Https://discuss.ai.google.dev/t/search-grounding-metadata-is-empty-even-when-search-was-performed/79831/21

Gemini API
1

Hi all,

Has anyone else seen a recent regression with File Search on gemini-3.1-flash-lite?

Since roughly June 1, 2026, we usually get correct answers that clearly use the File Search store, but groundingMetadata is empty (no groundingChunks / groundingSupports). File Search still appears to run (tool_use_prompt_token_count > 0).

Occasionally flash-lite still returns grounding metadata correctly — so it’s not 100% broken, but mostly broken since that date.

Same request on gemini-3.1-flash-preview consistently returns full grounding metadata.

We rolled back our app to a version from ~1 week ago and the issue persists, so it looks server-side / model-route specific, not our code.

Related thread (Google Search grounding, similar symptom): https://discuss.ai.google.dev/t/search-grounding-metadata-is-empty-even-when-search-was-performed/79831

Is anyone else hitting this on flash-lite right now?

2

Hello @Jorge_Lopez,

We were unable to reproduce the issue on our end, as the grounding_metadata was successfully generated using a File Search store. If you are still missing metadata, try reducing the size of your system instructions or overall context. Large prompts that exceed certain token thresholds can sometimes cause the server to drop metadata arrays. If the issue persists, please share a minimal reproducible code snippet so we can investigate further.