helios-prompts

name	helios-prompts
description	Write effective prompt sequences for Reactor's Helios model, a real-time video frame generation API. Use when creating Helios prompts, video generation prompts, or when the user mentions Helios or Reactor. Covers start prompts, follow-ups, sequence planning, camera anchoring, lighting consistency, and progressive state tracking.

Helios Prompt Writing

Helios generates video sequences through multi-prompt continuation. Each prompt builds on the previous frame state with controlled variations while maintaining visual coherence.

Start Prompt Structure

Every start prompt follows this exact order:

[SUBJECT ESTABLISHMENT]    2-3 sentences. Specific physical details, clothing, posture, name.
[ENVIRONMENT DESCRIPTION]  2-3 sentences. Setting, props, background elements. Concrete details.
[LIGHTING CONDITIONS]      1 sentence. Source + quality. This becomes the "lighting anchor."
[ATMOSPHERE/MOOD]          1 sentence. Emotional tone.
[STYLE (optional)]         1 sentence. Only if non-default (VHS, anime, vintage).
[CAMERA INSTRUCTION]       1 sentence. Shot type + angle + focus. IDENTICAL in every prompt.

Subject: Not "a lion" but "a majestic lion named Leo." Include name, posture, clothing, key features.

Environment: Not "a table" but "a wooden dining table." Include specific props and background.

Lighting anchor: Be specific — "warm afternoon sunlight streaming through linen curtains," not just "daylight." This exact description repeats in every follow-up.

Camera instruction: This line is copied VERBATIM to every prompt in the sequence. Lock shot type, angle, and focus.

Follow-Up Prompt Structure

Each follow-up = Base State + ONE New Action.

[SUBJECT REESTABLISHMENT]       1-2 sentences. Abbreviated restate of position/details.
[NEW ACTION]                    1-2 sentences. Temporal connector + single action.
[ENVIRONMENTAL INTERACTION]     1-2 sentences. How environment reacts (steam, smoke, reflections).
[LIGHTING ANCHOR]               1 sentence. Copied from start, minor wording variations OK.
[ATMOSPHERE (if changed)]       1 sentence. Only if mood shifted.
[CAMERA INSTRUCTION]            IDENTICAL to start prompt. Not one word different.

Reestablishment pattern: "The [subject] remains/sits/stands [location], [key visuals]. [Clothing reminder]."

Temporal connectors: "Suddenly...", "Now...", "As [subject]...", "[Subject] suddenly..."

Action categories (pick ONE per prompt):

• Micro-gestures: reaching, turning head, leaning, raising hand
• Object interaction: picking up, setting down, holding
• Facial expression: smiling, eyes widening, mouth opening
• Environmental trigger: breeze starting, something appearing

Environmental reactions — always describe how the world responds:

• Objects affected by movement
• Light interacting with surfaces
• Particles (steam, smoke, petals, sparks)
• Reflections changing

Progressive State Tracking

Track cumulative changes across prompts. Objects and subjects evolve:

• Candles: lit → flickering → extinguished → smoking → smoke dissipated
• Flower: closed bud → separating → half-open → fully bloomed
• Party hat: slightly tilted → crooked → slipped to one side
• Petals: scattered → swirling → covering blanket → landing on face

Each follow-up must reflect the accumulated state from all previous prompts.

Sequence Planning

Optimal length: 4-5 prompts.

Prompt	Role
0 (Start)	Establish scene
1-2	Build action
3	Climax / payoff
4 (optional)	Resolution / settling

Avoid: >6 prompts (coherence degrades), single follow-ups (no arc), unnecessary intermediate steps.

Common Patterns

Choose one to structure the sequence. See references/patterns.md for detailed examples.

1. Environmental Interaction — Subject experiences active environment (rain, wind, petals, fireworks). Calm → activate → interact → peak → settle.
2. Object Reveal/Transformation — Something hidden is revealed or changes state. Initial → transition → reveal → reaction → enjoyment.
3. Escalating Intensity — Single element increases in quantity/power. Calm → first → multiple → peak → sustained.
4. Character Action Sequence — Subject performs related micro-actions. Rest → prepare → act → result → settle.

Critical Rules

DO:

• Keep lighting consistent (only minor wording variations)
• Reestablish subject (abbreviated) in every follow-up
• Introduce exactly ONE new action per follow-up
• Describe environmental reactions (steam, smoke, reflections, particles)
• Use specific object descriptions ("a plastic cake server with a bright green handle")
• Copy camera instruction verbatim to every prompt
• Use temporal connectors to signal changes
• Track progressive state changes across prompts
• Introduce objects with action verbs (picks up, pulls out, grabs)

DON'T:

• Change lighting dramatically (no dawn → noon transitions)
• Stack multiple new actions in one prompt
• Modify the camera instruction between prompts
• Let subjects interact with dangerous elements in motion
• Introduce objects without describing how they appear
• Skip environmental reaction descriptions

Checklist

Before finalizing any sequence, verify:

• Start prompt has: subject, environment, lighting, mood, camera
• Camera instruction identical in every prompt
• Lighting consistent (minor wording variations only)
• Each follow-up has exactly ONE new action
• Subject reestablished (abbreviated) in each follow-up
• Environmental reactions described
• Progressive state changes tracked
• Objects introduced with action verbs
• No dramatic lighting shifts
• Temporal connectors used
• Sequence is 4-5 prompts
• Final prompt provides resolution or peak moment