fable-agent/PHASES/phase-15-fusion.md

Phase 15: Multi-Model Fusion

Date: 2026-06-14

Drivers:

• Fable 5 / Mythos 5 blocked by US export control directive (June 12, 2026)
• OpenRouter Fusion API achieves Fable-tier intelligence at half the price
• fusion-fable pattern proves fan-out panel + judge synthesis matches or exceeds single best model
• Fable 5 leaked system prompt provides tone, citation, refusal, and behavior patterns
• CineFable provides visual media generation patterns (image/video via fal.ai)

---

What Was Built

1. Fusion Executor (src/examples/executors/fusion-executor.ts)

• PhaseExecutor-compatible multi-model panel execution
• Draft → Critique → Fuse pipeline
• Configurable panels: opus4.8-4.8, opus4.8-gpt5.5, opus4.8-gpt5.5-gemini, sonnet-haiku-opus
• Structured analysis output: Consensus, Contradictions, Unique Insights, Blind Spots
• Judge model always synthesizes final answer grounded in panel analysis

2. OpenRouter Fusion Executor (src/examples/executors/openrouter-fusion-executor.ts)

• Direct integration with OpenRouter Fusion API
• PhaseExecutor-compatible for drop-in use in feedback loop
• Configurable draft/critic/fusion model overrides
• Graceful fallback when API key not configured

3. Fable 5 Prompt Engine (src/upgrades/fable5-prompt-engine.ts)

• Tone & behavior rules extracted from leaked Fable 5 system prompt
• Citation format helpers (inline and footnote)
• Refusal handling (cybersecurity_exploit, harmful_content, financial/medical)
• Effort-level prompt builder (Low → Ultracode)
• Self-check utility

4. Media Generator (src/upgrades/media-generator.ts)

• CineFable-style image generation (fal-ai/nano-banana-pro)
• Image-to-video generation (alibaba/happy-horse/image-to-video)
• Gallery persistence (local storage)
• Storyboard creation with reorderable shots
• Mock mode for development without API key

5. Fusion Workflow Pattern (src/fable5/dynamic-workflows.ts)

• New "fusion-panel" workflow pattern
• Parallel dispatch with configurable concurrency
• Judge synthesis with verification

6. Compound Stack Integration (src/fable5/compound-stack.ts)

• Fusion as a stakable layer in CompoundStack
• fusionPanel() method with panel slug selection

7. CLI Commands (src/index.ts)

• fusion run — execute fusion panel with model selection
• fusion panels — list available panel configurations
• generate image — CineFable-style image generation
• generate video — Happy Horse video generation

---

File Map

File	Purpose
src/core/fusion-types.ts	Shared fusion types, panel configs
src/examples/executors/fusion-executor.ts	Fusion PhaseExecutor
src/examples/executors/openrouter-fusion-executor.ts	OpenRouter Fusion API executor
src/upgrades/fable5-prompt-engine.ts	Fable 5 tone/citation/refusal patterns
src/upgrades/media-generator.ts	CineFable image/video generation
src/fable5/dynamic-workflows.ts	Fusion workflow pattern
src/fable5/compound-stack.ts	Fusion layer integration
src/fable5/model-router.ts	OpenRouter Fusion model route
src/index.ts	Fusion + generate CLI commands
SKILLS/fusion/SKILL.md	Fusion skill definition
PHASES/phase-15-fusion.md	This file

---

How to Use

# Quick fusion (default: opus4.8-4.8)
node dist/index.js fusion run "Design the architecture for a distributed task queue"

# Use OpenRouter Fusion API instead
OPENROUTER_API_KEY=sk-... node dist/index.js fusion run "Compare database options" --openrouter

# Cheap fusion panel
node dist/index.js fusion run "Review this PR" --panel sonnet-haiku-opus

# Generate image (needs FAL_KEY)
node dist/index.js generate image "A futuristic cityscape at sunset" --aspect "16:9"

# Generate video from image
node dist/index.js generate video ./input.png --prompt "gentle camera pan"

What's Next

• Integrate fusion executor with EnhancedMetaAgent for automatic fusion routing
• Add real API calls to FusionExecutor.callModel() for production use
• Add OpenRouter Fusion API response caching
• Wire MediaGenerator into DreamingSystem for visual distillation
• Add scene detection to video generation pipeline