| --- |
| license: apache-2.0 |
| pretty_name: Hydrogen computer-use environment from a one-line request (REA) |
| tags: |
| - computer-use |
| - cua |
| - gui-agent |
| - rl-environment |
| - agentenv |
| - desktop |
| - linux |
| - rea |
| - music |
| - drum-machine |
| - audio |
| - from-request |
| --- |
| |
| # Hydrogen: a computer-use environment built from a one-line request |
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|  |
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| **The real Hydrogen 1.2 (beta) drum machine running on an Ubuntu 24.04 desktop, as an [agentenv](https://pypi.org/project/agentenv-framework/) computer environment. An agent completes the task only through screenshots, mouse and keyboard, and a verifier grades the saved files with no model.** |
|
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| Claude Code built this environment from a one-line request in about 30 minutes, with only REA's build skill and MCP tools; [How it was made](#how-it-was-made) has the request and the steps. Hydrogen opens a small drum-machine song, `Documents/backbeat.h2song`, at launch: Backbeat Sketch, at 96 BPM, with an eight-note Verse Groove pattern. The agent has to change the song's tempo to 112 BPM and save. It sees only the screen and acts only with the mouse and keyboard. |
|
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| ## Watch |
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| - Agent runs (Claude Code with Claude Sonnet 5.5): [run 1](media/solve-1.mp4), [run 2](media/solve-2.mp4), [run 3](media/solve-3.mp4) |
| - Witness, which proves the task can be done through the computer: [witness.mp4](media/witness.mp4) |
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| Each video is the computer's own screen recording at 10 frames per second. |
|
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| ## The task |
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| > In Hydrogen, change the tempo of the Backbeat Sketch song in Documents/backbeat.h2song to 112 BPM and save it. |
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| `bundle/artifacts/change-tempo-check/verify.py` reads the app's files through the computer's `data/get` view and passes only if every check holds: |
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| | Check | Kind | File | |
| | --- | --- | --- | |
| | `tempo` | `text_equals` | `Documents/backbeat.h2song` | |
| | `song-name-kept` | `text_equals` | `Documents/backbeat.h2song` | |
| | `groove-notes-kept` | `member_count` | `Documents/backbeat.h2song` | |
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| An `.h2song` file is XML. The checks read the song's top-level elements: `bpm` must be 112, the song's `name` must still be Backbeat Sketch, and the pattern named Verse Groove (`[>name=Verse Groove]`, a selector on a child element's text) must still hold its eight notes (`member_count`). REA's draft suggested the tempo check, kept exactly as written; Claude Code added the other two. |
|
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| ## Results |
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| 3 of 3 runs passed, about $0.67 per run. |
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| | Run | Outcome | Turns | Cost | Video | |
| | --- | --- | --- | --- | --- | |
| | 1 | passed | 8 | $0.94 | [video](media/solve-1.mp4) | |
| | 2 | passed | 8 | $0.41 | [video](media/solve-2.mp4) | |
| | 3 | passed | 8 | $0.66 | [video](media/solve-3.mp4) | |
|
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| ## Run it |
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| You need Docker. `agentenv-framework` builds the computer: Ubuntu 24.04 with the app installed from Ubuntu's archive (`hydrogen` 1.2.0~beta1, with `pulseaudio`). |
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| ```bash |
| pip install agentenv-framework==0.9.1431 |
| hf download earakely-scale/HydrogenFromRequestComputerEnv-REA --repo-type dataset --local-dir hydrogen-request |
| agent-env run hydrogen-request/bundle --task change-tempo --agent claude-code --model <model> |
| ``` |
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| The agent needs a model provider configured for agentenv. `--task smoke` only boots the computer, with no agent. `bundle/README.md` describes the bundle in detail. |
|
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| ## How it was made |
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| Claude Code built this environment from a one-line request, given only [REA](https://github.com/morluto/rea)'s build skill and REA's MCP tools: |
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| > Build me a Hydrogen environment where the agent changes a song's tempo in a small drum pattern project and saves it. |
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| It asked only the skill's upfront questions, wrote no app-specific scripts, and finished in about 30 minutes. |
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| Claude Code abandoned one build computer and started again on a fresh one. With no audio device in the computer, a tempo typed into Hydrogen's BPM field snapped back to 120, so before saving the seed Claude Code set Hydrogen's ALSA audio device to `null` in its preferences; the seed keeps that setting. It had also asked for `pulseaudio` as an extra package, which did not help. The steps were REA's usual ones: |
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| 1. **Capture.** REA launched Hydrogen on a Linux desktop and recorded its package, windows and opened files while the edit was made. It also recorded the app's state folders before and after. |
| 2. **Export.** REA turned the capture into an agentenv `computer_app`. It installs the app, seeds the starting files, starts the app, and waits for its main window. It also serves typed views of the app's files for verifiers. |
| 3. **Task.** The task's checks were validated against the capture: they fail on the starting state and pass on the captured end state. |
| 4. **Witness.** In a fresh computer, the edit was made through computer actions alone, and the checks were read at four stages. They held on the first try: |
|
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| | Stage | Checks | |
| | --- | --- | |
| | `seed` | fail, as expected: the tempo is 96; the kept checks pass | |
| | `after_edit` | pass | |
| | `near_miss` | fail, as expected: the tempo was typed as 121 | |
| | `after_reset` | fail, as expected: `data/reset` restored the seed | |
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| The agent runs came after the build: Claude Code with Claude Sonnet 5.5 (`--model anthropic/claude-sonnet-5-5 --no-emulate`, on an amd64 host) solved the task 3 times, each run recorded. |
|
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| ## What's inside |
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| ``` |
| bundle/ the agentenv bundle: envs/ (app module, seed files), tasks/, artifacts/ (verifier), evals/ |
| media/ witness and agent-run recordings (MP4) with short GIF previews |
| results.json the runs above, with each check's result |
| ``` |
|
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| ## Limits |
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| - The seed sets Hydrogen's ALSA audio device to `null` (in `~/.hydrogen/hydrogen.conf`). The computer has no sound card, and without that setting a tempo typed into Hydrogen's BPM field snaps back to 120. The null device keeps about one CPU core busy while Hydrogen runs. |
| - The bundle also installs `pulseaudio` beside the app as an extra package, which the build asked for. It does not help: the null device is what makes the tempo stick. |
| - Only the tempo, the song's name and the Verse Groove pattern's note count are checked; the instruments and the song's other settings are not. |
| - The seed also holds Hydrogen's autosave of the song from before it was first saved (`~/.hydrogen/data/.emptySong.autosave.h2song`), which the capture picked up; the checks read only `Documents/backbeat.h2song`. |
| - The computer installs whatever `hydrogen` Ubuntu 24.04's archive holds at build time (1.2.0~beta1, a beta release, for these runs); it is not pinned. |
| - Three runs is a small sample: the solve rate shows the task is solvable, not how hard it is. |
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| ## Licences |
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| The bundle code, the task and the synthetic seed files are Apache-2.0. Hydrogen itself is not included: the computer installs it from Ubuntu's archive (`hydrogen` 1.2.0~beta1, with `pulseaudio`) at build time, under its own licence (GPL-2.0-or-later). |
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