Context window sizes and economics. Claude Opus/Sonnet: 200K tokens (~150K words, ~500 pages). Gemini 2.5 Pro: 1M tokens. GPT-4o: 128K tokens. Llama 3 405B: 128K tokens. Bigger isn't free — cost...

Implement token budget management. Build a context assembler that: counts tokens per section, enforces per-section caps, truncates gracefully (summarize long documents, drop old conversation turns,...

"Walk me through how you'd manage context for a system processing large documents." First decision: does the full document fit in the context window? If yes (<200K tokens for Claude), use long...