Agent Host: Show Dev Container setting

[Christof Marti (chrmarti)]

Summary

Register the Dev Container Agent Host settings from a globally loaded platform contribution so chat.agentHost.devContainer.enabled appears in the normal VS Code Settings editor.

Tracking issue: #317380

Session Context

Key decisions from the development session:

• The setting is user-visible: chat.agentHost.devContainer.enabled is an experimental user setting and should appear in the normal Settings UI.
• The combination gate stays hidden: chat.agentHost.devContainer.worktree.enabled remains excluded from Settings and controlled through EXP treatments.
• Configuration is not connector-owned: The previous registration lived in a Sessions-window-only Electron connector contribution, so the standard workbench never loaded it. The registration now lives in the platform Agent Host layer.
• Both workbenches load the schema: Shared Chat imports the platform configuration contribution and is loaded by both the normal workbench and the Agents Window.
• No runtime behavior change: Connector availability and checkbox gating continue to consume the same setting identifiers and defaults.

Changes

• Move Dev Container setting identifiers to the platform Agent Host contract.
• Add a dedicated platform configuration contribution for the visible Dev Container setting and hidden combination gate.
• Load that contribution through shared Chat in both workbenches.
• Remove configuration registration from the Sessions-only connector contribution.
• Move setting-registration tests beside the platform contribution and retain connector/picker coverage.

Validation

• 23 focused unit tests passing
• npm run typecheck-client
• npm run transpile-client
• npm run valid-layers-check
• ESLint on changed files
• Repository pre-commit hygiene
• git diff --check

[Copilot]

Copilot review overview

🟢 Approval recommended

The ownership move is complete, preserves runtime behavior, respects layering, and includes focused registration coverage.

Review tier: Balanced
Findings: None

What changed in this PR

Moves Dev Container Agent Host configuration ownership into the shared platform layer so settings are registered in both VS Code workbenches.

Changes:

• Centralizes Dev Container setting identifiers and schema registration.
• Loads the schema through the shared Chat contribution.
• Relocates configuration tests while preserving connector and picker behavior.

File	Description
src/​vs/​workbench/​contrib/​chat/​browser/​chat.shared.contribution.ts	Loads the shared configuration contribution.
src/​vs/​sessions/​contrib/​providers/​remoteAgentHost/​test/​electron-browser/​devContainerAgentHostConnector.test.ts	Removes relocated schema tests and updates imports.
src/​vs/​sessions/​contrib/​providers/​remoteAgentHost/​electron-browser/​devContainerAgentHostConnector.contribution.ts	Removes Sessions-owned registration and uses the platform identifier.
src/​vs/​sessions/​contrib/​providers/​agentHost/​test/​browser/​agentHost/​agentHostSessionConfigPicker.test.ts	Updates the worktree setting import.
src/​vs/​sessions/​contrib/​providers/​agentHost/​browser/​agentHostSessionConfigPicker.ts	Uses the platform-owned setting identifier.
src/​vs/​sessions/​common/​devContainerAgentHostService.ts	Removes relocated setting identifiers.
src/​vs/​platform/​agentHost/​test/​common/​devContainerAgentHostConfiguration.test.ts	Tests visible and hidden setting registration.
src/​vs/​platform/​agentHost/​common/​devContainerAgentHost.ts	Defines the shared setting identifiers.
src/​vs/​platform/​agentHost/​common/​devContainerAgentHost.config.contribution.ts	Registers the visible setting and hidden combination gate.

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[Christof Marti (chrmarti)]

Closing for now: the setting is already available in the Agents Window Settings UI, so moving its registration into the normal workbench is not needed.