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Tokens and Context — Professional

At professional level, focus on this question:

Can you set token-budget and caching standards for a team — and make token growth a regression that gets caught, not a bill that gets explained?


Token budgets per feature

  • Assign every feature an explicit token budget: max input per call, max output, max tokens per task (summed across a multi-call workflow).
  • Budgets force the design conversation early: a feature whose budget doesn't close must retrieve, summarize, or compact — not silently exceed (see Compaction and Memory).
  • Publish budgets where designs happen (design docs, PR templates), not in someone's head.

Cache-aware prompt design as a standard

  • Make the ordering rule org-wide: static prefix first, volatile last, byte-identical prefixes, no timestamps or per-request noise injected mid-prefix.
  • Track cache-hit rate as a first-class metric — a drop in hit rate is a regression someone shipped, visible before the invoice confirms it.
  • Standardize which components are cacheable (system prompt, tool definitions, static docs) and which never are (user input, fresh retrieval results).

Token growth as a tracked regression

  • Record input/output tokens per call in traces (see Tracing and Observability).
  • Add token totals to the eval pipeline: a prompt change that inflates tokens per call fails review like a correctness regression — because at volume, it is one.
  • Alert on trend, not just absolute: gradual growth across many small edits is the common shape of token bloat.

The org-level bill

  • Aggregate spend by feature/team/tenant (see Cost and Performance) so accountability lands with the people who can act on it.
  • Review budget-vs-actual monthly; a widening gap means either volume shifted or per-call tokens grew — the traces tell you which.

Common Mistakes

  • Budgets as guidance instead of gates. "Try to keep it small" produces exactly the slow bloat budgets exist to prevent.
  • Optimizing tokens while ignoring cache-hit rate. A prompt refactor that saves 100 tokens but breaks caching loses money.
  • Catching token growth from the invoice. Weeks late and attributed to nobody; catch it in CI instead.
  • Per-team prompt conventions. Every team re-learns cache rules and budget discipline; write it once as standard.

Apply It

  1. Write the token-budget standard: per-call maxima, per-task maxima, and where budgets must appear in design docs.
  2. Adopt the cache-ordering rule org-wide and add cache-hit rate to your dashboards.
  3. Add per-call token totals to traces and token deltas to your eval pipeline's review bar.
  4. Set up spend aggregation by feature/team and a monthly budget-vs-actual review.

Verify Your Work

  • Every feature has numeric token budgets visible in its design artifacts.
  • Cache-hit rate is tracked, and its drop is treated as a regression.
  • Token totals are in traces and token growth blocks review like a correctness failure.
  • Spend is attributable to feature/team without manual archaeology.

Review Questions

  • Why must a token budget be a gate rather than guidance?
  • Why can a small per-call token saving be a net loss after a refactor?
  • What makes token growth a regression rather than an invoice surprise?