Documentation Index
Fetch the complete documentation index at: https://mintlify.com/firebase/genkit/llms.txt
Use this file to discover all available pages before exploring further.
Prompts encapsulate model configuration, templates, and schemas.
See genkit.DefinePrompt() for full API documentation.
Quick Reference
type Input struct {
Name string `json:"name"`
}
type Output struct {
Greeting string `json:"greeting"`
}
prompt := genkit.DefinePrompt(g, "greet",
ai.WithModelName("googleai/gemini-2.0-flash"),
ai.WithPrompt("Say hello to {{name}}"),
ai.WithInputType(Input{}),
ai.WithOutputType(Output{}),
)
// Execute
resp, err := prompt.Execute(ctx,
ai.WithInput(Input{Name: "Alice"}),
)
var out Output
resp.Output(&out)
Prompt Options
Model Configuration
ai.WithModel(model)ai.WithModelName(string)ai.WithConfig(any)
Prompt Content
ai.WithPrompt(string) - User prompt templateai.WithPromptFn(func) - Dynamic user promptai.WithSystem(string) - System instructionsai.WithSystemFn(func) - Dynamic system instructionsai.WithMessages([]*Message) - Conversation historyai.WithMessagesFn(func) - Dynamic messages
ai.WithInputType(T) - Input schema from typeai.WithInputSchema(map[string]any) - Custom input schemaai.WithOutputType(T) - Output schema from typeai.WithOutputSchema(map[string]any) - Custom output schemaai.WithOutputFormat(string) - Output format (json, text)
ai.WithTools(...Tool) - Enable toolsai.WithToolChoice(ToolChoice) - Control tool usageai.WithMaxTurns(int) - Max tool iterations
Prompt Methods
Execute()
resp, err := prompt.Execute(ctx,
ai.WithInput(input),
ai.WithConfig(config),
)
ExecuteStream()
for value, err := range prompt.ExecuteStream(ctx,
ai.WithInput(input),
) {
if err != nil {
log.Fatal(err)
}
if value.Done {
fmt.Println(value.Response.Text())
} else {
fmt.Print(value.Chunk.Text())
}
}
Render()
opts, err := prompt.Render(ctx, input)
if err != nil {
log.Fatal(err)
}
// Modify opts if needed
resp, err := genkit.GenerateWithRequest(ctx, g, opts, nil, nil)
DataPrompt (Typed)
type GeoInput struct {
Country string `json:"country"`
}
type GeoOutput struct {
Capital string `json:"capital"`
}
prompt := genkit.DefineDataPrompt[GeoInput, GeoOutput](g, "findCapital",
ai.WithModelName("googleai/gemini-2.0-flash"),
ai.WithPrompt("Capital of {{country}}?"),
)
// Execute with type safety
output, resp, err := prompt.Execute(ctx, GeoInput{Country: "France"})
fmt.Println(output.Capital) // "Paris"
Loading .prompt Files
// Auto-load from directory
g := genkit.Init(ctx,
genkit.WithPromptDir("./prompts"),
)
// Or load manually
genkit.LoadPromptDir(g.Registry(), "./prompts", "")
// Lookup loaded prompt
prompt := genkit.LookupPrompt(g, "myPrompt")
if prompt != nil {
resp, err := prompt.Execute(ctx, nil)
}