# api

OpenAI's GPT-5.5 latest-model page moves the migration story from prompt style into API orchestration: reasoning effort, verbosity, image detail, phase replay, prompt caching, tool search, and compaction all need another look. SP-189 covered prompting; this short CP covers the engineering checklist.

Simon Willison shared Gemini API's new spend caps feature, saying it's great news for anyone running Gemini prompts in CI or letting agents experiment with the API — less fear of surprise bills.

Box CEO Aaron Levie argues that as agents expand from coding into all knowledge work, existing software simply wasn't built for them. Every platform needs dedicated Agent APIs and CLIs, and agent interoperability will become software's core competitive edge.

Anthropic's prompt caching got major updates in 2026: Automatic Caching removes manual breakpoint headaches, 1-hour TTL keeps caches alive longer, and the invalidation hierarchy decides what blows up when you change things. Plus our real-world $13.86 billing disaster story.

Fintool founder Nicolas Bustamante shares how he runs an entire company through Agent + API integrations (Brex, QuickBooks, HubSpot, Stripe) with just 6 people—handling more than he did with 100+. He introduces the B2A (Business to Agent) concept and warns that SaaS without good APIs will be bypassed by agents through WebMCP or browser automation.

OpenAI's Responses API now uses 'Skills' via the shell tool: reusable instruction bundles loaded by models as needed. Simon Willison found inline base64 skills in JSON requests neatest. Skills fill the 'missing middle layer' between system prompts and tools, preventing bloat.

Google just launched the Developer Knowledge API and an official MCP Server (Public Preview) that lets AI coding tools query the latest Google docs—Firebase, Android, Google Cloud, Chrome, you name it. No more debugging AI-generated code that uses APIs from three versions ago or functions that literally don't exist.