Module sub_agent 

Sub-agent tool — delegates tasks to a child agent loop.

The SubAgentTool implements AgentTool and internally runs agent_loop() with its own system prompt, tools, and provider. The parent LLM invokes it like any other tool, passing a natural-language task string.

Design

• Context isolation: each invocation starts a fresh conversation
• Depth limiting: sub-agents are not given other SubAgentTools (static, no runtime counter)
• Cancellation propagation: the parent’s cancel token is forwarded
• Event forwarding: sub-agent events stream to the parent via on_update

Example

use phi_core::agents::SubAgentTool;
use phi_core::provider::ModelConfig;

let researcher = SubAgentTool::new(
    "researcher",
    ModelConfig::anthropic("claude-sonnet-4-20250514", "Claude Sonnet 4", "sk-..."),
)
.with_description("Searches codebases and documents")
.with_system_prompt("You are a research assistant.");

Structs

SubAgentTool

A tool that delegates work to a child agent loop.