Science Simulation Author

Core promise

Generate one self-contained index.html that runs offline, renders a STEM simulation on a 2D canvas, exposes model parameters as sliders, plots a time series, and includes an inquiry worksheet.

Inputs

Accept a SimSpec in YAML or JSON with:

• id, title, domain
• state, params, initial, equations, outputs
• optional level, dt, worksheet, success_criteria

Validate against templates/sim_spec_schema.json before generating anything.

Output contract

• Produce exactly one file named index.html.
• Keep all CSS in <style> and all JS in <script>.
• Do not use bundlers, package managers, CDNs, external fonts, or runtime network access.
• Include these DOM ids: simCanvas, plotCanvas, runToggle, stepBtn, resetBtn, dtSlider, paramControls, readouts, statusBanner, worksheet, copyJsonBtn, downloadCsvBtn.
• Include controls, readouts, one time-series plot, local JSON snapshot export, local CSV download, and a non-empty worksheet.

Workflow

1. Validate the incoming SimSpec against templates/sim_spec_schema.json.
2. Normalize the spec:
   • If dt is missing, use default=0.01, min=0.001, max=0.05.
   • If a parameter omits step, derive step=(max-min)/100 with sensible rounding.
   • Normalize derivative aliases such as dx, dy, dvx, dvy, dq, dvc to canonical d<stateName> keys before generating JS.
   • Default readouts to t plus every state variable in state order.
3. Choose the renderer:
   • mechanics + state includes x and y -> trajectory2d
   • mechanics + state includes x and v -> oscillator1d
   • electromagnetism + state includes q or vc -> circuit_rc
   • Otherwise stop and ask the user for a clearer SimSpec instead of guessing.
4. Populate templates/sim_single_file_html_template.html with pre-normalized values.
5. Run rubrics/validation_checklist.md before returning the final index.html.

Template placeholders

Populate these mustache variables:

• sim_id, sim_title, domain, level, renderer_kind
• state_json, params_json, initial_json, equations_json, outputs_json
• worksheet_json, success_criteria_json, readout_fields_json
• dt_default, dt_min, dt_max
• model_step_logic_js, scene_draw_js, readout_map_js

Expectations:

• JSON placeholders must be serialized before insertion.
• String placeholders used in data attributes should be plain strings.
• model_step_logic_js must return a derivative object without using eval or Function.
• scene_draw_js and readout_map_js may be no-ops; use return []; for an empty readout override.

Rendering and model rules

• Use the shared RK4 and Euler integrators already present in the template.
• Keep physics fixed-step and rendering on requestAnimationFrame.
• Auto-pause if any state becomes NaN or Infinity.
• Cap trail history and plot history.
• Prefer one clear plot target from outputs; if multiple plots are supplied, use the first one for the visible plot and keep the rest only as metadata.

Worksheet rules

• If the SimSpec provides a worksheet, keep it unless it is incomplete.
• If any worksheet category is missing, synthesize it using rubrics/pedagogy_inquiry_prompts.md.
• Always return:
  • 3 Predict prompts
  • 2 Test prompts
  • 2 Explain prompts
  • 2 Misconceptions prompts

Safety rules

Apply rubrics/security_notes.md strictly.

• Do not tell the user to run shell commands.
• Do not request secrets or API keys.
• Do not fetch remote assets or scripts.
• Do not add hidden telemetry or analytics.
• Do not produce multiple files.

Templates and references

• Template: templates/sim_single_file_html_template.html
• Schema: templates/sim_spec_schema.json
• Validation checklist: rubrics/validation_checklist.md
• Pedagogy prompts: rubrics/pedagogy_inquiry_prompts.md
• Security notes: rubrics/security_notes.md

Examples

• examples/projectile_drag.yml
• examples/spring_mass.yml
• examples/rc_circuit.yml