fix(ollama): accept prompt alias on /api/embed for Ollama parity (#9780)

Ollama's embedding endpoint accepts both `input` and `prompt` as the
input string value (see ollama/ollama docs/api.md#generate-embeddings).
LocalAI only accepted `input`, which broke client libraries that send
the `prompt` form.

Add `Prompt` to OllamaEmbedRequest and have GetInputStrings fall back
to it when Input is unset. Input still wins when both are provided.

Fixes #9767.

Assisted-by: Claude:claude-opus-4-7 [Claude Code]

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

core/schema/ollama.go

@@ -120,10 +120,14 @@ type OllamaGenerateResponse struct {
 	EvalDuration       int64     `json:"eval_duration,omitempty"`
 }
 
-// OllamaEmbedRequest represents a request to the Ollama Embed API
+// OllamaEmbedRequest represents a request to the Ollama Embed API.
+// Ollama's /api/embed endpoint accepts both `input` and `prompt` as the
+// input string value (see https://github.com/ollama/ollama/blob/main/docs/api.md#generate-embeddings),
+// so both keys are deserialized here for client compatibility.
 type OllamaEmbedRequest struct {
-	Model   string `json:"model"`
-	Input   any    `json:"input"` // string or []string
+	Model   string         `json:"model"`
+	Input   any            `json:"input,omitempty"`  // string or []string
+	Prompt  any            `json:"prompt,omitempty"` // string or []string (Ollama alias for Input)
 	Options *OllamaOptions `json:"options,omitempty"`
 }
 
@@ -135,10 +139,21 @@ func (r *OllamaEmbedRequest) ModelName(s *string) string {
 	return r.Model
 }
 
-// GetInputStrings normalizes the Input field to a string slice
+// GetInputStrings normalizes the Input/Prompt field to a string slice.
+// Input takes precedence over Prompt when both are provided.
 func (r *OllamaEmbedRequest) GetInputStrings() []string {
-	switch v := r.Input.(type) {
+	if v := normalizeOllamaEmbedInput(r.Input); v != nil {
+		return v
+	}
+	return normalizeOllamaEmbedInput(r.Prompt)
+}
+
+func normalizeOllamaEmbedInput(v any) []string {
+	switch v := v.(type) {
 	case string:
+		if v == "" {
+			return nil
+		}
 		return []string{v}
 	case []any:
 		var result []string

core/schema/ollama_test.go

@@ -0,0 +1,86 @@
+package schema_test
+
+import (
+	"encoding/json"
+
+	. "github.com/mudler/LocalAI/core/schema"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("OllamaEmbedRequest", func() {
+
+	Context("GetInputStrings", func() {
+		It("returns a single string when Input is a string", func() {
+			req := OllamaEmbedRequest{Input: "hello world"}
+
+			Expect(req.GetInputStrings()).To(Equal([]string{"hello world"}))
+		})
+
+		It("returns a list of strings when Input is a []string", func() {
+			req := OllamaEmbedRequest{Input: []string{"hello", "world"}}
+
+			Expect(req.GetInputStrings()).To(Equal([]string{"hello", "world"}))
+		})
+
+		It("returns a list of strings when Input is a []any (post JSON unmarshal)", func() {
+			req := OllamaEmbedRequest{Input: []any{"hello", "world"}}
+
+			Expect(req.GetInputStrings()).To(Equal([]string{"hello", "world"}))
+		})
+	})
+
+	Context("JSON unmarshaling (Ollama API compatibility)", func() {
+		It("accepts the 'input' field as a single string", func() {
+			body := []byte(`{"model": "m", "input": "why is the sky blue?"}`)
+
+			var req OllamaEmbedRequest
+			Expect(json.Unmarshal(body, &req)).To(Succeed())
+
+			Expect(req.Model).To(Equal("m"))
+			Expect(req.GetInputStrings()).To(Equal([]string{"why is the sky blue?"}))
+		})
+
+		It("accepts the 'input' field as an array of strings", func() {
+			body := []byte(`{"model": "m", "input": ["why is the sky blue?", "why is the grass green?"]}`)
+
+			var req OllamaEmbedRequest
+			Expect(json.Unmarshal(body, &req)).To(Succeed())
+
+			Expect(req.GetInputStrings()).To(Equal([]string{"why is the sky blue?", "why is the grass green?"}))
+		})
+
+		// Ollama's embedding endpoint accepts both `input` and `prompt` keys:
+		// https://github.com/ollama/ollama/blob/main/docs/api.md#generate-embeddings
+		// LocalAI must accept `prompt` so client libraries using that key are not broken.
+		// See https://github.com/mudler/LocalAI/issues/9767.
+		It("accepts the 'prompt' field as a single string (Ollama compatibility)", func() {
+			body := []byte(`{"model": "m", "prompt": "why is the sky blue?"}`)
+
+			var req OllamaEmbedRequest
+			Expect(json.Unmarshal(body, &req)).To(Succeed())
+
+			Expect(req.Model).To(Equal("m"))
+			Expect(req.GetInputStrings()).To(Equal([]string{"why is the sky blue?"}))
+		})
+
+		It("accepts the 'prompt' field as an array of strings (Ollama compatibility)", func() {
+			body := []byte(`{"model": "m", "prompt": ["why is the sky blue?", "why is the grass green?"]}`)
+
+			var req OllamaEmbedRequest
+			Expect(json.Unmarshal(body, &req)).To(Succeed())
+
+			Expect(req.GetInputStrings()).To(Equal([]string{"why is the sky blue?", "why is the grass green?"}))
+		})
+
+		It("prefers 'input' when both 'input' and 'prompt' are provided", func() {
+			body := []byte(`{"model": "m", "input": "from input", "prompt": "from prompt"}`)
+
+			var req OllamaEmbedRequest
+			Expect(json.Unmarshal(body, &req)).To(Succeed())
+
+			Expect(req.GetInputStrings()).To(Equal([]string{"from input"}))
+		})
+	})
+})