Taproot multisig PSBT shows “missing information about inputs” even though it can be signed #36035

Is there an existing issue for this?

• I have searched the existing issues

Current behaviour

<img width="2880" height="1800" alt="Image" src="https://github.com/user-attachments/assets/aa70a4b7-ffaa-4246-8d1f-813cbea82d2b" />

This is my first time reporting an issue, so please let me know if I am missing something.

I have been testing Bitcoin Core more intensively over the last few days, mostly on Signet, and while testing a 2-of-3 Taproot multisig setup I noticed something that confused me.

I created a PSBT from a watch-only multisig wallet and loaded it into one of the signer wallets.

The GUI shows this message:

Transaction is missing some information about inputs

At first I thought something was wrong with the PSBT and that the signer would not be able to sign it.

However, when I process the same PSBT with walletprocesspsbt, the signer successfully adds its Taproot script-path signature. The result is complete: false, as expected after the first signature in a 2-of-3 multisig.

I also checked the original PSBT with analyzepsbt, and it reports:

{
  "inputs": [
    {
      "has_utxo": true,
      "is_final": false,
      "next": "updater"
    }
  ],
  "next": "updater"
}

But decodepsbt shows that the PSBT already contains the Taproot information such as:

• witness_utxo
• taproot_scripts
• taproot_bip32_derivs
• taproot_internal_key
• taproot_merkle_root

And after running walletprocesspsbt, the decoded PSBT contains a valid taproot_script_path_sigs entry.

So what confused me is that both the GUI and analyzepsbt suggest that more input information is required, while the signer is actually able to sign the PSBT successfully.

I would have expected analyzepsbt to report signer as the next step, or for the GUI to avoid showing the “missing information” message if the PSBT is already signable.

Setup:

• Bitcoin Core 31.1.0
• Signet
• macOS 26.5.2, Build 25F84
• Descriptor wallets
• 2-of-3 Taproot script-path multisig using sortedmulti_a
• Watch-only coordinator wallet with private keys disabled

If useful, I can provide the public descriptor, Signet transaction IDs, PSBT and more detailed reproduction steps.

Expected behaviour

If the PSBT already contains enough information for the signer wallet to successfully add a valid signature, I would expect the GUI not to show the message:

Transaction is missing some information about inputs

I would also expect analyzepsbt to report the next role as signer rather than updater.

If some additional information is actually missing, it would be helpful if Bitcoin Core indicated exactly which information is missing.

Steps to reproduce

1. Create three descriptor wallets to act as signers.

2. Create a 2-of-3 Taproot script-path multisig descriptor using sortedmulti_a.

3. Import the public multisig descriptor into a watch-only coordinator wallet.

4. Import the corresponding multisig descriptor into each signer wallet, with that signer’s private key and the other two signer keys public.

5. Fund an address generated from the watch-only multisig wallet.

6. Create an unsigned PSBT from the watch-only wallet spending the multisig UTXO.

7. Load that PSBT into one of the signer wallets using the GUI.

8. The GUI displays:

Transaction is missing some information about inputs

9. Run analyzepsbt on the same PSBT. It reports:

"next": "updater"

10. Run walletprocesspsbt <PSBT> in the signer wallet.

11. The signer successfully adds a Taproot script-path signature and returns:

"complete": false

12. Decode the returned PSBT and confirm that taproot_script_path_sigs contains the new signature.

How did you obtain Bitcoin Core

Pre-built binaries

What version of Bitcoin Core are you using?

31.1.0

Operating system and version

MacOS 26.5.2 Build 25F84

Machine specifications

Macbook Air M1, 2020