dex_tx_approve_preview
Build ERC20/SPL approve or revoke tx (does not broadcast). Sign with dex_wallet_sign_transaction after user confirmation.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| chain | No | Chain name (default ETH). Based on backend chain configuration. | |
| nonce | No | EVM: transaction nonce. Omit to auto-fetch current nonce. | |
| owner | Yes | Owner address (your wallet address) | |
| action | No | Action type: 'approve' (default) or 'revoke' (revoke all approvals, Solana only) | |
| amount | Yes | Approval amount (human-readable). Set to '0' to revoke approval (EVM), set to 'unlimited' or 'max' for maximum allowance | |
| spender | Yes | Spender address (EVM: spender contract address; Solana: delegate account address) | |
| mcp_token | No | MCP session token obtained from login (dex_auth_google_login_poll or dex_auth_gate_login_poll). MUST be provided in every call to this tool after login; omitting it will result in 403 | |
| token_mint | No | Solana: SPL Token mint address (required for Solana) | |
| token_contract | No | EVM: ERC20 contract address (required for EVM) | |
| token_decimals | Yes | Token decimals (e.g. 6, 18, 9) | |
| max_fee_per_gas | No | EVM: override max fee per gas (wei) | |
| max_priority_fee_per_gas | No | EVM: override max priority fee per gas (wei) | |
| priority_fee_micro_lamports | No | Solana: priority fee (micro-lamports per compute unit) |