fix(copilot): move file output write-permission gate after no-op skip branches

Address Cursor review: in maybeWriteOutputToFile the gate ran before the
sandbox-export skip branch (which returns the result unchanged without
writing), so a read-only caller with a sandbox files payload was denied
even though no workspace write would occur. Move the check to immediately
before writeWorkspaceFileByPath so it only fires when a write is actually
performed.

Author: waleedlatif1

apps/sim/lib/copilot/request/tools/files.test.ts

@@ -141,6 +141,18 @@ describe('maybeWriteOutputToFile', () => {
     expect(mockWriteWorkspaceFileByPath).not.toHaveBeenCalled()
   })
 
+  it('does not deny a read-only principal when no workspace write occurs (sandbox export active)', async () => {
+    const result = await maybeWriteOutputToFile(
+      FunctionExecute.id,
+      { outputs: { files: [{ path: 'files/report.csv', mode: 'overwrite' }] } },
+      { success: true, output: { result: { files: [{ path: 'report.csv' }] }, stdout: '' } },
+      buildContext({ userPermission: 'read' })
+    )
+
+    expect(result.success).toBe(true)
+    expect(mockWriteWorkspaceFileByPath).not.toHaveBeenCalled()
+  })
+
   it('writes the output file for a write principal', async () => {
     const result = await maybeWriteOutputToFile(
       FunctionExecute.id,

apps/sim/lib/copilot/request/tools/files.ts

@@ -211,9 +211,6 @@ export async function maybeWriteOutputToFile(
   const outputFiles = getOutputFileDeclarations(params).filter((file) => !file.sandboxPath)
   if (outputFiles.length === 0) return result
 
-  const denied = denyOutputWriteWithoutWritePermission(context)
-  if (denied) return denied
-
   const outputObject =
     result.output && typeof result.output === 'object' && !Array.isArray(result.output)
       ? (result.output as Record<string, unknown>)
@@ -232,6 +229,9 @@ export async function maybeWriteOutputToFile(
     return result
   }
 
+  const denied = denyOutputWriteWithoutWritePermission(context)
+  if (denied) return denied
+
   // Only span the actual write path (where we upload to storage). Fast
   // no-op returns above don't need a span — they'd just pad the trace
   // with empty work.