MODEL-VARIANTS.md

Model Variants

OpenCode's variant system allows you to configure thinking budget dynamically instead of defining separate models for each thinking level.

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How Variants Work

When you define a model with variants, OpenCode shows variant options in the model picker. Selecting a variant passes the providerOptions to the plugin, which extracts the thinking configuration.

opencode run "Hello" --model=google/antigravity-claude-opus-4-6-thinking --variant=max

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Variant Configuration

Define variants in your model configuration:

{
  "antigravity-claude-opus-4-6-thinking": {
    "name": "Claude Opus 4.6 Thinking",
    "limit": { "context": 200000, "output": 64000 },
    "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
    "variants": {
      "low": { "thinkingConfig": { "thinkingBudget": 8192 } },
      "max": { "thinkingConfig": { "thinkingBudget": 32768 } }
    }
  }
}

---

Supported Variant Formats

The plugin accepts different variant formats depending on the model family:

Model Family	Variant Format	Example
Claude	thinkingConfig.thinkingBudget	{ "thinkingConfig": { "thinkingBudget": 8192 } }
Gemini 3	thinkingLevel	{ "thinkingLevel": "high" }
Gemini 2.5	thinkingConfig.thinkingBudget	{ "thinkingConfig": { "thinkingBudget": 8192 } }

---

Gemini 3 Thinking Levels

Gemini 3 models use string-based thinking levels. Available levels differ by model:

Level	Flash	Pro	Description
minimal	✅	❌	Minimal thinking, lowest latency
low	✅	✅	Light thinking
medium	✅	❌	Balanced thinking
high	✅	✅	Maximum thinking (default)

Note: The API rejects invalid levels (e.g., "minimal" on Pro). Configure variants accordingly.

Gemini 3 Pro Example

{
  "antigravity-gemini-3-pro": {
    "name": "Gemini 3 Pro (Antigravity)",
    "limit": { "context": 1048576, "output": 65535 },
    "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
    "variants": {
      "low": { "thinkingLevel": "low" },
      "high": { "thinkingLevel": "high" }
    }
  }
}

Gemini 3 Flash Example

{
  "antigravity-gemini-3-flash": {
    "name": "Gemini 3 Flash (Antigravity)",
    "limit": { "context": 1048576, "output": 65536 },
    "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
    "variants": {
      "minimal": { "thinkingLevel": "minimal" },
      "low": { "thinkingLevel": "low" },
      "medium": { "thinkingLevel": "medium" },
      "high": { "thinkingLevel": "high" }
    }
  }
}

---

Claude Thinking Budget

Claude models use token-based thinking budgets:

Variant	Budget	Description
low	8192	Light thinking
max	32768	Maximum thinking

Claude Example

{
  "antigravity-claude-opus-4-6-thinking": {
    "name": "Claude Opus 4.6 Thinking (Antigravity)",
    "limit": { "context": 200000, "output": 64000 },
    "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
    "variants": {
      "low": { "thinkingConfig": { "thinkingBudget": 8192 } },
      "max": { "thinkingConfig": { "thinkingBudget": 32768 } }
    }
  }
}

You can define custom budgets:

{
  "variants": {
    "minimal": { "thinkingConfig": { "thinkingBudget": 4096 } },
    "low": { "thinkingConfig": { "thinkingBudget": 8192 } },
    "medium": { "thinkingConfig": { "thinkingBudget": 16384 } },
    "high": { "thinkingConfig": { "thinkingBudget": 24576 } },
    "max": { "thinkingConfig": { "thinkingBudget": 32768 } }
  }
}

---

Legacy Budget Format (Deprecated)

For Gemini 3 models, the old thinkingBudget format is still supported but deprecated:

Budget Range	Maps to Level
≤ 8192	low
≤ 16384	medium
> 16384	high

Recommended: Use thinkingLevel directly for Gemini 3 models.

---

Tier-Suffixed Names

Tier-suffixed model names are still accepted:

• antigravity-claude-opus-4-6-thinking-low
• antigravity-claude-opus-4-6-thinking-medium
• antigravity-claude-opus-4-6-thinking-high
• antigravity-gemini-3-pro-low
• antigravity-gemini-3-pro-high
• gemini-3-pro-low
• gemini-3-flash-medium

However, we recommend using simplified model names with variants for:

• Cleaner model picker — 7 models instead of 12+
• Simpler config — No need to configure both antigravity- and -preview versions
• Automatic quota routing — Plugin handles model name transformation
• Flexible budgets — Define any budget, not just preset tiers
• Future-proof — Works with OpenCode's native variant system

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Benefits of Variants

Before (tier-suffixed)	After (variants)
12+ separate models	4 models with variants
Fixed thinking budgets	Customizable budgets
Cluttered model picker	Clean model picker
Hard to add new tiers	Easy to add new variants