diff --git a/packages/core/src/tool/plugin/opencode.ts b/packages/core/src/tool/plugin/opencode.ts
index 94ca72cc983..bfd091e1cdb 100644
--- a/packages/core/src/tool/plugin/opencode.ts
+++ b/packages/core/src/tool/plugin/opencode.ts
@@ -6,6 +6,7 @@ import type { SessionHooks } from "@opencode/plugin/effect/session"
 import { Model } from "@opencode/schema/model"
 import { AbsolutePath } from "@opencode/schema/schema"
 import { Session } from "@opencode/schema/session"
+import { FSUtil } from "@opencode/util/fs-util"
 import { Effect, Schema } from "effect"
 import { toolFailure } from "../runtime.js"
 import { FileAccess } from "../../file-access.js"
@@ -145,14 +146,26 @@ export const Plugin = {
           execute: (input, context) =>
             Effect.gen(function* () {
               const sessionID = input.sessionID ?? context.sessionID
+              const session = yield* ctx.session.get({ sessionID })
+              const directory = AbsolutePath.make(
+                FileAccess.resolvePath(session.location.directory, input.directory.trim()),
+              )
+              // The destination becomes the session's internal directory, so leaving the project
+              // needs the same approval as reaching outside it. The project's own worktrees don't.
+              const target = yield* access.resolve({ path: directory, kind: "directory" })
+              const worktrees = target.externalDirectory
+                ? yield* ctx.worktree.list({ projectID: ctx.location.project.id })
+                : []
+              if (!worktrees.some((worktree) => FSUtil.contains(worktree.directory, directory)))
+                yield* access.authorizeExternal([target], context)
               yield* ctx.session.move({
                 sessionID,
-                directory: input.directory,
+                directory,
                 delivery: "steer",
               })
               return {
-                output: { sessionID, directory: input.directory },
-                content: `Moved session ${sessionID} to ${input.directory}.`,
+                output: { sessionID, directory },
+                content: `Moved session ${sessionID} to ${directory}.`,
               }
             }).pipe(
               Effect.mapError(
diff --git a/services/www/src/docs/content/tools.mdx b/services/www/src/docs/content/tools.mdx
index 25ee3b0d6c9..2277ba6faa6 100644
--- a/services/www/src/docs/content/tools.mdx
+++ b/services/www/src/docs/content/tools.mdx
@@ -253,8 +253,6 @@ The `opencode` Code Mode namespace contains session utilities:
 Rename this session to "Timeout cleanup", then move it to the new worktree.
 ```
 
-These utilities do not request a built-in permission action.
-
 ### Worktrees
 
 The same namespace manages worktrees for the session's project: