Key findings
- Provider switching earns the most consistent praise, with 16 of 17 accounts positive.
- Provider translation bugs come up in 15 accounts, most of them GitHub issues.
- 13 accounts build their own software on the SDK, among them Hatchet's Pickaxe library, Output.ai, and openstatus's Slack incident agent.
- Of the 11 accounts that say whether the SDK alone can run a production agent, 9 wrap it in a runtime or their own loop.
- 5 accounts describe moving off the SDK, to their own code, a smaller library, or another agent framework.
Teams pick the AI SDK for fast feature work and easy provider switching, and most add a durable runtime or their own loop before agents run in production. Their most common complaint is bugs in how the SDK translates requests for each provider.
Why teams choose it
Practitioners praise development speed and provider choice. BrainGrid's tool streaming ended frozen-UI tickets. Hatchet chose the SDK for Pickaxe tool calls because many teams already used it. Developers switch between Claude, Gemini, and local models by changing a model id. Xata saves the full response object for agent evals.
Developers moving from LangChain describe the AI SDK as simpler to start with. One built a working chatbot quickly after finding LangChain over-engineered.
Where it breaks
Most complaints concern the translation layer between the SDK and a provider. Anthropic reasoning blocks were lost across tool steps, and Anthropic's structured outputs rejected valid Zod schemas. Others report a silent 4,096-token default for models newer than the installed SDK and a Bedrock change that degraded structured output.
UI hook and memory problems come next. Developers report useChat re-render loops and tools that stop silently when client and server maxSteps differ. Redeploys have also wiped chat history. Teams report out-of-memory kills while encoding large files or buffering streams.
When teams add a runtime
The in-memory loop supports agents that finish within a request. Output.ai uses Temporal workflow steps for durable SDK calls. One developer runs the loop themselves because neither the AI SDK nor Pydantic AI supplies durable execution. Another moved to LangGraph when flows stopped being linear. AI SDK 7 now adds WorkflowAgent on Vercel's Workflow DevKit.
Others keep the SDK for the model and interface layer only. A Mastra builder calls the SDK the low-level library and Mastra the framework, and a developer who shipped production apps with both draws the same line.
Why some leave
Those who leave name bugs, package size, or the need for a fuller agent loop. One developer replaced the SDK with native code in a production app, an open-source team built a library a hundred times smaller. A team moved to the Claude Code SDK for its agent loop, and Cloudflare OS switched to pi-agent-core.
What to settle before choosing
Four questions decide the choice more than feature lists do.
- Does the agent live inside a request, or must it survive restarts and wait for people?
- Which providers will you use, and have you tested each through the SDK?
- Who owns upgrades across majors?
- Will traffic go through AI Gateway or straight to providers?
Methodology
GILD read 84 English-language public accounts of the AI SDK, published between February 2025 and September 2026. GILD opened them on October 12, 2026, except nine added on October 25, 2026 and five new leader or team accounts added on October 26, 2026. They are Hacker News comments, Reddit posts and comments from r/vercel and r/nextjs read through the Arctic Shift archive, and GitHub issues filed by users on vercel/ai. The rest are named engineering and personal blogs, and recorded talks and videos. Every count on this page refers to those accounts. GitHub issues supply 29 of them, so problems weigh more here than in the wider user base. Vercel's customer stories are left out. On October 28, 2026 GILD added 11 more accounts to the Signals page, 5 Reddit comments, 5 GitHub issues and 1 video, and the counts on this page still describe the first 84.
Products in this piece
Sources
- Public source
- 20
- Official documentation
- 4
- Felipe Cadavid, BrainGrid blog: Migrating to AI SDK v5 (Jul 24, 2025)
- Hacker News comment from Hatchet's co-founder on building Pickaxe's tool calls on the AI SDK (Jun 23, 2025)
- Richard Gill, Xata blog: Writing an LLM eval with Vercel's AI SDK and Vitest (Apr 2, 2025)
- Hacker News comment on Output.ai's LLM package, a thin wrapper around the AI SDK with Temporal workflow steps (Apr 9, 2026)
- r/vercel comment on hitting limits once flows stopped being linear (Apr 15, 2025)
- Hacker News comment on Mastra using the AI SDK as its low-level library (Jan 20, 2026)
- r/nextjs: Vercel AI SDK silent failure, mismatched maxSteps between useChat and streamText (Jun 5, 2025)
- r/vercel: How are you persisting useChat history across redeploys? (Jul 20, 2026)
- Rafael Saraceni: What I learned building my first AI agent (May 6, 2025)
- Hacker News comment on replacing the AI SDK with a native implementation in a production app (Feb 20, 2025)
- vercel/ai issue #4741: useChat messages as a useEffect dependency cause infinite re-renders (Feb 6, 2025)
- vercel/ai issue #20149: base64 encoding of a 14 MB PDF killed a 2 GB container (Sep 1, 2026)
- vercel/ai issue #16753: streamText textStream retains large outputs in memory (Jul 6, 2026)
- vercel/ai issue #11602: Anthropic reasoning blocks lost in multi-step tool calls (Jan 7, 2026)
- vercel/ai issue #14342: Anthropic structured outputs reject valid Zod schemas (Apr 10, 2026)
- vercel/ai issue #17588: max_tokens silently defaults to 4096 for unknown models (Jul 21, 2026)
- vercel/ai issue #17881: Bedrock native structured output degenerates on claude-sonnet-4-6 (Jul 23, 2026)
- Hacker News comment on driving the agent loop yourself for durable execution (Nov 3, 2025)
- Hacker News comment on moving Cloudflare OS from the AI SDK to pi-agent-core (Aug 6, 2026)
- Kristian: Mastra vs AI SDK, I built production apps with both (YouTube, Jun 17, 2026)
- AI SDK docs: WorkflowAgent
- AI SDK adapters: LangChain and LangGraph
- LangChain docs: LangGraph overview (TypeScript)
- OpenAI Agents SDK for TypeScript: AI SDK integration