When a role is defined as an object instead of a string, you can specify fine-grained parameters and fallback behaviors. This is useful for ensuring plan stability when encountering context limits or API errors.
Role Config Object Properties:
modelId (required): The ID of the model to use.temperature: Controls randomness (0-2).topP: Alternative randomness control (0-1).largeContextFallback: Model to use when the context window is exceeded.largeOutputFallback: Model to use when the required output size is large.errorFallback: Model to use if the primary model fails (e.g., due to an API error).strongModel: A more capable model for complex tasks.
{
"$schema": "https://plandex.ai/schemas/model-pack-inline.schema.json",
"planner": {
"modelId": "anthropic/claude-opus-4",
"temperature": 0.7,
"topP": 0.9,
"largeContextFallback": "google/gemini-2.5-pro"
},
"coder": "anthropic/claude-sonnet-4",
"architect": "anthropic/claude-sonnet-4",
"summarizer": "anthropic/claude-3.5-haiku",
"builder": {
"modelId": "anthropic/claude-sonnet-4",
"errorFallback": "openai/gpt-4.1"
},
"wholeFileBuilder": {
"modelId": "anthropic/claude-sonnet-4",
"largeContextFallback": {
"modelId": "google/gemini-2.5-pro",
"largeOutputFallback": "openai/o4-mini-low"
}
},
"names": "anthropic/claude-3.5-haiku",
"commitMessages": "anthropic/claude-3.5-haiku",
"autoContinue": "anthropic/claude-3.5-haiku"
}