BIP394: rawtr() Output Script Descriptors #2251

jeanpablojp commented at 11:10 AM on August 12, 2026: contributor

This is a BIP draft for the rawtr() script expression, following the style of BIPs 381-387. Bitcoin Core has implemented it since 24.0 and it has never had a BIP; sipa noted that on #2050 in March.

While writing this I did some digging and found rawtr in more places than I expected. BIP 390 allows musig() inside it, and two of the BIP 390 test vectors are rawtr() descriptors, so a published BIP already points at an expression no BIP defines. Outside Core it's a gap people route around: rust-miniscript prints rawtr_not_supported_yet where a descriptor should be, and bdk-ffi's tests cite rawtr as BIP-386.

Mail list discussion: https://groups.google.com/g/bitcoindev/c/CCZN_qQ5C1s

jonatack added the label New BIP on Aug 12, 2026

achow101 commented at 10:55 PM on August 12, 2026: member

Concept ACK

danielabrozzoni commented at 7:00 PM on August 13, 2026: member

This was a very good read, thanks for submitting! It's coincise and easy to understand. Looks good to me! Though I think someone who knows more about descriptors than I do should also take a look :)

EDIT: I just realized, you should change BIP380's Appendix B to point to this page.

in bip-rawtr.mediawiki:7 in 54fea1a294

   0 | @@ -0,0 +1,104 @@
   1 | +<pre>
   2 | +  BIP: ?
   3 | +  Layer: Applications
   4 | +  Title: rawtr() Output Script Descriptors
   5 | +  Authors: Jean Moreira <jeanpablo.jp@hotmail.com>
   6 | +  Status: Draft
   7 | +  Type: Specification

danielabrozzoni commented at 5:43 PM on August 14, 2026:

I think the type should be "Informational", similarly to other descriptor BIPs:

BIP	Description	Type
380	Output Script Descriptors (general)	Informational
381	pk(), pkh(), multi() etc.	Informational
382	wpkh(), wsh()	Informational
383	sh()	Informational
384	combo()	Informational
385	raw(), addr()	Informational
386	tr()	Informational
387	multi_a(), sortedmulti_a()	Informational
389	Multipath descriptors	Informational
390	musig() (used inside rawtr())	Informational

jeanpablojp commented at 8:46 PM on August 14, 2026:

You are right, I just pushed the change. Thanks.

murchandamus commented at 6:19 PM on September 9, 2026:

Actually, I think all of these should be Specification BIPs. The criteria for BIP types were amended by BIP3 compared to BIP2, but we haven’t updated all of the affected BIPs, yet.

danielabrozzoni commented at 1:36 PM on September 17, 2026:

@murchandamus understood, thanks for pointing this out! I implemented the change of type in #2292 :)

jeanpablojp force-pushed on Aug 14, 2026

jeanpablojp commented at 3:10 PM on August 15, 2026: contributor

@danielabrozzoni about the Appendix B, BIP 3 says only the editor assigns the number, and until then the BIP is referred to by name. I can add the row now pointing to bip-rawtr.mediawiki, or wait for the editor to assign the number in this PR and register it with the number. Which do you prefer?

in bip-rawtr.mediawiki:7 in 4af973fc90

   0 | @@ -0,0 +1,104 @@
   1 | +<pre>
   2 | +  BIP: ?
   3 | +  Layer: Applications
   4 | +  Title: rawtr() Output Script Descriptors
   5 | +  Authors: jeanpablojp <me@jeanpablo.jp>
   6 | +  Status: Draft
   7 | +  Type: Informational

murchandamus commented at 6:25 PM on September 9, 2026:

Sorry for the back-and-forth on this, but this should please be a Specification BIP.

  Type: Specification

murchandamus commented at 7:53 PM on September 9, 2026: member

Thanks for your submission, this looks great already. I noticed that there was no Rationale section, yet. Please include one if you get any questions or comments about design decisions or related work, or you feel that content in that regard is missing.

Perhaps @achow101 could take a more thorough look at this, too.

Let’s call this BIP394. Please update the file name of your document, the corresponding preamble headers and add the README entry you were asking about with that number.

murchandamus renamed this:
~~BIP Draft: rawtr() Output Script Descriptors~~
BIP394: rawtr() Output Script Descriptors
on Sep 9, 2026

jeanpablojp force-pushed on Sep 14, 2026

BIP394: rawtr() Output Script Descriptors bf51f956d9

jeanpablojp force-pushed on Sep 14, 2026

jeanpablojp commented at 1:53 PM on September 14, 2026: contributor

Thanks for the number, @murchandamus.

Renamed to bip-0394.mediawiki, Rationale added, preamble updated, the Type: Specification suggestion taken, and the README row added.

I also added the rawtr(KEY) row to BIP 380's Appendix B, which is what @danielabrozzoni asked for and what BIP 392 and BIP 393 did in their own PRs.

murchandamus requested review from achow101 on Sep 23, 2026

fametrano commented at 8:18 PM on October 3, 2026: contributor

I recomputed every vector in the Test Vectors section with btclib's descriptor parser, and the single-key ranged ones a second time with plain BIP32 derivation and no descriptor code; all match. One normative sentence has no vector behind it: "compressed public keys would be implicitly converted to x-only public keys". The WIF vector covers it only indirectly, and nothing shows that the 02 and 03 forms of the same x give the same script. Core also rejects a 32-byte key whose x is not on the curve, which "must only create x-only public keys" does not make obvious. The two suggestions below, checked the same way, close both gaps in the format the section already uses.

in bip-0394.mediawiki:69 in bf51f956d9

  64 | +Valid descriptors followed by the scripts they produce. Descriptors involving derived child keys will have the 0th, 1st, and 2nd scripts listed. These vectors were generated with Bitcoin Core's descriptor implementation. Note that the first vector uses the same key as the first <tt>tr()</tt> vector of [[bip-0386.mediawiki|BIP 386]]: with <tt>rawtr()</tt> the key appears in the script unchanged, while <tt>tr()</tt> tweaks it. The third vector takes the output key that the BIP 386 vector produced and reproduces its script.
  65 | +
  66 | +* <tt>rawtr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)</tt>
  67 | +** <tt>5120a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd</tt>
  68 | +* <tt>rawtr(L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1)</tt>
  69 | +** <tt>5120a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd</tt>

fametrano commented at 8:18 PM on October 3, 2026:

** <tt>5120a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd</tt>
* <tt>rawtr(03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)</tt>
** <tt>5120a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd</tt>
* <tt>rawtr(02a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd)</tt>
** <tt>5120a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd</tt>

in bip-0394.mediawiki:101 in bf51f956d9

  96 | +* Script expression instead of a key expression: <tt>rawtr(pk(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd))</tt>
  97 | +* More than one key: <tt>rawtr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd,77aab6e066f8a7419c5ab714c12c67d25007ed55a43cadcacb4d7a970a093f11)</tt>
  98 | +* Tree expression, which <tt>rawtr()</tt> does not take: <tt>rawtr(a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd,pk(77aab6e066f8a7419c5ab714c12c67d25007ed55a43cadcacb4d7a970a093f11))</tt>
  99 | +* Uncompressed private key: <tt>rawtr(5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss)</tt>
 100 | +* Uncompressed public key: <tt>rawtr(04a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd5b8dec5235a0fa8722476c7709c02559e3aa73aa03918ba2d492eea75abea235)</tt>
 101 | +* No key: <tt>rawtr()</tt>

fametrano commented at 8:18 PM on October 3, 2026:

* No key: <tt>rawtr()</tt>
* X-only key with no point on the curve: <tt>rawtr(0000000000000000000000000000000000000000000000000000000000000005)</tt>