with the exact parameters you intend to build. Mandatory before every borrow and withdraw; run it for supply and repay too. An error-level warning means the action cannot succeed as specified: fix the inputs or tell the user, rather than building it.
4. Build — prepare_action with the same selectors and amount. Follow the returned plan in order: an approval step comes before the action, and a sent transaction is confirmed with get_transaction_processed before building one that depends on it.
5. Hand over — show the unsigned transaction, the simulated outcome (the health factor after, for anything touching debt or collateral), and every warning (warning level succeeds but must reach the user). Then stop: signing is the user's move.

Rules

• Amounts are in main units ("10.5" = 10.5 USDC), never base units or wei.
• Borrowing needs collateral enabled: a plain supply backs nothing. Pass enableCollateral: true when the plan includes borrowing against it.
• The same chain — discover, inspect, simulate, build, hand over unsigned — applies to every other prepare_* tool (swaps, collateral toggles, e-mode, rewards, sGHO).

Done when

• The simulation ran on the exact parameters that were built, and its outcome is in the answer.
• Every warning the server returned reached the user, by level.
• The transaction is presented unsigned, with the post-action health factor wherever debt or collateral moved.

Why simulate first

preview_action is the cheapest place for an action to fail, and the only place that reports the position's shape: it returns the resulting health factor, which the build step does not. Skipping it costs a round trip on a refusal and, worse, hands the user a transaction whose effect on their health factor nobody has read. A clean simulation reports the position's own limits, not token allowances — an approval step can still be waiting in the plan.