Fill-in-the-Middle (FIM)

Code completion that takes a Prompt (code before the cursor) and an optional Suffix (code after the cursor) and fills in the middle. Useful for code editors and IDE integrations. The fim modality lives at fim/; vendors under fim/<name>/.

Mistral Codestral

import (
    "github.com/joakimcarlsson/ai/fim"
    fimmistral "github.com/joakimcarlsson/ai/fim/mistral"
    "github.com/joakimcarlsson/ai/model"
)

client := fimmistral.NewFIM(
    fimmistral.WithAPIKey(os.Getenv("MISTRAL_API_KEY")),
    fimmistral.WithModel(model.MistralModels[model.Codestral]),
)

resp, err := client.Complete(ctx, fim.Request{
    Prompt: "def add(a, b):\n    ",
    Suffix: "\n    return result",
})
fmt.Println(resp.Content)

DeepSeek

import fimdeepseek "github.com/joakimcarlsson/ai/fim/deepseek"

client := fimdeepseek.NewFIM(
    fimdeepseek.WithAPIKey(os.Getenv("DEEPSEEK_API_KEY")),
    fimdeepseek.WithModel(model.DeepSeekModels[model.DeepSeekCoder]),
)

Streaming

events := client.CompleteStream(ctx, fim.Request{
    Prompt: prompt,
    Suffix: suffix,
})

for event := range events {
    switch event.Type {
    case fim.EventContentDelta:
        fmt.Print(event.Content)
    case fim.EventComplete:
        fmt.Printf("\nFinish: %s\n", event.Response.FinishReason)
    case fim.EventError:
        log.Fatal(event.Error)
    }
}

Per-request overrides

The fim.Request struct lets you override constructor defaults per call:

maxTokens := int64(500)
temp := 0.2

resp, err := client.Complete(ctx, fim.Request{
    Prompt:      prompt,
    Suffix:      suffix,
    MaxTokens:   &maxTokens,
    Temperature: &temp,
    Stop:        []string{"\n\n"},
})

Vendor-specific options

Mistral:

fimmistral.WithMinTokens(20)

DeepSeek:

fimdeepseek.WithFrequencyPenalty(0.3)
fimdeepseek.WithPresencePenalty(0.3)
fimdeepseek.WithEcho(true)