How do I install the Vhs skill?

Run npx skillmds@latest add juspay/vhs 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.

What does the Vhs skill do?

Techniques for creating deterministic terminal demo screencasts with VHS It is listed under Coding & Dev Tools on SkillMD.

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Vhs?

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.

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

juspay (@juspay) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Vhs by juspay — Agent Skill

Name: Vhs
Author: juspay

File contents

VHS Demo Recording

VHS records terminal sessions by scripting keystrokes in .tape files and rendering them as GIFs. Use Wait+Screen /regex/ to synchronize with interactive TUI elements instead of fragile fixed Sleep durations. VHS can only detect text appearing on screen, not disappearing — keep this constraint in mind when designing wait conditions.

Non-Deterministic TUI Responses

When recording an LLM-powered TUI, detecting when a response is complete requires special care. Naive approaches all fail:

Approach	Why it fails
Fixed `Sleep`	Not deterministic
Unique marker in prompt (`XYZENDXYZ`)	Appears in the typed prompt on screen — `Wait+Screen` matches immediately
Math formula (`347+829` → wait for `1176`)	LLM computes the answer in its visible thinking trace before the response finishes
`Wait+Line /^MARKER$/`	TUI padding/borders prevent exact line matching
`Hide` + type marker	`Hide` only hides VHS command log, not terminal content

The concatenation trick

Ask the LLM to concatenate two words and print the result. The prompt contains both words separately but never the combined string:

Type "briefly explain this repo. Then print ALFA concatenated with BRAVO."
Enter
Wait+Screen /ALFABRAVO/

Why it works:

Typed prompt shows ...ALFA concatenated with BRAVO — no ALFABRAVO
Thinking trace says "I need to concatenate ALFA and BRAVO" — no ALFABRAVO
Response outputs ALFABRAVO — the only match

Use uncommon words (ALFA, BRAVO, ZULU) so the combined form can't appear accidentally.

Tips

Run VHS from the correct CWD — it inherits the working directory. If the prompt references "this repo", the CWD must be the repo root, not a subdirectory.

Inspect GIF frames when debugging timing issues:

ffmpeg -i demo.gif -vf "select='eq(n\,100)'" -vsync vfr /tmp/frame.png

Nix Integration

If the project uses Nix, create a dedicated flake.nix for the demo (e.g., doc/demo/flake.nix) so anyone can reproduce the recording with nix run.
Reference tape by Nix store path in flake apps (vhs "${./.}/demo.tape") — don't cd into the store, as it may contain a flake.nix that confuses nix run inside the recording.

---name: vhsdescription: Techniques for creating deterministic terminal demo screencasts with VHS---# VHS Demo Recording[VHS](https://github.com/charmbracelet/vhs) records terminal sessions by scripting keystrokes in `.tape` files and rendering them as GIFs. Use `Wait+Screen /regex/` to synchronize with interactive TUI elements instead of fragile fixed `Sleep` durations. VHS can only detect text *appearing* on screen, not disappearing — keep this constraint in mind when designing wait conditions.## Non-Deterministic TUI ResponsesWhen recording an LLM-powered TUI, detecting when a response is **complete** requires special care. Naive approaches all fail:| Approach | Why it fails ||---|---|| Fixed `Sleep` | Not deterministic || Unique marker in prompt (`XYZENDXYZ`) | Appears in the typed prompt on screen — `Wait+Screen` matches immediately || Math formula (`347+829` → wait for `1176`) | LLM computes the answer in its visible *thinking trace* before the response finishes || `Wait+Line /^MARKER$/` | TUI padding/borders prevent exact line matching || `Hide` + type marker | `Hide` only hides VHS command log, not terminal content |### The concatenation trickAsk the LLM to **concatenate two words** and print the result. The prompt contains both words *separately* but never the combined string:```tapeType "briefly explain this repo. Then print ALFA concatenated with BRAVO."EnterWait+Screen /ALFABRAVO/```**Why it works:**1. **Typed prompt** shows `...ALFA concatenated with BRAVO` — no `ALFABRAVO`2. **Thinking trace** says "I need to concatenate ALFA and BRAVO" — no `ALFABRAVO`3. **Response** outputs `ALFABRAVO` — the only matchUse uncommon words (ALFA, BRAVO, ZULU) so the combined form can't appear accidentally.## Tips- **Run VHS from the correct CWD** — it inherits the working directory. If the prompt references "this repo", the CWD must be the repo root, not a subdirectory.- **Inspect GIF frames** when debugging timing issues: ```bash ffmpeg -i demo.gif -vf "select='eq(n\,100)'" -vsync vfr /tmp/frame.png ```## Nix Integration- If the project uses Nix, create a dedicated `flake.nix` for the demo (e.g., `doc/demo/flake.nix`) so anyone can reproduce the recording with `nix run`.- **Reference tape by Nix store path** in flake apps (`vhs "${./.}/demo.tape"`) — don't `cd` into the store, as it may contain a `flake.nix` that confuses `nix run` inside the recording.

Frequently asked questions

Vhs