Prompt Budget Preflight

Run this before calling the Agent tool. It takes under 30 seconds and prevents the most common subagent failure mode: rejection with "Prompt is too long".

Why this exists

Subagents inherit a large base context before your prompt is even appended:

• Global ~/.claude/CLAUDE.md
• Project .claude/CLAUDE.md chain (including any rules files referenced via @)
• Any auto-loaded plugin CLAUDE.md in the subagent's cwd
• MEMORY.md and auto-memory entries
• System prompts for the selected subagent_type
• Tool definitions for tools the subagent can see

In our own telemetry from one 9-spawn session: