@ClaudeDevs: With Opus 4.8, you can add system instructions mid-conversation without breaking the prompt cache. More cache hits mean…
Summary
Claude Opus 4.8 allows adding system instructions mid-conversation without breaking the prompt cache, reducing cost and latency for API requests.
View Cached Full Text
Cached at: 05/30/26, 12:15 PM
With Opus 4.8, you can add system instructions mid-conversation without breaking the prompt cache.
More cache hits means lower cost and latency for your API requests. https://t.co/42C7wqnLhD
Similar Articles
Changes in the system prompt between Claude Opus 4.6 and 4.7
Anthropic released Claude Opus 4.7 with notable system prompt changes including expanded child safety instructions, new tool integrations (Claude in PowerPoint, Chrome, Excel), and behavioral adjustments to reduce verbosity and improve task completion without unnecessary clarification.
Prompting Claude Opus 5.5
This guide details prompting patterns specific to Claude Opus 5.5, addressing behavioral differences from Claude Opus 5 and providing strategies for effort calibration, API integrations, and unattended agentic tasks.
@dbreunig: Went down a system prompt rabbit-hole today, looking at when instructions arrived and when they dropped from Opus 4.6 t…
The author explores changes in system prompts from Opus version 4.6 to 5, noting that the word 'honestly' remains stubbornly persistent in model behavior.
@obie: Claude Code's prompt cache expires an hour after your last message. Step away from a long session and your next turn re…
Obie Fernandes notes that Claude Code's prompt cache expires one hour after your last message, causing expensive full-price re-reads after stepping away, and shares a plugin that writes a handoff doc at the 50-minute mark while the cache is still warm.
@addyosmani: Glad Claude limits feel different! The lower Opus 5.5 price goes straight into your limits. They go about 25% further t…
The article details cost improvements and performance enhancements in Claude's Opus 5.5 model, including 25% extended limits, 60% cheaper cache reads, and 30% faster output generation.