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agentHost: enable multi-root by default - #342188
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roblourens merged 3 commits intoOct 16, 2026
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Remove the Copilot, Claude, and Codex multi-root settings and provider gates so all three providers always advertise multiple working directories. Update directory handling, tests, and documentation for unconditional support. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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🟡 Changes recommended
Committed Copilot prompt baselines still expect the old tool schema and must be regenerated and validated.
1 open issue
What changed in this PR
Enables multi-root support by default for Copilot, Claude, and Codex agent-host sessions while retaining capability-based client interoperability.
Changes:
- Removes experimental multi-root settings and host flags.
- Uses additional workspace roots without opt-in gates.
- Updates tests, integration setup, and documentation.
| File | Description |
|---|---|
| src/vs/workbench/contrib/chat/test/browser/agentSessions/agentHostUntitledProvisionalSessionService.test.ts | Updates capability-change comments only. |
| src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/agentHostUntitledProvisionalSessionService.ts | Simplifies the capability-rebinding comment only. |
| src/vs/platform/agentHost/test/node/providerIntegration/codexSandbox.integrationTest.ts | Removes sandbox test opt-in setup. |
| src/vs/platform/agentHost/test/node/e2e/suites/workingDirectoriesSuite.ts | Removes multi-root flag setup and restoration. |
| src/vs/platform/agentHost/test/node/e2e/suites/hostFeaturesSuite.ts | Removes completion-test opt-in setup. |
| src/vs/platform/agentHost/test/node/e2e/providers/codexAgentHostE2E.integrationTest.ts | Tests secondary-root skills without opt-in. |
| src/vs/platform/agentHost/test/node/copilotAgent.test.ts | Updates default capability and root-handling assertions. |
| src/vs/platform/agentHost/test/node/codex/codexPrewarmEviction.test.ts | Updates workspace-root and single-folder coverage. |
| src/vs/platform/agentHost/test/node/codex/codexModelRefresh.test.ts | Asserts default multi-root capability. |
| src/vs/platform/agentHost/test/node/claudeAgent.test.ts | Removes opt-in setup and updates capability assertions. |
| src/vs/platform/agentHost/node/copilot/copilotAgent.ts | Removes capability, discovery, and folder-picker gates. |
| src/vs/platform/agentHost/node/codex/codexAgent.ts | Removes provider and per-session multi-root flags. |
| src/vs/platform/agentHost/node/claude/claudeAgent.ts | Always advertises capability and enables folder decisions. |
| src/vs/platform/agentHost/common/agentService.ts | Removes setting identifiers. |
| src/vs/platform/agentHost/common/agentHostStarter.config.contribution.ts | Removes setting registrations. |
| src/vs/platform/agentHost/common/agentHostSchema.ts | Removes host configuration keys and schema entries. |
| src/vs/platform/agentHost/AGENTS.md | Documents unconditional provider support. |
Review effort: Balanced
Preserve the upstream session-sync test import while removing the retired multi-root configuration flag. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Regenerate all 19 Copilot model prompt baselines in tokenless replay for the always-enabled multi-root create_session schema. The complete prompt suite passes strict replay with 24 tests. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Contributor
Screenshot ChangesBase: Changed (1)
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| Before | After |
|---|---|
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Connor Peet (connor4312)
approved these changes
Oct 16, 2026
roblourens
marked this pull request as ready for review
October 16, 2026 23:17
roblourens
deleted the
roblou/agents/enable-agent-host-multi-root-default
branch
October 16, 2026 23:17
Contributor
📬 CODENOTIFYThe following users are being notified based on files changed in this PR: TylerLeonhardtMatched files:
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Summary
Enable multi-root support unconditionally for Copilot, Claude, and Codex agent-host sessions rather than retaining experimental opt-in switches.
chat.agentHost.*Agent.multiRootEnabledsettings and their host-side configuration flags.multipleWorkingDirectoriesand use additional roots for SDK launch/resume, customization discovery, and folder selection.create_sessiontool schema.Validation
Passed locally on macOS:
npm run build-fast -- --client-onlynpm run typecheck-clientgit diff --name-only --diff-filter=ACM -z -- '*.ts' | xargs -0 npm run eslint --— all 16 changed TypeScript files passed; subsequently edited test files were linted again.git diff --checkAffected unit suites: 1,326 passed, 1 skipped:
Strict-replay multi-root completion tests: 9 passed:
./scripts/test-integration.sh --reporter dot \ --run src/vs/platform/agentHost/test/node/e2e/providers/copilotAgentHostE2E.integrationTest.ts \ --grep 'multi-root file completion|empty multi-root file completion|duplicate basenames in separate roots|duplicate working directory URIs|overlapping roots|non-file roots|colliding root basenames|multi-root relative path query'Strict-replay lifecycle tests across all three providers, plus Codex secondary-root skill coverage: 7 passed:
Complete Copilot prompt suite after regenerating the baselines: 24 passed in strict replay, with no recording or snapshot-update flags:
After merging current
main, client build, type-check, and conflict-resolved test lint passed again. Focused multi-root and session-sync coverage: 7 passed:env -u COPILOT_HOME ./scripts/test.sh --reporter dot \ --run src/vs/platform/agentHost/test/node/copilotAgent.test.ts \ --grep 'multipleWorkingDirectories|additional roots|computeFolderPickerDecision|session.sync|session sync'The initial build encountered stale installed SDK/runtime versions;
npm run install-fastrestored matching dependencies. The unit suites require unsetting inheritedCOPILOT_HOMEso their fixtures do not resolve into the developer's real session storage.Cross-platform Azure validation, the full E2E suite, and real-provider sandbox integration tests have not been run locally.
CI
All current-head GitHub workflows passed: Code OSS, Component Fixtures, CodeQL, Monaco Editor checks, Telemetry, and chat-lib tests. Code OSS covers Windows, Linux, and macOS. Its macOS WebKit unit job passed on a targeted retry after an unrelated chat-pet pixel-equivalence assertion failed; the exact assertion also passed in a focused local WebKit run.
Manual Testing
Open a multi-root workspace and create a new Copilot, Claude, or Codex agent-host session without configuring a multi-root setting. Verify that the session includes the workspace folders and offers file completions and customizations from its selected roots. Verify that a single-folder session continues to use only its selected folder.
(Written by Copilot)