Feature Request: Add --plan flag and default_plan_mode config to start in plan mode

[leonidlouis]

Summary

Add ability to start Kimi CLI in plan mode via CLI flag and config option.

Motivation

Currently, plan mode can only be triggered interactively via:

• Keyboard shortcut: Shift-Tab
• Slash command: /plan or /plan on

There is no way to start a session directly in plan mode, unlike --yolo which has both CLI flag and config option (default_yolo).

This feature is useful for users who:

• Prefer to always start in plan mode for careful, step-by-step planning <- this is me :)

Proposed Solution

CLI Flag

kimi --plan

Config Option

In ~/.kimi/config.toml:

default_plan_mode = true

Behavior

Scenario	resumed	default_plan_mode Applied?
New session (no flags)	False	✅ Yes
--session EXISTING_ID	True	❌ No (session state preserved)
--session NEW_ID (not found)	False	✅ Yes
--continue	True	❌ No (session state preserved)
ACP / Web worker	True	❌ No (session state preserved)

Implementation

PR #1665 implements this feature.

Checklist

• CLI flag (--plan)
• Config option (default_plan_mode)
• Proper precedence logic (CLI flag > config > default)
• Session restoration handling
• ACP server support
• Web worker support