From 393b70fc7e8048d36653fa342b6ed2a9f777226a Mon Sep 17 00:00:00 2001
From: mayor <daniel.a.d.sauer@gmail.com>
Date: Tue, 13 Jan 2026 18:10:43 +0100
Subject: [PATCH] fix(mcp): close existing client before reassignment to
 prevent leaks

When MCP.add() or finishAuth() assigns a new client to s.clients[name],
any existing client at that key is orphaned without being closed. This
causes connection/resource leaks over time.

Add existingClient.close() before reassignment in both locations to
properly clean up replaced clients.
---
 packages/opencode/src/mcp/index.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/packages/opencode/src/mcp/index.ts b/packages/opencode/src/mcp/index.ts
index aca0c663152..4e0968391f3 100644
--- a/packages/opencode/src/mcp/index.ts
+++ b/packages/opencode/src/mcp/index.ts
@@ -266,6 +266,13 @@ export namespace MCP {
         status: s.status,
       }
     }
+    // Close existing client if present to prevent memory leaks
+    const existingClient = s.clients[name]
+    if (existingClient) {
+      await existingClient.close().catch((error) => {
+        log.error("Failed to close existing MCP client", { name, error })
+      })
+    }
     s.clients[name] = result.mcpClient
     s.status[name] = result.status
 
@@ -523,6 +530,13 @@ export namespace MCP {
     const s = await state()
     s.status[name] = result.status
     if (result.mcpClient) {
+      // Close existing client if present to prevent memory leaks
+      const existingClient = s.clients[name]
+      if (existingClient) {
+        await existingClient.close().catch((error) => {
+          log.error("Failed to close existing MCP client", { name, error })
+        })
+      }
       s.clients[name] = result.mcpClient
     }
   }