Create Gemini Chat Object

Create a reusable chat object for interactive conversations with Google Gemini. The returned object provides $chat() for text responses, $stream() for streaming, and $chat_structured() for structured data extraction.

Use gemini_chat() for interactive, multi-turn conversations with streaming. Use gemini_generate() for single-turn, structured output (e.g., pipeline tasks).

Usage

gemini_chat(
  sys_prompt = NULL,
  ml = NULL,
  temp = 1,
  tools = NULL,
  echo = "none"
)

Arguments

sys_prompt

Character. System prompt to set model behavior. Default NULL.

ml

Character. Model ID. Default from ART_GEMINI_MODEL env var.

temp

Numeric. Temperature (0-2). Default 1.

tools

List. Tools to register. Create with ellmer::tool(). Default NULL.

echo

Character. Output mode: "none", "output", or "all". Default "none".

Value

ellmer Chat object with methods:

• $chat(...): Send message(s), receive text response

• $chat_structured(prompt, type): Send message, receive structured data

• $stream(...): Stream response chunks (for real-time display)

• $register_tool(tool): Add a tool after creation

See also

• gemini_generate() for low-level single-turn requests

• gemini_continue() for manual conversation continuation

Examples

if (FALSE) { # \dontrun{
# Basic chat
chat <- gemini_chat()
chat$chat("Explain Impressionism in 2 sentences.")

# With system prompt
chat <- gemini_chat(sys_prompt = "You are an art historian.")
chat$chat("What is Baroque?")

# Multi-turn conversation
chat <- gemini_chat(sys_prompt = "You are an art expert.")
chat$chat("What is Baroque art?")
chat$chat("How does it differ from Renaissance?")

# Streaming for real-time UI
stream <- chat$stream("Tell me a story about an artist.")
coro::loop(for (chunk in stream) cat(chunk))

# Image input
chat$chat(ellmer::content_image_file("artwork.png"), "Describe this.")

# Structured output
schema <- ellmer::type_object(
  style = ellmer::type_string("Art style"),
  period = ellmer::type_string("Time period")
)
chat$chat_structured("Describe Impressionism", type = schema)
} # }