fix(opencode): default custom provider capabilities to true for image…

[RheagalFire]

Issue for this PR

Closes #22673

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Custom models added via config get restrictive capability defaults — reasoning, attachment, temperature, and image input all default to false. This means models behind a LiteLLM proxy are classified as
text-only even when they support images and reasoning.

The fix changes the fallback defaults in provider.ts for config-provided models:

• temperature: false → true
• reasoning: false → true
• attachment: false → true
• input.image: false → true

These only apply when no explicit value is set by the user or inherited from models.dev. Users can still set false explicitly in their config.

How did you verify your code works?

• bun turbo typecheck passes (12/12 packages)
• Husky pre-push hook passes

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found one potentially related PR that addresses similar custom provider capability issues:

Related PR:

• PR fix(opencode): default temperature for openai-compatible config models #25919: "fix(opencode): default temperature for openai-compatible config models"
  • fix(opencode): default temperature for openai-compatible config models #25919
  • This PR addresses a similar issue where temperature defaults for OpenAI-compatible config models needed adjustment

The current PR (#26422) is a more comprehensive fix that addresses multiple capability defaults (temperature, reasoning, attachment, image) for all custom config-provided models, building on the targeted fix in #25919.

These are related efforts but #25919 appears to be a narrower predecessor fix that handles temperature specifically, while the current PR provides a broader solution.