Kiln Desktop - v1.2.1

What's New in V1.2.1

Kiln v1.2.1 adds support for Kiln Harness Tuner, OpenEnv environments, Cloudflare AI, and much more!

• Kiln Harness Tuner: optimize your agent harnesses with Kiln (coming soon in new repo, this app release supports features it requires)
• OpenEnv Suport: Support environments built with OpenEnv
• Cloudflare Workers AI: new AI provider
• New Models: Claude Fable 5.2, Claude Sonnet 5.5, GPT-6.1 Sol, GPT-6.1 Terra, GPT-6 Sol Pro, GPT-6 Luna Pro and GPT-6.1 Sol Pro , Mistral Large 4, add Claude 5.5 Haiku, Muse Wonder 1.0, Gemini 4 Argon, Gemini 4 Carbon, Nemotron 3.5 Super VL, Muse Spark Open, DeepSeek V4.1 Flash 1017, Kimi K3.1 Pro, Muse Ember
• And More: progress UI for Jobs, experiment Lineage page, rename eval scores, bug fixes

CI Build Source for this release Mac Apple Silicon (needed re-build): /Kiln-AI/Kiln/actions/runs/43044308057
CI Build Source for this release Mac x64 and Linux (all): /Kiln-AI/Kiln/actions/runs/42939335217
CI Build Source for this release Windows: /Kiln-AI/Kiln/actions/runs/42939335411

Full Changelog: v1.2.0...v1.2.1

New Contributors

• @pratikgx made their first contribution in #1893