Context window inspection / analysis command

[planger]

It would be very useful to have a built-in command to inspect and analyze the current context window of a session, similar to Claude Code /context.

What it should show (example):

• Total context window size and current usage
• Breakdown by category (system prompt, tools, messages, etc.)
• Remaining free space

Why this matters:

• Helps debug agent system message, design and MCP server for agents
• Helps giving an indication when a session slides into the "dumb zone" of the LLM

[planger]