Ollama v0.21.0 — Release Notes & Engineering Impact

## Hermes Agent ``` ollama launch hermes ``` Hermes learns with you, automatically creating skills to better serve your workflows. Great for research and engineering tasks. <img width="1329" height="946" alt="image" src="https://github.com/user-attachments/assets/771d3383-95ed-4652-81e5-cf89514d25cc" /> ## What's Changed - **Gemma 4 on MLX.** Added support for running Gemma 4 via MLX on Apple Silicon, including a text-only MLX runtime for the model. The MLX backend also picked up mixed-precision quantization, better capability detection, and a batch of new op wrappers (Conv2d, Pad, activations, trig, masked SDPA, and RoPE-with-freqs). - **Hermes and GitHub Copilot CLI in `ollama launch`.** Added both integrations, which can now be configured in one command alongside the rest of the supported coding agents. - **OpenCode moved to inline config.** `ollama launch opencode` now writes its config inline rather than to a separate file, matching how other integrations are handled. - **`ollama launch` no longer rewrites config when nothing changed.** Pressing → on a configured multi-model integration, or passing `--model` with the current primary, used to trigger a confirmation prompt and rewrite both the editor's config file and `config.json`. Now it's a no-op when the resolved model list matches what's already saved. - **Fixed `ollama launch openclaw --yes`** so it correctly skips the channels configuration step, so non-interactive setups complete cleanly. - **Restored the Gemma 4 nothink renderer** with the e2b-style prompt. - **Fixed the Gemma 4 compiler error** that was breaking Metal builds. - **Fixed macOS cross-compiles** so they no longer trigger `generate`, which was breaking cmake builds on some Xcode versions. - **Quieted cgo builds** by suppressing deprecated warnings during `go build`. **Full Changelog**: https://github.com/ollama/ollama/compare/v0.20.7...v0.21.0