How do I install the Bitcoin Hardware Psbt Flows skill?

Run npx skillmds@latest add claude-dev-suite/bitcoin-hardware-psbt-flows in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Bitcoin Hardware Psbt Flows safe to use?

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Which AI agents work with Bitcoin Hardware Psbt Flows?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Bitcoin Hardware Psbt Flows free to use?

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Who published Bitcoin Hardware Psbt Flows?

claude-dev-suite (@claude-dev-suite) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Bitcoin Hardware Psbt Flows by claude-dev-suite

Name: Bitcoin Hardware Psbt Flows
Rating: 4.2 (5 reviews)
Author: claude-dev-suite

Bitcoin Hardware Psbt Flows

PSBT signing flow patterns across HW vendors: USB direct, microSD airgap, QR airgap, NFC, multi-device coordination. USE WHEN: designing HW signing UX, debugging cross-device PSBT flow, supporting multi-vendor multisig.

claude-dev-suite Updated Sep 8, 2026 28 repo stars

File contents

PSBT Signing Flow Patterns

A summary of how PSBTs flow through different hardware wallet transports.

Flow types

USB direct (online signer)

Host wallet ──── PSBT ────► HW (via USB)
            ◄── signed PSBT

Wallets: Trezor, Ledger, BitBox02, Coldcard via USB, Jade USB, Keystone (charging only).

Pro: fastest. Con: USB connectivity = potentially compromised host.

microSD airgap (true offline)

Host wallet → save PSBT to SD → eject → insert into HW → sign on
HW → eject → insert into Host

Wallets: Coldcard, Passport, Jade (with SD), Keystone.

Pro: no USB connection; truly airgapped. Con: SD card handling overhead.

QR airgap (animated QR / BCUR)

Host wallet displays animated QR → HW reads via camera
→ HW signs → HW displays animated QR → Host reads

Wallets: Passport, Coldcard Q, Jade, Keystone, SeedSigner, Krux.

Pro: no physical connection. Con: scan time for big PSBTs.

BCUR (Blockchain Commons UR Format) is the standard encoding for multi-frame QR. Compatible wallets must understand BCUR.

NFC tap

Host (phone) → NFC tap to HW → HW signs → NFC tap back

Wallets: Coldcard Mk4 / Q, Passport (limited), some others.

Pro: convenient with Android. Con: iOS NFC limited; PSBT size limits.

Coordinator role

For multisig, a coordinator wallet handles:

Build PSBT.
Send to signer 1, get partial sig.
Send to signer 2, get partial sig.
Combine + finalize.
Broadcast.

Coordinators:

Sparrow Desktop — best for cross-vendor multisig.
Specter Desktop — multisig + multiple HW.
Caravan — web-based multisig.
Bitcoin Core with HWI external signer.

PSBT versions

v0 (BIP174): widely supported.
v2 (BIP370): newer; spec-compliant signing only on modern devices.

For multi-device multisig, all signers must agree on PSBT version or coordinator transcodes between them.

Cross-vendor multisig

Best practice: use descriptors with key origins:

wsh(sortedmulti(2,
  [fp1/48'/0'/0'/2']xpub1.../<0;1>/*,
  [fp2/48'/0'/0'/2']xpub2.../<0;1>/*,
  [fp3/48'/0'/0'/2']xpub3.../<0;1>/*
))#chk

Each signer's device must:

Have its xpub at the declared path.
Match key origin fingerprint.
Recognize the wallet policy (Ledger requires explicit registration with HMAC).

Common pitfalls

PSBT missing data: device rejects if non_witness_utxo or tap_internal_key missing for the input type.
Path mismatch: device can't find the key for declared derivation.
Multi-vendor wallet policy registration: Ledger requires explicit wallet-policy + HMAC registration before multisig signing.
Stale PSBT: signer signed an old version; coordinator must reconcile.
Air-gap delays: long PSBTs via QR/SD take minutes; users abandon.

---name: bitcoin-hardware-psbt-flowsdescription: PSBT signing flow patterns across HW vendors: USB direct, microSD airgap, QR airgap, NFC, multi-device coordination. USE WHEN: designing HW signing UX, debugging cross-device PSBT flow, supporting multi-vendor multisig.---# PSBT Signing Flow PatternsA summary of how PSBTs flow through different hardware wallettransports.## Flow types### USB direct (online signer)```Host wallet ──── PSBT ────► HW (via USB) ◄── signed PSBT```Wallets: Trezor, Ledger, BitBox02, Coldcard via USB, Jade USB,Keystone (charging only).Pro: fastest. Con: USB connectivity = potentially compromised host.### microSD airgap (true offline)```Host wallet → save PSBT to SD → eject → insert into HW → sign onHW → eject → insert into Host```Wallets: Coldcard, Passport, Jade (with SD), Keystone.Pro: no USB connection; truly airgapped. Con: SD card handlingoverhead.### QR airgap (animated QR / BCUR)```Host wallet displays animated QR → HW reads via camera→ HW signs → HW displays animated QR → Host reads```Wallets: Passport, Coldcard Q, Jade, Keystone, SeedSigner, Krux.Pro: no physical connection. Con: scan time for big PSBTs.BCUR (Blockchain Commons UR Format) is the standard encoding formulti-frame QR. Compatible wallets must understand BCUR.### NFC tap```Host (phone) → NFC tap to HW → HW signs → NFC tap back```Wallets: Coldcard Mk4 / Q, Passport (limited), some others.Pro: convenient with Android. Con: iOS NFC limited; PSBT sizelimits.## Coordinator roleFor multisig, a **coordinator** wallet handles:1. Build PSBT.2. Send to signer 1, get partial sig.3. Send to signer 2, get partial sig.4. Combine + finalize.5. Broadcast.Coordinators:- **Sparrow Desktop** — best for cross-vendor multisig.- **Specter Desktop** — multisig + multiple HW.- **Caravan** — web-based multisig.- **Bitcoin Core** with HWI external signer.## PSBT versions- v0 (BIP174): widely supported.- v2 (BIP370): newer; spec-compliant signing only on modern devices.For multi-device multisig, **all** signers must agree on PSBT versionor coordinator transcodes between them.## Cross-vendor multisigBest practice: use **descriptors with key origins**:```wsh(sortedmulti(2, [fp1/48'/0'/0'/2']xpub1.../<0;1>/*, [fp2/48'/0'/0'/2']xpub2.../<0;1>/*, [fp3/48'/0'/0'/2']xpub3.../<0;1>/*))#chk```Each signer's device must:- Have its xpub at the declared path.- Match key origin fingerprint.- Recognize the wallet policy (Ledger requires explicit registration with HMAC).## Common pitfalls- **PSBT missing data**: device rejects if `non_witness_utxo` or `tap_internal_key` missing for the input type.- **Path mismatch**: device can't find the key for declared derivation.- **Multi-vendor wallet policy registration**: Ledger requires explicit wallet-policy + HMAC registration before multisig signing.- **Stale PSBT**: signer signed an old version; coordinator must reconcile.- **Air-gap delays**: long PSBTs via QR/SD take minutes; users abandon.## See also- [hwi/SKILL.md](../hwi/SKILL.md)- [multi-vendor-multisig/SKILL.md](../multi-vendor-multisig/SKILL.md)- [../wallets/hd/SKILL.md](../../wallets/hd/SKILL.md)- [../../protocol/psbt/SKILL.md](../../protocol/psbt/SKILL.md)

Frequently asked questions