Summary
delegate_task currently inherits the parent session's model/provider for all subagents. A global override exists via delegation.model and delegation.provider in config.yaml, but there is no way to specify a different model on a per-call basis.
Motivation
Different subagent roles benefit from different models. For example:
- Heavy reasoning tasks (architecture, security, code review) → a large reasoning model (e.g.
claude-opus-4-5)
- Code generation tasks (backend, frontend, devops) → a strong coding model (e.g.
gpt-4-1)
- Long-context planning tasks (PM, docs) → a long-context model (e.g.
gemini-2-5-pro)
Without per-call model routing, all subagents are forced onto the same model as the parent session, regardless of what's optimal for the task.
What already exists
The internal _build_child_agent() function in tools/delegate_tool.py already accepts a model parameter, and the delegation config block supports model + provider overrides globally. The plumbing is there — it just isn't exposed in the delegate_task tool schema.
Proposed change
Add optional model and provider parameters to the delegate_task tool schema, mirroring the existing delegation.model/provider config keys but scoped to a single call:
{
"model": {
"type": "object",
"properties": {
"model": { "type": "string", "description": "Model name (e.g. 'claude-opus-4-5')" },
"provider": { "type": "string", "description": "Provider name (e.g. 'anthropic'). Omit to pin current provider." }
},
"required": ["model"]
}
}This should also apply to per-task entries in batch mode (tasks[].model).
Workaround today
acp_command + acp_args can route to a specific model if an ACP-capable CLI (e.g. Claude Code) is installed, but this requires an external binary and adds overhead for simple use cases.
Use case example
Skills that define specialized agent personas (e.g. a "crew" of architects, security engineers, PMs) need to route each persona to the model best suited for their domain — without requiring the user to switch their global session model or install a second agent binary.
Summary
delegate_taskcurrently inherits the parent session's model/provider for all subagents. A global override exists viadelegation.modelanddelegation.providerinconfig.yaml, but there is no way to specify a different model on a per-call basis.Motivation
Different subagent roles benefit from different models. For example:
claude-opus-4-5)gpt-4-1)gemini-2-5-pro)Without per-call model routing, all subagents are forced onto the same model as the parent session, regardless of what's optimal for the task.
What already exists
The internal
_build_child_agent()function intools/delegate_tool.pyalready accepts amodelparameter, and thedelegationconfig block supportsmodel+provideroverrides globally. The plumbing is there — it just isn't exposed in thedelegate_tasktool schema.Proposed change
Add optional
modelandproviderparameters to thedelegate_tasktool schema, mirroring the existingdelegation.model/providerconfig keys but scoped to a single call:{ "model": { "type": "object", "properties": { "model": { "type": "string", "description": "Model name (e.g. 'claude-opus-4-5')" }, "provider": { "type": "string", "description": "Provider name (e.g. 'anthropic'). Omit to pin current provider." } }, "required": ["model"] } }This should also apply to per-task entries in batch mode (
tasks[].model).Workaround today
acp_command+acp_argscan route to a specific model if an ACP-capable CLI (e.g. Claude Code) is installed, but this requires an external binary and adds overhead for simple use cases.Use case example
Skills that define specialized agent personas (e.g. a "crew" of architects, security engineers, PMs) need to route each persona to the model best suited for their domain — without requiring the user to switch their global session model or install a second agent binary.