Copilot Not Respecting Disablement on Agent Host

Type: Bug

I am trying to limit the harness providers to just Codex and Claude on the agent host.

However, even after disabling all of the Copilot settings:

```
{
// Codex enablement
"chat.agentHost.codexAgent.enabled": true,
"chat.editor.codex.preferAgentHost": true,

// Claude enablement
"chat.agentHost.claudeAgent.enabled": true,

// Allow using agent host
"chat.agentHost.allowSignedOutWhenUsable": true,

// Local, BYOK, Copilot local, Copilot Cloud, and Copilot Background Agent disablement
"chat.agentHost.byokModels.enabled": false,
"chat.byokUtilityModelDefault": "none",
"chat.defaultToCopilotHarness": false,
"chat.editor.localAgent.enabled": false,
"github.copilot.chat.cloudAgent.enabled": false,
"github.copilot.chat.backgroundAgent.enabled": false,
"chat.editor.preferCopilotHarness": false,
}
```

Even with these settings, Copilot is still an option on the harness selector.

The hover text is `Run a Copilot SDK agent in the local agent host process` which indicates its pointing at a local harness and not respecting the `chat.editor.localAgent.enabled` and `chat.defaultToCopilotHarness`.

VS Code version: Code - Insiders 1.135.0-insider (7437923619df0b080f2fc0f85e7033558bd2865c, 2026-08-25T10:46:44Z)
OS version: Darwin arm64 25.6.0
Modes:

System Info

|Item|Value|
|---|---|
|CPUs|Apple M2 Pro (12 x 2400)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x106b [Google Inc. (Apple)], DEVICE=0x0000 [ANGLE (Apple, ANGLE Metal Renderer: Apple M2 Pro, Version 26.6.2 (Build 25G83))], DRIVER_VENDOR=Apple, DRIVER_VERSION=26.6.2 *ACTIVE*
Machine model name: Mac
Machine model version: 14.10
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: enabled_on
trees_in_viz: disabled_off
video_decode: enabled
video_encode: enabled
webgl: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|11, 11, 9|
|Memory (System)|32.00GB (0.08GB free)|
|Process Argv||
|Screen Reader|yes|
|VM|0%|
Extensions (1)

Name|Identifier|Author|Version
---|---|---|---
Claude Code for VS Code|anthropic.claude-code|Anthropic|2.1.245

A/B Experiments

```
vsliv368:30146709
pythonvspyt551:31249597
nativeloc1:31118317
dwcopilot:31158714
dwoutputs:31242946
copilot_t_ci:31333650
g012b348:31231168
pythonrdcb7:31268811
pythonpcpt1:31399616
6518g693:31302842
envsactivate1:31349248
editstats-enabled:31346256
cloudbuttont:31366566
3efgi100_wstrepl:31403338
bj468946:31457056
ddidt:31398484
diffpatch-lysithea-24-production:31572515
cp_cls_t_966_ss:31526232
4je02754:31565972
8hhj4413:31478653
cp_cls_t_1081:31454832
conptydll_true:31485575
e9c30283:31453065
test_treatment2:31471001
46204921:31447328
capico_a_098a3278:31555650
ei9d7968:31462942
nes-extended-on:31455475
f860i809:31458078
89g7j272:31506658
7e884298:31462391
i2gc6536:31472020
52612955:31508042
h08i8180:31475367
ddid_c:31478205
hmra_i5g22:31518061
bjc72774_agent_sandbox:31538428
7df3h592:31491241
cp_cls_t_1082:31535311
logging_enabled_new:31490725
jb_cp_cls_t_632:31543129
32d76977:31503652
ha629193:31508444
a1ije391_t:31533808
jbcp_cls_pctr_t:31531130
cp_intellij_t_nes:31548657
d7b18187:31526828
hide-eh-duplicates:31543293
replace-eh-with-ah:31545853
ihg5j128:31534457
f412h606:31543414
sandbox-ui-on-2:31543161
enable_editor_pane_layout:31551200
52258b4d:31547953
36h42362:31560305
c7c27ce7:31551212
6577i413_copy:31558653
1h923230:31564177
0dg73464:31554309
treatment-23-1:31555779
unuse_dynamic_mcp:31555281
0c1h4866:31562347
vrbsty_tr:31561056
5b8j3302:31564600
mangle-name-treatment:31568054
signed-out-control:31566874
codex-agent-enabled:31566739
77cef475:31568526
lunaclean:31570525

```