Built-in Copilot Inline Chat slash commands are missing from autocomplete

Type: Bug

Steps to reproduce

1. Use VS Code 1.133.0 with the bundled GitHub Copilot Chat extension 0.61.0.
2. Open a source file in the editor.
3. Select some code, or place the cursor in the editor.
4. Open Inline Chat with Ctrl+I.
5. Type / in the Inline Chat input.
6. Observe the slash-command completion list.
7. Type /doc, /explain, /fix, tests, or /help.
8. Observe that none of these built-in commands are proposed by autocomplete.
9. Submit /doc manually.

Expected behavior

The Inline Chat completion list should propose the built-in commands applicable to editor Inline Chat, including:
/doc
/explain
/fix
/tests
/help

The commands should be discoverable by typing / or their respective prefixes.

Actual behavior

None of the commands above are proposed by autocomplete.

Instead, the completion list includes commands such as:
/chronicle standup
/chronicle reindex

These appear to come from the prompt/skill command provider.

When /doc is entered manually, it is still recognized and executes correctly. This suggests that command execution works, but built-in command discovery or completion registration is incomplete.

Environment

VS Code: 1.133.0
Platform: Linux, remote VS Code Server
Bundled GitHub Copilot Chat extension: 0.61.0
GitHub Copilot completions extension: 1.388.0
Chat surface: Editor Inline Chat

The issue was reproduced with the workspace open and with code selected in the editor.

Please include the automatically generated environment and extension list from Help > Report Issue.

Additional information

The issue persists after reloading the VS Code window.

The bundled Copilot Chat extension appears to register the editor participant without built-in slash commands, while the corresponding panel participant exposes commands such as explain, tests, and fix. The editor Inline Chat request handler nevertheless continues to recognize manually entered commands such as /doc.

I have not included any project-specific code because the issue is reproducible with a minimal source file.

Console output

No error message has been observed so far in Help > Toggle Developer Tools > Console.

Before submitting, search the open VS Code issues for an existing report with the same symptoms and run the reproduction once with unrelated extensions disabled. Since the behavior concerns the bundled Copilot integration itself, Copilot should remain enabled during that test.

VS Code version: Code 1.133.0 (a5b500951314efd502d07465bd138dfbd714a960, 2026-08-11T22:14:08Z)
OS version: Windows_NT x64 10.0.26100
Modes:
Remote OS version: Linux x64 5.14.0-687.33.1.el9_8.x86_64
Remote OS version: Linux x64 5.14.0-687.33.1.el9_8.x86_64

System Info

|Item|Value|
|---|---|
|CPUs|12th Gen Intel(R) Core(TM) i7-1280P (20 x 1997)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x8086, DEVICE=0x46a6 [Intel(R) Iris(R) Xe Graphics], DRIVER_VENDOR=Intel, DRIVER_VERSION=32.0.101.7084 *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 (7.72GB free)|
|Process Argv|--crash-reporter-id 7a797cac-1c62-46dd-92ab-23a1e29eae05|
|Screen Reader|no|
|VM|0%|

|Item|Value|
|---|---|
|Remote|SSH: ACRS.Shopping.obe-hcr-shp-develop-romantic-rhel-obe-shp-NCEL138303|
|OS|Linux x64 5.14.0-687.33.1.el9_8.x86_64|
|CPUs|Intel(R) Xeon(R) Platinum 8370C CPU @ 2.80GHz (16 x 3487)|
|Memory (System)|62.79GB (36.73GB free)|
|VM|0%|

|Item|Value|
|---|---|
|Remote|SSH: ACRS.Shopping.obe-hcr-shp-develop-romantic-rhel-obe-shp-NCEL138303|
|OS|Linux x64 5.14.0-687.33.1.el9_8.x86_64|
|CPUs|Intel(R) Xeon(R) Platinum 8370C CPU @ 2.80GHz (16 x 3440)|
|Memory (System)|62.79GB (36.73GB free)|
|VM|0%|
Extensions (36)

Name|Identifier|Author|Version
---|---|---|---
CDS|amadeus.vscode-cds|amadeus|1.0.116
CDS installer|amadeus.vscode-cds-installer|amadeus|1.0.109
OBE installer|amadeus.vscode-obe-installer|amadeus|1.0.109
AI Primitives Hub|amadeusitgroup.prompt-registry|AmadeusITGroup|0.0.40
Auto Close Tag|formulahendry.auto-close-tag|formulahendry|0.5.15
Auto Rename Tag|formulahendry.auto-rename-tag|formulahendry|0.1.10
Private Extension Manager: Remote Helper|garmin.private-extension-manager-remote-helper|garmin|1.8.0
Better C++ Syntax|jeff-hykin.better-cpp-syntax|jeff-hykin|1.27.1
Angular Snippets (Version 22)|johnpapa.angular2|johnpapa|22.0.0
Peacock|johnpapa.vscode-peacock|johnpapa|4.3.4
Jupyter Keymap|ms-toolsai.jupyter-keymap|ms-toolsai|1.1.2
Dev Containers|ms-vscode-remote.remote-containers|ms-vscode-remote|0.466.0
Remote - SSH|ms-vscode-remote.remote-ssh|ms-vscode-remote|0.124.0
Remote - SSH: Editing Configuration Files|ms-vscode-remote.remote-ssh-edit|ms-vscode-remote|0.87.0
WSL|ms-vscode-remote.remote-wsl|ms-vscode-remote|0.104.3
Remote Explorer|ms-vscode.remote-explorer|ms-vscode|0.5.0
Protobuf support|peterj.proto|peterj|0.0.4
vscode-icons|vscode-icons-team.vscode-icons|vscode-icons-team|12.19.0
Jinja|wholroyd.jinja|wholroyd|0.0.8
Aproach|amadeus.vscode-aproach|Amadeus|1.1.11
CDS remote helper|amadeus.vscode-cds-remote-helper|amadeus|1.0.15
Amadeus Extensions Manager|amadeus.vscode-extensions-manager|amadeus|1.0.131
TTS Test Explorer|amadeus.vscode-tts-test-adapter|amadeus|1.0.116
vscode-walle|amadeus.vscode-walle|amadeus|1.0.9
AI Primitives Hub|amadeusitgroup.prompt-registry|AmadeusITGroup|0.0.40
Post startup hook|colas.post-startup-hook|colas|1.7.0
GitLens — Git supercharged|eamodio.gitlens|eamodio|19.0.1
flatbuffers|gaborv.flatbuffers|gaborv|0.3.1
Private Extension Manager|garmin.private-extension-manager|garmin|1.8.0
clangd|llvm-vs-code-extensions.vscode-clangd|llvm-vs-code-extensions|0.6.0
Explorer Exclude Manager|madcatpx.explorer-exclude-manager|MadCatPX|1.4.1
TestMate C++|matepek.vscode-catch2-test-adapter|matepek|4.26.0
C/C++|ms-vscode.cpptools|ms-vscode|1.32.2
vscode-bms-cpp|vscode-community.vscode-bms-cpp|vscode-community|1.0.61
vscode-obe-logviewer|vscode-community.vscode-obe-logviewer|vscode-community|1.0.63
Clang-Format|xaver.clang-format|xaver|1.9.0

A/B Experiments

```
vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
4f60g487:31327383
envsactivate1:31551504
gh487529:31544284
cloudbuttont:31379625
42190218_ostrepl:31403339
ec5jj548:31422691
cp_cls_t_966_ss:31526232
4je02754:31466945
8hhj4413:31478653
ge8j1254_inline_auto_hint_haiku:31490510
cp_cls_c_1081:31454833
conptydll_true:31498968
e9c30283:31461165
test_treatment2:31471001
46204921:31447328
control_6dc23131:31555649
ei9d7968:31496641
nes-extended-on:31455476
chat:31457767
8hig5102:31480529
89g7j272:31518289
i2gc6536:31499202
52612955:31516516
githubstableflight:31469463
ghj88844:31499326
ddid_c:31478207
hmra_i5g22:31518061
7df3h592:31512476
cp_cls_t_1082:31535311
logging_enabled_new:31498466
j0d79568:31499440
jb_cp_cls_t_632:31543129
748c7209:31512887
32d76977:31512328
ha629193:31508444
cdk-lw-on:31524445
jh5f2457_c:31540921
jbcp_cls_pctr_t:31531130
61138546:31518536
cp_intellij_t_nes:31548657
jf4hg949:31526829
ahp-both-windows:31556933
session_8:31532895
ihg5j128:31534457
f412h606:31551416
7g2b5551:31542111
enable_editor_pane_layout:31566738
allow-none:31555437
6i51c363:31551401
36h42362:31564511
c7c27ce7:31554789
1h923230:31564177
1532g621_copy:31554320
treatment-23-1:31555779
unuse_dynamic_mcp:31555281
0d8dfbc3:31566037
a1hcc538:31559322
0c1h4866:31566224
vrbsty_fls:31561059
session-archive:31558132
5b8j3302:31564601

```