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BlocksTools & Utilities
Preliminary Tool Results
Preliminary Tool Results
Return preliminary tool results using async iterables. Stream status updates during tool execution before the final result is available.
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Problems solved
Technical challenges this implementation handles out of the box.
- Yield intermediate tool status with async generator execute
- Show progressive tool updates before the final result
- Keep users informed during long-running tool work
Use cases
Products and workflows this pattern is designed to support.
- Weather or lookup tools with staged status
- Long-running enrichment operations
- Progressive tool result UIs
- Teaching async iterable tool execute patterns
Compare with
Similar patterns, and when each one is the better fit.
Multi-Step Tool PatternUse this when a chat agent must call several typed tools in a row, feeding each result into the next step, with a step limit to stop runaway loops.
HIL Needs ApprovalDemonstrate tool approval with async generators. Includes real-time feedback, approval workflows, and interactive management.
Tool ExecutionUse this when your chat app calls tools and you want each call's input, output, and status rendered inline as it streams.
Tool Input Lifecycle HooksUse this when you want UI state, like a spinner or progress label, to react to tool input starting, streaming, and becoming fully available.
Setup
Requirements, wiring steps, and what this pattern adds to your project.
Getting started
Pick how you want to pull this pattern in. Then wire env vars and routes the same way.
- 1
Download → Next.js app
Use Download → Next.js app in the preview toolbar. You get a zip scaffold (Pro downloads rewrite preview `/view/.../api/*` paths to `/api/*` automatically).
- 2
Extract the zip and install dependencies
Unzip the archive, then run `pnpm install` (or npm / yarn) in the project folder.
- 3
Fill .env.local
The download includes .env.local placeholders when needed. Add real values for: OPENAI_API_KEY.
- 4
Customize the agent and tool files
Adapt prompts, tools, and stop conditions in the generated project for your product.
- 5
Run the app and open the pattern route
Run `pnpm dev`, open the setup/checklist page if present, then navigate to the generated pattern route and verify responses.
Environment variables
OPENAI_API_KEYGet key
Capabilities
AI SDK APIs
streamTextconvertToModelMessagestooluseChatProviders
OpenAI
Files added
6 files
app/page.tsxapp/layout.tsxapp/api/tool-preliminary-results/route.tscomponents/preliminary-results-demo.tsxtools/weather.tstools/weather-ui.tsx
Dependencies
15 total
npm packages
7AISDKshadcn/uilucide-reactNext.jsReactstreamdownZod
Registry components
alertemptyinput-groupseparatormessage-scrollermessagebubbletooltip
Critical files
1 file
tools/weather.tsWeather tool demonstrating the preliminary tool results pattern using async generator (async *execute with yield). Yields intermediate status updates before the final result.
Requirements
- Complexity
- Beginner
- Setup time
- ~5 minutes
- Node
- 24+
- Memory
- 512MB
