How can I set gpt-oss:20b reasoning effort?

[esperanza-esperanza]

Issue

Warning: ollama_chat/gpt-oss:20b does not support 'reasoning_effort', ignoring.
Warning for ollama_chat/gpt-oss:20b: Unknown context window size and costs, using sane defaults.
https://docs.ollama.com/capabilities/thinking#enable-thinking-in-api-calls

curl http://localhost:11434/api/chat -d '{
  "model": "qwen3",
  "messages": [{
    "role": "user",
    "content": "How many letter r are in strawberry?"
  }],
  "think": true,
  "stream": false
}'

GPT-OSS requires think to be set to "low", "medium", or "high". Passing true/false is ignored for that model.

Version and model info

Aider 0.86.1
Model: gpt-oss:20b diff
Git repo: .git with 4 files
Repo-map: 4096 tokens, auto refresh
Using a tiny example project.