Problem

When a non-default session mode (e.g., acceptEdits, auto, dontAsk, plan) is configured, setSessionMode is called twice in succession during ACP session startup:

1. Inside AcpAgent.start() via applySessionMode() (L348-351 in acp/index.ts)
2. Immediately after start() resolves via this.agent.setMode(this.currentMode) in AcpAgentManager (L518-521)

This double-apply was already present for YOLO modes; after the applySessionMode extraction it now also applies to non-YOLO modes. The calls are functionally harmless (idempotent) but add unnecessary latency to session startup and produce duplicate perf log entries.

Suggested Fix

Option A (lower risk): Add a flag this.sessionModeApplied = true in start() so the manager can skip re-application.

Option B (cleaner): Remove mode application from inside start() and let the manager's post-start block be the single owner. Note: this changes error semantics for YOLO (manager logs a warning but does not throw).

Files

• src/process/agent/acp/index.ts (L336-352, L406-424)
• src/process/task/AcpAgentManager.ts (L515-525)