LangChain4j — ThingsBoard Fork

This is a fork of LangChain4j maintained by ThingsBoard.

Published under the org.thingsboard.langchain4j group ID.

Conventions

Commit messages

All ThingsBoard-specific commits must use the [TB] prefix in the commit message (e.g., [TB] feat: add caching support).

Versioning

Versions follow the {upstream_version}-TB{N} scheme, where {upstream_version} is the base LangChain4j release and {N} is an incrementing number for each TB-specific release on top of it (e.g., 1.11.0-TB1, 1.11.0-TB2, 1.11.0-TB3). The counter starts at 1 and resets to 1 when upgrading to a new upstream version.

Changes compared to upstream

Gemini caching support

• Full integration with the Google Gemini cached content API — reuse large contexts across requests to save cost and latency (a13c8fb).
• Checksum-based deduplication to avoid re-caching identical content (cd48ffb).
• Caching of systemInstruction alongside user content (ab27f35).
• Handling of cached content duplicates (55486d9).
• TTL extension via PATCH instead of delete+recreate (2982dfc).

Gemini enhancements

• Send original content parts back to the model when continuing a conversation (df6179c).
• Accumulate original content parts across streaming chunks instead of overwriting with last chunk's data (f30e554).
• VALIDATED function calling mode — Gemini validates tool call arguments against the schema before returning them (7219c5f).

AiServices framework extensions

• Custom metadata support for AiServices and Result (token counts, model info, etc.) (aa3063d).
• Per-request ResponseFormat via @Format annotation — each AiService method can specify its own response format (d6953f5).
• Deferred async tool execution in streaming — tools are submitted to the executor after intermediateResponseHandler fires, ensuring intermediate text is delivered before tool execution events (95b9b3d).

Build & distribution

• Maven group ID changed to org.thingsboard.langchain4j (d18c050).
• Distribution management configured for ThingsBoard's Maven repository (4075ddf, ae6de7e, 615a46d).
• Upstream GitHub workflows removed (TB uses its own CI) (b79d357).