diff --git a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
index 5f47562d2e3..e4f2b28c9c8 100644
--- a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
@@ -152,7 +152,7 @@ export function Session() {
   const sidebarVisible = createMemo(() => {
     if (session()?.parentID) return false
     if (sidebarOpen()) return true
-    if (sidebar() === "auto" && wide()) return true
+    if (sidebar() === "auto" && ((sync.data.config.tui as any)?.no_sidebar_auto || wide())) return true
     return false
   })
   const showTimestamps = createMemo(() => timestamps() === "show")
diff --git a/packages/opencode/src/config/config.ts b/packages/opencode/src/config/config.ts
index 020e626cba8..915440799c1 100644
--- a/packages/opencode/src/config/config.ts
+++ b/packages/opencode/src/config/config.ts
@@ -810,6 +810,10 @@ export namespace Config {
       .enum(["auto", "stacked"])
       .optional()
       .describe("Control diff rendering style: 'auto' adapts to terminal width, 'stacked' always shows single column"),
+    no_sidebar_auto: z
+      .boolean()
+      .optional()
+      .describe("When true, 'auto' sidebar mode always shows the sidebar regardless of window width"),
   })
 
   export const Server = z
diff --git a/packages/opencode/test/config/config.test.ts b/packages/opencode/test/config/config.test.ts
index decd18446c1..63094db2827 100644
--- a/packages/opencode/test/config/config.test.ts
+++ b/packages/opencode/test/config/config.test.ts
@@ -1413,6 +1413,29 @@ describe("deduplicatePlugins", () => {
   })
 })
 
+test("loads tui.no_sidebar_auto config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.jsonc"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          tui: {
+            no_sidebar_auto: true,
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const config = await Config.get()
+      expect(config.tui?.no_sidebar_auto).toBe(true)
+    },
+  })
+})
+
 describe("OPENCODE_DISABLE_PROJECT_CONFIG", () => {
   test("skips project config files when flag is set", async () => {
     const originalEnv = process.env["OPENCODE_DISABLE_PROJECT_CONFIG"]
@@ -1524,7 +1547,7 @@ describe("OPENCODE_DISABLE_PROJECT_CONFIG", () => {
               instructions: ["./CUSTOM.md"],
             }),
           )
-          // Create the instruction file (should be skipped)
+          // Create instruction file (should be skipped)
           await Bun.write(path.join(dir, "CUSTOM.md"), "# Custom Instructions")
         },
       })
@@ -1533,12 +1556,12 @@ describe("OPENCODE_DISABLE_PROJECT_CONFIG", () => {
         directory: tmp.path,
         fn: async () => {
           // The relative instruction should be skipped without error
-          // We're mainly verifying this doesn't throw and the config loads
+          // We're mainly verifying this doesn't throw and config loads
           const config = await Config.get()
           expect(config).toBeDefined()
           // The instruction should have been skipped (warning logged)
           // We can't easily test the warning was logged, but we verify
-          // the relative path didn't cause an error
+          // relative path didn't cause an error
         },
       })
     } finally {
@@ -1562,7 +1585,7 @@ describe("OPENCODE_DISABLE_PROJECT_CONFIG", () => {
     try {
       await using configDirTmp = await tmpdir({
         init: async (dir) => {
-          // Create config in the custom config dir
+          // Create config in custom config dir
           await Bun.write(
             path.join(dir, "opencode.json"),
             JSON.stringify({