Context Tax Audit

Every request carries more than the user's sentence: system prompt, environment info, the skill list, tool definitions, per-turn context blocks, reminders. Most of it is worth paying for. The audit finds what is not, and what is placed so that it breaks the prompt cache.

Companion to MCode Engineering Notes 05 (how the agent learns the current time — and why stuffing date into the system prompt breaks the prefix cache). Plain-text checklist: checklists/context-tax.md.

1. Inventory one real request

Capture an actual request the agent sends (debug log, proxy, or the code that assembles it). List every part except the user's message: