One changelog for all your AI dev tools.

29 Sept

• Agents can control a browser to complete web tasks↗

  Agents can now interact with websites by controlling a browser environment hosted by OpenAI, with your application handling access approvals and authentication.

• Multi-agent support added to Responses API in beta↗

  GPT-6.1 Sol supports multi-agent delegation in beta via the Responses API, letting the model spawn and coordinate subagents for complex tasks.

28 Sept

• Thinking blocks are now account-bound and cannot be shared↗

  Sonnet 5.5 thinking blocks are account-bound for security. Sending one from another account silently drops it; the request still succeeds. Earlier models' blocks are unaffected.

• Claude Sonnet 5.5 released with breaking API changes↗

  Claude Sonnet 5.5 has breaking changes to thinking, tool use, and computer use APIs. Forced tool choice now errors; thinking syntax changed; older models can't be advisors. Migration guide available.

29 Sept

• Subagent permission requests now route to prompt tool↗

  Background subagents with `--permission-prompt-tool` now correctly route permission requests to the prompt tool instead of auto-denying them.

• Disable WebFetch tool via environment variable↗

  New environment variable `CLAUDE_CODE_DISABLE_WEB_FETCH` lets you disable the WebFetch tool, useful for restricted environments or when you want to limit agent capabilities.

• Configure MCP server settings at install time↗

  MCP server settings can now be configured during `claude plugin install` using `<server>.<key>=<value>` syntax, avoiding the need to visit the Configure UI afterward.

• Limit API providers per machine with managed setting↗

  New `allowedProviders` managed setting lets administrators restrict which API providers a machine can connect to, supporting Anthropic API, custom endpoints, Bedrock, Mantle, Vertex AI, Foundry, Claude Platform on AWS, and Cloud gateways.

28 Sept

• MCP tool calls now wait for servers to connect in resumed sessions↗

  When you resume a session and call an MCP tool whose server is still connecting, Claude Code now waits up to 10 seconds instead of failing with 'No such tool available'.

• Malformed images and documents no longer crash Agent SDK sessions↗

  Agent SDK sessions no longer crash when a user message contains an image with malformed metadata or a malformed document block; they replace it with an explanatory note.

• Prompt compaction now retries when still too long after first compact↗

  When a compacted prompt still exceeds the token limit, Claude Code now compacts a second time instead of failing, preserving more of the conversation where possible.

• Claude Sonnet 5.5 is now the default Sonnet model↗

  Claude Sonnet 5.5 is now the default Sonnet model on the Anthropic API, with 1M context window and updated pricing including cache read discounts.

30 Sept

• Streamed text parts now preserve partial reasoning tags↗

  When streaming text with reasoning, partial tags that span chunk boundaries are now preserved instead of being lost, fixing output corruption.

• Idle UI message streams stay open with optional SSE heartbeats↗

  Server-sent event streams for UI messages can now send heartbeats during idle periods, preventing proxies and load balancers from closing long-lived connections.

28 Sept

• Tool execution errors from providers skip the UI stream error callback↗

  When a provider executes a tool and it fails, that error no longer fires the UI stream's `onError` callback—this preserves the provider's error context. Stream errors and malformed tool calls still use the callback as before.

• UI message parts resume correctly after network disconnection↗

  If a user's connection drops mid-stream, UI message parts that were being rendered will now properly resume instead of being lost or duplicated.

• Tool metadata now preserved through streaming output chunks↗

  When tools return data through streaming, their metadata (like names and descriptions) now persists through the output pipeline instead of being lost.

• Prevent unhandled rejections from stream completion in non-Node runtimes↗

  Fixed unhandled promise rejections from stream completion in non-Node environments like browsers and edge functions, improving stability.

• Advertise image model capabilities with confirmed model IDs↗

  The SDK now accurately advertises which image models support file inputs and masks, using verified model IDs. Adds support declarations for Together AI FLUX.2 Pro, Flex, and QuiverAI Arrow 2, while marking unsupported capabilities as unknown.

• Cancel response streams when clients disconnect↗

  Response streams are cancelled immediately when a client disconnects, reducing unnecessary compute and API costs.

29 Sept

• Vercel Connect now accepts community service submissions↗

  You can now submit services to Vercel Connect's directory instead of waiting for Vercel to build connectors. Submissions require OAuth or API key support and go through review.

• Search trace spans from the CLI without opening the dashboard↗

  You can now search request traces directly from the terminal instead of the dashboard, filtering by multiple fields and time range. Agents can parse structured JSON output to investigate errors and latency.

• GPT-6.1 Sol model available on AI Gateway↗

  GPT-6.1 Sol, OpenAI's latest model optimized for coding and multi-step workflows, is now accessible through Vercel's AI Gateway with improved factual accuracy and reduced token costs for cached contexts.

28 Sept

• Search domain availability without authentication↗

  You can discover and price domains through the CLI or API without signing in to Vercel. Authentication remains required only for purchase and management.

• Claude Sonnet 5.5 available on AI Gateway↗

  Anthropic's Claude Sonnet 5.5 is now available through Vercel's AI Gateway with zero data retention, supporting multiple API formats for inference in your product.