Product Updates

Gemini API Interactions breaking changes (May 2026): outputs → steps, new response_format, and migration timeline

Google’s Gemini API Interactions endpoint is changing its response schema (outputs → steps), consolidating output format controls into response_format, and updating streaming event names, with a May 26 default flip and a June 8 legacy sunset.

By AI Coding Tools Directory•2026-05-16•10 min read
Last reviewed: 2026-05-16
ACTD
AI Coding Tools Directory

Editorial Team

The AI Coding Tools Directory editorial team researches and reviews AI-powered development tools to help developers find the best solutions for their workflows.

Google published a migration guide for upcoming breaking changes to the Gemini API Interactions endpoint, including a response schema change from outputs to steps, plus a firm timeline for rollout. (https://ai.google.dev/gemini-api/docs/interactions-breaking-changes-may-2026)

1) Response schema: outputs → steps

Google says responses move from a flat outputs array to a structured steps array:

  • POST /interactions returns only output steps.
  • GET /interactions/{id} returns the full step timeline (including the initial user_input step).

(https://ai.google.dev/gemini-api/docs/interactions-breaking-changes-may-2026)

2) Output format changes: response_mime_type removed

Google says response_mime_type is removed and output control moves into a polymorphic response_format field.

The guide also notes that image output configuration previously under generation_config.image_config moves into a response_format entry with type: "image". (https://ai.google.dev/gemini-api/docs/interactions-breaking-changes-may-2026)

3) Streaming event names change

Google’s guide lists new server-sent-event types (e.g. interaction.created, interaction.completed, step.start, step.delta, step.stop) replacing older event names. (https://ai.google.dev/gemini-api/docs/interactions-breaking-changes-may-2026)

For streaming function calls, Google says function arguments arrive as partial JSON string deltas (arguments_delta), and clients must accumulate deltas to reconstruct full arguments. (https://ai.google.dev/gemini-api/docs/interactions-breaking-changes-may-2026)

Migration timeline (key dates)

The guide lists a staged rollout:

Sources

Free Resource

2026 AI Coding Tools Comparison Chart

Side-by-side comparison of features, pricing, and capabilities for every major AI coding tool.

No spam, unsubscribe anytime.

Frequently Asked Questions

What is Gemini API Interactions breaking changes (May 2026): outputs → steps, new response_format, and migration timeline?
Google’s Gemini API Interactions endpoint is changing its response schema (outputs → steps), consolidating output format controls into response_format, and updating streaming event names, with a May 26 default flip and a June 8 legacy sunset.

Related Articles

Product Updates

Warp 2026.07.03: Tab Groups, custom model routers, and native agy (Antigravity) CLI support

Warp's July 3, 2026 release adds Tab Groups for organizing tabs, custom model routers to route agent requests by your own rules, and native support for the agy (Antigravity) CLI agent.

Read more →Product Updates

OpenAI GPT-5.6 (July 2026): Sol, Terra, and Luna arrive for developers

OpenAI launched the GPT-5.6 model family — Sol, Terra, and Luna — publicly on July 9, 2026. Here's what each model is for, how they reach developers (including the API and Amazon Bedrock), and reported pricing.

Read more →Product Updates

Cursor for iOS: launch and control AI coding agents from your phone

Cursor launched a native iOS app (public beta on paid plans) that lets you start cloud agents, remote-control agents running on your computer, use voice input, and review and merge PRs from your phone.

Read more →
← Back to Blog