Export a watch-only output-script descriptor¶

Who this page is for: anyone who wants another wallet, an indexer, or a radiant-cli node to watch a pyrxd wallet’s addresses without holding its seed — and anyone who has already tried and been told Invalid descriptor.

An output script descriptor is a single string that says everything a watching tool needs: the script type, the extended public key, which master key it came from, at which derivation path, and which range to walk.

pkh([73c5da0a/44h/512h/0h]xpub6BmWw…NZpB/0/*)
 │    │        │           │            └── walk /0/0, /0/1, /0/2, …
 │    │        │           └── the account-level xpub
 │    │        └── the BIP44 path that produced it
 │    └── the master key's fingerprint
 └── P2PKH — the only script type Radiant has

A bare xpub carries only the middle piece. The consumer then has to guess the script type and has no way to tell which seed the key came from. The descriptor removes both guesses.

The one thing that will waste your afternoon¶

Radiant Core rejects the checksummed descriptor form that Bitcoin Core requires.

Radiant Core forked from Bitcoin Core before the 0.18 release that introduced descriptor checksums. Its src/script/descriptor.cpp has no checksum machinery at all, so the trailing #xxxxxxxx is unparseable input rather than an optional extra:

$ radiant-cli scantxoutset start '["pkh([73c5da0a/44h/512h/0h]xpub6BmWw…/0/*)#w5v8ec5w"]'
error code: -5
error message:
Invalid descriptor 'pkh([73c5da0a/44h/512h/0h]xpub6BmWw…/0/*)#w5v8ec5w'

Drop the checksum and the same descriptor is accepted. That is why pyrxd wallet export-xpub --descriptor emits no checksum by default. Add --checksum only when the consumer is a Bitcoin-Core-lineage tool that demands one — and expect Radiant Core to refuse that string.

Export the descriptors¶

$ pyrxd wallet export-xpub --descriptor

xpub at m/44'/512'/0':
  xpub6BmWwzAQXJ1dYPpnP3eQNN3XMCYD1Tvvy455NDJ6xDMAqAUfZHEzwZUWrCTgJw7Nr9PhpkZ9Kc7nNScnuanf7DB7PTEkL78kiaejmenNZpB

output script descriptors (master fingerprint 73c5da0a):
  receive: pkh([73c5da0a/44h/512h/0h]xpub6BmWw…NZpB/0/*)
  change:  pkh([73c5da0a/44h/512h/0h]xpub6BmWw…NZpB/1/*)

--json gives descriptor_receive, descriptor_change, master_fingerprint, and descriptor_origin_path alongside the existing xpub / account / path fields. --quiet prints the receive descriptor alone, for piping.

Import both, or under-report the balance¶

Two descriptors come out because a BIP44 wallet uses two chains: /0/* for the addresses you hand out, /1/* for change returning from your own spends. A watch-only import that takes only the receive descriptor will show a balance that is missing every change output — which, after a few spends, is most of the wallet. Import both.

Hardened steps are written `h`, not `'`¶

Both notations parse. h is the default because a descriptor containing ' cannot be pasted inside a shell’s single quotes without escaping, and that is exactly how radiant-cli invocations get written. If a consumer insists on apostrophes, rewriting 44h as 44' is a safe textual substitution — Radiant Core accepts either.

Scan the UTXO set with radiant-cli¶

scantxoutset is the descriptor consumer that ships with Radiant Core. It is marked EXPERIMENTAL in its own help text, and it walks the entire UTXO set on every call — expect it to take ten seconds or more and to load the node, so do not put it in a polling loop.

$ radiant-cli scantxoutset start '[{"desc":"pkh([73c5da0a/44h/512h/0h]xpub6BmWwzAQXJ1dYPpnP3eQNN3XMCYD1Tvvy455NDJ6xDMAqAUfZHEzwZUWrCTgJw7Nr9PhpkZ9Kc7nNScnuanf7DB7PTEkL78kiaejmenNZpB/0/*)","range":20}]'
{
  "success": true,
  "searched_items": 25950373,
  "unspents": [
  ],
  "total_amount": 0.00000000
}

(The xpub above is derived from the published BIP39 all-zero-entropy test mnemonic — a world-known key that must never hold value. Substitute your own.)

range is the highest child index to derive, and it defaults to 1000. Set it to at least your wallet’s highest used index plus the gap limit (pyrxd uses 20), or the scan will silently miss funds past the end of the range. Run the same command a second time with the /1/* descriptor for change.

What Radiant Core does not have¶

Habits from Bitcoin Core that will not transfer:

Bitcoin Core RPC	On Radiant Core
`getdescriptorinfo`	Absent — no way to ask the node for a checksum.
`deriveaddresses`	Absent — derive addresses client-side.
`importdescriptors`	Absent — no descriptor wallet import.
`scantxoutset`	Present. The only descriptor consumer.

Supported descriptor functions are pk, pkh, combo, multi, sh, addr, and raw. There is no wpkh, wsh, or tr — Radiant has no segwit and no taproot, which is why pyrxd emits pkh(...).

Privacy: what you are actually handing over¶

The descriptor exports no private key material. Someone holding it can derive your addresses and watch them; they cannot spend.

Note that this is a property of what pyrxd emits, not a property the format enforces: Radiant Core’s own scantxoutset help says a descriptor key may be “an xpub/xprv”, so the parser will happily accept a descriptor carrying a private key and nothing downstream will complain. pyrxd’s descriptor builders refuse a non-xpub key outright for that reason. If you are hand-assembling a descriptor, check the key starts with xpub before you send it anywhere.

But “cannot spend” is not “harmless.” An xpub — and therefore a descriptor — reveals every address the wallet will ever derive, on both chains, plus the fact that those addresses belong together. That is a permanent, whole-history disclosure, and it is a far larger one than handing someone a single receive address. Give it only to a party you would let read your entire transaction history, and prefer a single address for one-off payments.

Rotating away from a leaked xpub means moving the funds to a new seed. There is no revoking it.

Use it from Python¶

from pyrxd.hd import HdWallet

wallet = HdWallet.load(path, mnemonic)
d = wallet.descriptors()
print(d.receive, d.change, d.master_fingerprint)

checked = wallet.descriptors(checksum=True)   # BIP380 suffix; Radiant Core rejects it

pyrxd.hd.descriptor also exposes descriptor_checksum, append_checksum, and verify_checksum if you are handling descriptors from elsewhere.

The fingerprint is the master fingerprint¶

wallet.master_fingerprint() returns hash160(master pubkey)[:4] — the identifier of the key at m. It is deliberately not wallet.account_xpub().fingerprint, which is the BIP32 parent fingerprint stored inside the account key (the fingerprint of m/44'/<coin>', one level up). The two differ for any account below depth 1.

This distinction is easy to get wrong and hard to notice: a descriptor built with the parent fingerprint still derives all the right addresses, so balances look correct and nothing appears broken. It only fails later, when some consumer tries to match the descriptor against a signing device or against another descriptor from the same seed, and the origins do not line up.