From 989e6a609b9667c3c01f1c53912c63d5b0b5f7a8 Mon Sep 17 00:00:00 2001
From: dsgn93-creator <dsgn93-creator@users.noreply.github.com>
Date: Tue, 28 Apr 2026 21:08:26 +0300
Subject: [PATCH] fix(messages): preserve Claude 4.x version suffix and convert
 to dot form
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Copilot exposes models as claude-opus-4.7 / claude-opus-4.6 / claude-sonnet-4.6
(dot-versioned), but Claude Code sends dash-versioned IDs with date suffixes
like claude-opus-4-7-20251030. The previous translateModelName regex stripped
the entire suffix and rewrote everything to claude-opus-4 / claude-sonnet-4,
which (a) loses the 4.5/4.6/4.7 capability tier and (b) routes vision
requests to a fallback model that may not have vision enabled — producing
an internal server error when image_url parts are present even though
copilot-vision-request: true is sent.

Convert dash-versioned 4.x families to their dot form
(claude-opus-4-7-20251030 -> claude-opus-4.7) so vision-capable variants
route correctly. Falls back to the previous behavior for unknown shapes.
---
 bun.lock                                      |  1 +
 src/routes/messages/non-stream-translation.ts | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/bun.lock b/bun.lock
index 20e895e7f..9ece87578 100644
--- a/bun.lock
+++ b/bun.lock
@@ -1,5 +1,6 @@
 {
   "lockfileVersion": 1,
+  "configVersion": 0,
   "workspaces": {
     "": {
       "name": "copilot-api",
diff --git a/src/routes/messages/non-stream-translation.ts b/src/routes/messages/non-stream-translation.ts
index dc41e6382..7bae454d4 100644
--- a/src/routes/messages/non-stream-translation.ts
+++ b/src/routes/messages/non-stream-translation.ts
@@ -47,7 +47,18 @@ export function translateToOpenAI(
 }
 
 function translateModelName(model: string): string {
-  // Subagent requests use a specific model number which Copilot doesn't support
+  // Claude Code sends dash-versioned model IDs with date suffixes
+  // (e.g. "claude-opus-4-7-20251030"), but Copilot exposes dot-versioned
+  // IDs (e.g. "claude-opus-4.7"). Convert dash → dot for known 4.x families
+  // so that vision-capable models route correctly instead of falling back.
+  const versioned = model.match(
+    /^claude-(opus|sonnet|haiku)-(\d+)-(\d+)(?:-\d{6,8})?$/,
+  )
+  if (versioned) {
+    return `claude-${versioned[1]}-${versioned[2]}.${versioned[3]}`
+  }
+
+  // Legacy fallback: subagent requests with unsupported numeric suffixes
   if (model.startsWith("claude-sonnet-4-")) {
     return model.replace(/^claude-sonnet-4-.*/, "claude-sonnet-4")
   } else if (model.startsWith("claude-opus-")) {