openharness

<!-- Generated by store/tools/hands-on.mjs. Edit store/hands-on.json, not this file. -->
# Get your hands on it

The agent brings the tools of a craft. You bring the idea, the taste and the next thing to try.

[Interactive guide](hands-on.html) — open this HTML file from the checkout in a browser for the craft picker, copyable prompts and local video players. [Start a Harness project](../README.md#run-it).

These eight experiences are included in this source checkout. The recorded demos show separately authored projects; the prompts below are starting ideas for your own work. Jev's demo uses offline practice answers.

[Run a native starter](try-hands-on.md) to try the physics, music or circuit panes directly from this checkout with installed harness assets.

## MuJoCo: Try a different world.

Take one moment in a robot's run and see two futures unfold together. Change the ground, gravity or a sideways shove, then scrub to the moment they part ways.

[Watch the real session](images/mujoco-what-if-demo.mp4) · [See the pane](images/mujoco-what-if-shove.png) · [Harness guide](../store/viewers/mujoco-viewer/README.md)

A real MuJoCo session: a 100 N sideways force for 0.15 seconds, with the same recorded controls in both worlds.

**Start a MuJoCo project and give the agent a direction:**

> Load the Unitree Go2 and make it stand, then do three slow squats. Record the motion so I can open What if, change the surface friction and compare what happens from the same moment.

1. **Catch a moment.** Open What if, choose a body to follow and pin the current state.
2. **Change one thing.** Try Slippery ground or Lunar gravity, then Compare futures. Scrub both worlds together, or click Farthest apart to inspect the greatest sampled difference.
3. **Keep the experiment.** Save experiment preserves the model, its assets, the starting state, controls and measured frames. Measurements CSV keeps the numbers too.

**Yours to keep:** A reproducible physics experiment and measurements CSV.

**Continue from your kept work:**

> Read my saved physics-experiment.json and reproduce it with the MuJoCo experiment tool. Explain when the robot first loses height, then help me change the controller and record another run.

Keep the result in this project, or give the agent the path to your downloaded copy.

Both futures use the same recorded controls. This compares open-loop physics; it does not rerun the Python controller.

## Blender: Shape it until it feels right.

Ask for the controls that matter to your design. Turn them yourself, watch Blender rebuild the geometry, and keep the directions you want to come back to.

[Watch the real session](images/blender-shape-lab-demo.mp4) · [See the pane](images/blender-shape-lab.png) · [Harness guide](../store/agents/blender/README.md)

A real Blender build of an authored ribbon lamp, with saved design variants.

**Start a Blender project and give the agent a direction:**

> Design a sculptural desk lamp from twisting ribbons. Give me Shape Lab controls for height, twist, ribbon count and finish, with sensible ranges. I want to explore the proportions myself and keep a few directions before the final render.

1. **Choose your controls.** Ask the agent for meaningful Shape Lab controls in the scene it builds. The starter mug already has a set to try.
2. **Find a direction.** Change the values and build a preview. Orbit the actual geometry, keep a named design and compare it with another.
3. **Make it yours.** Download a kept design's project ZIP. Use values on next build carries your chosen values into the agent's next full export and render.

**Yours to keep:** Source, chosen values, model, measurements and a standalone rebuild script.

**Continue from your kept work:**

> Use my chosen Shape Lab values for the next build. Refine the base and cable opening without losing these proportions, then export the model and render a turntable.

Keep the result in this project, or give the agent the path to your downloaded copy.

Each preview builds real Blender geometry. Build time depends on the scene; previews stay separate from the main export until the next full build.

## Godogen: Try that moment again.

Miss a jump, rewind and try another move. When something feels great or needs work, pin the exact moment so the agent can see what you mean.

[Watch the real session](images/godogen-rewind-demo.mp4) · [See the pane](images/godogen-rewind.png) · [Harness guide](../store/viewers/game-viewer/README.md)

A real playable browser game, including state restoration and saved playtest feedback.

**Start a Godogen project and give the agent a direction:**

> Make a small rooftop delivery game with three jumps, a visible destination and forgiving controls. Make Rewind and Try from here work for the complete game state, so I can replay a difficult moment and leave useful playtest notes.

1. **Play a little.** Enter Play in a game with Rewind support. The viewer remembers the recent run while you play.
2. **Try another move.** Open Rewind and scrub back. Try from here resumes from that state; returning to the live moment restores the run you left.
3. **Pin what matters.** Pin moment with a Keep, Change or Explore note. Saved moments reopens that game version, screenshot and state after later edits.

**Yours to keep:** A screenshot, complete game state, feedback and that version's compiled game.

**Continue from your kept work:**

> Read the saved playtest moments in out/playtests. Make the jump in my Change note easier to read, preserve the movement I marked Keep, then let me play the revised version.

Keep the result in this project, or give the agent the path to your downloaded copy.

Rewind needs snapshot support in the authored game. Saved moments preserve compiled output; editable source stays in the project, and external assets still need their original service.

## Strudel: Perform the version you love.

A track is an instrument you can play. Bring voices in and out, try a code change and mark the part you want to hear again. Keep the sound of that performance.

[Watch the real session](images/strudel-live-take-demo.mp4) · [See the pane](images/strudel-live-take.png) · [Harness guide](../store/agents/strudel/README.md)

A real performance of the original Lantern room track. The video includes the captured audio.

**Start a Strudel project and give the agent a direction:**

> Write a warm 96 bpm evening groove with drums, a rounded bass, soft chords and a small bell melody. Use synths so it works offline, name the voices, and leave space for me to mute, solo and record a live take.

1. **Start the instrument.** Click Play, listen to the voices and choose Record take when you are ready.
2. **Perform it.** Mute or solo a voice, run a code change and mark a moment. Finish take opens the captured stereo audio with a seekable waveform.
3. **Keep the sound.** Name the performance and Keep take. Reopen it from Takes or download Audio + source to carry it away.

**Yours to keep:** A stereo WAV, played code versions and a timed performance journal in a ZIP.

**Continue from your kept work:**

> Listen to the take I kept and read its journal in out/takes. Build the next arrangement around the quiet section I marked, using the source version that was playing there.

Keep the result in this project, or give the agent the path to your downloaded copy.

Takes capture up to two minutes of the instrument's output. The WAV preserves what you heard from it; external samples and custom imports are not bundled.

## RDKit: See a molecule turn.

Choose a flexible bond and move through its sampled shapes. Watch atoms approach one another, follow the calculated energy curve and keep a pose worth investigating.

[Watch the real session](images/rdkit-bond-scan-demo.mp4) · [See the pane](images/rdkit-bond-scan.png) · [Harness guide](../store/agents/rdkit/README.md)

A native RDKit bond scan on an authored molecule, shown with its starting conformer.

**Start a RDKit project and give the agent a direction:**

> Build a 3D conformer of 2-phenylethanol with explicit hydrogens. I want to explore a flexible non-ring single bond in Bond scan, compare its shapes and understand where steric crowding raises the rigid MMFF94 energy.

1. **Pick a bond.** Open Bond scan and Use current conformer. Choose a four-atom chain, or measure a dihedral with T and four atom clicks.
2. **Explore its shapes.** Scan bond, then drag the energy curve, scrub the rotation or jump to the lowest sampled point. Compare against the starting pose.
3. **Keep a study.** Choose a pose, add a note and Keep study. Download the full scan and its Python reproducer, or reopen it from the saved library.

**Yours to keep:** Input and sampled conformers, selected SDF, energy CSV and reproducible calculation source.

**Continue from your kept work:**

> Read the note and selected.sdf from my kept study in out/torsions. Reproduce its energy curve, explain the crowded poses and suggest another bond to explore.

Keep the result in this project, or give the agent the path to your downloaded copy.

This is a rigid MMFF94 scan, with the other internal coordinates fixed. It does not establish a relaxed barrier, equilibrium population or biological activity.

## Typst: Point at what you mean.

Hold a draft still while you read it. Quote a sentence, circle a detail or leave a page note, then compare the next draft without losing the one you reviewed.

[Watch the real session](images/doc-review-demo.mp4) · [See the pane](images/doc-review.png) · [Harness guide](../store/viewers/doc-viewer/README.md)

A real Typst PDF rendered by pdf.js, with review notes carried into a later revision.

**Start a Typst project and give the agent a direction:**

> Make a two-page design brief for a small desk lamp: the idea, intended use, dimensions, materials and three open questions. Use Typst and give it a clear visual hierarchy. I want to review the PDF in the pane before we revise it.

1. **Hold this draft.** Open Review and Hold this draft. The exact PDF stays still while the agent continues working.
2. **Point and explain.** Select text and Note selected text, Pin an area or add a Page note. Mark it Change, Keep or Question and write what you mean.
3. **Carry it forward.** Keep review, then ask the agent to read its review.md. Compare latest deliberately; unique exact quotations can follow text to another page.

**Yours to keep:** The reviewed PDF, anchored notes, readable feedback and a portable review ZIP.

**Continue from your kept work:**

> Read the kept review in .harness/doc-reviews, including review.md and reference.pdf. Revise the editable Typst source around my Change notes and preserve the details marked Keep.

Keep the result in this project, or give the agent the path to your downloaded copy.

Changed or repeated quotations need human inspection. Area and page notes stay with the reviewed PDF. The packet includes the PDF and feedback; editable source stays in the workspace.

## Jev Sheets: Ask a better question.

Before asking a whole spreadsheet, compare two versions of a question on frozen rows. Read the answers side by side and use your judgment to decide what the wording missed.

[Watch the real session](images/question-lab-demo.mp4) · [See the pane](images/question-lab.png) · [Harness guide](../store/agents/jev-sheets/README.md)

Offline practice with fictional rows. The demo shows the workflow, not Jev's live judgment quality.

**Start a Jev Sheets project and give the agent a direction:**

> Help me turn our support tickets into a sheet. Start with an urgency question, then suggest clearer wording to compare in Question Lab. I want to review a small sample and the unsure rows before asking the entire file.

1. **Freeze a sample.** Open Question Lab, choose an existing question and write a candidate. Preview 10, 20 or 40 rows and inspect the exact text and context.
2. **Compare the wording.** Compare asks both versions together. Inspect changed answers and full probabilities, then mark Original, New wording or Unsure and add your notes.
3. **Keep your reasoning.** Keep this trial saves the evidence. Try on whole sheet adds the candidate as a separate column; ask the agent to retain the chosen header in sheet.json.

**Yours to keep:** Frozen rows, exact questions, answers, probabilities, provider details, your notes and CSV/ZIP exports.

**Continue from your kept work:**

> Read my kept trial in .harness/question-trials, including the rows and review.md. Help me choose clearer wording and retain that header in sheet.json before running the whole file.

Keep the result in this project, or give the agent the path to your downloaded copy.

Real answers send sampled rows to your connected Jev provider and require a key. Offline mode is practice only. Confidence and reviewer preferences are not measures of accuracy.

## CircuitJS: See what changed in the signal.

Capture a circuit, turn a component value and overlay the new trace. Place two cursors around the part that interests you and keep the observations with the circuit that produced them.

[Watch the real session](images/scope-lab-demo.mp4) · [See the pane](images/scope-lab.png) · [Harness guide](../store/agents/circuitjs/README.md)

A native CircuitJS RC filter at two resistance values, captured by its real solver.

**Start a CircuitJS project and give the agent a direction:**

> Build a 100 Hz RC low-pass filter with a 1 kΩ resistor and 1 µF capacitor. Label the input and output nodes. I want to capture both in Scope Lab, double the resistance and compare the amplitude and timing.

1. **Capture a window.** Open Scope Lab, choose named nodes or component voltage/current, select a duration and Capture circuit.
2. **Compare a change.** Change a component in the circuit and capture again. Choose the earlier take in Compare with; place A and B cursors and zoom between them.
3. **Keep both traces.** Name each take, record what you noticed and Keep capture. Your captures reopens saved traces; Download capture.zip carries the circuit and observations away.

**Yours to keep:** Native circuit exports, timestamped measurements, an SVG plot, notes and a checksummed ZIP.

**Continue from your kept work:**

> Read both kept captures in .harness/circuit-captures. Compare their CSV measurements and my notes, explain what changing the resistance did, then help me choose the next circuit value to try.

Keep the result in this project, or give the agent the path to your downloaded copy.

Each capture starts a separate native simulation from the current circuit export. It uses a fresh time origin; initial transients can differ. Keep both captures to preserve a comparison.

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[Browse all harnesses](../README.md#domain-specific-harnesses-dsh). To update this guide, edit [store/hands-on.json](../store/hands-on.json), keep each starting prompt in its harness's store.json, and run `node store/tools/hands-on.mjs --sync-store`. This places the matching recorded example first on each Store detail page while retaining the other examples. Suggested starting prompts stay separate from the projects shown in the recordings. `--check` verifies generated files, matching Store demo pairs and all referenced local assets without installing or running a harness.