Grok WorldGrok Build CLI field station

Retrospective edition / PERFORMANCE

Design stable prefixes for prompt caching

Keep durable instructions and reusable context stable while placing volatile user data later in the request.

01 / DECIDE

Architecture decision

Use it for repeated large context where cache behavior can reduce latency and usage.

Keep durable instructions and reusable context stable while placing volatile user data later in the request. Map input, output, state, tools, and side effects as one observable path, then name the owner of design stable prefixes for prompt caching.

02 / OPERATE

Three-step field procedure

  1. 01

    Lock the contract

    Write down the caller, data classification, success condition, timeout, cancellation, and ownership. Use it for repeated large context where cache behavior can reduce latency and usage.

  2. 02

    Run one bounded path

    Build one end-to-end path with correlation, typed state, and reversible failure handling. Keep durable instructions and reusable context stable while placing volatile user data later in the request.

  3. 03

    Verify the signal

    Turn acceptance into a repeatable fixture, contract test, or browser test. Telemetry compares cached tokens, latency, cost, and task quality without logging private content.

03 / BOUND

Operational boundary

Do not duplicate sensitive content merely to improve cache hits; retention and authorization remain primary.

04 / PROVE

Acceptance evidence

Telemetry compares cached tokens, latency, cost, and task quality without logging private content.

SOURCE / HTTP

Reproducible source probe

curl -fsSI 'https://docs.x.ai/developers/advanced-api-usage/prompt-caching' | sed -n '1,5p'

PRIMARY / OFFICIAL

Official xAI sources

Sources checked · 2026-08-10

  1. 01Prompt Caching