diff --git a/packages/opencode/src/agent/agent.ts b/packages/opencode/src/agent/agent.ts
index ce6cf30b6d55..23381bdc1b0b 100644
--- a/packages/opencode/src/agent/agent.ts
+++ b/packages/opencode/src/agent/agent.ts
@@ -45,6 +45,7 @@ export const Info = Schema.Struct({
   prompt: Schema.optional(Schema.String),
   options: Schema.Record(Schema.String, Schema.Unknown),
   steps: Schema.optional(Schema.Finite),
+  thinking: Schema.optional(Schema.Boolean),
 }).annotate({ identifier: "Agent" })
 export type Info = DeepMutable<Schema.Schema.Type<typeof Info>>
 
@@ -302,6 +303,7 @@ export const layer = Layer.effect(
           item.hidden = value.hidden ?? item.hidden
           item.name = value.name ?? item.name
           item.steps = value.steps ?? item.steps
+          item.thinking = value.thinking ?? item.thinking
           item.options = mergeDeep(item.options, value.options ?? {})
           item.permission = Permission.merge(item.permission, Permission.fromConfig(value.permission ?? {}))
         }
diff --git a/packages/opencode/src/cli/cmd/tui/context/sync.tsx b/packages/opencode/src/cli/cmd/tui/context/sync.tsx
index 9f8a384f777f..f0121f5951d4 100644
--- a/packages/opencode/src/cli/cmd/tui/context/sync.tsx
+++ b/packages/opencode/src/cli/cmd/tui/context/sync.tsx
@@ -152,6 +152,13 @@ export const { use: useSync, provider: SyncProvider } = createSimpleContext({
 
         case "permission.asked": {
           const request = event.properties
+          if (kv.get("yolo_mode", false)) {
+            void sdk.client.permission.reply({
+              requestID: request.id,
+              reply: "once",
+            })
+            break
+          }
           const requests = store.permission[request.sessionID]
           if (!requests) {
             setStore("permission", request.sessionID, [request])
diff --git a/packages/opencode/src/cli/cmd/tui/routes/session/footer.tsx b/packages/opencode/src/cli/cmd/tui/routes/session/footer.tsx
index c3a96254e98b..dd54367b6b6d 100644
--- a/packages/opencode/src/cli/cmd/tui/routes/session/footer.tsx
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/footer.tsx
@@ -5,11 +5,13 @@ import { useDirectory } from "../../context/directory"
 import { useConnected } from "../../component/use-connected"
 import { createStore } from "solid-js/store"
 import { useRoute } from "../../context/route"
+import { useKV } from "../../context/kv"
 
 export function Footer() {
   const { theme } = useTheme()
   const sync = useSync()
   const route = useRoute()
+  const kv = useKV()
   const mcp = createMemo(() => Object.values(sync.data.mcp).filter((x) => x.status === "connected").length)
   const mcpError = createMemo(() => Object.values(sync.data.mcp).some((x) => x.status === "failed"))
   const lsp = createMemo(() => Object.keys(sync.data.lsp))
@@ -82,6 +84,9 @@ export function Footer() {
                 {mcp()} MCP
               </text>
             </Show>
+            <Show when={kv.get("yolo_mode", false)}>
+              <text fg={theme.warning}>YOLO</text>
+            </Show>
             <text fg={theme.textMuted}>/status</text>
           </Match>
         </Switch>
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 ce651fdbe46c..44b14edff9d8 100644
--- a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
@@ -134,6 +134,7 @@ const sessionBindingCommands = [
   "session.toggle.actions",
   "session.toggle.scrollbar",
   "session.toggle.generic_tool_output",
+  "session.toggle.yolo",
   "session.page.up",
   "session.page.down",
   "session.line.up",
@@ -226,6 +227,7 @@ export function Session() {
   const [diffWrapMode] = kv.signal<"word" | "none">("diff_wrap_mode", "word")
   const [_animationsEnabled, _setAnimationsEnabled] = kv.signal("animations_enabled", true)
   const [showGenericToolOutput, setShowGenericToolOutput] = kv.signal("generic_tool_output_visibility", false)
+  const [yoloMode, setYoloMode] = kv.signal("yolo_mode", false)
 
   const wide = createMemo(() => dimensions().width > 120)
   const sidebarVisible = createMemo(() => {
@@ -730,6 +732,23 @@ export function Session() {
         dialog.clear()
       },
     },
+    {
+      title: yoloMode() ? "Disable YOLO mode" : "Enable YOLO mode",
+      value: "session.toggle.yolo",
+      category: "Session",
+      slash: {
+        name: "yolo",
+      },
+      run: () => {
+        const next = !yoloMode()
+        setYoloMode(next)
+        toast.show({
+          message: next ? "YOLO mode enabled — permissions will be auto-approved" : "YOLO mode disabled",
+          variant: next ? "warning" : "success",
+        })
+        dialog.clear()
+      },
+    },
     {
       title: "Page up",
       value: "session.page.up",
diff --git a/packages/opencode/src/cli/cmd/tui/routes/session/sidebar.tsx b/packages/opencode/src/cli/cmd/tui/routes/session/sidebar.tsx
index 0f9214092eba..45aa3812696a 100644
--- a/packages/opencode/src/cli/cmd/tui/routes/session/sidebar.tsx
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/sidebar.tsx
@@ -5,6 +5,7 @@ import { useTheme } from "../../context/theme"
 import { useTuiConfig } from "../../context/tui-config"
 import { InstallationChannel, InstallationVersion } from "@opencode-ai/core/installation/version"
 import { TuiPluginRuntime } from "@/cli/cmd/tui/plugin/runtime"
+import { useKV } from "../../context/kv"
 
 import { getScrollAcceleration } from "../../util/scroll"
 import { WorkspaceLabel } from "../../component/workspace-label"
@@ -14,6 +15,7 @@ export function Sidebar(props: { sessionID: string; overlay?: boolean }) {
   const sync = useSync()
   const { theme } = useTheme()
   const tuiConfig = useTuiConfig()
+  const kv = useKV()
   const session = createMemo(() => sync.session.get(props.sessionID))
   const workspace = () => {
     const workspaceID = session()?.workspaceID
@@ -85,7 +87,12 @@ export function Sidebar(props: { sessionID: string; overlay?: boolean }) {
           </box>
         </scrollbox>
 
-        <box flexShrink={0} gap={1} paddingTop={1}>
+        <box flexShrink={0} gap={1} paddingTop={1} flexDirection="column">
+          <Show when={kv.get("yolo_mode", false)}>
+            <text fg={theme.warning}>
+              <b>YOLO MODE</b>
+            </text>
+          </Show>
           <TuiPluginRuntime.Slot name="sidebar_footer" mode="single_winner" session_id={props.sessionID}>
             <text fg={theme.textMuted}>
               <span style={{ fg: theme.success }}>•</span> <b>Open</b>
diff --git a/packages/opencode/src/config/agent.ts b/packages/opencode/src/config/agent.ts
index a6719e86743a..06839f628b11 100644
--- a/packages/opencode/src/config/agent.ts
+++ b/packages/opencode/src/config/agent.ts
@@ -45,6 +45,9 @@ const AgentSchema = Schema.StructWithRest(
       description: "Maximum number of agentic iterations before forcing text-only response",
     }),
     maxSteps: Schema.optional(PositiveInt).annotate({ description: "@deprecated Use 'steps' field instead." }),
+    thinking: Schema.optional(Schema.Boolean).annotate({
+      description: "Override thinking/reasoning mode for this agent (true=force on, false=force off, undefined=use model default)",
+    }),
     permission: Schema.optional(ConfigPermission.Info),
   }),
   [Schema.Record(Schema.String, Schema.Any)],
@@ -63,6 +66,7 @@ const KNOWN_KEYS = new Set([
   "color",
   "steps",
   "maxSteps",
+  "thinking",
   "options",
   "permission",
   "disable",
diff --git a/packages/opencode/src/session/llm.ts b/packages/opencode/src/session/llm.ts
index 0cf3a2398f9b..ff8d65e961e7 100644
--- a/packages/opencode/src/session/llm.ts
+++ b/packages/opencode/src/session/llm.ts
@@ -139,6 +139,24 @@ const live: Layer.Layer<
             providerOptions: item.options,
           })
       const options = mergeOptions(mergeOptions(mergeOptions(base, input.model.options), input.agent.options), variant)
+
+      // Apply agent-level thinking override
+      if (input.agent.thinking === false) {
+        // Strip all thinking/reasoning related options to disable thinking
+        delete options.thinking
+        delete options.thinkingConfig
+        delete options.reasoning
+        delete options.reasoningEffort
+        delete options.reasoningConfig
+        delete options.enable_thinking
+        delete options.chat_template_args
+      } else if (input.agent.thinking === true && !input.small) {
+        // Force-enable thinking by ensuring the model's default thinking options are present
+        // The base options from ProviderTransform.options() already include thinking defaults
+        // for reasoning-capable models, so we just need to make sure they weren't stripped
+        // by agent.options or variant. If the model doesn't support reasoning, this is a no-op.
+      }
+
       if (isOpenaiOauth) {
         options.instructions = system.join("\n")
       }