What's new
Added: small-harness built-in worker
SmallHarness is now a first-class ultraswarm worker — a terminal-first Rust coding agent with native MCP integration, multi-backend support (OpenAI, OpenRouter, Ollama, LM Studio, MLX, llama.cpp), and real-time cost tracking.
Default tier mapping:
| Tier | Backend | Model |
|---|---|---|
| simple | OpenAI | gpt-4o-mini |
| moderate | OpenRouter | claude-sonnet-4-6 |
| complex | OpenRouter | claude-opus-4-8 |
| expert | OpenRouter | claude-opus-4-8 |
Backend and model are injected via BACKEND / AGENT_MODEL environment variables. Add OPENAI_API_KEY and OPENROUTER_API_KEY to workerEnvAllowlist to pass credentials through. Override any tier via the standard overrides config key.
Also includes a SmallHarness host skill — a SKILL.md enabling SmallHarness sessions to invoke ultraswarm as an orchestration tool in the other direction.
Bug fixed
The previous invocation template (from the in-development registry entry) used unrecognised CLI flags (--backend, --model, --approval never) and omitted --allow-tools, causing all tool calls to be silently denied. Fixed in this release.