A one-word Finnish weather query blocked Gemini's search tool every time

A grounded answer and a memory answer arrive in the same shape. Nothing in the Gemini reply separates them, and there is no field a caller can read to tell which one turned up ^[1]. Withholding a tool per turn is cheap and defensible engineering, and the dev.to write-up grants that case in full ^[13]; the interface choice is to publish nothing about the decision.

The test that pins the mechanism is well built, and worth reading for the construction. Weather works as a probe because, per that write-up, Gemini has no separate weather feed, so current conditions come through the same search tool as everything else ^[5]. Hold the account and the settings fixed, ask in English, and it searches. Ask the same thing with the single Finnish word "saa" and search is blocked, on every attempt ^[4]. In the visible reasoning, the model works out that it should check current conditions, then notes it has not been handed the tool ^[6]. One variable moved, and it was the language, which puts the deciding step before inference ^[1]. dev.to reads the result the same way, as a routing decision made before the model starts rather than a limit of the model ^[2].

The leaked system prompt is the weaker leg. The line is verbatim, "Do NOT issue search queries to the google search tool for this prompt", in a repository the article describes as public, heavily starred and covered by mainstream press, and the author states plainly that they cannot audit Google's internal prompts and do not claim to ^[7][8]. For that line to explain your session, it would have to be the prompt served to your account, on your surface, in your language, on that turn. What survives without the repository is the behaviour and the model's own account of it, including reports of Gemini reproducing the line back to users ^[9].

The conflict case is the one I would want logged. On some turns the model is handed the search tool, an instruction to always use it, and the instruction not to issue search queries, all at once, and users have watched it referee that in its chain of thought, at one point wondering whether one of the instructions is a prompt injection ^[10]. A classifier that resolves its own contradictions inside the model's reasoning has moved the decision to the one place you cannot query.

Everything above is the consumer assistant: help threads named for Android and Web ^[3], a Reddit report from late August, and a complaint the article says has persisted across app updates through August 2026 ^[12]. The material says nothing about the developer API, so none of it is evidence about API grounding parameters. Google has published no explanation, no switch and no timeline ^[11]. Until there is a marker in the response, the paired-language probe is the only instrument on offer, and it needs re-running after each app release, since the behaviour has already outlived several ^[12].