fix(ai-openai): migrate WebRTC realtime adapter to OpenAI GA API

[amitsaroj]

🎯 Changes

Fixes #586

Migrates the @tanstack/ai-openai WebRTC realtime adapter from the deprecated OpenAI Beta realtime API to the GA (generally available) API. OpenAI deprecated the Beta realtime endpoint on 2026-05-12, causing all openaiRealtime() connections to fail with beta_api_shape_disabled.

Root Cause

Two GA-shape mismatches in packages/ai-openai/src/realtime/adapter.ts:

1. Wrong SDP-exchange endpoint (connection fails immediately)

The Beta API used /v1/realtime?model=<model> for WebRTC SDP negotiation. OpenAI's GA API uses /v1/realtime/calls.

// Before (Beta — returns HTTP 400 beta_api_shape_disabled)
const sdpResponse = await fetch(`${OPENAI_REALTIME_URL}?model=${model}`, { ... })

// After (GA)
const sdpResponse = await fetch(`${OPENAI_REALTIME_URL}/calls`, { ... })

2. Missing session.type in updateSession (session config silently rejected)

The GA API requires session.type on every session.update event. Without it, the server rejects the update with missing_required_parameter: session.type, which means instructions, tools, and voice settings are never applied.

// Before (Beta — session.type not required)
const sessionUpdate: Record<string, unknown> = {}

// After (GA — "realtime" is the session type for openaiRealtime())
const sessionUpdate: Record<string, unknown> = { type: 'realtime' }

Fix

Minimal two-line change, consistent with the issue reporter's verified local fix.

✅ Checklist

• I have followed the steps in the Contributing guide.
• - [ ] I have tested this code locally with pnpm run test:pr.

🚀 Release Impact

• This change affects published code, and I have generated a changeset.

🧪 Test Plan

1. Call new RealtimeClient({ adapter: openaiRealtime(), ... }).connect() against OpenAI's live API.
2. 2. Verify no beta_api_shape_disabled 400 error.
3. 3. Verify session.update is accepted (instructions, tools, and voice apply correctly).
4. 4. Existing unit tests in packages/ai-openai/tests/openai-adapter.test.ts cover the session update shape.

Summary by CodeRabbit

• Bug Fixes
  • Updated WebRTC endpoint configuration for realtime API SDP exchange.
  • Improved session update payload handling to ensure proper session event delivery.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 62bd639f-8888-45b9-bc78-4df549e5bb50

📥 Commits

Reviewing files that changed from the base of the PR and between 769a6c7 and b6841a8.

📒 Files selected for processing (1)

• packages/ai-openai/src/realtime/adapter.ts

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📝 Walkthrough

Walkthrough

The adapter updates address OpenAI's deprecated Beta realtime API and session event initialization. The SDP exchange endpoint migrates from the Beta shape using a model query parameter to the GA /calls endpoint, and updateSession now initializes with type: 'realtime' to ensure session update events emit when no other config fields are provided.

Changes

OpenAI Realtime Adapter Fixes

Layer / File(s)	Summary
WebRTC endpoint and session initialization packages/ai-openai/src/realtime/adapter.ts	SDP exchange URL migrated from deprecated Beta endpoint (?model=...) to GA endpoint (/calls). Session update initialization changed from empty object to { type: 'realtime' } to ensure events emit when no other config is set.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

🐰 The Beta's gone, the GA's here,
/calls replaces query cheer,
Session types now always flow,
Real-time whispers, all aglow! 🌟

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: migrating the WebRTC realtime adapter to OpenAI's GA API, which is the central focus of the PR.
Description check	✅ Passed	The description comprehensively covers the changes, provides clear root cause analysis with before/after code examples, and includes release impact and test plan information.
Linked Issues check	✅ Passed	The PR successfully addresses both objectives from issue #586: updating the SDP endpoint from Beta /v1/realtime?model=... to GA /v1/realtime/calls and adding required session.type: 'realtime' field.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the immediate GA API migration issues identified in #586; follow-up concerns about event type renames are explicitly noted as out-of-scope future work.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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