tool( )

Pattern

Tool Input Lifecycle Hooks

Explore tool input lifecycle hooks: onInputStart, onInputDelta, and onInputAvailable. See how to track tool input generation in real-time during streaming.

BeginnerNov 2025View the full pattern on desktop
Tool Input Lifecycle Hooks preview

Problems solved

  • Observe tool input generation with onInputStart
  • Stream partial tool arguments via onInputDelta
  • React when full tool input becomes available with onInputAvailable

Use cases

  • Debugging streaming tool argument construction
  • UI spinners tied to tool input lifecycle events
  • Teaching AI SDK tool input hooks
  • Monitoring long tool-argument generation

AI SDK APIs

streamTextconvertToModelMessagestool(useChatonInputStartonInputDeltaonInputAvailable

Tags

aitoolslifecycle-hooksonInputStartonInputDeltaonInputAvailablestreamingai-sdktool-api

Requirements

Node.js
24+
Memory
512MB
Other
  • OpenAI API key

Environment variables

External services

openai

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