Runs sub-agent tool calls concurrently
Claude Agent SDK now runs sub-agent tools concurrently and expands its model catalog to 209 providers with 6,237 models.
Changed Sub-agents spawned in the same step now run their tool calls at the same time rather than one after another. Tools that must run in order still do, and the parent still waits for every result before its next turn. Models that advertise a large output limit now get a bigger default output budget — 30% of the limit rather than a flat 32,000 tokens, whichever is larger. Nothing changes for models under roughly 107k output tokens; longer responses can mean higher per-turn cost and latency. Refreshed the model catalog: 203 to 209 providers and 6,079 to 6,237 models. Kimi For Coding splits into separate kimi.com and kimi.ai providers, and AI21 Labs, ainetcafe, Inco, OCI Generative AI, Tempr, and Vispark are new.
The resolved default model changes for 36 providers that do not pin one — most landing on DeepSeek V4.1 Flash, GLM 5.3 Flash, or MiMo V2.6 Flash. If you use one of those providers without pinning a model, expect a different default. Fixed UserPromptSubmit and TaskStart hooks can inject context again. What those hooks returned as `contextModification` was being dropped — only `cancel` survived — so a hook meant to add repository facts or house rules to a task silently…
- github.comCline v4.1.20primary