Fix Compound dust rendering and add tx simulation - #7
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When the base token's decimals() multicall entry transiently fails, the reader silently fell back to 18. For USDC-backed markets (6 decimals) a nonzero supply rendered as ~0.0000002 USDC — which is how wallet C0f5...4075's 184k USDC cUSDCv3 position appeared in get_portfolio_summary while get_compound_positions (on a retry) decoded correctly. Skip the market when decimals are unknown and the base balance is nonzero, so the aggregator doesn't surface wrong-scale numbers. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Two related changes to the signing path: - New simulate_transaction MCP tool — generic eth_call with viem-decoded revert reasons. Lets the agent verify a contract call (e.g. is sending ETH to WETH9's fallback actually safe, does this custom calldata revert) without asking for a Ledger signature. - enrichTx now runs an eth_call on every prepared tx and attaches the result as tx.simulation; send_transaction re-simulates right before forwarding to Ledger and refuses when the tx would revert. The agent previously had no way to check, and the user would spend gas on a guaranteed failure to find out. Multi-step approve→action pairs legitimately show ok:false on step 2 at prepare time (no allowance yet) and pass at send time once the approve is mined. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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The address-book PR (#284) and the pre-existing sign_message_btc / sign_message_ltc tools together expand the signing surface beyond sign-transaction flows. SECURITY.md previously covered only the contacts blob signing trade-off (path C) and did not describe the free-form public sign-message tools at all. This commit: - Updates the contacts "EVM signing trade-off" paragraph to point at skill v4 Invariant #7 as the agent-side defense (decoration, tamper warning, sign-message-during-prepare anomaly check, post- add_contact verify cross-check), correctly attributing the contacts JSON preimage as NOT subject to character-by-character matching (its user-side defense is the recognizable domain prefix + JSON shape, per the skill's own carve-out). - Adds a new "Free-form message signing" section describing the public sign_message_btc / sign_message_ltc tools, the substitution threat, and skill v4 Invariant #8's MESSAGE-PREVIEW block as the agent-side defense (the user verifies the previewed string against the device screen character-by-character). - Notes that EVM has no equivalent public free-form signer (personal_sign is restricted to the contacts signer) and eth_signTypedData_v4 remains excluded from the WC namespace. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Summary
Two fixes surfaced during a live session with wallet
0xC0f5…4075:Compound V3 dust rendering — when the base token's
decimals()multicall entry transiently failed, the reader fell back to18. A 184 K USDC (6-decimal) supply incUSDCv3then rendered as~0.0000002 USDCinget_portfolio_summary, whileget_compound_positions(on a retry) decoded correctly. Fix: skip the market when decimals are unknown and the base balance is nonzero, rather than emit wrong-scale amounts.Blind signing without simulation — the agent had no way to verify a contract call before asking for a Ledger signature (e.g. is sending ETH to WETH9's fallback actually the canonical wrap). Now:
simulate_transactionMCP tool — genericeth_callwith viem-decoded revert reasons.enrichTxruns aneth_callon every prepared tx and attachestx.simulationto the preview.send_transactionre-simulates right before forwarding to Ledger and refuses when the tx would revert — no gas burned, no misleading device prompt for a guaranteed failure.Multi-step
approve → actionpairs legitimately showok: falseon step 2 at prepare time (no allowance yet) and pass at send time once the approve is mined.Test plan
npm test— 209 tests pass (6 new intest/simulation.test.ts, 1 new intest/session-regression.test.ts)npm run build— clean typechecksimulate_transactionagainst WETH9 withvalue: 0.5 ETHand confirmok: trueget_portfolio_summarynow correctly shows Compound V3 USDC supply for the affected wallet🤖 Generated with Claude Code