The Context Window Is a Commons, and Every Team Is Grazing It
Open a production agent and count what is in the context window before the user has typed a single character. There is a system prompt the platform team owns. There are tool definitions — forty of them, maybe more — each carrying a name, a description, a JSON schema, field-level docs, and a handful of enums. There is a block of retrieved examples that the search team added because few-shot helped one eval. There are six lines of safety instructions from trust and safety, four lines of formatting rules from the design team, and a paragraph of domain glossary that someone added during an incident and nobody removed.
Add it up and the agent boots with 30,000 tokens of overhead. On a connected setup with three MCP servers, that number is routinely far worse — one widely cited measurement put three servers at 143,000 of a 200,000-token budget, 72% of the window consumed before the conversation starts. None of it is wrong. Every line was added by someone solving a real problem. And that is exactly why the context window is being destroyed.
