Chat lifecycle middleware hooks: onConfig, onStart, onChunk, onBeforeToolCall, onAfterToolCall, onUsage, onFinish, onAbort, onError. Use for analytics, event firing, tool caching (toolCacheMiddleware), logging, and tracing. Middleware array in chat() config, left-to-right execution order. NOT onEnd/onFinish callbacks on chat() — use middleware.
$npx -y skills add tanstack/ai --skill middlewareInstalls into the current project.
Run `npx skills use "https://github.com/tanstack/ai" --skill "tanstack/ai/middleware"` and follow the generated skill instructions now. Read its complete output, redirecting it to a temporary file first if necessary. Resolve relative paths from the supporting-files directory it provides.
Use the skills in "https://github.com/tanstack/ai" that are relevant to the current task. Run `npx skills add "https://github.com/tanstack/ai"` and select the relevant skills, then follow their instructions.