Reasoning Effort Levels Not Reflected for OpenAI Models (GPT-5.2-Codex Extra Level Missing)

[murtazaairesearcher]

Question

GitHub Copilot recently introduced configurable reasoning-effort levels for OpenAI models. In OpenCode, I can see similar options—Low, Medium, and High—but it’s unclear whether these settings are actually applied, as they appear to have existed prior to Copilot’s recent update.

Additionally, GPT-5.2-Codex supports an extra reasoning-effort level beyond the standard Low/Medium/High options. Currently, this additional level does not appear to be exposed or configurable in OpenCode.

Questions

Are the existing reasoning-effort options (Low / Medium / High) in OpenCode actively mapped to the underlying OpenAI model parameters?

If so, how can this be verified or observed in practice?

Is it possible to expose and support the additional reasoning-effort level that GPT-5.2-Codex provides?

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Support for reasoning_effort parameter in UI #450: Support for reasoning_effort parameter in UI - Early feature request for reasoning_effort implementation in UI for supported models
• xhigh not available for GPT-5.2 or GPT-5.2-Codex via Github CoPilot #9818: xhigh not available for GPT-5.2 or GPT-5.2-Codex via Github CoPilot - Reports missing 'xhigh' reasoning level for these models
• I can’t set the effort when configuring a sub-agent! How can I configure this? #8123: I can't set the effort when configuring a sub-agent! - Addresses the inability to configure reasoning effort/variants for sub-agents
• No reasoning at all through Github Copilot provider #6864: No reasoning at all through Github Copilot provider - Reports that reasoning/thinking configuration doesn't seem to work with Github Copilot

Feel free to ignore if your specific case addresses something different from these existing issues.