Cohere

Cohere provider using the native Chat v2 and Embed APIs. This is not an OpenAI-compatible provider - it uses Cohere's own wire format.

Setup

go get github.com/zendev-sh/goai@latest

import "github.com/zendev-sh/goai/provider/cohere"

Set the COHERE_API_KEY environment variable, or pass WithAPIKey() directly.

Models

Chat: command-r-plus, command-r, command-a-reasoning

Embeddings: embed-v4.0, embed-english-v3.0, embed-multilingual-v3.0

Tested Models

Unit tested (mock HTTP server, 2026-03-15): command-r-plus, command-a-reasoning, embed-v4.0

Usage

Chat

model := cohere.Chat("command-r-plus")

result, err := goai.GenerateText(ctx, model, goai.WithPrompt("Explain RAG"))
if err != nil {
    log.Fatal(err)
}
fmt.Println(result.Text)

Reasoning Models

The command-a-reasoning model supports thinking/reasoning via provider options:

model := cohere.Chat("command-a-reasoning")

result, err := goai.GenerateText(ctx, model,
    goai.WithPrompt("Solve this step by step: what is 127 * 53?"),
    goai.WithProviderOptions(map[string]any{
        "thinking": map[string]any{
            "type":        "enabled",
            "tokenBudget": 4096,
        },
    }),
)

When streaming, reasoning chunks arrive as provider.ChunkReasoning type. In non-streaming mode (GenerateText), reasoning content is not surfaced in TextResult; use streaming to access it.

Embeddings

embedModel := cohere.Embedding("embed-v4.0")

result, err := goai.Embed(ctx, embedModel, "hello world")

Embedding provider options (pass in EmbedParams.ProviderOptions):

Option	Type	Description
inputType	string	search_document (default), search_query, classification, clustering
truncate	string	NONE, START, END

Citations

Cohere models can return citations with their responses. These are available in the result's Sources field:

for _, source := range result.Sources {
    fmt.Printf("Citation: %s (chars %d-%d)\n", source.Title, source.StartIndex, source.EndIndex)
}

Options

Option	Type	Description
WithAPIKey(key)	string	Set a static API key
WithTokenSource(ts)	provider.TokenSource	Set a dynamic token source
WithBaseURL(url)	string	Override the default https://api.cohere.com/v2 endpoint
WithHeaders(h)	map[string]string	Set additional HTTP headers
WithHTTPClient(c)	*http.Client	Set a custom *http.Client

Notes

• Uses Cohere's native API format, not OpenAI-compatible. Request/response mapping is handled internally.
• Max embedding batch size: 96 values per call.
• Streaming uses Cohere-specific SSE event types (content-delta, tool-call-start, tool-call-delta, tool-call-end, message-end, citation-start).
• Environment variable COHERE_BASE_URL can override the default endpoint.