Interactions API: Spanner UTF-8 error when generating Korean response after tool calls

Gemini API
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Environment

  • Model: gemini-3-flash-preview

  • SDK: @google/genai (JavaScript/TypeScript)

  • API: Interactions API

Issue

After successfully executing function calls and sending results back via ai.interactions.create(), the API throws an internal Spanner database error when the model attempts to generate a response in Korean.

Error

BadRequestError: 400 {“error”:{“message”:“[original: spanner::Bad usage] New value is not valid UTF-8 for string column: Interactions.ResponseTruncatedText; at participant db88977682989677/g6332_1960988”,“code”:“invalid_request”}}

Context

  • User message was in Korean

  • Model successfully called multiple tools (function calls)

  • Tool results were sent back as JSON via ai.interactions.create() with previous_interaction_id

  • Error occurred when model tried to generate its final Korean response

Observations

  • The error references internal column Interactions.ResponseTruncatedText

  • Tool execution completed successfully before the error

  • Appears to happen when model generates non-ASCII (Korean) response text

  • Error is intermittent

Expected Behavior

Model should generate Korean response without internal database errors.

1 Like
3

same for me with hebrew…

for now, disable store work for me…

(i want the store…)