Agent Loop

The core execution engine lives in kerux-core/src/agent.rs.

ReAct Cycle

1. Build context — system prompt + conversation history (+ [CONTEXT SUMMARY] if compaction active)
2. Call LLM — streaming or non-streaming via the configured provider
3. Parse response — text chunks, reasoning, tool calls (tolerant parsing)
4. Execute tools — with optional approval gate (F1); results appended as tool messages
5. Loop — repeat until the model produces a final text response with no tool calls

Cooperative Cancellation

Every iteration checks an Arc<AtomicBool> cancel flag — at loop boundaries, between SSE chunks, and before each tool execution. On cancel, repair_conversation_after_cancel() fixes any dangling assistant/tool message pairs so the conversation stays valid.

Event Emission

The agent emits events (ToolStart, ToolEnd, TextChunk, RunProgress) via a bounded channel using non-blocking try_send() — a slow or dead event pump can never deadlock the ReAct loop.

Context Compaction (F2)

When the conversation approaches the session cap, compact_history() summarizes the oldest messages via a one-shot LLM chat. The summary is stored in the session file (format v2) and injected as a [CONTEXT SUMMARY] marker, keeping recent messages intact.