2.6.0 upgrade guide
Promote the tested beta features to stable SDK versions and understand the compatibility changes
The 2.6.0 production candidate for both SDKs carries the feature set tested in LLM SDK 2.6.0-beta.3 and Copilot SDK 2.5.1-beta.3, including the compatibility hotfix. Its runtime source matches those betas. npm publication is a separate step; merging the production PR does not publish packages.
Installation
After the stable versions are published:
npm install @yourgpt/llm-sdk@2.6.0 @yourgpt/copilot-sdk@2.6.0Use matching stable versions when validating the upgrade. The beta tag is a separate release channel for subsequent work. Provider clients such as openai and @anthropic-ai/sdk remain optional dependencies for the corresponding chat adapters.
Until stable publication, use the verified versions @yourgpt/llm-sdk@2.6.0-beta.3 and @yourgpt/copilot-sdk@2.5.1-beta.3.
Included in this release
| Feature or fix | Guide |
|---|---|
| OpenAI reasoning-model parameters and selective compatibility fallback | Parameters, fallback |
| Anthropic Runtime system-role preservation | System prompts |
| OpenAI Responses transport, stored/stateless continuation, and tool replay | Responses |
| Native image tool results on OpenAI Responses and Anthropic | Image results |
| Buffered OpenAI text-to-speech and recorded-file speech-to-text | Speech, transcription |
| Browser microphone recording, cancellation, and transcript review | Voice input |
| Structured output translation and token usage fixes across existing adapters | Structured output, token tracking |
The release also retains the tested fixes for mixed server/client tool turns, tool-loop iteration limits, cancellation, stream reader reuse, interleaved tool arguments, screenshot attachments, trailing usage, and public CJS/ESM declarations. Feature guides mention the beta versions where the APIs first appeared; those APIs are included in stable 2.6.0.
Compatibility checks
- Anthropic instructions: Runtime uses
systemPrompt; modern generation usessystem. System-role messages reach Anthropic. The effective explicit/default prompt comes first, followed by distinct system instructions in order. Text repeated between that prompt and a system message is sent once. Unsupported non-text system content is ignored; valid text is retained. - OpenAI parameters: reasoning requests omit unsupported temperature values with a warning. Use supported
reasoningEffort: 'none'explicitly when sampling is needed. Custom compatible servers can select passthrough behavior. - Continuation: preserve reduced continuation metadata, native tool output, and matching tool-call IDs in saved history. Raw provider diagnostics are not replay state. At application response boundaries, remove top-level Runtime billing
usageand debugeventsafter accounting. A transcript containing only visible text cannot restore every Responses conversation. - Tools: raw array/object tool results are preserved rather than converted to
[object Object]; provider content schemas still apply. Malformed Responses calls can trigger configured fallback before output or tool execution begins. Native image tool output requires a supported provider/endpoint. A screenshot with native output does not add a duplicate user-image turn. - Audio: speech and transcription are separate APIs from chat generation. Browser recording returns a transcript for review; it does not submit a chat message automatically.
Known limits
The hosted YourGPT storage adapter does not yet preserve all Responses/image replay metadata. Use a lossless custom store and test save/reload/continue for those workflows. Physical microphones, browser permission flows, and recorded-container compatibility still require validation on your target devices.
OpenAI is the built-in TTS/STT provider. Live media checks covered inline images and WAV/MP3; other supported formats have fixture coverage. Cache option forwarding is available for OpenAI Responses, while unified cache usage/cost accounting remains pending. See storage and prompt caching.
Prompt delivery checks do not establish strict JSON output or application guardrail accuracy. The backend's TRAINING_CONFLICT schema and failure policy still need application-level evaluation.
Next beta
Native Decisions for Jev/TypeSafe, OpenAI, OpenRouter, and Cloudflare, experimental realtime voice, and image generation/editing are implemented on the separate next-beta branch. Those features, the new Feature Lab and the later UI/PR adaptations are outside this production candidate. Remaining provider/caching and persistence work stays on the roadmap.
For historical beta versions and validation evidence, see the beta release record.