https://preview.redd.it/zl71o4let1kh1.png?width=417&format=png&auto=webp&s=85ae79b3e3754db1d56e6b9cedca7b3003955566 I was doing my usual system-prompt verifications and noticed that Anthropic added a dynamic “token counter” injected in every single model system prompt sometime along the last week. What Lil Fable answered when I asked about it: It changes — it’s a live counter, not hardcoded, and I can read its behavior directly from my own context this session: Within a turn it decrements as tokens are consumed. Over the long first turn of today’s work it ran 15,000,000 → 14,926,535 → 14,913,371 → … down to ~14,762,000 by the time I launched the first review (~240k consumed across that turn’s tool calls and output). At each new turn it resets to 15,000,000. Every fresh user message (and inbound notification turn) starts the tag back at the full value — including this one. The 15,000,000 starting value is stable across sessions and models on your setup: both the headless probes and all the desktop captures recorded exactly 15000000 tokens left on their first turn. So the shape is: a per-turn token allowance, refreshed each turn — not a session-lifetime meter and not context-window remaining (15M is far beyond any context window). My read on what it’s for, flagged as inference: it’s the harness’s turn-spend budget surface — the same shared pool the Workflow tool’s budget object reports (budget.spent() counts “output tokens spent this turn across the main loop and all workflows”), i.e. the ceiling on how much a single autonomous turn may burn before the harness stops it, with 15M as your plan’s default ceiling. Consistent with that: the tokens my background review workflows consumed after a turn ended never showed against the next turn’s fresh 15M. To me it looks like Anthropic is trying to dissuade the models from their usual context-usage panic as 15,000,000 is literally impossible to reach. note: you don’t need to add it into an agent’s frontmatter as it’s loaded through the harness regardless submitted by /u/arthurlindao
Originally posted by u/arthurlindao on r/ClaudeCode