✨ forward 'thoughtSignature' with Google Gemini

[simonpcouch]

Closes #869.

library(ellmer)

tool_rnorm <- tool(
  function() rnorm(1),
  description = "Draw a number from a standard normal distribution"
)

gemini_3 <- chat_google_gemini(
  system_prompt = "Be terse.",
  model = "gemini-3-pro-preview"
)
gemini_3$register_tool(tool_rnorm)

gemini_3$chat("Draw a number from a standorm normal.")
#> ◯ [tool call] tool_001()
#> ● #> 0.8896
#> 0.8896

^{Created on 2025-11-18 with reprex v2.1.1}

[hadley]

I think you could drop the hasName check and use compact to eliminate the NULL.

[hadley]

Also did we need some adjustment to params? I noticed you didn’t use it in the example.

[simonpcouch]

You got it, thank you!

Also did we need some adjustment to params? I noticed you didn’t use it in the example.

This references using params(reasoning_effort) rather than api_args(...(thinkingLevel))?

gemini_3 <- chat_google_gemini(
  model = "gemini-3-pro-preview",
  api_args = list(
    generationConfig = list(thinkingConfig = list(thinkingLevel = "low"))
  )
)

There's a default thinkingLevel, so setting that argument isn't required. The above is the same syntax as was used for Gemini 2.5 Pro, so I figured there might have been some other reason yall didn't incorporate that argument into params(reasoning_effort). I do agree that setting that params entry would be easier, but since this isn't a new API argument I left it for another PR.