From 1485decdbb29b954c5c13254faada99d0199781f Mon Sep 17 00:00:00 2001
From: Levi Neely <141506390+lneely@users.noreply.github.com>
Date: Thu, 21 May 2026 19:40:41 +0200
Subject: [PATCH] backend: fix copilot API paths

Copilot API has no /v1 prefix. Add pathPrefix field to OpenAIBackend
(defaults to /v1) and apply extraHeaders in fetchModels. Copilot sets
pathPrefix to / so it hits /models and /chat/completions directly.
---
 pkg/backend/copilot.go |  9 +++++----
 pkg/backend/openai.go  | 16 ++++++++++++++--
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/pkg/backend/copilot.go b/pkg/backend/copilot.go
index 4802820..0876175 100644
--- a/pkg/backend/copilot.go
+++ b/pkg/backend/copilot.go
@@ -10,10 +10,11 @@ import (
 func NewCopilot(token string) (*OpenAIBackend, error) {
 	u, _ := url.Parse("https://api.githubcopilot.com")
 	return &OpenAIBackend{
-		name:    "copilot",
-		baseURL: u,
-		apiKey:  token,
-		client:  &http.Client{},
+		name:       "copilot",
+		baseURL:    u,
+		apiKey:     token,
+		client:     &http.Client{},
+		pathPrefix: "/",
 		extraHeaders: map[string]string{
 			"Openai-Intent": "conversation-edits",
 			"User-Agent":    "opencode/local",
diff --git a/pkg/backend/openai.go b/pkg/backend/openai.go
index f58aee7..7b444dd 100644
--- a/pkg/backend/openai.go
+++ b/pkg/backend/openai.go
@@ -23,6 +23,7 @@ type OpenAIBackend struct {
 	model        string
 	client       *http.Client
 	extraHeaders map[string]string // optional; applied after Authorization
+	pathPrefix   string            // API path prefix (default: /v1); set to "/" for no prefix
 	ctxLength    int               // cached; 0 = not yet fetched
 	ctxModel     string            // model the cached value is for
 	cachedModels []openAIModelInfo // cached model list
@@ -54,10 +55,17 @@ func (b *OpenAIBackend) fetchModels(ctx context.Context) []openAIModelInfo {
 	if len(b.cachedModels) > 0 {
 		return b.cachedModels
 	}
-	req, _ := http.NewRequestWithContext(ctx, "GET", b.baseURL.JoinPath("/v1/models").String(), nil)
+	prefix := b.pathPrefix
+	if prefix == "" {
+		prefix = "/v1"
+	}
+	req, _ := http.NewRequestWithContext(ctx, "GET", b.baseURL.JoinPath(prefix, "models").String(), nil)
 	if b.apiKey != "" {
 		req.Header.Set("Authorization", "Bearer "+b.apiKey)
 	}
+	for k, v := range b.extraHeaders {
+		req.Header.Set(k, v)
+	}
 	resp, err := b.client.Do(req)
 	if err != nil || resp.StatusCode != 200 {
 		if resp != nil {
@@ -493,7 +501,11 @@ func (b *OpenAIBackend) ChatStream(ctx context.Context, messages []Message, tool
 
 	data, _ := json.Marshal(req)
 
-	httpReq, _ := http.NewRequestWithContext(ctx, http.MethodPost, b.baseURL.JoinPath("/v1/chat/completions").String(), bytes.NewReader(data))
+	pp := b.pathPrefix
+	if pp == "" {
+		pp = "/v1"
+	}
+	httpReq, _ := http.NewRequestWithContext(ctx, http.MethodPost, b.baseURL.JoinPath(pp, "chat/completions").String(), bytes.NewReader(data))
 	httpReq.Header.Set("Content-Type", "application/json")
 	if b.apiKey != "" {
 		httpReq.Header.Set("Authorization", "Bearer "+b.apiKey)