Who contributed to Vercel on August 20, 2026?

19 developers shipped this update, including Josh Story, Janka Uryga, Will Binns-Smith, mischnic, eps1lon, Pranay Prakash, Peter Wielander, and karthikscale3, and 11 more.

What were the notable Vercel updates?

[PPF] Remove `unstable_eager` (#97524), Remove HmrTarget (#97253), and Turbopack: cross-module constants.

@vercel

Next.js + the Vercel platform - frontend infrastructure for the web

github ↗

Pick a date

Topics: JavaScript Full archive →

The Wire · Showcase

NEXT.JS REMOVES UNSTABLE_EAGER AS AI SDK BLOCKS UNSAFE TOOL EXECUTION

By RepoJournal · Filed 06:55 UTC on August 20, 2026 · About Vercel

19 people shipped this

ai-sdk-factory @ai-sdk-factory 2 cited

Janka Uryga @lubieowoce 1 cited

Will Binns-Smith @wbinnssmith 1 cited

mischnic @mischnic 1 cited

Pranay Prakash @pranaygp 1 cited

ruiconti @ruiconti 1 cited

n1ckoates @n1ckoates 1 cited

Josh Story @gnoff

eps1lon @eps1lon

Peter Wielander @VaguelySerious

karthikscale3 @karthikscale3

bensabic @bensabic

allenzhou101 @allenzhou101

benpankow @benpankow

ctgowrie @ctgowrie

OwenKephart @OwenKephart

cmpadden @cmpadden

yu-ya4 @yu-ya4

aayush-kapoor @aayush-kapoor

Next.js is cleaning house on Partial Prefetching while the AI SDK ships a safety patch that stops side-effecting tools from running after truncated model outputs.

Next.js pulled the plug on `unstable_eager`, an incomplete Partial Prefetching experiment that was causing speculative prefetches in incremental opt-in apps [1]. The team also reverted the HMR client to the firehose feed, keeping the split after Server HMR moved to pull-based [2]. Turbopack now evaluates cross-module constants at compile time, so `if (IS_DEV)` truly dead-code-eliminates [3]. Meanwhile, the AI SDK patched a serious hole where side-effecting tools could execute after "length", "error", "content-filter", or other terminal finish reasons, allowing automatic execution only for stop and tool-calls [4]. Tool call IDs that arrive as empty strings, as seen with Gemini 2.5 Pro, now get generated fallback IDs [5]. WorkflowAgent retries no longer leave stale partial tool calls blocking approvals, thanks to a new invalidation event [6]. Over in vercel/workflow, a batch pre-claim optimization folds lazy-inline steps into the same `createBatch` POST, trimming individual claim requests in a 20-step fan-out [7]. And vercel/eve added versioned wire schema for session inbox hooks, so payloads survive redeploys without stranding sessions [8].

Action items

→ If you use Partial Prefetching with incremental opt-in, verify the speculative prefetch bug is fixed after upgrading Next.js vercel/next.js [plan]
→ Upgrade @ai-sdk/react to include the tool-execution safety patch before running agents in production vercel/ai [immediate]
→ Update your eve session inbox hooks to use the new versioned wire encoding vercel/eve [plan]
→ Monitor the workflow pre-claim change for batched step execution in high-fanout runs vercel/workflow [monitor]

References

[1] [PPF] Remove `unstable_eager` (#97524) vercel/next.js
[2] Remove HmrTarget (#97253) vercel/next.js
[3] Turbopack: cross-module constants ↗ vercel/next.js
[4] fix: prevent automatic tool execution after unsafe model finish reasons ↗ vercel/ai
[5] fix: handle empty string tool call IDs ↗ vercel/ai
[6] fix: WorkflowAgent retries leave stale partial tool calls blocking approvals ↗ vercel/ai
[7] Batch: pre-claim inline steps in the same batch ↗ vercel/workflow
[8] feat(eve): versioned wire schema for session inbox hook payloads ↗ vercel/eve

Quick answers

What shipped in Vercel on August 20, 2026?: Next.js is cleaning house on Partial Prefetching while the AI SDK ships a safety patch that stops side-effecting tools from running after truncated model outputs. In total, 71 commits, 77 pull requests, and 17 releases landed.
Who contributed to Vercel on August 20, 2026?: 19 developers shipped this update, including Josh Story, Janka Uryga, Will Binns-Smith, mischnic, eps1lon, Pranay Prakash, Peter Wielander, and karthikscale3, and 11 more.
What were the notable Vercel updates?: [PPF] Remove `unstable_eager` (#97524), Remove HmrTarget (#97253), and Turbopack: cross-module constants.

BREAKING: Vercel SDK Ship Double Breaking Changes

Two TypeScript SDK releases in two days break response shapes across projects, feature flags, and deployments.

+13

javascript 143 shipped

@vercel Aug 19

MCP OAuth hardening lands, Fireworks structured outputs fixed

AI SDK patches a security hole in OAuth client registration while unlocking structured outputs for Fireworks models.

+11

javascript 118 shipped

@vercel Aug 18

AI SDK fixes Gemini 3.7 Flash as chat and Eve harden core flows

Gemini 3.7 Flash just broke for minimal reasoning, and the fix that landed overnight says more about the AI SDK's trajectory than any feature release.

javascript 70 shipped

@vercel Aug 17

NEXT.JS TURBO LAYER GETS GARBAGE COLLECTION PLUMBING, AI PACKAGE FIXES PROVIDER USAGE DATA

Next.js is laying the foundation for task garbage collection across its persistence layer while fixing a critical gap in how OpenAI-compatible providers report token usage.

javascript 20 shipped

Elsewhere on the wire

AI Agents Aug 21

CLINE V4.1.11 SHIPS IMAGE GENERATION AND AGENT-UI FIXES

Cline's latest release lets models generate images mid-task, while LlamaIndex quietly breaks frontend tool handlers.

ai-agents 78 shipped

Local LLMs Aug 21

DeepSeek V4 fuses shared experts, as vLLM ships a security guard

The biggest local-LLM repos are moving fast: DeepSeek V4's MoE kernel gets a massive fusion, while vLLM patches a security hole.

+12

llms 274 shipped

@CachyOS Aug 21

CachyOS Scheduler Hotfixes and Kernel Upgrades Lead the Day

A hotfix for the scx_cake scheduler and the latest Linux 7.2 kernel are rolling out across CachyOS repos.

infra 66 shipped

Elixir & Phoenix Aug 21

Phoenix 1.8.12 patches channel message drop

Phoenix shipped a patch release that fixes a channel bug silently dropping messages without a join_ref, and LiveView is quietly rewriting the rules of navigation.