Agents Window used Opus 5 instead of GPT-5.6 Terra

Type: Bug

Hello,

I never experienced this before.
I used the Agents window with Autopilot and Allow all to handoff a task to an agent. I already did a good design document and it should only follow the plan. I intentionally selected GPT-5.6 Terra to safe credits. But the agent started a subagent with Opus 5 model and it did cost way more token than expected..

VS Code version: Code 1.135.0 (08d4889f9ec4a1685d257b9b95de036c8e1ce1e5, 2026-08-25T14:26:52Z)
OS version: Windows_NT x64 10.0.26100
Modes:

System Info

|Item|Value|
|---|---|
|CPUs|13th Gen Intel(R) Core(TM) i5-1350P (16 x 2189)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x8086, DEVICE=0xa7a0 [Intel(R) Iris(R) Xe Graphics], DRIVER_VENDOR=Intel, DRIVER_VERSION=32.0.101.7088 *ACTIVE*
GPU1: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8875
Machine model name:
Machine model version:
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: disabled_off
trees_in_viz: disabled_off
video_decode: enabled
video_encode: enabled
webgl: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|undefined|
|Memory (System)|31.69GB (7.28GB free)|
|Process Argv|--crash-reporter-id efb9f954-b8c8-4c80-b7be-486bc7c4f9c6|
|Screen Reader|no|
|VM|0%|
Extensions (37)

Name|Identifier|Author|Version
---|---|---|---
Markdown Preview Mermaid Support|bierner.markdown-mermaid|bierner|1.32.1
markdownlint|davidanson.vscode-markdownlint|DavidAnson|0.62.1
learn-markdown|docsmsft.docs-markdown|docsmsft|1.0.18
CMake Test Explorer|fredericbonnet.cmake-test-adapter|fredericbonnet|1.1.2
GitHub Repositories|github.remotehub|GitHub|0.64.0
Test Explorer UI|hbenl.vscode-test-explorer|hbenl|2.22.1
Markdown Attribute Lists|jonah.markdown-attrs|jonah|0.0.2
Rainbow CSV|mechatroner.rainbow-csv|mechatroner|3.24.1
VB6 Syntax Highlighter|mrf86.vbsyxer|MrF86|0.0.3
C# Dev Kit|ms-dotnettools.csdevkit|ms-dotnettools|3.20.199
C#|ms-dotnettools.csharp|ms-dotnettools|2.140.9
.NET Install Tool|ms-dotnettools.vscode-dotnet-runtime|ms-dotnettools|3.1.0
Python Debugger|ms-python.debugpy|ms-python|2026.6.0
Python|ms-python.python|ms-python|2026.4.0
Pylance|ms-python.vscode-pylance|ms-python|2026.3.1
Python Environments|ms-python.vscode-python-envs|ms-python|1.36.0
Jupyter|ms-toolsai.jupyter|ms-toolsai|2025.9.1
Jupyter Keymap|ms-toolsai.jupyter-keymap|ms-toolsai|1.1.2
Jupyter Notebook Renderers|ms-toolsai.jupyter-renderers|ms-toolsai|1.3.0
Jupyter Cell Tags|ms-toolsai.vscode-jupyter-cell-tags|ms-toolsai|0.1.9
Jupyter Slide Show|ms-toolsai.vscode-jupyter-slideshow|ms-toolsai|0.1.6
WSL|ms-vscode-remote.remote-wsl|ms-vscode-remote|0.104.3
Azure Repos|ms-vscode.azure-repos|ms-vscode|0.40.0
CMake Tools|ms-vscode.cmake-tools|ms-vscode|1.23.52
C/C++ DevTools|ms-vscode.cpp-devtools|ms-vscode|0.6.18
C/C++|ms-vscode.cpptools|ms-vscode|1.33.8
C/C++ Extension Pack|ms-vscode.cpptools-extension-pack|ms-vscode|1.5.1
PowerShell|ms-vscode.powershell|ms-vscode|2025.4.0
Remote Repositories|ms-vscode.remote-repositories|ms-vscode|0.42.0
Test Adapter Converter|ms-vscode.test-adapter-converter|ms-vscode|0.2.1
Chat Customizations Evaluations|ms-vscode.vscode-chat-customizations-evaluations|ms-vscode|1.0.8
Pester Tests|pspester.pester-test|pspester|2023.7.7
AI Engineering Fluency|robbos.ai-engineering-fluency|RobBos|0.17.2
Markdown Preview Enhanced|shd101wyy.markdown-preview-enhanced|shd101wyy|0.8.32
Code Spell Checker|streetsidesoftware.code-spell-checker|streetsidesoftware|4.7.3
Markdown Admonitions|tomasdahlqvist.markdown-admonitions|tomasdahlqvist|0.9.1
CMake|twxs.cmake|twxs|0.0.17

A/B Experiments

```
vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
bajee813:31263137
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
envsactivate1:31551504
cloudbuttont:31379625
3efgi100_wstrepl:31403338
839jf696:31457053
ec5jj548:31422691
diffpatch-lysithea-24-production:31577085
cp_cls_t_966_ss:31526232
4je02754:31466945
8hhj4413:31478653
ge8j1254_inline_auto_hint_haiku:31490510
cp_cls_t_1081:31454832
conptydll_true:31498968
e9c30283:31461165
46204921:31447328
ei9d7968:31496641
nes-extended-on:31455476
chat:31457767
8hig5102:31480529
89g7j272:31518289
i2gc6536:31499202
52612955:31516516
ddid_t:31478206
hmra_i5g22:31518061
7df3h592:31512476
cp_cls_t_1082:31535311
logging_enabled_new:31498466
db5d2638:31499441
jb_cp_cls_t_632:31543129
56dj4588:31512888
32d76977:31512328
ha629193:31508444
jh5f2457_c:31540921
jbcp_cls_pctr_t:31531130
61138546:31518536
cp_intellij_t_nes:31548657
gf14b233:31526830
ahp-both-windows:31556933
ihg5j128:31534457
f412h606:31551416
7g2b5551:31542111
enable_editor_pane_layout:31569726
allow-none:31555437
ac562147:31564510
c7c27ce7:31554789
1h923230:31564177
1532g621_copy:31554320
treatment-23-1:31555779
unuse_dynamic_mcp:31555281
0d8dfbc3:31570291
a1hcc538:31559322
0c1h4866:31566224
vrbsty_tr:31561058
session-archive:31558132
5b8j3302:31564601
mangle-name-control:31572633
multiv2:31574985

```