fix(sdk-core): pass txParams on EdDSA MPCv2 re-sign and PA paths

[bitgo-ai-agent-dev]

Summary

EdDSA MPCv2 TSOL signing fails on the pending-approval (PA) path with:

failed to sign transaction Error: Number of tx outputs does not match with number
of txParams recipients

Root cause: eddsaMPCv2.signRequestBase re-verifies the transaction against
txParams.recipients before DSG starts:

  await this.baseCoin.verifyTransaction({
    txPrebuild: { txHex: unsignedTx.serializedTxHex ?? txOrMessageToSign },
    txParams: params.txParams || { recipients: [] },  // ← falls back to []
    ...
  });

Solana's verifyTransaction does a strict length check:

if (filteredRecipients.length !== filteredOutputs.length) {
  throw new Error('Number of tx outputs does not match with number of txParams
recipients');
}

Why ECDSA MPCv2 is unaffected: ETH's verifyTssTransaction gates its strict
recipient checks on txParams.type. Without a type, those checks are skipped and {
recipients: [] } passes silently.

Why EdDSA MPCv1 is unaffected: MPCv1's signRequestBase does not call
verifyTransaction with txParams in normal flows.

Fix

Derive txParams from the persisted txRequest.intent inside recreateTxRequest,
guarded to EdDSA MPCv2 only — matching the pattern established by WCI-505:

Ticket: WCI-765

[linear-code]

WCI-765

[danielpeng1]

nice work; look into the fix for UI re-sign as well, unless you're planning to do that in a second PR, although it might be easier to reuse something for both paths.

[danielpeng1]

@claude review and verify validity of requested changes

[github-actions]

Claude finished @danielpeng1's task —— View job

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Review Analysis - Daniel's Feedback Valid ✅

I've analyzed the current PR implementation and Daniel's review feedback. All of Daniel's concerns are technically valid and should be addressed for a complete fix.

• Read current PR implementation
• Examine UI re-sign path in wallet.ts
• Analyze recipient mapping concerns
• Review test coverage issues
• Provide comprehensive assessment

Key Issues Identified

1. UI Re-sign Path Missing Fix ⚠️

Valid Concern: The current fix only covers the PA path in recreateTxRequest(), but the UI re-sign path via signAndSendTxRequest() → getUserKeyAndSignTssTransaction() → signTransactionTss() is also broken.

Root Cause: In wallet.ts:4733, signTransactionTss() calls:

this.tssUtils!.signTxRequest({
  txRequest: params.txPrebuild.txRequestId,  // Just the ID
  txParams: params.txPrebuild.buildParams,   // Always undefined for re-sign
  ...
})

When re-signing, buildParams is undefined because only txRequestId is passed, leading to the same empty recipients: [] fallback.

2. Recipient Mapping Issues ⚠️

Valid Concerns:

• Native SOL: Intent stores symbol: 'tsol' but native SOL txParams should NOT have tokenName (see test example)
• Token mapping: Only set tokenName when r.amount.symbol !== this.baseCoin.getChain()
• Non-payment txs: Need to map txParams.type for enableToken, etc., since SOL skips recipient checks when txParams.type === 'enabletoken'

3. Test Coverage Gaps ⚠️

Valid Concerns:

• Current test expects tokenName: 'tsol' but should be { address, amount } only for native SOL
• Missing test coverage for UI re-sign path (signAndSendTxRequest with only txRequestId)
• Missing SPL token test case with symbol: 'tsol:usdc' → tokenName: 'tsol:usdc'

Recommended Implementation Strategy

Daniel's suggestion for a shared helper function is the best approach:

1. Extract shared helper used by both baseTSSUtils.ts and wallet.ts
2. Handle all recipient mapping edge cases in one place
3. Add comprehensive test coverage for both paths

This would ensure consistency and avoid code duplication while fixing both the PA path (already implemented) and the UI re-sign path (currently missing).

Technical Validation

• ✅ PR correctly identifies the root cause (empty txParams.recipients)
• ✅ Guard condition is appropriate (EdDSA MPCv2 only)
• ✅ Intent parsing approach matches WCI-505 pattern
• ❌ Missing UI re-sign path coverage
• ❌ Incomplete recipient mapping logic
• ❌ Test expectations don't match SOL verification requirements

Verdict: Daniel's requested changes are technically sound and necessary for a complete fix.

---

Job: https://github.com/BitGo/BitGoJS/actions/runs/12224654675
Branch: wci-765-fix-eddsa-mpcv2-txparams

[danielpeng1]

lgtm for both paths 👍