Updated LLM Models for SquiggleAI

We've upgraded SquiggleAI to use Claude Sonnet 4.5, Claude Haiku 4.5, and Grok Code Fast 1. This is a significant upgrade over the previous Claude Sonnet 3.7 and Claude Haiku 3.5. All three are available now.

Initial testing shows meaningful improvements in code generation quality, though complex Squiggle models still typically require multiple iterations across all models. The upgrades don't fundamentally change SquiggleAI's capabilities, but they do seem to improve baseline performance.

Model characteristics from preliminary testing

Claude Sonnet 4.5 tends toward ambitious, longer implementations. Haiku 3.5 generates more concise models. Grok Code Fast 1 produces models roughly 2/3rds the length of Sonnet 4.5 at approximately 1/4th the cost per line - concretely, Claude Code runs ~$0.90 for 400 lines while Grok averages ~$0.15 for 250 lines on comparable tasks.

Future Technical Work

SquiggleAI predates Claude Code and similar agentic coding tools. Generic agentic frameworks are the obvious long-term architecture, but current tooling remains immature and expensive. We're monitoring developments and will migrate when the technology stabilizes.