From f9d99f044df4d506aac897a1c27d1a0b1f894ae9 Mon Sep 17 00:00:00 2001
From: Luke Parker <10430890+Hona@users.noreply.github.com>
Date: Wed, 15 Apr 2026 08:02:27 +1000
Subject: [PATCH] fix(session): keep GitHub Copilot compaction requests valid
 (#22371)

---
 packages/opencode/src/session/llm.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/opencode/src/session/llm.ts b/packages/opencode/src/session/llm.ts
index 3ab35958a4..732ad7a9f3 100644
--- a/packages/opencode/src/session/llm.ts
+++ b/packages/opencode/src/session/llm.ts
@@ -205,7 +205,11 @@ export namespace LLM {
           // calls but no tools param is present. When there are no active tools (e.g.
           // during compaction), inject a stub tool to satisfy the validation requirement.
           // The stub description explicitly tells the model not to call it.
-          if (isLiteLLMProxy && Object.keys(tools).length === 0 && hasToolCalls(input.messages)) {
+          if (
+            (isLiteLLMProxy || input.model.providerID.includes("github-copilot")) &&
+            Object.keys(tools).length === 0 &&
+            hasToolCalls(input.messages)
+          ) {
             tools["_noop"] = tool({
               description: "Do not call this tool. It exists only for API compatibility and must never be invoked.",
               inputSchema: jsonSchema({