diff --git a/src/config/schema/tmux.ts b/src/config/schema/tmux.ts
index a10edc7f9b..d3104c99f4 100644
--- a/src/config/schema/tmux.ts
+++ b/src/config/schema/tmux.ts
@@ -20,6 +20,17 @@ export const TmuxConfigSchema = z.object({
   main_pane_size: z.number().min(20).max(80).default(60),
   main_pane_min_width: z.number().min(40).default(120),
   agent_pane_min_width: z.number().min(20).default(40),
+  /**
+   * Override the server URL used for health checks and pane spawning.
+   * Use this when opencode auto-detects the wrong IP (e.g., Tailscale).
+   * Example: "http://localhost:4096"
+   */
+  server_url_override: z
+    .preprocess(
+      (val) => (val === "" || val === null ? undefined : val),
+      z.string().url().optional()
+    )
+    .optional(),
   isolation: TmuxIsolationSchema.default("inline"),
 })
 
diff --git a/src/features/tmux-subagent/manager.ts b/src/features/tmux-subagent/manager.ts
index 7bab2d215f..6e39a638d7 100644
--- a/src/features/tmux-subagent/manager.ts
+++ b/src/features/tmux-subagent/manager.ts
@@ -69,22 +69,24 @@ export class TmuxSessionManager {
     this.deps = deps
     const defaultPort = process.env.OPENCODE_PORT ?? "4096"
     const fallbackUrl = `http://localhost:${defaultPort}`
-    const rawServerUrl = ctx.serverUrl?.toString()
-    try {
-      if (rawServerUrl) {
-        const parsed = new URL(rawServerUrl)
-        const port = parsed.port || (parsed.protocol === 'https:' ? '443' : '80')
-        this.serverUrl = port === '0' ? fallbackUrl : rawServerUrl
-      } else {
-        this.serverUrl = fallbackUrl
-      }
-    } catch (error) {
-      log("[tmux-session-manager] failed to parse server URL, using fallback", {
-        serverUrl: rawServerUrl,
-        error: String(error),
-      })
-      this.serverUrl = fallbackUrl
-    }
+      try {
+        const rawServerUrl = tmuxConfig.server_url_override || ctx.serverUrl?.toString()
+        try {
+          if (rawServerUrl) {uest? I'm adding react query to my project and wondering if I have to have server/client-specific query functions or if I can get away with sharing a single server query function between the two use cases?
+
+            const parsed = new URL(rawServerUrl)
+            const port = parsed.port || (parsed.protocol === 'https:' ? '443' : '80')
+            this.serverUrl = port === '0' ? fallbackUrl : rawServerUrl
+          } else {
+            this.serverUrl = fallbackUrl
+          }
+        } catch (error) {
+          log("[tmux-session-manager] failed to parse server URL, using fallback", {
+            serverUrl: rawServerUrl,
+            error: String(error),
+          })
+          this.serverUrl = fallbackUrl
+        }
     this.sourcePaneId = deps.getCurrentPaneId()
     this.pollingManager = new TmuxPollingManager(
       this.client,
diff --git a/src/plugin/types.ts b/src/plugin/types.ts
index b713781bd3..30359cbe5e 100644
--- a/src/plugin/types.ts
+++ b/src/plugin/types.ts
@@ -23,4 +23,5 @@ export type TmuxConfig = {
   main_pane_min_width: number
   agent_pane_min_width: number
   isolation: "inline" | "window" | "session"
+  server_url_override?: string
 }