# Amazon Bedrock adds prompt caching to reduce AI agent token costs

Digest AI · Agents & Tools · published 2026-10-26T17:27:20Z

Canonical: https://digestai.news/story/amazon-bedrock-adds-prompt-caching-to-reduce-ai-agent-token-costs

## Summary

Amazon Bedrock now supports prompt caching, letting developers store a reusable prefix of an agent’s prompt—tools, instructions, and static content—and reuse it on subsequent calls. By saving the model’s key‑value state after the first prefill, later requests only process new tokens, cutting input‑token charges.

In internal tests, a roughly 4,000‑token tools‑and‑instructions prefix wrote 4,120 tokens on the first request and read the same 4,120 tokens on later requests. Using GPT‑6 Astra, implicit caching achieved about 62 percent lower input cost, while explicit rolling breakpoints saved about 61 percent. Cached prefixes have a minimum 30‑minute TTL and are refreshed by reuse.

The blog explains both implicit (Bedrock‑chosen) and explicit (promptcachebreakpoint) modes, how to mark static sections, handle new tools, and share cached prefixes across sub‑agents. It also warns that cached prompts can leak sensitive data, so responsible AI governance is recommended.

## Key points

- Prompt caching stores the model’s KV state after the first request, so later calls only process new tokens
- Implicit caching cut GPT‑6 Astra input cost by about 62 percent; explicit breakpoints saved about 61 percent
- Cached prefixes require an exact text match and have a minimum 30‑minute TTL before expiration

## Why it matters

Cutting token usage lowers operating costs for agentic applications and makes real‑time AI assistants more affordable and responsive.

## Sources

1. [Groundhog Day for AI agents: Prompt caching patterns for using OpenAI models on Amazon Bedrock](https://aws.amazon.com/blogs/machine-learning/groundhog-day-for-ai-agents-prompt-caching-patterns-for-using-openai-models-on-amazon-bedrock) (AWS Machine Learning Blog, 2026-10-26, primary source)

Part of the developing story: [Amazon Bedrock Expands Claude Model Capabilities](https://digestai.news/thread/amazon-bedrock-adds-structured-json-outputs-for-anthropic-claude-models) (2 stories)

## Cite

Digest AI, "Amazon Bedrock adds prompt caching to reduce AI agent token costs", 26 October 2026, https://digestai.news/story/amazon-bedrock-adds-prompt-caching-to-reduce-ai-agent-token-costs

---

Written by Digest AI's editorial model from the linked sources; the sources are the record. Headlines, digests and key points are written by Digest AI and may be quoted with a link to the story page. Linked articles belong to their publishers. Terms: https://digestai.news/terms#reuse
JSON: https://digestai.news/story/amazon-bedrock-adds-prompt-caching-to-reduce-ai-agent-token-costs.json