From acf293de96d1d0e83fbfc7d16cb4f8da5d9f727f Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Mon, 27 Apr 2026 14:24:42 +0900
Subject: [PATCH] fix(tmux): validate fallback port

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
---
 src/features/tmux-subagent/manager.test.ts | 32 ++++++++++++++++++++++
 src/features/tmux-subagent/manager.ts      |  6 +++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/src/features/tmux-subagent/manager.test.ts b/src/features/tmux-subagent/manager.test.ts
index 11724d1a6..943f246fb 100644
--- a/src/features/tmux-subagent/manager.test.ts
+++ b/src/features/tmux-subagent/manager.test.ts
@@ -348,6 +348,38 @@ describe('TmuxSessionManager', () => {
       // then
       expect((manager as any).serverUrl).toBe('http://localhost:5678')
     })
+
+    test('ignores invalid OPENCODE_PORT when serverUrl has port 0', async () => {
+      // given
+      const previousOpenCodePort = process.env.OPENCODE_PORT
+      process.env.OPENCODE_PORT = 'not-a-port'
+      let manager: TmuxSessionManagerType | undefined
+      try {
+        mockIsInsideTmux.mockReturnValue(true)
+        const { TmuxSessionManager } = await import('./manager')
+        const ctx = {
+          ...createMockContext(),
+          serverUrl: new URL('http://127.0.0.1:0/'),
+        }
+        const config = createTmuxConfig({ enabled: true,
+        layout: 'main-vertical',
+        main_pane_size: 60,
+        main_pane_min_width: 80,
+        agent_pane_min_width: 40, })
+
+        // when
+        manager = new TmuxSessionManager(ctx, config, mockTmuxDeps)
+      } finally {
+        if (previousOpenCodePort === undefined) {
+          delete process.env.OPENCODE_PORT
+        } else {
+          process.env.OPENCODE_PORT = previousOpenCodePort
+        }
+      }
+
+      // then
+      expect((manager as any).serverUrl).toBe('http://localhost:4096')
+    })
   })
 
   describe('onSessionCreated', () => {
diff --git a/src/features/tmux-subagent/manager.ts b/src/features/tmux-subagent/manager.ts
index 3340fb55d..353bdffec 100644
--- a/src/features/tmux-subagent/manager.ts
+++ b/src/features/tmux-subagent/manager.ts
@@ -72,7 +72,11 @@ export class TmuxSessionManager {
     this.client = ctx.client
     this.tmuxConfig = tmuxConfig
     this.deps = deps
-    const defaultPort = process.env.OPENCODE_PORT ?? "4096"
+    const configuredPort = process.env.OPENCODE_PORT
+    const parsedPort = configuredPort ? Number(configuredPort) : 4096
+    const defaultPort = Number.isInteger(parsedPort) && parsedPort > 0 && parsedPort <= 65535
+      ? String(parsedPort)
+      : "4096"
     const fallbackUrl = `http://localhost:${defaultPort}`
     const rawServerUrl = ctx.serverUrl?.toString()
     try {